WO2001026180A1 - Tamper-resistant wireless article including an antenna - Google Patents

Tamper-resistant wireless article including an antenna Download PDF

Info

Publication number
WO2001026180A1
WO2001026180A1 PCT/US2000/027227 US0027227W WO0126180A1 WO 2001026180 A1 WO2001026180 A1 WO 2001026180A1 US 0027227 W US0027227 W US 0027227W WO 0126180 A1 WO0126180 A1 WO 0126180A1
Authority
WO
WIPO (PCT)
Prior art keywords
substrate
adhesive
electrically
article
electronic device
Prior art date
Application number
PCT/US2000/027227
Other languages
French (fr)
Inventor
Kevin Kwong-Tai Chung
Original Assignee
Amerasia International Technology, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/411,849 external-priority patent/US6353420B1/en
Priority claimed from US09/412,058 external-priority patent/US6404643B1/en
Application filed by Amerasia International Technology, Inc. filed Critical Amerasia International Technology, Inc.
Publication of WO2001026180A1 publication Critical patent/WO2001026180A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
    • H01Q1/2225—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G06K19/0775—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card arrangements for connecting the integrated circuit to the antenna
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/93—Batch processes
    • H01L24/95—Batch processes at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
    • H01L24/97—Batch processes at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q23/00—Antennas with active circuits or circuit elements integrated within them or attached to them
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/005—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop with variable reactance for tuning the antenna
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2223/00—Details relating to semiconductor or other solid state devices covered by the group H01L23/00
    • H01L2223/58—Structural electrical arrangements for semiconductor devices not otherwise provided for
    • H01L2223/64—Impedance arrangements
    • H01L2223/66—High-frequency adaptations
    • H01L2223/6661—High-frequency adaptations for passive devices
    • H01L2223/6677—High-frequency adaptations for passive devices for antenna, e.g. antenna included within housing of semiconductor device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161—Disposition
    • H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161—Disposition
    • H01L2224/16151—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H01L2224/16227—Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation the bump connector connecting to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01004—Beryllium [Be]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01005—Boron [B]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01006—Carbon [C]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01013—Aluminum [Al]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01019—Potassium [K]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01021—Scandium [Sc]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01023—Vanadium [V]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01029—Copper [Cu]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01033—Arsenic [As]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01041—Niobium [Nb]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01046—Palladium [Pd]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01047—Silver [Ag]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01074—Tungsten [W]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01078—Platinum [Pt]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01079—Gold [Au]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/06—Polymers
    • H01L2924/078—Adhesive characteristics other than chemical
    • H01L2924/07802—Adhesive characteristics other than chemical not being an ohmic electrical conductor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/14—Integrated circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/19—Details of hybrid assemblies other than the semiconductor or other solid state devices to be connected
    • H01L2924/1901—Structure
    • H01L2924/1904—Component type
    • H01L2924/19041—Component type being a capacitor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/19—Details of hybrid assemblies other than the semiconductor or other solid state devices to be connected
    • H01L2924/1901—Structure
    • H01L2924/1904—Component type
    • H01L2924/19042—Component type being an inductor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/19—Details of hybrid assemblies other than the semiconductor or other solid state devices to be connected
    • H01L2924/1901—Structure
    • H01L2924/1904—Component type
    • H01L2924/19043—Component type being a resistor
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/11—Printed elements for providing electric connections to or between printed circuits
    • H05K1/111—Pads for surface mounting, e.g. lay-out
    • H05K1/112—Pads for surface mounting, e.g. lay-out directly combined with via connections
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/16—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor
    • H05K1/165—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor incorporating printed inductors
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/03—Conductive materials
    • H05K2201/0332—Structure of the conductor
    • H05K2201/0388—Other aspects of conductors
    • H05K2201/0394—Conductor crossing over a hole in the substrate or a gap between two separate substrate parts
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/14—Related to the order of processing steps
    • H05K2203/1453—Applying the circuit pattern before another process, e.g. before filling of vias with conductive paste, before making printed resistors

Definitions

  • the present invention relates to a wireless article and, in particular, to a wireless article including an antenna.
  • Wireless articles such as tags, identification badges, smart cards and the like, are in wireless communication with a base unit or reader via a radio-frequency (RF) communication link
  • RF transmissions transmitted by the base unit may be received by an antenna on the wireless article or RF transmissions transmitted by the wireless article by an antenna thereon may be received by the base unit.
  • RF transmissions by each of the wireless article and the base unit may be received by the other one thereof
  • the RF signals either received or transmitted by the wireless article are received or transmitted by an antenna thereon. Because wireless articles are usually desired to be small in size, the antenna thereon must also be small in size.
  • the sensitivity of the antenna to small amplitude RF signals and the amplitude of the RF signals transmitted by the antenna are a direct function of the area enclosed by the antenna loop and the number of turns of the conductor forming the loop
  • the size thereof limits the area that an antenna loop can enclose, thereby limiting the RF performance of the antenna
  • RF identification tags operate in the frequency range of 100 KHz to 3 GHz, or higher
  • Wireless articles, such as RF tags are often used for purposes of secu ⁇ ty or other purposes where it is desirable that a rugged wireless article be permanently attached to an object and that any attempt to remove, alter or otherwise tamper with the wireless article, or attach the wireless article to a substitute object, be evident.
  • the tamper-resistant article of the present invention comp ⁇ ses a substrate including at least one layer of a strong dielectric adhesive having an exposed surface adapted for attaching said substrate to an object.
  • a pattern of elect ⁇ cally- conductive mate ⁇ al including an elongated elect ⁇ cal conductor is on one surface of the substrate and has at least one elect ⁇ cal contact.
  • At least one electronic device is attached to the substrate by a strong adhesive and has at least one contact elect ⁇ cally connected to the contact of the pattern of elect ⁇ cally-conductive adhesive, whereby at least one of the strong dielect ⁇ c adhesive of the substrate and the strong adhesive attaching the electronic device render the article resistant to tampe ⁇ ng.
  • a tamper-destruct article comp ⁇ ses a substrate including at least one layer of a dielect ⁇ c adhesive having an exposed surface adapted for attaching the substrate to an object.
  • a pattern of elect ⁇ cally-conductive mate ⁇ al including an elongated elect ⁇ cal conductor is on one surface of the substrate and has at least one elect ⁇ cal contact.
  • At least one electronic device is attached to the substrate by an adhesive and has at least one contact elect ⁇ cally connected to the contact of the pattern of elect ⁇ cally-conductive adhesive, wherein at least one of the pattern of elect ⁇ cally conductive mate ⁇ al and the electrical connection of the contact of the electronic device to the substrate includes at least one frangible region.
  • FIGURE 1 is a plan view schematic diagram of one surface of an exemplary embodiment of a substrate useful in an article according to the present invention
  • FIGURE 2 is a plan view of the article of FIGURE 1 with an electronic device attached thereto,
  • FIGURES 3A and 3B are side cross-sectional view schematic diagrams of part of the article of FIGURE 2 showing the connection of the electronic device thereto,
  • FIGURES 4 and 5 are plan view schematic diagrams of respective opposing surfaces of an exemplary embodiment of a substrate useful in an article according to the present invention
  • FIGURE 6 is a sectional view schematic diagram of an article including the exemplary substrate of FIGURES 4 and 5 having an electronic device attached thereto,
  • FIGURES 7 and 8 are plan view schematic diagrams of opposing surfaces of an alternative exemplary embodiment of an article according to the present invention.
  • FIGURES 9 and 10 are side view schematic diagrams of exemplary articles according to the invention.
  • FIGURES 11A and 11B are side and plan view schematic diagrams, respectively, of another exemplary article according to the invention.
  • FIGURE 12 is a plan view schematic diagram of an alternative exemplary embodiment of a contact-less card according to the present invention
  • FIGURES 13 and 14 are cross-sectional side view schematic diagrams of the article of FIGURE 12 and an alternative embodiment thereof,
  • FIGURES 15 and 16 are plan view schematic diagrams of an alternative exemplary substrate for a contact-less card according to the present invention.
  • FIGURE 17 is a schematic diagram of a manufactu ⁇ ng arrangement useful with the foregoing electronic substrates and cards
  • the articles desc ⁇ bed herein, in particular, wireless articles having electronic circuitry for communicating with an external device such as a reader or interrogator, are desired to be resistant to tampe ⁇ ng and attempts to tamper with the article and/or the electronic circuitry thereof.
  • Such articles may be desc ⁇ bed as being “tamper- destruct” and or “tamper-resistant” articles.
  • a "tamper-destruct" article becomes disabled, non-functional and/or inoperative if one attempts to tamper with or change the article.
  • tamper destruct properties are provided by one or more elements of the wireless article being made so as to be frangible and tend to break easily if one attempts to alter the wireless article, to remove it from the object to which it is attached or is otherwise tampers with the article.
  • a thm or narrow portion e.g., less than about 25 ⁇ m (about 1 mil) m either thickness or width or both, or a relatively-weak bonding, may be provided so as to be fragile and not withstand an attempt to remove the article from the object to which it is attached, thereby providing a tamper-destruct property.
  • Wireless articles may also be "tamper- resistant" in that they are physically strong so as to be capable to withstand severe physical handling and/or environments, and/or so as to not be removable from an object to which they are attached without physically damaging or destroying the wireless article and/or the object
  • tampe ⁇ ng with a tamper-destruct or a tamper-resistant article produces evidence thereof that is apparent to an observer.
  • Tamper resistant articles are typically also tamper destruct articles, but need not be.
  • the tamper resistant and/or tamper destruct properties are provided by the structure of the wireless article according to the invention, and the elements thereof, without the addition of special structure or extra processing steps which would undesirably increase the complexity and/or the cost of the article.
  • the structure and mate ⁇ als providing a frangible tamper resistant feature may also be utilized to produce a wireless article that is capable of withstanding exposure to harsh environments, such as those encountered in laundry and cleaning processes as well as in industrial processes
  • substrate 20 for a wireless article 10 is a generally planar sheet of an insulating mate ⁇ al
  • a loop antenna 30 is formed of an elongated conductor having a plurality of loops or turns 36, 37, 38 generally in a spiral pattern on one surface of substrate 20.
  • an electronic device 40 such as a semiconductor integrated circuit, a hybrid circuit or other suitable electronic device, has two spaced-apart contacts 42. 44.
  • the spacing between the two contacts 42, 44 of electronic device 40 are a given dimension that is determined by the supplier of the electronic device 40 and so is not easily changed.
  • the spacing between contacts 42, 44 of electronic device 40 defines the spacing of the contacts on substrate 20 to which electronic device 40 connects, i.e. the desired spacing between holes 22, 24 of substrate 20 Regarding the exemplary substrate 20 of FIGURE 1, the width of and the number of turns of loop antenna 30 are sufficiently large so that electronic device
  • substrate 20 has two vias or holes 32, 34 spaced apart a distance corresponding substantially to the spacing between antenna terminals 32, 34.
  • Loop antenna 30 and substrate 20 are positioned so that the two terminals 32, 34 of loop antenna 30 overlie the two vias or holes 22, 24 through substrate 20, whereby elect ⁇ cal contact may be made with antenna terminals 32, 34 from the other surface of substrate 20 through holes 22, 24, respectively.
  • antenna 30 is preferably, but need not be, a generally spiral conductor pattern located close to the edges of substrate 20 so as to increase the area encompassed thereby, and may be of a circular spiral, oval or elliptical spiral, square or rectangular spiral, or other convenient pattern, including a free-form shape.
  • loop antenna 30 may include one or more "weakened” portions at which it is easily broken or fractured if substrate 20 is tampered with.
  • Such weakened portions may take the form of notches 31 provided by notching one or both edges of the conductor loops 36, 37, 38 or the thickness thereof.
  • Notches 31 may include, for example, one or more directly opposing "V"-shaped notches, offset opposing "V"-shaped notches or a single "V"- shaped notch, or may include one or more narrowed lengths of conductor 36, 37, and/or 38, whether directly opposing or offset, as is desired.
  • antenna 30 may be weakened by employing a very thin layer of metal foil or deposited metal to form antenna 30.
  • the thicknesses of such thin metal mate ⁇ als is less than 25 ⁇ m (about 1 mil), and may preferably be in the range of about 2.5 to 12.5 ⁇ m (about 0.1 to 0.5 mils).
  • antenna 30 is frangible and tends to break easily if article 10 is attempted to be removed from the object to which it is attached or is otherwise tampered with.
  • antenna 30 is formed on or attached to a first surface of substrate 20, the holes 22, 24 of substrate 20 are filled with an elect ⁇ cally-conductive material that will form the electrical connections between antenna terminals 32, 34 and device contacts 42, 44, respectively, and the electronic device 40 (shown in phantom) is attached to the opposing surface of substrate 20
  • the resulting wireless article 10 includes substrate 20 having holes 22, 24 therein filled with elect ⁇ cally-conductive mate ⁇ al 50 which extends therefrom to form conductive features or "bumps" 52, 54 Conductive mate ⁇ al 50 also provides elect ⁇ cal connection to terminals 32, 34 of antenna 30
  • Contacts 42, 44 of electronic device 40 connect to conductive bumps 52, 54 and may be pressed into place when the mate ⁇ al of bumps 52, 54 is an elect ⁇ cally-conductive adhesive Connection of contacts 42, 44 to bumps 52, 54 of electrically-conductive adhesive may be made by pressing electronic device 40 in place against substrate 20 when elect ⁇ c
  • FIGURES 1 and 2 is particularly advantageous where the number of turns of antenna 30 is sufficiently large that the distance between antenna contacts 32 and 34 is greater than the distance between contacts 42, 44 of electronic device 40
  • conductive mate ⁇ al 50 is deposited to fill holes 22, 24 and to form conductive st ⁇ ps
  • the portion of conductors 50 filling holes 22, 24 may be formed of a va ⁇ ety of materials, such as by building up metal, such as by plating copper, beryllium copper, brass and other copper alloys, or nickel or aluminum or other suitable metal, to fill holes 22, 24, or may be made by depositing electrically- conductive adhesive to fill holes 22, 24, such as by screen p ⁇ ntmg, stenciling and the like. It is further noted that one or more additional deposits of electrically-conductive adhesive onto substrate 20 may be utilized if it is desired to increase the height of conductors and/or bumps 52 from what is obtained with a single deposition of adhesive Further, elect ⁇ cally-conductive adhesive bumps may be deposited on the contacts 42, 44 of electronic device 40 with like result.
  • a layer of metal such as nickel, gold, nickel-gold and the like may be deposited, such as by plating, onto conductors 50, 52, 54 formed of elect ⁇ cally-conductive adhesive.
  • This plated metal layer in addition to serving to resist oxidation of the conductors, increases the height thereof and/or otherwise facilitates connection of the contacts of electronic devices 40 to the plated contacts 50, 52, 54 with solder, e.g., with solder bumps as in the mounting of conventional flip-chip components.
  • This embodiment is substantially different from conventional plated-through holes as in conventional printed circuit wi ⁇ ng boards, whether of single layer or multi-layer type, and whether of ⁇ gid or flexible type, wherein plating is deposited on the mte ⁇ or surface of the holes to make elect ⁇ cal contact with the thm edges of metal conductors that are on va ⁇ ous ones of the surfaces and layers thereof.
  • conductive mate ⁇ al is built up to fill the hole and contacts the broad surface of the conductors on the surface of the substrate, either through physical contact or by being part thereof as in the case of deposited conductive adhesive.
  • Wireless article 10 is fab ⁇ cated as follows.
  • the sheet is typically about 0.75 mm thick (about 0.03 inch thick), but may range between 0.05 and 1.0 mm thick (about 0.002 to 0.040 inch thick, i.e. 2 - 40 mils).
  • a sheet of the substrate mate ⁇ al that is large enough to be cut into a plurality of substrates is provided, such as a 280 mm by 280 mm (about 11 inch by 11 inch) sheet on which a 3 by 4 array of 12 substrates, each about 83.5 mm by 132.9 mm (about 2.125 inch by 3.375 inch), may be formed.
  • the sheet is processed to contemporaneously form an array of wireless articles 10 thereon before it is excised or cut to separate the individual wireless articles 10
  • substrate 20 can be formed by screen p ⁇ nting or stencil p ⁇ ntmg a dielect ⁇ c adhesive layer having holes 22, 24 therein defined by the pattern of the screen or stencil utilized. This method is preferred where the loops 36, 37, 38 of antenna 30 are photo-etched from a sheet of metal foil laminated to such dielect ⁇ c adhesive layer substrate 20, such as by photo-etching as utilized in the making of conventional p ⁇ nted wi ⁇ ng circuit boards.
  • a stencil, screen or mask defining the pattern of an array of antenna 30 corresponding to the array of substrates is positioned with the sheet of substrate material and an elect ⁇ cally conductive adhesive 50 is deposited on a first surface thereof in the pattern of the array of antenna 30
  • the substrate 20 is between about 0.25 mm and 1 mm thick (about 10 - 40 mils thick)
  • the conductors 36, 37, 38 forming antenna 30 are about 250 m (about 10 mils) wide and are within the range of about 25 m to 125 m thick (about 1.0 to 5 mils thick).
  • conductors 36, 37, 38 of antenna 30 are about 50 - 100 m thick (about 2 - 4 mils thick) when wet and about 25 - 75 m thick (about 1 - 3 mils thick) after drying or B- stagmg.
  • the conductive adhesive 50 may completely or partially fill holes 22, 24 in substrates 20. Where holes 22, 24 are larger than about 0.1 mm (about 4 mils) diameter, it is relatively easy to pass sufficient conductive adhesive 50 through the corresponding holes in the stencil, screen or mask to fill holes 22, 24 of substrate 20 Suitable conductive adhesives 50 include, for example, type PSS8150 thermosettmg conductive adhesive and type ESS8450 flexible conductive adhesive, both of which are filled with silver particles and are available from AI Technology, Inc.
  • the deposited conductive adhesive 50 is d ⁇ ed or B-staged by heating in an oven to about 60 C for about 60 minutes
  • a second deposit of the same conductive adhesive 50 is made in like manner on the opposing surface of the sheet of substrate mate ⁇ al.
  • a stencil, screen or mask defining the pattern of contact sets corresponding to the contacts 42, 44 of electronic device 40 and holes 22, 24 for the array of substrates is positioned with the sheet of substrate mate ⁇ al and the elect ⁇ cally conductive adhesive 50 is deposited on the opposing surface thereof in the pattern of the array of contacts 42, 44.
  • the elect ⁇ cally conductive adhesive 50 deposited on this second surface of the array of substrates flows into holes 22, 24 to contact the like adhesive deposited of the first surface thereof to form antenna 30 and to form contacts 52, 54 to which contacts 42, 44 of electronic device 40 connect.
  • the mate ⁇ als, application and processing of conductive adhesive 50 is like that utilized with respect to the first surface of the sheet of substrates.
  • Electronic devices 40 may be positioned to the sheet of substrates either when the adhesive 50 is still wet from being deposited or after adhesive 50 is d ⁇ ed or B- staged.
  • electronic devices 40 are flip-chip semiconductor devices with plated or otherwise oxidation resistant contacts 42, 44 that are positioned onto substrates 20 by conventional pick-and-place or flip-chip assembly equipment.
  • the sheet of substrates 20 with electronic devices 40 attached thereon is cured to form a sheet of wireless articles 10 which is then excised or cut apart, as by die cutting, laser cutting or the like, into the individual wireless articles 10.
  • Curing of type ESS8450 thermosetting adhesive is performed by heating the wireless article in an oven to a temperature above 100 C for about 30 minutes or more.
  • attachment may be completed by drying out the solvent from the adhesive, e.g., by heating to about 60 C for about 60 minutes.
  • the deposited conductive adhesive is preferably d ⁇ ed or B-staged before attachment of electronic device 40.
  • a second deposition of the same elect ⁇ cally-conductive adhesive is made to deposit a second layer of adhesive on bumps 52, 54 to which electronic device 40 may be attached while the second layer of adhesive is wet or after drying or B-staging.
  • the conductor width or spacing is small, it is preferred that attachment of electronic device 40 be after the second deposition of conductive adhesive on bumps 52, 54 has been d ⁇ ed or B- staged.
  • an insulating adhesive underfill in liquid form may be applied along the edges of electronic device 40 from where it flows by capillary action to substantially fill the remaining volume between electronic device 40 and substrate 20 that is not filled by conductive adhesive 50.
  • adhesive underfill provides additional mechanical strength to the attachment of electronic device 40 to substrate 20 and resistance to moisture and other potential contaminants.
  • the electrically-conductive adhesive 50 is a flexible adhesive such as type PSS8150, as is desirable where the substrate 20 is somewhat flexible
  • a flexible adhesive underfill such as types MEE7650 and MEE7650-5 flexible epoxy adhesive or type MEE7660 high-strength epoxy adhesive, also available from AI
  • a spot or drop of adhesive may be deposited onto substrate 20 in an area to be covered by electronic device 40, but not including any elect ⁇ cal contacts of substrate 20 or device 40, for mechanical attachment between substrate 20 and device 40.
  • electronic device 40 has an insulating, e.g., passivated, top surface, then the drop of adhesive could be either electrically conductive or insulating, as desired, however, if elect ⁇ cal contact to that surface of device 40 would adversely affect its operation or performance, then insulating adhesive should be employed.
  • a protective coating may be applied to wireless article 10 to protect against mechanical damage and environmental conditions, such as moisture, water, solvents, dirt and other mate ⁇ als.
  • One suitable protective coating mate ⁇ al is the type MEE7650 flexible insulating adhesive that is also used for underfill of electronic device 40.
  • the application of the underfill adhesive and of the overcoat adhesive may be accomplished in one operation.
  • the over coating mate ⁇ al is applied in liquid form as by spraying or dipping, the insulating adhesive will flow under electronic device 40 to form the underfill adhesive thereunder contemporaneously with it forming the protective coating.
  • the protective coating may also be sheets of dried or B-staged insulating adhesive laminated to one or both surfaces of wireless article 10. Where type ESP7450 flexible adhesive is laminated on substrate 20 to cover electronic device 40, underfill is not required between device 40 and substrate 20.
  • Flexibility of a mate ⁇ al is related to the degree of elongation that a mate ⁇ al exhibits before it fails.
  • flexible mate ⁇ als have a modulus of elasticity that is less than about 35,000 kg/m 2 (about 500,000 psi) and are capable of >30% elongation without failure.
  • substrate 20 has a given degree of flexibility, it is preferred that the flexible conductive adhesive mate ⁇ al that forms conductors 30, 50 and adhesive layer 58 thereon, for example, be at least as flexible as is substrate 20, i.e. exhibit at least the same or a greater percentage elongation p ⁇ or to failure
  • a dielect ⁇ c layer is deposited on a sheet of release lmer material to serve as substrate 20, such as by roll coating, screening stenciling, or other suitable method Where dielect ⁇ c layer
  • the pattern of loop antenna 30 may be formed of conductive adhesive deposited on a sheet of release liner with conductive adhesive bumps 52, 54 formed thereon at the terminals of antenna 30. The deposited conductive adhesive is then d ⁇ ed or B-staged.
  • dielectric layer 20 is applied directly over deposited antenna 30 and bumps 52, 54 to a thickness less than or equal to the height of bumps 52, 54, resulting in substrate 20 with antenna 30 and conductive bumps 52, 54 therein, ready for attachment of electronic device 40 thereto.
  • an array of wireless articles 10 are made contemporaneously by depositing an array of antennae 30, an array of substrates 20 in one layer, an array of conductive bumps 52, 54, and so forth, resulting in a panel of an array of wireless articles 10 that are then excised, such as by die cutting, rotary cuttmg, or other suitable method, into individual articles 10.
  • An alternative embodiment of wireless article 10 employs a metal foil loop antenna 30.
  • a sheet of metal foil such as a copper foil, an aluminum foil or a silver foil, is provided, typically between about 0.013 mm and 0.10 mm thick (about 0.5 to 4 mils thick).
  • a layer of dielect ⁇ c mate ⁇ al 20 is applied thereto, such as by roll coating, screening or stenciling an insulating adhesive thereon, including holes formed at the locations at which antenna terminals 32, 24 are to be formed in the metal foil.
  • the dielectric layer is preferably formed of an insulating adhesive, such as type ESP7450 thermosetting epoxy adhesive, type MB7100 thermoplastic adhesive or type CB7200-E thermosetting adhesive, each available from AI Technology, Inc. located in P ⁇ nceton, New Jersey.
  • substrate 20 has a dry thickness between about 0.05 mm and 0.5 mm (about 2 - 20 mils) when employed m an article compliant with an international standard for cards and tags with embedded integrated circuits, but may have a dry thickness between about 0.25 mm and 1 mm (about 10 - 40 mils) for other uses, and is B-staged and/or cured p ⁇ or to photo-etchmg of antenna 30 desc ⁇ bed below.
  • Conductive adhesive 50 is deposited to fill holes 22, 24 m substrate 20 and to provide contacts 52, 54 to which electronic device is to attach, as above, and is also cured prior to photo-etching of antenna 30.
  • Antenna 30 is made by photo-etching, i.e. by depositing a photoresist mate ⁇ al to the exposed surface of the metal foil, exposing and developing the photoresist material to define the pattern of antenna 30 and then etching away the unwanted metal foil mate ⁇ al to leave antenna 30 on substrate 20, in like manner to the etching of conventional p ⁇ nted wi ⁇ ng circuit boards, for example.
  • Suitable photoresist and photo-etchmg mate ⁇ als are widely available in liquid, paste and film form, such as from MacDermid Company located in Connecticut and from E.I duPont de Nemoirs
  • an array of wireless articles 10 are made contemporaneously by depositing an array of substrates 20 in one layer, depositing an array of conductive bumps 52, 54, and etching an array of metal foil antennae 30. and so forth, resulting in a panel of an array of wireless articles 10 that are then excised into individual articles 10
  • a photoresist pattern may be employed to define locations for depositing conductive metal onto antenna 30, either before or after the metal foil is etched to form antenna 30.
  • conductive metal is deposited onto antenna 30 not only on the exposed surface thereof adjacent the surface of substrate 20, but also onto antenna terminals 32, 34 accessible via holes 22, 24 to plate or otherwise build up a metal conductor to fill holes 22, 24 in substrate 20
  • the plating mate ⁇ al is copper or other mate ⁇ al susceptible to oxidation or other degradation of conduction and adhesion properties
  • a metallization or moisture resistant layer or layers of a non-oxidizing or precious metal such as tin, nickel, silver, gold, palladium, platinum, nickel-gold, or nickel-palladium, or the like, should be applied over the built-up via conductors in holes 22, 24.
  • antenna 30 is on the surface of substrate 20 opposite to antenna 30, it is preferred to have the portion of the metal antenna 30 near holes 22, 24 to overlie holes 22, 24, i.e. that the metal trace be left completely or substantially intact, to ease or facilitate making of elect ⁇ cal connection thereto, either directly or through holes 22, 24 Similarly, where antenna 30 is deposited of conductive adhesive, it is preferred to deposit the conductive adhesive to cover holes 22, 24 for the same reason.
  • FIGURES 4 and 5 are plan views of opposing surfaces of an exemplary embodiment of a substrate of an article having such greater number of turns.
  • Antenna 30 thereof comp ⁇ ses antenna portion 30A on the one surface of substrate 20 in se ⁇ es with antenna portion 30B on the other surface thereof.
  • Antenna portion 30A includes outermost turn 36A, innermost tum 38A, and intermediate turns 37A therebetween, and may be formed of a pattern of a thin metal foil as shown or of a pattern of deposited conductive adhesive, as desc ⁇ bed above in relation to
  • FIGURES 1 - 3 The ends 34, 39 of antenna portion 30A are positioned over holes 24, 22, respectively, in substrate 20, and end 34 serves as one terminal of antenna 30
  • Antenna portion 30B includes outermost turn 36B, innermost turn 38B, and intermediate turns 37B therebetween, and is formed of a pattern of conductive adhesive deposited onto substrate 20, as desc ⁇ bed above in relation to FIGURES 1 -
  • the depositing of conductive adhesive to form antenna portion 30B preferably also provides conductive material 50 substantially filling holes 22, 24 through substrate 20, although the filling of holes 22, 24 may be accomplished in a separate deposition
  • terminal 34 of antenna 30 is connected to conductive contact 54 by conductive mate ⁇ al 50 filling hole 24 through and deposited on substrate 20.
  • end 39 of outermost turn 36A of antenna portion 30A is connected to the end of outermost turn 36B of antenna portion 30B by conductive mate ⁇ al 50 filling hole 22 in substrate 20.
  • the other end 34 of deposited antenna portion 30B serves as the second terminal 32 of antenna 30 at which is formed conductive adhesive contact 52.
  • Conductive adhesive contacts 52, 54 which are spaced apart an approp ⁇ ate distance for receiving the contacts 42, 44, respectively, of electronic device 40 for elect ⁇ cally connecting antenna 30 to electronic device 40, are formed by the deposition forming antenna portion 30A and may be augmented in height by one or more additional depositions of conductive adhesive, as desc ⁇ bed above. It is noted that each of antenna portions
  • 30A, 30B of antenna 30 is preferably, but need not be, a generally spiral conductor pattern located close to the edges of substrate 20 so as to increase the area encompassed thereby, and may be of a circular spiral, oval or elliptical spiral, square or rectangular spiral, or other convenient pattern, including a free-form shape.
  • the conductors can be narrowed where they are close to features, such as is shown in FIGURES 4 and 5 where turns 37A and 37B pass near hole 22, that restrict the space available for such conductors to pass through.
  • These narrowed portions may provide the weakened easily-breakable portions 31 of antenna 30 that provide tamper destruct properties or additional weakened portions 31 A, 3 IB may be included in antenna portion 30A and 30B, respectively.
  • the conductors of loops 36A, 36B, 37A and/or 37B may be reduced from the typical width of about 0.5 -2 mm (about 20 - 40 mils) to about 0.125 mm (about 5 mil) conductors at a spacing of about 0.25 mm (about 10 mils). This is particularly helpful where the conductors 37B pass underneath electronic device 40 and the number of conductors, i.e. the number of turns of antenna 30, is restricted by the distance between contacts 42, 44 of electronic device 40.
  • the larger dimension features such as the full width portions of conductors 37 A, 37B, may be deposited by mesh screen printing and the finer features, such as the narrowed portions of conductors 37A, may be deposited by stenciling, with sufficient overlap to provide reliable electrical connection.
  • Antenna portions 30A, 30B, conductive material 50 and conductive strips 52, 54 may be deposited of any suitable electrically-conductive adhesive, such as type PSS8150 flexible electrically-conductive thermoplastic adhesive, or type CB8130, PS8090, ME8456, ME8550-SMT or ME8650, all available from AI Technology, which may serve as conductors 32, 36, 37, 38, 39, 50, 52, 54 as well as the contacts
  • any suitable electrically-conductive adhesive such as type PSS8150 flexible electrically-conductive thermoplastic adhesive, or type CB8130, PS8090, ME8456, ME8550-SMT or ME8650, all available from AI Technology, which may serve as conductors 32, 36, 37, 38, 39, 50, 52, 54 as well as the contacts
  • an etched or otherwise patterned metal loop 30A be coated or plated with a precious or other suitable metal to preserve the conductive and adhesion properties thereof, in addition, a suitable dielectric underfill may be employed to strengthen the attachment of electronic device 40 to substrate 20 as described above.
  • Articles having conductors, including articles having a plural-turn loop antenna, on both surfaces of a substrate may be formed by at least the two following methods.
  • a substrate is provided of a conventional high-strength thermoplastic film material, such as an acrynitrile-butadiene-styrene (ABS), polyester, polyimide, polyphynylene sulfide, polysulfone, polyether sulfone, or other high-temperature resin or other suitable material.
  • ABS acrynitrile-butadiene-styrene
  • polyester polyimide
  • polyphynylene sulfide polysulfone
  • polyether sulfone polyether sulfone
  • An about 25 mm by 50 mm (about 10 inch by 20 inch) or larger sheet is convenient for screen printing deposition of adhesive and is conveniently diced or cut into individual substrates, such as by rotary dicing.
  • a pattern of holes or vias 22, 24 are cut in the substrates 20 and may be of sufficient size, e.g., about 1 mm (about 40 mils) or larger (which is comparable to the 1 mm width commonly utilized for antenna 30 conductors), as can be readily cut or punched out with suitable conventional tools, such as punches, drills and dies.
  • Commonly available electrically-conductive inks and adhesives may then be deposited, such as by screen printing or stenciling, onto both surfaces of the sheet of substrates 20 to cover and fill holes 22, 24 as well as deposit the plural turn loop patterns of antenna portions 30A, 30B and antenna 30.
  • the substrate or sheet of substrates After one surface of the substrate or the sheet of substrates is printed with its pattern (or geometric pattern) of conductive adhesive, the substrate or sheet is heated to dry, B-stage or cure the conductive adhesive before the other surface thereof is printed with a related pattern (or geometric pattern) of the same conductive adhesive.
  • the printed conductive adhesive patterns on the two surfaces of the substrate or sheet are electrically connected by the conductive adhesive filling holes 22, 24, and provide suitable contact bumps or strips 52, 54 corresponding to the contacts of an electronic device 40 that provide the input and output (I/O) connections thereto.
  • Electronic device 40 is attached to substrate 20 either while the conductive adhesive of contacts 52, 54 is wet or after it is dry or B-staged and heated to a melt-flow condition, as described above.
  • Electrically-conductive adhesives types PSS8090, CB8130, PSS8150, ESS8450, ME8456, ME8550-SMT and ME8650 available from AI Technology are suitable for screening and/or stenciling to produce the described conductive patterns.
  • antenna portion 30A on one surface of the substrate 20 may be formed of a stamped or etched metal foil.
  • a substrate 20 preferably of a sheet of a laminatable B-staged epoxy or other suitable laminatable structural adhesive substrate material, typically having a thickness of about 25 - 250 m (about 1 - 10 mils) is provided, again preferably in a sheet of sufficient size to form an array of substrates 20.
  • the sheet of substrate material is formed with a pattern of holes or vias 22, 24 therein, but holes 22, 24 may be cut with suitable conventional tools.
  • the sheet of substrate 20 material is laminated with a sheet of a thin metal foil, for example, a thin metal foil of about 2.5 - 12.5 m (about 0.1 - 0.5 mils) thickness, such as by heat-stamped transfer of a copper, aluminum or silver foil.
  • a metal foil of about 25 - 125 m (about 1 - 5 mils) thickness is laminated to the substrate 20 and is then patterned by photo-etching to form antenna 30, or antenna portion 30A using conventional photo-etching, with the ends thereof in place over and either partially or completely covering holes 22, 24.
  • the material of substrate 20 is a material that is, when B-staged or cured, as the case may be, not adversely affected by such processing as the photo-etching and plating of the metal foil.
  • At least the portion of the remaining metal foil at holes 22, 24 is spot plated or coated with a precious or other metal, such as silver, nickel, nickel-gold, nickel palladium, to preserve its conductivity and adhesion against degradation by oxidation, for example.
  • a precious or other metal such as silver, nickel, nickel-gold, nickel palladium
  • An electrically- conductive ink adhesive is then printed on the second surface of the sheet of substrate material to form the pattern of antenna portion 30B, contacts 52, 54 and other conductive features thereon, as described above.
  • Holes 22, 24 may be filled with the deposited conductive adhesive or the metal foil may be built up by plating metal thereon to fill or partially fill holes 22, 24 before the spot plating or coating of a precious or other metal thereon and deposition of the conductive adhesive, to complete a conductive connection from antenna 30, 30A to the second surface of the sheet of substrates, as described above.
  • Electronic device 40 is attached to substrate 20 either while the conductive adhesive of contacts 52, 54 is wet or after it is dry or B- staged and heated to a melt-flow condition, as described above.
  • ME7850 are suitable for the substrate 20 material, either directly in liquid or paste form or in the form of a laminatable B-staged sheet, and electrically-conductive adhesives types PSS8090, CB8130, PSS8150, ESS8450, ME8456, ME8550-SMT and ME8650 are suitable for screening and/or stenciling to produce the described conductive patterns, which adhesives are available from AI Technology.
  • an article according to the present invention may be covered with a layer of protective material.
  • a layer 56 of an insulating adhesive may be applied to one surface of substrate to cover and protect antenna portion 30A and/or a layer 58 of an insulating adhesive may be applied to the other surface of substrate to cover and protect antenna portion 30B and electronic device 40.
  • Layers 56, 58 may be applied by roll coating, screening, laminating or other suitable method, and may be covered by a layer of ABS, PVC, PET or other material, preferably a material similar to the material of substrate 20.
  • Suitable insulating adhesives include, for example, insulating thermoplastic adhesives such as types MB7100, TP7090 and MB7100, and insulating thermosetting adhesives such as types CB-7200-E, MEE7650 and ESP7450-SC, all available from AI Technology.
  • FIGURES 7 and 8 are plan views of opposing surfaces of an alternative exemplary embodiment of a wireless article 100 according to the present invention that includes, in addition to a plural turn antenna 130 for wireless communication with an external card reader by electromagnetic waves, a pattern 110 of contacts 112 located in a predetermined location on substrate 120 for making physical electrical connection to the contacts of an external card reader.
  • the pattern 110 of metal contacts 112 are formed on one surface of substrate 120 which may be of any of the aforementioned substrate materials, but which is preferably a sheet of insulating adhesive such as type MB7100 thermoplastic or type, CB7200-E, ESP7250 or ESP7450 thermosetting insulating epoxy adhesive available from AI Technology.
  • Contacts 112 are preferably of hot stamped thin copper, aluminum or silver foil, or of laminated copper applied to substrate 120 and photo-etched into pattern 110, and plated with one or more layers of protective metal, such as nickel and gold layers or nickel and palladium layers, all as described above.
  • Substrate 120 has at least two holes 122, 124 therethrough at which are located the ends or terminals 132, 134 of plural-turn antenna 130 formed on the same surface of substrate as is pattern 110 of contacts 112, and has an additional hole (not visible in FIGURE 7) located beneath each of contacts 112 for making electrical connection thereto.
  • plural-turn antenna 130 is located towards the edges of substrate to the extent practicable in view of the required predetermined position of contact pattern 110.
  • Antenna 130 may be formed of hot stamped thin metal foil or of photo-etched metal in like manner to contacts 112 or may be deposited electrically conductive material, such as plated copper, aluminum or silver metal or an electrically-conductive adhesive, for example, types CB8130 PSS8090, PSS8150, ME8456, ME8550-SMT and ME8650 adhesives available from AI Technology, all as described above.
  • a pattern of conductors 152, 154, 156, 158 is formed on the other surface of substrate 120 by hot-stamping a copper, aluminum, silver or other metal foil thereon or depositing a pattern of electrically conductive material, such as copper, aluminum, silver, gold, and/or an electrically-conductive adhesive, for example, types CB8130 PSS8090, PSS8150, ME8456, ME8550-SMT and ME8650 adhesives available from AI Technology, all as described above.
  • electrically-conductive material fills holes 122, 124, which are typically about 75 - 250 m (about 3 - 10 mils) in diameter, to form conductive connections or vias 150 to terminals 132, 134, respectively, of antenna 130 and fills the holes beneath contacts 112, which holes are typically about 250 - 1000 m (about 10 - 40 mils) in diameter, to form conductive connections or vias thereto providing contacts 156.
  • Conductor 152 provides electrical connection between terminal 132 of antenna 130 and one of the contacts 158 and conductor 154 provides electrical connection between terminal 134 of antenna 130 and the other of the contacts 158.
  • One or more additional deposits of conductive material may be made in the locations of contacts 156, 158 to increase the height thereof for facilitating attachment of an electronic device 140 thereto.
  • a thin metal foil such as a hot-stamped silver, copper, aluminum or gold foil
  • the thickness of the conductor provided thereby may be increased by plating conductive metal thereon, such a electroless silver, silver, nickel-gold, copper and the like, to decrease the electrical resistance of the conductor, as may be important for proper antenna performance.
  • Electronic device 140 has a pattern of contacts and is attached to the other surface of substrate 120 with its pattern of contacts facing the surface of substrate 120 and adhering thereto by a plurality of electrically conductive adhesive connections to the corresponding contacts 156, 158 on substrate 120, i.e. in a flip-chip mounting manner.
  • Certain of the contacts of electronic device 140 i.e. those arranged in two parallel rows of three contacts each, are connected through vias 156 to the contacts 112 of article 100, which are likewise arranged in two parallel rows of three contacts each.
  • Two other contacts of electronic device 140 i.e. those not in the 2-row by 3- contact arrangement, are connected by conductors 152, 154 to plural-turn antenna 130 thereof.
  • any of the articles of FIGURES 1 - 8 herein may be coated with a layer 56, 58 of insulating adhesive to cover and protect the antenna 30, 130 and the electronic device 40, 140 attached to substrate 20, 120, on either one or both sides of substrate 20, 120, and whether or not a card blank is or is not employed.
  • Such wireless articles may be employed as an identification tag, an identification badge, a luggage tag, a pallet identification tag, a laundry tag, an access card, a credit card, a debit card, a cash card, a phone card, or like article.
  • the wireless article is preferably of flexible adhesive substrate, e.g., type
  • ESP7450 flexible dielectric adhesive on a polyester film, such as Mellinex polyester film available from E.I. duPont de Nemoirs located in Delaware.
  • the electronic devices preferably connected to the substrate with a flexible electrically-conductive adhesive and a similar high-strength flexible dielectric underfill adhesive, e.g., types MEE7650 and MEE7660, respectively.
  • the completed wireless tag is preferably laminated with a melt-bondable flexible adhesive that melts almost instantly and that withstands immersion in boiling water and other high-temperature and high-moisture conditions, so as to encapsulate and protect the substrate and electronic device.
  • a preferred such adhesive is type ESP7450 flexible dielectric thermoplastic adhesive.
  • FIGURE 9 is a side view of an exemplary article 200 according to the invention.
  • Tamper-resistant wireless article 200 includes a substrate 220 that is an adhesive that also serves for attaching article 200 to the object to be identified.
  • Suitable adhesives include thermoplastic adhesive that may be bonded to the object by either heat or a solvent or thermosetting adhesive that is attached to the object and cured, such as by application of heat.
  • Suitable strong dielectric adhesives for tamper- resistant articles include, for example, type MB7100 thermoplastic dielectric adhesive, type CB7200-E thermosetting dielectric adhesive, and type ESP7450 thermosetting flexible adhesive, all available from AI Technology, Inc.
  • the adhesive may comprise the entire substrate 220 or may be an outer layer or layers of a laminated substrate 220.
  • a "strong" adhesive will have a "peel strength" that is at least 1000 gm/inch of width (about 400 gm/cm of width), and preferably more than 2000 gm inch (about 800 gm cm) of width, measured by a conventional pull test.
  • Antenna 230 is, for example, an etched copper pattern, and is preferably passivated by a layer of precious metal, such as silver or gold, to resist oxidation, at least at the contacts thereof at connections 252, 254.
  • the plated metal layer also desirably serves to increase the height of the contacts and to reduce the resistance of antenna 230.
  • the shape and size of substrate 220 and antenna 230 are established to fit the desired physical size requirements, if any, for article 200 in conjunction with the number of turns or loops of antenna 230 for receiving sufficient electromagnetic flux for operability with electronic device 240.
  • Contacts on electronic device 240 are attached to antenna terminals on substrate 220 in a flip-chip manner by connections 252, 254, such as by a relatively weakly bonding flexible electrically-conductive adhesive, so as to easily separate (de- bond) if article 200 is tampered with.
  • "Weakly bonding" adhesives have a bond strength that is less than about 1000 psi (about 70 kg/m 2 ) measured by a conventional shear strength test.
  • Suitable conductive adhesives include type PSS8090 where device 240 is not encapsulated and type CB8130 where device is covered or encapsulated, such as by type MB7100 thermoplastic adhesive.
  • the contacts of device 240 and the antenna 230 terminals are passivated by a precious metal, such as gold on nickel (“nickel-gold”), to resist oxidation.
  • Article 200 may be made to "tamper destruct" rather than to be just tamper resistant as follows.
  • Antenna 230 is a heat stamped transfer of a thin foil of copper or aluminum or silver foil, and may retain the weakened feature about 25 ⁇ m (about 1 mil) in size.
  • a typical loop or turn of a hot stamped metal foil antenna 230 exhibits a resistance of about 10 to 100 ohms, which is reduced to less than 10 ohms, and typically to 0 2 to 2 ohms, by the plated precious metal layer so as to be effective with a typical electronic device 240, such as a "smart tag" type integrated circuit operating at a frequency of about 245 GHz available from Single Chip Systems Corporation located in California
  • a typical electronic device 240 such as a "smart tag" type integrated circuit operating at a frequency of about 245 GHz available from Single Chip Systems Corporation located in California
  • antenna 230 may be an etched copper pattern having a thin portion 231, e g , less than about 25 ⁇ m (about 1
  • Antenna 230 of a tamper-destruct article 200 may also be provided by depositing an electroless activatable thermoplastic such as ABS plastic on substrate
  • ABS plastic may be deposited, for example, by dissolving it in a solvent and printing, screening or stenciling it in the desired pattern of antenna 30 on substrate 220
  • the patterned ABS is plated with electroless silver or gold or combination of precious metals (plating will only adhere to the activatable ABS) to reduce the resistance to less than about 10 ohms, all as desc ⁇ bed above
  • Electronic device 240 is connected to antenna 230 terminals by a relatively strong elect ⁇ cally-conductive adhesive, e g , an adhesive having a strength m excess of about 1000 psi (about 70 kg/m 2 ), and preferably in excess of about 2000 psi (about 140 kg/m 2 )
  • a strong adhesive will tend to cause the thin antenna 230 to be pulled away from substrate 220 with device 240 and break Suitable strongly bonding adhesives include, for example, AI Technology types ME8456, ME8550-SMT and ME8650 which may be encapsulated with type MEE7660 thermosetting dielect ⁇ c adhesive for tamper resistant applications
  • pressure sensitive (non-cured) adhesives have a peel strength of about 200-500 gm inch of width, and are considered to relatively weakly bond
  • Cured adhesives typically have a peel strength of 1000 gm/inch of width and are considered to relatively strongly bond.
  • FIGURE 10 is a side v_ f an exemplary article 200' according to the invention which is similar to article 200 of FIGURE 9 described above.
  • Article 200' differs from FIGURE 9 in that antenna 230' has one or more small gaps 233 or discontinuities along its length that are filled or bridged by an electrically conductive adhesive 235 that strongly bonds to substrate 220 and will separate from the plated copper portions of antenna 230' so that antenna 230' is destroyed if article 200' is tampered with.
  • the electrically-conductive gap-filling adhesive 235 utilizes the same type resin binders as the dielectric adhesive utilized for substrate 220.
  • type CB8130 electrically conductive adhesive is utilized with type MB7100 thermoplastic adhesive substrate and type CB8205-E electrically conductive adhesive is utilized with type CB7200-E thermosetting adhesive substrate.
  • Antenna 230' may also include thin or narrow frangible portions 231.
  • electronic device 240 is encapsulated to substrate 220 by an epoxy encapsulant 245, such as AI Technology type MEE7650 or MEE7660.
  • FIGURES 11A and 11B are side and plan views, respectively, of another exemplary article 300 according to the invention which differs from articles 200 and 200' in that electronic device 340 is on a surface of substrate 320 opposite antenna 330.
  • Substrate 320 is like substrate 220 in structure and materials, except that electrically-conductive vias 350 are formed in holes 250 through substrate 320 to connect to the underside of antenna 330 and to connect to electronic device 340 by means of conductors 352, 354.
  • the holes in which conductive vias 350 are disposed are formed contemporaneously with substrate 320, such as by features on the mask, stencil or screen utilized in printing the dielectric adhesive forming substrate 320.
  • conductive vias 350 are of electrically-conductive adhesive deposited into the holes in substrate 320.
  • Connections 352, 354 between conductive vias 350 and contacts of electronic device 340 are preferably also of electrically- conductive adhesive and are deposited contemporaneously with conductive vias 350 in a single screen printing, stenciling or mask printing operation.
  • Suitable electrically-conductive adhesives include types PSS8090, CB8130 and PSS8150, and may be deposited, for example, in a width of 50 - 500 ⁇ m (about 2 - 20 mils) and at a thickness of 25 - 100 ⁇ m (about 1 - 4 mils).
  • connections 352, 354 may be of like structure and material as is antenna 330 which is like antenna 230 and/or 230' in structure and materials, e.g., is of etch-patterned copper, hot-stamped copper foil with electroless silver plating, hot- stamped silver foil or electroless silver plated on an activated plastic such as ABS plastic.
  • Antenna 330 may be plated with silver, electroless silver, copper, aluminum and the like to increase its thickness and to decrease the resistance thereof, e.g., to less than five ohms, and typically to about two ohms.
  • Conductors 352, 354 are preferably bonded to substrate 320 and at least partially encapsulated so as to be frangible and tend to break easily if article 300 is attempted to be removed from the object to which it is attached or is otherwise tampered with.
  • FIGURES 9-1 IB in particular lend themselves to inexpensive fabrication and to have tamper resistant and tamper destruct properties, as desired.
  • an electronic article is adapted for attachment to a utilization object (e.g., an object to which the electronic article is attached for identification, inventory, cleaning, laundering, processing or other purpose) and comprises a layer of electrically insulating adhesive providing a substrate adapted for adhering to a utilization object.
  • the adhesive preferably has an adhesive bond strength to the utilization object that substantially exceeds the intrinsic shear strength of the adhesive, whereby attempting to remove the substrate from a utilization object results in damage to the substrate before separation of the substrate from a utilization object.
  • the intrinsic strength or shear strength of a material is a measure of the physical force necessary to damage or destroy the sheet of material, such as by it tearing, breaking or otherwise suffering a loss of physical integrity or function.
  • An electronic device is either mounted to or embedded in the adhesive substrate and is electrically connected to an antenna on a surface of an adhesive layer of the adhesive substrate.
  • Typical adhesives having greater bond strength than intrinsic strength have a peel strength greater than about 1000 gm/inch of width and a shear strength greater than about 2000 psi (about 140 kg/cm 2 ), and preferably greater than about 1000 psi (about 70 kg/cm 2 ).
  • Suitable adhesives include, for example, thermoplastic and thermoset adhesives types CB7130 and ESP7450.
  • At least a portion of the antenna is preferably a frangible region having a strength substantially less than the mt ⁇ nsic strength of the adhesive of the substrate, whereby attempting to remove the electronic article from the utilization object by physical force tends to damage the antenna.
  • the frangible region includes either a thm region, a narrowed region, a notch, a thin foil of copper, aluminum or silver, electroless plated silver on activated plastic, electroless plated silver on activated ABS, or elect ⁇ cally-conductive adhesive b ⁇ dgmg a gap in the pattern of elect ⁇ cally- conductive material.
  • the frangible region has a thickness less than about
  • the antenna preferably includes alternatively either a patterned metal foil of copper, aluminum or silver, having a thickness of at least about 0.01 mm, and typically about 0.025 mm, and a width at least in part of at least about 0.10 mm, or a pattern of electroless plated silver on activated plastic or electroless plated silver on activated ABS, wherein the electroless silver has a thickness of less than about 0.025 mm, and typically about 0.01 mm, and a width at least in part of at least about 0.10 mm.
  • the electronic device is electrically connected to the antenna by elect ⁇ cally- conductive adhesive that is either (a) of substantially lower intrinsic strength than the int ⁇ nsic strength of the adhesive of said substrate, or (b) soluble in a solvent that dissolves the adhesive of said substrate, whereby attempting to remove the electronic article from a utilization object by physical force or solvent tends to damage the elect ⁇ cal connection of the antenna to the electronic device.
  • the antenna includes a patterned metal foil of one of copper, aluminum and silver, and has electroless silver plating thereon for providing an antenna having a resistance of less than about 2 ohms.
  • FIGURES 12 and 13 are plan and side view schematic diagrams, respectively, of an exemplary substrate 402 for a contact-less card 400 having an electronic device therem.
  • Substrate 402 is formed of a thin sheet of substrate mate ⁇ al, such as thermoplastic or thermosetting dielect ⁇ c adhesive, PVC, PET, ABS or HIPS, polyimide, polymer film, or other plastic, or paper film, or other suitable mate ⁇ al, on which is deposited an elongated elect ⁇ cal conductor 404 that serves as an RF loop antenna 404.
  • substrate mate ⁇ al such as thermoplastic or thermosetting dielect ⁇ c adhesive, PVC, PET, ABS or HIPS, polyimide, polymer film, or other plastic, or paper film, or other suitable mate ⁇ al, on which is deposited an elongated elect ⁇ cal conductor 404 that serves as an RF loop antenna 404.
  • Antenna 404 is formed of a thermoplastic or thermosetting polymer adhesive that is made electrically conductive by the inclusion of elect ⁇ cally conductive particles therein, and which may include one or more regions of reduced width and/or thickness to provide frangible areas that break easily to provide tamper- destruct properties, or of a hot-stamped metal foil or the like.
  • Electronic device 410 is attached to substrate 402 in a flip-chip manner by elect ⁇ cal connections 406 that bond the contact pads thereof to the ends of the elongated conductive pattern 404 of conductive adhesive that serve as the contacts of RF loop antenna 404. Connections 406 to electronic device 410 at the ends of conductive pattern 404 may be made while the conductive adhesive thereof is wet by placing electronic device 410 thereon or conductive adhesive pattern 404 may be d ⁇ ed or B-staged before electronic device
  • the substrate 410 is placed to contact the ends thereof by melting or cu ⁇ ng the conductive adhesive.
  • the substrate is made in a single deposition rather than requi ⁇ ng the deposition of a thick-film mk to form the antenna conventionally and conductive bumps to form interconnections between the antenna and the electronic device.
  • a stencil, screen or mask defining the pattern of antenna 404 is employed to deposit elect ⁇ cally conductive adhesive on substrate 402 in the pattern of antenna 404.
  • the substrate 402 is between about 0.025 mm and 1 mm thick (about 1 - 40 mils thick), and the conductors forming antenna 404 are about 250 m (about 10 mils) wide and are within the range of about 25 m to 125 m thick (about 0.5 to 5 mils thick).
  • the conductors of antenna 404 are about 50 - 100 m thick (about 2 - 4 mils thick) when wet and about 12.5 - 75 m thick (about 0.5 - 3 mils thick) after drying or B-staging.
  • Suitable conductive adhesives include, for example, type PSS8150 thermosetting conductive adhesive filled with silver particles which is available from AI Technology, Inc. and type CB025 silver-filled conductive ink available from E.I. duPont de Nemoirs located in Delaware.
  • the deposited conductive adhesive is d ⁇ ed or B-staged by heating in an oven.
  • Electronic devices 410 may be positioned to the substrate 402 either when the adhesive is still wet from being deposited or after the conductive adhesive is d ⁇ ed or B-staged
  • antenna 402 has plural turns and electronic device 410 b ⁇ dges one or more turns of antenna 404 or other conductors formed of elect ⁇ cally-conductive adhesive, and particularly where the width or spacing of such conductors is small, i.e. less than about 0.25 - 0.5 mm (about 10 - 20 mils), the deposited conductive adhesive is preferably d ⁇ ed or B-staged before attachment of electronic device 410 A second deposition of the same elect ⁇ cally-conductive adhesive is made to deposit a second layer of adhesive on bumps 406 to which electronic device 410 may be attached while the second layer of adhesive is wet or after drying or B-stagmg.
  • an insulating adhesive underfill in liquid form may be applied along the edges of electronic device 410 from where it flows by capillary action to substantially fill the remaining volume between electronic device 410 and substrate 402 that is not filled by conductive adhesive.
  • adhesive underfill provides additional mechanical strength to the attachment of electronic device 410 to substrate 402 and resistance to moisture and other potential contaminants, as is desirable in a tamper-resistant article.
  • the elect ⁇ cally- conductive adhesive is a flexible adhesive such as type PSS8150, as is desirable where the substrate 402 is somewhat flexible, a flexible adhesive underfill, such as type MEE7650 or type MEE7650-5 thermoplastic epoxy adhesive, is preferably utilized.
  • FIGURE 14 is a cross-sectional side view of another alternative exemplary embodiment of a contact-less card 400' according to the present invention
  • Card 400' like card 400 desc ⁇ bed above, includes a prepared substrate 402 with loop antenna 404 and electronic device 410 mounted thereon as desc ⁇ bed in relation to FIGURES 12 and 13
  • Substrate 402 is encapsulated by roll coating a layer 424 or laminating a sheet 424 of melt-flowable adhesive thereto
  • Adhesive layer 424 has a thickness greater than the height (thickness) of electronic device 410 above substrate 402 so that it is sufficient to cover and encapsulate electronic device 410.
  • the adhesive of which layer 424 is formed is preferably selected to be of a different type than is the conductive adhesive of which loop antenna 402 and contacts 406 are formed so as to avoid the smearing thereof, such as an adhesive based upon a different chemistry of its molecular and physical structure, such as one being a thermosetting adhesive and the other being a thermoplastic adhesive or two adhesives employing different solvent so that the solvent of the one adhesive does not affect or dissolve the other adhesive. Smearing is also avoided if layer 424 is formed by laminating a sheet of dried or B-staged, i.e. solvent-free, adhesive to substrate 402.
  • Substrate 402 may be attached or laminated to an object to be identified by placing them together between heated flat plates or heated rollers, at a temperature and for a time appropriate for adhesive layer 424 to melt flow and form a permanent bond between substrate 402 and the object, thereby to attach the complete contact-less card 400' with electronic device 410 positioned and encapsulated between substrate 402 and the object by melt-flowable adhesive 424.
  • FIGURE 15 is a plan view of a substrate 402 as for cards 400, 400' above in which an alternative arrangement for mounting an electronic device 410' to substrate 402 is employed.
  • Electronic device 410' for example, a semiconductor die, which is illustrated apart from substrate 402, has two contact pads 412' located, for example, spaced apart along opposing edges thereof.
  • RF loop antenna 404' of suitable width and conductivity is deposited, as by screen printing, stenciling or other suitable method of depositing an electrically-conductive adhesive, onto substrate 402 and has at the ends thereof contacts 406' of RF loop antenna 404' spaced apart the same distance as are contact pads 412' of electronic device 410' for making electrical connection thereto.
  • a support 408 is deposited onto substrate 402 for supporting a part of electronic device 410' apart from contact pads 412' thereof.
  • Support 408 may be deposited at the same time and of the same material as is antenna 404' if the surface of electronic device 410' to which it will be attached is passivated or coated so that the function of electronic device 410' will not be compromised by having electrically-conductive adhesive attached thereto, or support 408 may be deposited separately or of a different mate ⁇ al, such as an elect ⁇ cally insulating adhesive.
  • a second deposit of elect ⁇ cally-conductive adhesive may be made onto contacts 406' to increase the height thereof, and a second deposit of adhesive may be made onto support 408 to similarly increase the height thereof.
  • Electronic device 40' is flipped over and mounted to substrate 402, as is shown in FIGURE 16, with contact pads 412' connecting to antenna contacts 406' and with electronic device 410 also being supported by support 408.
  • Electronic device 410' can be attached to substrate 402 while the adhesive deposited to form contacts 406' and support 408 are still wet, or the adhesives forming contacts 406' and support 408 may be d ⁇ ed or B-staged prior to attachment of electronic device
  • thermoplastic adhesive utilized for contacts 406' and support 408
  • electronic device 410' may be attached to substrate 402 by heating substrate 402 and/or electronic device 410' to an elevated temperature sufficient to melt flow the thermoplastic adhesive (i.e. make it wettable for bonding and cu ⁇ ng) when substrate 402 and device 410' are pressed together.
  • thermosetting adhesive utilized for contacts 406' and support 408
  • electronic device 410' may be attached to substrate 402 by pressing device 410' into the wet thermosetting adhesive or by heating substrate 402 and/or electronic device 410' to an elevated temperature sufficient to melt flow the B-staged thermosetting adhesive (i.e. make it wettable for bonding and cu ⁇ ng) and pressing substrate 402 and device 410' together.
  • the thermosetting adhesive may then be cured by heating for a sufficient time at an approp ⁇ ate elevated temperature.
  • the preferred adhesive for card 400, 400' is a type PSS8150 elect ⁇ cally- conductive, flexible thermosetting adhesive also available from AI Technology, which may be p ⁇ nted with a suitable width and thickness, e.g., about 1 mm wide and 0.1 mm thick, to provide suitable conductivity and quality factor Q of antenna 404'.
  • An underfill may be employed to better secure electronic device 410' to substrate 402 after it is attached thereto by contacts 406' and support 408'. Where electronic device 410' is of small size, e.g., less than about 5 mm along its edge, an underfill of ⁇ gid mate ⁇ al or of flexible mate ⁇ al may be employed, with a flexible underfill mate ⁇ al being employed where substrate 402 is flexible.
  • a flexible adhesive underfill is preferred.
  • the underfill adhesive provides additional strength for the bond between device 410' and substrate 402, and also provides additional insulation and resistance to intrusion of contaminants, including migration of silver from the conductive particles that might be employed to impart conductivity to an electrically-conductive adhesive.
  • the preferred adhesive for flexible underfill is a type MEE7650-5 electrically-insulating, flexible thermosetting adhesive also available from AI Technology, which may be applied along the edges of electronic device 410' and is drawn between device 410' and substrate 402 by capillary action.
  • the same flexible insulating adhesive material may be employed as a protective coating for substrate 402 and card 400, 400' to resist mechanical abrasion of RF loop antenna 404' and contact of contaminants and other environments therewith. Because the size of the electronic devices usually utilized in these types of cards, rigid adhesive underfill may be utilized if additional mechanical protection is desired.
  • the method of making an exemplary card 400' is as follows. A 7-mil thick (0.178 mm) sheet of annealed, highly-printable PVC is obtained. Preferably, the sheet is of sufficient size that a plurality of substrates 402 may be made contemporaneously.
  • an 11-inch by 11-inch (about 28 mm by 28 mm) sheet is convenient for making a panel containing a 3 by 4 array of 12 substrates
  • an 11-inch by 18-inch (about 28 mm by 46 mm) sheet is convenient for making a panel containing a 3 by 8 array of 24 substrates, each with sufficient unused peripheral area of the sheet remaining for the placement of guide holes or other indexing and alignment indicia that facilitate placement and alignment of the sheet, for example, with respect to screens and stencils, pick-and-place equipment, laminating equipment, die-cutting equipment, and the like.
  • An electrically-conductive adhesive such as type PSS8090 thermoplastic highly-electrically-conductive (e.g., ⁇ 0.001 ohm-cm conductivity) adhesive available from AI Technology, is screen printed onto the PVC sheet at a thickness of about 2 mils (about 0.05 mm) to form the conductive loop antenna 404 and contacts 406 to which electronic devices 410 are to be attached in a single step, although stenciling, masking, ink-jet printing or other suitable deposition method could also be utilized. While the conductive adhesive is still wet, electronic devices 410 are placed onto the PVC sheet substrate in the proper positions for contacts thereon to make electrical contact and bond with the wet conductive adhesive at the ends of the 24 elongated patterns of conductive adhesive loop antenna by pick-and- place equipment.
  • type PSS8090 thermoplastic highly-electrically-conductive (e.g., ⁇ 0.001 ohm-cm conductivity) adhesive available from AI Technology is screen printed onto the PVC sheet at a thickness of about 2 mils (about 0.05 mm
  • the substrates 402 with electronic devices 410 thereon are then dried or B-staged in an oven at about 60 C, and may be inspected and electrically tested, if desired. If the conductive adhesive is dried before placement of electronic device 410, substrate 402 and/or device 410 are/is heated to a temperature sufficient to melt-flow the conductive adhesive before device 410 is placed on substrate 402. A
  • this adhesive sheet 424 is of like size to that of which the plurality of substrates 402 are made, i.e. an 11-inch by 18-inch (about 28 mm by 46 mm) sheet for making a 3 by 8 array of 24 cards 400' with sufficient unused peripheral area of the sheet remaining for the placement of guide holes or other indexing and alignment indicia corresponding to those on the sheet of substrates 402 that facilitate placement and alignment of these two sheets. With proper indexing and sufficient precision of size, individual panels can be laminated to a web form for ease of subsequent die cutting and further processing.
  • the sheet of substrates 402 and the sheet of adhesive is laminated to substrate 402 at a temperature of about 75 C.
  • this adhesive sheet 424 is of like size to that of which the plurality of substrates 402 are made, i.e. an 11-inch by 18-inch (about 28 mm by 46 mm) sheet for making a 3 by 8 array of 24 cards 400' with sufficient unused peripheral area of the sheet remaining for the placement of guide holes or other indexing and
  • the combined sheet of laminated cards 400' are then cut by a suitable rotary die cutter into individual cards , e.g., 24 cards, 400' each having an electronic device 410 embedded therein.
  • cards 400, 400' of PET and other materials may be made by the foregoing method where PET sheets and suitable melt-flowable adhesives, such as types MB7100 from AI Technology, and temperatures consistent therewith, are employed therein.
  • suitable melt-flowable adhesives such as types MB7100 from AI Technology, and temperatures consistent therewith.
  • electronic devices 410 may be attached with conductive adhesives at a melt-flow temperature of either 120 C or 200 C, such as types PSS8090 and PSS8150, respectively, as is convenient, because with the PET heated to about 120 C and the electronic device heated to about 200 C, the adhesive will melt flow and bond instantly without heating the PET appreciably above 120 C.
  • Lamination of the card thereafter requires a temperature in the range of about 60 - 120 C, and preferably about 80 C, depending on the particular melt-flowable adhesive employed, which does not disturb the connections attaching the electronic device embedded therein. If an optional adhesive underfill is desired between electronic device 410 and substrate 402, a flexible adhesive, such as types
  • thermosetting epoxy adhesives available from AI Technology, which cure at a temperature of less than about 80 C, is suitable. Where the size of the electronic device is small, conventional rigid adhesive underfill may be employed. It is noted that the arrangement of FIGURE 14 is particularly advantageous because no cavity is required to be machined or otherwise formed in the card blank to receive the electronic device therein. This not only saves time and reduces cost, but also simplifies processing, and in addition permits thin substrate 402 material, e.g., about 5 mils (about 0.127 mm) thick, to be employed with a relatively thicker adhesive layer 424, e.g., about 10 - 15 mils (about 0.25 - 0.38 mm) thick, to easily accommodate standard thickness electronic devices.
  • thin substrate 402 material e.g., about 5 mils (about 0.127 mm) thick
  • a relatively thicker adhesive layer 424 e.g., about 10 - 15 mils (about 0.25 - 0.38 mm) thick, to easily accommodate standard thickness electronic devices.
  • the melt flowable adhesive layer such as type MB7070 thermoplastic adhesive which flows at a low temperature of about 70 - 90 C, serves as the core of card 400' and flows around electronic device 410 to "form in place" the cavity therefor with precise size and location.
  • the melt flowable adhesive layer such as type MB7070 thermoplastic adhesive which flows at a low temperature of about 70 - 90 C
  • the foregoing method advantageously lends itself to being employed in a continuous process to produce a large number of cards having an electronic device embedded therein.
  • the material from which substrates 402 are made is provided as a long strip in roll form, i.e. on roll 510, as is the melt-flowable adhesive on roll 520 to be laminated therewith.
  • the conductive loops 404 and contacts 406 are roll printed onto the moving substrate strip 402 at printing station 512, the electronic devices 410 are placed thereon as substrate strip 402 moves past a pick-and-place equipment station 515, and the moving strip is dried as it passes through a drying oven station 518.
  • the prepared substrate strip 402 and the melt-flowable adhesive strip 424 420 are brought together, preferably after pre-heating, and roll laminated in a set of pinch rollers 535 heated to a suitable elevated temperature and spaced apart a fixed distance that is the final card thickness, to form a strip of completed cards.
  • panels having suitable sprocket holes may be butted together end-to-end and driven by a sprocket drive so as to be driven together with strips of adhesives.
  • the individual cards 400 are cut from the strip by a suitable rotary die cutter or other cutter 540.
  • FIGURE 17 may be employed with a roll 530 providing a strip 420 of release liner 420 which is interposed between adhesive 424 and pinch rollers 535 when substrate 402 is laminated with a strip of adhesive 424 by heated pinch rollers 535 so that adhesive 424 does not adhere to rollers 535.
  • Suitable pick-and-place equipment that is employed in the method described herein and in conventional surface mount technology is widely available commercially and typically has a placement inaccuracy of about 0.12 mm (about 5 mils) or less. Suitable pick-and-place equipment is commercially available from
  • Mydata Automation located in Peabody, Massachusetts, from Universal Instrument located in Binghamton, New York, from Zevatech Inc. located in Morrisville, North Carolina, and from Manncorp, and can place components onto substrates with a positional inaccuracy of one one-thousandth of an inch (about 25 ⁇ m) or less and at a rate greater than one component per second.
  • the contact pads on the substrates and those on the electronic devices are preferably passivated with an oxidation-resistant conductive material to further their making low resistance and reliable electrical connections.
  • copper contacts may be tinned with solder or plated, as are aluminum and other semiconductor contacts, or otherwise coated with layers of nickel, gold, nickel-gold, palladium, nickel-palladium, platinum or other precious metal, and combinations and alloys thereof.
  • preferred adhesives are thermoplastic and thermosetting adhesives that are "flexible" when cured, i.e. molecularly flexible.
  • Molecularly flexible adhesives have a modulus of elasticity that is less than about 500,000 psi (about 35,000 kg/cm 2 ) over most of the range of temperatures that the bonded electronic device is specified to operate over.
  • Suitable conductive adhesives include types PSS8090 and PSS8150 thermosetting paste adhesives which are melt-flow bondable at temperatures of about 120 C and 200 C, respectively.
  • Type PSS8090 may be melt-flow bonded at a lower temperature, such as 100 C, if a higher pressure is utilized, as is the case for type PSS8150 as well. If it is desired to employ an adhesive underfill between the electronic device and the substrate, an insulating adhesive that will be drawn under the electronic device when dispensed and having a modulus of elasticity no greater than that of the conductive adhesive utilized for the conductive electrical connections should be employed.
  • type MEE7650 flexible insulating thermosetting epoxy adhesive which has a modulus of elasticity of about 10,000 psi (about 700 kg/cm 2 ), is suitable for use with types PSS8090 and PSS8150 conductive adhesives, as is type MEE7650-5 which is more flexible.
  • Attachment of wireless articles according to the invention to objects to be identified or tracked may be by a layer of adhesive or by an adhesive that is the substrate of the article.
  • One suitable thermoplastic adhesive that melts and bonds instantly when pressed against PVC under a pressure of about 5 psi (about 0.35 kg/cm 2 ) at a temperature of 70 C is type MB7060 adhesive which is available commercially in sheet form.
  • an adhesive that bonds at a temperature below 120 C is preferred.
  • Suitable thermoplastic adhesives that melt and bond instantly when pressed against PET under a pressure of about 5 psi (about 0.35 kg/cm 2 ) include type MB7060 which bonds at a temperature of about 65 - 75 C, type MB7070 which bonds at a temperature of about 70 - 90 C, and type MB7100 which bonds at a temperature of about 110 C, all of which are commercially available in sheet form.
  • Type MB7060 may be bonded at a lower temperature, such as 60 C if a higher pressure is utilized, as is the case with types MB7070 and MB 7100 as well.
  • an epoxy adhesive such as type ESP7450-SC thermosetting epoxy adhesive available from AI Technology, may be employed.
  • Type ESP7450-SC has a high bond strength up to temperatures of about 125 - 150 C, yet is flowable (under a pressure of about 5 psi (about 0.35 kg/cm 2 )) and curable in less than 30 minutes at a temperature of about 80 C.
  • Each of these adhesives has a die-shear strength greater than 500 - 1000 psi (35 - 70 kg/cm 2 ) at temperatures below about 45 C, although a bond strength of about 200 psi (about 14 kg/cm 2 ) at temperatures below about 45 C is sufficient for many applications.
  • these adhesives are insensitive to exposure to moisture as is desirable for cards to be used in tropical climates, or to track items being laundered or otherwise processed.
  • the substrate of a wireless article, card or tag includes sheet material, either as the substrate or as a layer in a substrate, such sheet material is typically formed of a suitable electronic substrate material, such as conventional printed wiring circuit board material (e.g., FR4 material), PVC, PET, acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS), polyimide, polyester, polyimide or other plastic material, and the like.
  • FR4 material conventional printed wiring circuit board material
  • PVC polyVC
  • PET acrylonitrile-butadiene-styrene
  • ABS acrylonitrile-butadiene-styrene
  • HIPS high-impact polystyrene
  • polyimide polyimide
  • polyester polyimide or other plastic material
  • cards and other articles according to the invention may be utilized in other applications and in special environments, such as remotely identifiable tagging devices used to keep track of, identify, and/or account for personnel, animals, tools, equipment, laundry, and other items, or as smart-card type credit cards and the like.
  • remotely identifiable tagging devices used to keep track of, identify, and/or account for personnel, animals, tools, equipment, laundry, and other items, or as smart-card type credit cards and the like.
  • the articles described in U.S. Patent Applications Number 09/411,849 entitled “Wireless Article Including a Plural-Turn Loop Antenna” and Number 09/412,058, entitled “Article having an Embedded Electronic Device, And Method For Making Same,” both filed by Kevin K-T Chung on October 4, 1999, each of which applications is hereby incorporated herein by reference it its entirety, may be employed.
  • the cards and the electronic devices therein may be exposed to a totally different environment that requires the substrate to be of a material other than those described above in relation to typical applications.
  • the substrate is selected to withstand the higher temperature and the chemical environment, and so may be polyimide film, such as Kapton ® film, or other high temperature thermoplastics and thermoset materials.
  • the attached semiconductor die may be encapsulated with a resin that exhibits satisfactory resistance to the expected chemicals and solvents to which the card will be exposed, such as type MEE7650.
  • a resin that exhibits satisfactory resistance to the expected chemicals and solvents to which the card will be exposed.
  • Different layering and thicknesses of adhesives may also be utilized.
  • types ESP7450-SC or TP7205-E pressure sensitive adhesives may be pre-applied as an outer layer of an article and may subsequently be utilized to bond the article onto the object that the article is to identify.
  • the foregoing adhesives are also commercially available from AI Technology.
  • loop antenna pattern and other features may be deposited by hot-stamping, screening, stenciling and/or masking as described, or other methods of application such as printing, ink-jet printing, preform lamination and the like may be used.
  • it is likewise suitable to employ flexible or rigid electrically- conductive adhesives and flexible or rigid insulating adhesives, in addition to the preferred conductive and insulating adhesives described herein.
  • the electronic devices may be single or plural semiconductor devices such as integrated circuits, memories, microprocessors and the like, and can include networks of conductors and/or diodes for providing continuity and the lack thereof between particular contacts, or networks of resistors and/or capacitors and/or inductors, as may be necessary or convenient in any particular application.
  • Such devices are attached to substrates by solder or conductive adhesive connections, and suitable adhesive underfill materials may also be employed to fill the thin space between the electronic device and the substrate.
  • suitable underfill is a flexible insulating adhesive having a modulus of elasticity that is no greater than that of the flexible conductive adhesive.
  • Adhesive underfill may be applied as a preform or by capillary action, screening, stenciling, masking, ink-jet printing or other suitable method.
  • conventional rigid adhesive underfill may be employed.
  • contact-less cards as described herein may employ etched metal or wire conductive loops on the card substrate to serve as the RF antenna therefor. While not as advantageous as certain embodiments, wire loops may facilitate a multiple turn antenna having higher gain. A loop antenna having a small number of turns may be employed where the electronic device has spaced apart contacts that bridge over or straddle the intermediate turns of the antenna.
  • the antenna contacts to which the electronic devices electrically connect may be deposited onto the substrate or may be deposited onto the electronic devices, either at the individual semiconductor chip level or at the semiconductor wafer level, to make connect the loop antenna when the electronic device is attached to the substrate.

Abstract

A wireless article (10), such as an identification tag or badge, including an electronic device (40) mounted on a substrate (20) and connected a loop antenna (30) for receiving and/or transmitting radio frequency signals. Electrically conductive material (50) disposed on the substrate or in holes (22, 24) through the substrate of the wireless device connect the antenna terminals (32, 34) to the electronic device contacts (44, 42). The structure and materials of the wireless article may be rugged and strong to provide a tamper-resistant article, and/or may include one or more weakened or frangible portions that easily break to provide a tamper-destruct article. The wireless article (10) may be arranged to resist heat, moisture and/or solvents, to function in severe environments such as laundering and industrial processes.

Description

TAMPER-RESISTANT WIRELESS ARTICLE INCLUDING AN ANTENNA
This Application claims the benefit of U.S Provisional Application Seπal Number 60/169,790 filed December 9, 1999, of U.S Provisional Application Seπal Number 60/175,558 filed January 12, 2000, and of U.S. Provisional Application Seπal Number 60/212,401 filed June 19, 2000, and is a continuation-in-part of U.S Patent Applications Numbers 09/411,849 and 09/412,058, both filed October 4, 1999.
The present invention relates to a wireless article and, in particular, to a wireless article including an antenna.
Wireless articles, such as tags, identification badges, smart cards and the like, are in wireless communication with a base unit or reader via a radio-frequency (RF) communication link RF transmissions transmitted by the base unit may be received by an antenna on the wireless article or RF transmissions transmitted by the wireless article by an antenna thereon may be received by the base unit. Or RF transmissions by each of the wireless article and the base unit may be received by the other one thereof In each case, the RF signals either received or transmitted by the wireless article are received or transmitted by an antenna thereon. Because wireless articles are usually desired to be small in size, the antenna thereon must also be small in size. For a loop-type antenna, the sensitivity of the antenna to small amplitude RF signals and the amplitude of the RF signals transmitted by the antenna are a direct function of the area enclosed by the antenna loop and the number of turns of the conductor forming the loop For a small tag or badge, the size thereof limits the area that an antenna loop can enclose, thereby limiting the RF performance of the antenna Typically, RF identification tags operate in the frequency range of 100 KHz to 3 GHz, or higher Wireless articles, such as RF tags, are often used for purposes of secuπty or other purposes where it is desirable that a rugged wireless article be permanently attached to an object and that any attempt to remove, alter or otherwise tamper with the wireless article, or attach the wireless article to a substitute object, be evident. The need for such security is particularly acute when the value of the objects to be controlled or mventoπed is high. Conventional RF tags have been ruggedized and/or fortified so as to be physically resistant to tampeπng or to survive m hostile environments, such as laundeπng or mdustπal processing, or in repeated usage, however, the conventional approach has typically been to add physical reinforcement, thereby adding further undesirable complexity and cost to the conventional tag. Accordingly, there is a need for a wireless article having a structure that readily evidences and/or resists tampeπng and yet is relatively simple and relatively inexpensive to make
To this end, the tamper-resistant article of the present invention compπses a substrate including at least one layer of a strong dielectric adhesive having an exposed surface adapted for attaching said substrate to an object. A pattern of electπcally- conductive mateπal including an elongated electπcal conductor is on one surface of the substrate and has at least one electπcal contact. At least one electronic device is attached to the substrate by a strong adhesive and has at least one contact electπcally connected to the contact of the pattern of electπcally-conductive adhesive, whereby at least one of the strong dielectπc adhesive of the substrate and the strong adhesive attaching the electronic device render the article resistant to tampeπng.
According to another aspect of the invention, a tamper-destruct article compπses a substrate including at least one layer of a dielectπc adhesive having an exposed surface adapted for attaching the substrate to an object. A pattern of electπcally-conductive mateπal including an elongated electπcal conductor is on one surface of the substrate and has at least one electπcal contact. At least one electronic device is attached to the substrate by an adhesive and has at least one contact electπcally connected to the contact of the pattern of electπcally-conductive adhesive, wherein at least one of the pattern of electπcally conductive mateπal and the electrical connection of the contact of the electronic device to the substrate includes at least one frangible region. BRIEF DESCRIPTION OF THE DRAWING
The detailed descπption of the preferred embodiments of the present invention will be more easily and better understood when read in conjunction with the FIGURES of the Drawing which include FIGURE 1 is a plan view schematic diagram of one surface of an exemplary embodiment of a substrate useful in an article according to the present invention,
FIGURE 2 is a plan view of the article of FIGURE 1 with an electronic device attached thereto,
FIGURES 3A and 3B are side cross-sectional view schematic diagrams of part of the article of FIGURE 2 showing the connection of the electronic device thereto,
FIGURES 4 and 5 are plan view schematic diagrams of respective opposing surfaces of an exemplary embodiment of a substrate useful in an article according to the present invention,
FIGURE 6 is a sectional view schematic diagram of an article including the exemplary substrate of FIGURES 4 and 5 having an electronic device attached thereto,
FIGURES 7 and 8 are plan view schematic diagrams of opposing surfaces of an alternative exemplary embodiment of an article according to the present invention,
FIGURES 9 and 10 are side view schematic diagrams of exemplary articles according to the invention,
FIGURES 11A and 11B are side and plan view schematic diagrams, respectively, of another exemplary article according to the invention,
FIGURE 12 is a plan view schematic diagram of an alternative exemplary embodiment of a contact-less card according to the present invention, FIGURES 13 and 14 are cross-sectional side view schematic diagrams of the article of FIGURE 12 and an alternative embodiment thereof,
FIGURES 15 and 16 are plan view schematic diagrams of an alternative exemplary substrate for a contact-less card according to the present invention, and
FIGURE 17 is a schematic diagram of a manufactuπng arrangement useful with the foregoing electronic substrates and cards
In the Drawing, where an element or feature is shown in more than one drawmg figure, the same alphanumeric designation may be used to designate such element or feature in each figure, and where a closely related or modified element is shown in a figure, the same alphanumeπcal designation pπmed may be used to designate the modified element or feature. Similarly, similar elements or features may be designated by like alphanumeπc designations in different figures of the
Drawing and with similar nomenclature in the specification, but in the Drawing are preceded by digits unique to the embodiment descπbed. For example, a particular element may be designated as "xx" m one figure, by "lxx" in another figure, by "2xx" in another figure, and so on. As is typical, the figures are not to scale and may be partially enlarged or reduced for purposes of illustration.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The articles descπbed herein, in particular, wireless articles having electronic circuitry for communicating with an external device such as a reader or interrogator, are desired to be resistant to tampeπng and attempts to tamper with the article and/or the electronic circuitry thereof. Such articles may be descπbed as being "tamper- destruct" and or "tamper-resistant" articles. A "tamper-destruct" article becomes disabled, non-functional and/or inoperative if one attempts to tamper with or change the article. Typically, tamper destruct properties are provided by one or more elements of the wireless article being made so as to be frangible and tend to break easily if one attempts to alter the wireless article, to remove it from the object to which it is attached or is otherwise tampers with the article. Typically, a thm or narrow portion, e.g., less than about 25 μm (about 1 mil) m either thickness or width or both, or a relatively-weak bonding, may be provided so as to be fragile and not withstand an attempt to remove the article from the object to which it is attached, thereby providing a tamper-destruct property. Wireless articles may also be "tamper- resistant" in that they are physically strong so as to be capable to withstand severe physical handling and/or environments, and/or so as to not be removable from an object to which they are attached without physically damaging or destroying the wireless article and/or the object As a result, tampeπng with a tamper-destruct or a tamper-resistant article produces evidence thereof that is apparent to an observer. Tamper resistant articles are typically also tamper destruct articles, but need not be.
Advantageously, the tamper resistant and/or tamper destruct properties are provided by the structure of the wireless article according to the invention, and the elements thereof, without the addition of special structure or extra processing steps which would undesirably increase the complexity and/or the cost of the article. Further, the structure and mateπals providing a frangible tamper resistant feature may also be utilized to produce a wireless article that is capable of withstanding exposure to harsh environments, such as those encountered in laundry and cleaning processes as well as in industrial processes
In FIGURE 1, substrate 20 for a wireless article 10 is a generally planar sheet of an insulating mateπal A loop antenna 30 is formed of an elongated conductor having a plurality of loops or turns 36, 37, 38 generally in a spiral pattern on one surface of substrate 20. The ends 32, 34 of loop antenna 30 located at the respective ends of outermost loop or turn 36 and innermost loop or turn 38, respectively, define antenna terminals 32, 34. Illustrated along surface substrate 20, an electronic device 40, such as a semiconductor integrated circuit, a hybrid circuit or other suitable electronic device, has two spaced-apart contacts 42. 44.
Usually, the spacing between the two contacts 42, 44 of electronic device 40 are a given dimension that is determined by the supplier of the electronic device 40 and so is not easily changed. As a result, the spacing between contacts 42, 44 of electronic device 40 defines the spacing of the contacts on substrate 20 to which electronic device 40 connects, i.e. the desired spacing between holes 22, 24 of substrate 20 Regarding the exemplary substrate 20 of FIGURE 1, the width of and the number of turns of loop antenna 30 are sufficiently large so that electronic device
40 cannot be attached to substrate 20 on the same surface as loop antenna 30 because of the likelihood of an electπcal short circuit being formed. Such short may occur between adjacent loops, such as loops 36-37 or loops 37-38 of loop antenna 30 by the spreading or flowing of the electπcally-conductive mateπal which would be utilized to make electπcal connection between antenna terminals 32, 34 and electronic device contacts 42, 44 when electronic device 40 is attached to the same surface of substrate 20 as is antenna 30 Additionally, other parts of electronic device 40 could come into unwanted electπcal connection or coupling to one or more of the turns 36, 37, 38, for example, one or more of the intermediate turns 37, of antenna 30.
To avoid the possibility of such unwanted short circuits, substrate 20 has two vias or holes 32, 34 spaced apart a distance corresponding substantially to the spacing between antenna terminals 32, 34. Loop antenna 30 and substrate 20 are positioned so that the two terminals 32, 34 of loop antenna 30 overlie the two vias or holes 22, 24 through substrate 20, whereby electπcal contact may be made with antenna terminals 32, 34 from the other surface of substrate 20 through holes 22, 24, respectively. It is noted that antenna 30 is preferably, but need not be, a generally spiral conductor pattern located close to the edges of substrate 20 so as to increase the area encompassed thereby, and may be of a circular spiral, oval or elliptical spiral, square or rectangular spiral, or other convenient pattern, including a free-form shape.
To provide tamper-destruct features for substrate 20, loop antenna 30 may include one or more "weakened" portions at which it is easily broken or fractured if substrate 20 is tampered with. Such weakened portions may take the form of notches 31 provided by notching one or both edges of the conductor loops 36, 37, 38 or the thickness thereof. Notches 31 may include, for example, one or more directly opposing "V"-shaped notches, offset opposing "V"-shaped notches or a single "V"- shaped notch, or may include one or more narrowed lengths of conductor 36, 37, and/or 38, whether directly opposing or offset, as is desired. Alternatively or additionally, antenna 30 may be weakened by employing a very thin layer of metal foil or deposited metal to form antenna 30. Typically, the thicknesses of such thin metal mateπals is less than 25 μm (about 1 mil), and may preferably be in the range of about 2.5 to 12.5 μm (about 0.1 to 0.5 mils). Thus, antenna 30 is frangible and tends to break easily if article 10 is attempted to be removed from the object to which it is attached or is otherwise tampered with.
To assemble wireless article 10 of FIGURE 2, antenna 30 is formed on or attached to a first surface of substrate 20, the holes 22, 24 of substrate 20 are filled with an electπcally-conductive material that will form the electrical connections between antenna terminals 32, 34 and device contacts 42, 44, respectively, and the electronic device 40 (shown in phantom) is attached to the opposing surface of substrate 20 The resulting wireless article 10, a portion of which is shown in cross- section in FIGURE 3A, includes substrate 20 having holes 22, 24 therein filled with electπcally-conductive mateπal 50 which extends therefrom to form conductive features or "bumps" 52, 54 Conductive mateπal 50 also provides electπcal connection to terminals 32, 34 of antenna 30 Contacts 42, 44 of electronic device 40 connect to conductive bumps 52, 54 and may be pressed into place when the mateπal of bumps 52, 54 is an electπcally-conductive adhesive Connection of contacts 42, 44 to bumps 52, 54 of electrically-conductive adhesive may be made by pressing electronic device 40 in place against substrate 20 when electπcally-conductive adhesive of bumps 52, 54 is wet or may be made by so pressing device 40 into place with appropriate heating to provide melt flow bonding after adhesive bumps 52, 54 are dπed or B-staged Alternatively, electronic device 40 may be mounted on the same surface of substrate 20 as is antenna 30 with contacts 42, 44 directly connected to antenna terminals 32, 43, respectively, in which case, holes 52, 54 are unnecessary
The embodiment of FIGURES 1 and 2 is particularly advantageous where the number of turns of antenna 30 is sufficiently large that the distance between antenna contacts 32 and 34 is greater than the distance between contacts 42, 44 of electronic device 40 As shown in the exemplary embodiment of FIGURE 3B, for example, conductive mateπal 50 is deposited to fill holes 22, 24 and to form conductive stπps
(I e conductors) 52, 54 extending from the electπcally-conductive mateπal 50 in widely spaced holes 22, 24 to locations spaced apart the same distance as are contacts 42, 44 of electronic device 40 Contacts 42, 44 of electronic device 40 then connect to the ends of conductive stπps 52, 54 and may be pressed into place when the mateπal of bumps 52, 54 is an electπcally-conductive adhesive Connection of contacts 42, 44 to conductors 52, 54 of electπcally-conductive adhesive may be made by pressing electronic device 40 in place against substrate 20 when the electπcally-conductive adhesive of conductive stπps 52, 52 is wet or may be made by so pressing device 40 into place with appropπate heating to provide melt flow bonding after adhesive stπps 52, 54 are dred or B-staged
It is noted that the portion of conductors 50 filling holes 22, 24 may be formed of a vaπety of materials, such as by building up metal, such as by plating copper, beryllium copper, brass and other copper alloys, or nickel or aluminum or other suitable metal, to fill holes 22, 24, or may be made by depositing electrically- conductive adhesive to fill holes 22, 24, such as by screen pπntmg, stenciling and the like. It is further noted that one or more additional deposits of electrically-conductive adhesive onto substrate 20 may be utilized if it is desired to increase the height of conductors and/or bumps 52 from what is obtained with a single deposition of adhesive Further, electπcally-conductive adhesive bumps may be deposited on the contacts 42, 44 of electronic device 40 with like result. In addition, a layer of metal, such as nickel, gold, nickel-gold and the like may be deposited, such as by plating, onto conductors 50, 52, 54 formed of electπcally-conductive adhesive. This plated metal layer, in addition to serving to resist oxidation of the conductors, increases the height thereof and/or otherwise facilitates connection of the contacts of electronic devices 40 to the plated contacts 50, 52, 54 with solder, e.g., with solder bumps as in the mounting of conventional flip-chip components.
This embodiment is substantially different from conventional plated-through holes as in conventional printed circuit wiπng boards, whether of single layer or multi-layer type, and whether of πgid or flexible type, wherein plating is deposited on the mteπor surface of the holes to make electπcal contact with the thm edges of metal conductors that are on vaπous ones of the surfaces and layers thereof. Here, on the other hand, conductive mateπal is built up to fill the hole and contacts the broad surface of the conductors on the surface of the substrate, either through physical contact or by being part thereof as in the case of deposited conductive adhesive.
Wireless article 10 is fabπcated as follows. A substrate 20, preferably of sheet poly-vmyl-chloπde (PVC), polyimide, poly-ethylene terephthallate (PET), acrynitπle- butadiene-styrene (ABS), polybutylene terephthallate, or polyester such as polyester terephthallate, polymer blends, paper film, dπed or B-staged insulating adhesive or other suitable substrate mateπal, is provided, and holes 22, 24 are made therein, such as by die cutting, punching, drilling, mechanical drilling, laser dπlhng or cutting, photoresist and etching, or other suitable method. The sheet is typically about 0.75 mm thick (about 0.03 inch thick), but may range between 0.05 and 1.0 mm thick (about 0.002 to 0.040 inch thick, i.e. 2 - 40 mils). Preferably, a sheet of the substrate mateπal that is large enough to be cut into a plurality of substrates is provided, such as a 280 mm by 280 mm (about 11 inch by 11 inch) sheet on which a 3 by 4 array of 12 substrates, each about 83.5 mm by 132.9 mm (about 2.125 inch by 3.375 inch), may be formed. Preferably, the sheet is processed to contemporaneously form an array of wireless articles 10 thereon before it is excised or cut to separate the individual wireless articles 10
Alternatively, substrate 20 can be formed by screen pπnting or stencil pπntmg a dielectπc adhesive layer having holes 22, 24 therein defined by the pattern of the screen or stencil utilized. This method is preferred where the loops 36, 37, 38 of antenna 30 are photo-etched from a sheet of metal foil laminated to such dielectπc adhesive layer substrate 20, such as by photo-etching as utilized in the making of conventional pπnted wiπng circuit boards.
A stencil, screen or mask defining the pattern of an array of antenna 30 corresponding to the array of substrates is positioned with the sheet of substrate material and an electπcally conductive adhesive 50 is deposited on a first surface thereof in the pattern of the array of antenna 30 Typically, the substrate 20 is between about 0.25 mm and 1 mm thick (about 10 - 40 mils thick), and the conductors 36, 37, 38 forming antenna 30 are about 250 m (about 10 mils) wide and are within the range of about 25 m to 125 m thick (about 1.0 to 5 mils thick). In most cases, conductors 36, 37, 38 of antenna 30 are about 50 - 100 m thick (about 2 - 4 mils thick) when wet and about 25 - 75 m thick (about 1 - 3 mils thick) after drying or B- stagmg. The conductive adhesive 50 may completely or partially fill holes 22, 24 in substrates 20. Where holes 22, 24 are larger than about 0.1 mm (about 4 mils) diameter, it is relatively easy to pass sufficient conductive adhesive 50 through the corresponding holes in the stencil, screen or mask to fill holes 22, 24 of substrate 20 Suitable conductive adhesives 50 include, for example, type PSS8150 thermosettmg conductive adhesive and type ESS8450 flexible conductive adhesive, both of which are filled with silver particles and are available from AI Technology, Inc. located in Pπnceton, New Jersey. The deposited conductive adhesive 50 is dπed or B-staged by heating in an oven to about 60 C for about 60 minutes A second deposit of the same conductive adhesive 50 is made in like manner on the opposing surface of the sheet of substrate mateπal. A stencil, screen or mask defining the pattern of contact sets corresponding to the contacts 42, 44 of electronic device 40 and holes 22, 24 for the array of substrates is positioned with the sheet of substrate mateπal and the electπcally conductive adhesive 50 is deposited on the opposing surface thereof in the pattern of the array of contacts 42, 44. The electπcally conductive adhesive 50 deposited on this second surface of the array of substrates flows into holes 22, 24 to contact the like adhesive deposited of the first surface thereof to form antenna 30 and to form contacts 52, 54 to which contacts 42, 44 of electronic device 40 connect. The mateπals, application and processing of conductive adhesive 50 is like that utilized with respect to the first surface of the sheet of substrates.
Electronic devices 40 may be positioned to the sheet of substrates either when the adhesive 50 is still wet from being deposited or after adhesive 50 is dπed or B- staged. Preferably, electronic devices 40 are flip-chip semiconductor devices with plated or otherwise oxidation resistant contacts 42, 44 that are positioned onto substrates 20 by conventional pick-and-place or flip-chip assembly equipment. Where electronic devices 40 are placed when conductive adhesive 50 is still wet, the sheet of substrates 20 with electronic devices 40 attached thereon is cured to form a sheet of wireless articles 10 which is then excised or cut apart, as by die cutting, laser cutting or the like, into the individual wireless articles 10. Curing of type ESS8450 thermosetting adhesive is performed by heating the wireless article in an oven to a temperature above 100 C for about 30 minutes or more. For thermoplastic adhesives such as type PSS8150, attachment may be completed by drying out the solvent from the adhesive, e.g., by heating to about 60 C for about 60 minutes.
Where electronic device 40 bπdges one or more turns 37 of antenna 30 or other conductors formed of electπcally-conductive adhesive, and particularly where the width or spacing of such conductors is small, i.e. less than about 0.25 - 0.5 mm (about 10 - 20 mils), the deposited conductive adhesive is preferably dπed or B-staged before attachment of electronic device 40. A second deposition of the same electπcally-conductive adhesive is made to deposit a second layer of adhesive on bumps 52, 54 to which electronic device 40 may be attached while the second layer of adhesive is wet or after drying or B-staging. However, where the conductor width or spacing is small, it is preferred that attachment of electronic device 40 be after the second deposition of conductive adhesive on bumps 52, 54 has been dπed or B- staged.
Optionally, but in many applications, preferably, an insulating adhesive underfill in liquid form may be applied along the edges of electronic device 40 from where it flows by capillary action to substantially fill the remaining volume between electronic device 40 and substrate 20 that is not filled by conductive adhesive 50. Such adhesive underfill provides additional mechanical strength to the attachment of electronic device 40 to substrate 20 and resistance to moisture and other potential contaminants. Where the electrically-conductive adhesive 50 is a flexible adhesive such as type PSS8150, as is desirable where the substrate 20 is somewhat flexible, a flexible adhesive underfill, such as types MEE7650 and MEE7650-5 flexible epoxy adhesive or type MEE7660 high-strength epoxy adhesive, also available from AI
Technology, is preferably utilized. Alternatively to underfill of electronic device 40, a spot or drop of adhesive may be deposited onto substrate 20 in an area to be covered by electronic device 40, but not including any electπcal contacts of substrate 20 or device 40, for mechanical attachment between substrate 20 and device 40. If electronic device 40 has an insulating, e.g., passivated, top surface, then the drop of adhesive could be either electrically conductive or insulating, as desired, however, if electπcal contact to that surface of device 40 would adversely affect its operation or performance, then insulating adhesive should be employed.
Also optionally, a protective coating may be applied to wireless article 10 to protect against mechanical damage and environmental conditions, such as moisture, water, solvents, dirt and other mateπals. One suitable protective coating mateπal is the type MEE7650 flexible insulating adhesive that is also used for underfill of electronic device 40. In such case, the application of the underfill adhesive and of the overcoat adhesive may be accomplished in one operation. For example, where the over coating mateπal is applied in liquid form as by spraying or dipping, the insulating adhesive will flow under electronic device 40 to form the underfill adhesive thereunder contemporaneously with it forming the protective coating. The protective coating may also be sheets of dried or B-staged insulating adhesive laminated to one or both surfaces of wireless article 10. Where type ESP7450 flexible adhesive is laminated on substrate 20 to cover electronic device 40, underfill is not required between device 40 and substrate 20.
Flexibility of a mateπal is related to the degree of elongation that a mateπal exhibits before it fails. In general, flexible mateπals have a modulus of elasticity that is less than about 35,000 kg/m2 (about 500,000 psi) and are capable of >30% elongation without failure. Where substrate 20 has a given degree of flexibility, it is preferred that the flexible conductive adhesive mateπal that forms conductors 30, 50 and adhesive layer 58 thereon, for example, be at least as flexible as is substrate 20, i.e. exhibit at least the same or a greater percentage elongation pπor to failure
In an alternative embodiment of the making of wireless article 10, a dielectπc layer is deposited on a sheet of release lmer material to serve as substrate 20, such as by roll coating, screening stenciling, or other suitable method Where dielectπc layer
20 is formed by screening, stenciling, or other printing method, it is formed with holes 22, 24 therein for conductive adhesive 50. Otherwise, holes 22, 24 are formed in dielectric layer 20 after it is dπed or B-staged, such as by die cutting, laser dπlhng or other suitable method. After dielectπc layer 20 is dπed or B-staged, antenna 30 and conductive adhesive 50 are applied, electronic device 40 is attached and protective coating layers, if any, are applied, all as descπbed above. Alternatively, The pattern of loop antenna 30 may be formed of conductive adhesive deposited on a sheet of release liner with conductive adhesive bumps 52, 54 formed thereon at the terminals of antenna 30. The deposited conductive adhesive is then dπed or B-staged. Then dielectric layer 20 is applied directly over deposited antenna 30 and bumps 52, 54 to a thickness less than or equal to the height of bumps 52, 54, resulting in substrate 20 with antenna 30 and conductive bumps 52, 54 therein, ready for attachment of electronic device 40 thereto. Preferably, an array of wireless articles 10 are made contemporaneously by depositing an array of antennae 30, an array of substrates 20 in one layer, an array of conductive bumps 52, 54, and so forth, resulting in a panel of an array of wireless articles 10 that are then excised, such as by die cutting, rotary cuttmg, or other suitable method, into individual articles 10.
An alternative embodiment of wireless article 10 employs a metal foil loop antenna 30. A sheet of metal foil, such as a copper foil, an aluminum foil or a silver foil, is provided, typically between about 0.013 mm and 0.10 mm thick (about 0.5 to 4 mils thick). A layer of dielectπc mateπal 20 is applied thereto, such as by roll coating, screening or stenciling an insulating adhesive thereon, including holes formed at the locations at which antenna terminals 32, 24 are to be formed in the metal foil. The dielectric layer is preferably formed of an insulating adhesive, such as type ESP7450 thermosetting epoxy adhesive, type MB7100 thermoplastic adhesive or type CB7200-E thermosetting adhesive, each available from AI Technology, Inc. located in Pπnceton, New Jersey. Typically, substrate 20 has a dry thickness between about 0.05 mm and 0.5 mm (about 2 - 20 mils) when employed m an article compliant with an international standard for cards and tags with embedded integrated circuits, but may have a dry thickness between about 0.25 mm and 1 mm (about 10 - 40 mils) for other uses, and is B-staged and/or cured pπor to photo-etchmg of antenna 30 descπbed below. Conductive adhesive 50 is deposited to fill holes 22, 24 m substrate 20 and to provide contacts 52, 54 to which electronic device is to attach, as above, and is also cured prior to photo-etching of antenna 30.
Antenna 30 is made by photo-etching, i.e. by depositing a photoresist mateπal to the exposed surface of the metal foil, exposing and developing the photoresist material to define the pattern of antenna 30 and then etching away the unwanted metal foil mateπal to leave antenna 30 on substrate 20, in like manner to the etching of conventional pπnted wiπng circuit boards, for example. Suitable photoresist and photo-etchmg mateπals are widely available in liquid, paste and film form, such as from MacDermid Company located in Connecticut and from E.I duPont de Nemoirs
& Company located in Delaware Suitable insulating adhesives, such as AI Technology type ESP7450, when cured, withstand exposure to the chemicals and environments employed in the photo-etching processes. Preferably, an array of wireless articles 10 are made contemporaneously by depositing an array of substrates 20 in one layer, depositing an array of conductive bumps 52, 54, and etching an array of metal foil antennae 30. and so forth, resulting in a panel of an array of wireless articles 10 that are then excised into individual articles 10
Alternatively, instead of depositing conductive adhesive 50 into holes 22, 24 in the insulating adhesive substrate 20, a photoresist pattern may be employed to define locations for depositing conductive metal onto antenna 30, either before or after the metal foil is etched to form antenna 30. In particular, conductive metal is deposited onto antenna 30 not only on the exposed surface thereof adjacent the surface of substrate 20, but also onto antenna terminals 32, 34 accessible via holes 22, 24 to plate or otherwise build up a metal conductor to fill holes 22, 24 in substrate 20 If the plating mateπal is copper or other mateπal susceptible to oxidation or other degradation of conduction and adhesion properties, then a metallization or moisture resistant layer or layers of a non-oxidizing or precious metal, such as tin, nickel, silver, gold, palladium, platinum, nickel-gold, or nickel-palladium, or the like, should be applied over the built-up via conductors in holes 22, 24. The building up of such via conductors, which may be performed either before or after the metal layer is photo-etched to form the pattern of antenna 30, as is the plating thereof to facilitate solder bump attachment of the contacts of an electronic device thereto, is further descπbed in U.S. Patent Application Serial Number 09/412,052 (AI-TECH-13) entitled "Contact Module, As For a Smart Card, And Method For Making Same" filed by Kevin Kwong-Tai Chung on October 4, 1999, and which is hereby incorporated herein by reference in its entirety. Conductive adhesive contacts 52, 54 are thereafter deposited onto the filled via holes 52, 54 for connecting to contacts 42, 44 of electronic device 40 and attaching same to substrate 20. Conductive adhesive types PSS8090, CB8130, PSS8150, ESS8450, ME8456, ME8550-SMT or ME8650 and underfill insulating adhesive type MEE7650 or type MEE7660, all available from AI Technology, are preferred in this embodiment
Where electronic device 40 is on the surface of substrate 20 opposite to antenna 30, it is preferred to have the portion of the metal antenna 30 near holes 22, 24 to overlie holes 22, 24, i.e. that the metal trace be left completely or substantially intact, to ease or facilitate making of electπcal connection thereto, either directly or through holes 22, 24 Similarly, where antenna 30 is deposited of conductive adhesive, it is preferred to deposit the conductive adhesive to cover holes 22, 24 for the same reason.
The present invention is also advantageous for wireless articles having antennas with a greater number of turns than can or might be desired to be formed on one surface of a substrate FIGURES 4 and 5 are plan views of opposing surfaces of an exemplary embodiment of a substrate of an article having such greater number of turns. Antenna 30 thereof compπses antenna portion 30A on the one surface of substrate 20 in seπes with antenna portion 30B on the other surface thereof. Antenna portion 30A includes outermost turn 36A, innermost tum 38A, and intermediate turns 37A therebetween, and may be formed of a pattern of a thin metal foil as shown or of a pattern of deposited conductive adhesive, as descπbed above in relation to
FIGURES 1 - 3. The ends 34, 39 of antenna portion 30A are positioned over holes 24, 22, respectively, in substrate 20, and end 34 serves as one terminal of antenna 30
Antenna portion 30B includes outermost turn 36B, innermost turn 38B, and intermediate turns 37B therebetween, and is formed of a pattern of conductive adhesive deposited onto substrate 20, as descπbed above in relation to FIGURES 1 -
3. The depositing of conductive adhesive to form antenna portion 30B preferably also provides conductive material 50 substantially filling holes 22, 24 through substrate 20, although the filling of holes 22, 24 may be accomplished in a separate deposition As most easily seen in FIGURE 5 in conjunction with the sectional view of FIGURE 6, terminal 34 of antenna 30 is connected to conductive contact 54 by conductive mateπal 50 filling hole 24 through and deposited on substrate 20. Similarly, end 39 of outermost turn 36A of antenna portion 30A is connected to the end of outermost turn 36B of antenna portion 30B by conductive mateπal 50 filling hole 22 in substrate 20. The other end 34 of deposited antenna portion 30B serves as the second terminal 32 of antenna 30 at which is formed conductive adhesive contact 52. Conductive adhesive contacts 52, 54, which are spaced apart an appropπate distance for receiving the contacts 42, 44, respectively, of electronic device 40 for electπcally connecting antenna 30 to electronic device 40, are formed by the deposition forming antenna portion 30A and may be augmented in height by one or more additional depositions of conductive adhesive, as descπbed above. It is noted that each of antenna portions
30A, 30B of antenna 30 is preferably, but need not be, a generally spiral conductor pattern located close to the edges of substrate 20 so as to increase the area encompassed thereby, and may be of a circular spiral, oval or elliptical spiral, square or rectangular spiral, or other convenient pattern, including a free-form shape.
In order to increase the number of turns of antenna portions 30 A, 30B, the conductors can be narrowed where they are close to features, such as is shown in FIGURES 4 and 5 where turns 37A and 37B pass near hole 22, that restrict the space available for such conductors to pass through. These narrowed portions may provide the weakened easily-breakable portions 31 of antenna 30 that provide tamper destruct properties or additional weakened portions 31 A, 3 IB may be included in antenna portion 30A and 30B, respectively. The conductors of loops 36A, 36B, 37A and/or 37B, for example may be reduced from the typical width of about 0.5 -2 mm (about 20 - 40 mils) to about 0.125 mm (about 5 mil) conductors at a spacing of about 0.25 mm (about 10 mils). This is particularly helpful where the conductors 37B pass underneath electronic device 40 and the number of conductors, i.e. the number of turns of antenna 30, is restricted by the distance between contacts 42, 44 of electronic device 40. Where the width of conductors 37 or contacts 52, 54 are too small for deposition by conventional screen printing, the larger dimension features, such as the full width portions of conductors 37 A, 37B, may be deposited by mesh screen printing and the finer features, such as the narrowed portions of conductors 37A, may be deposited by stenciling, with sufficient overlap to provide reliable electrical connection.
For example, consider the dimensions (approximate) to pass eight conductors 37 of the dimensions given ( which may be reduced dimensioned of narrowed conductors) under a device 40 which has its contacts 42, 44 located close to diagonally opposite corners:
Figure imgf000017_0001
Antenna portions 30A, 30B, conductive material 50 and conductive strips 52, 54 may be deposited of any suitable electrically-conductive adhesive, such as type PSS8150 flexible electrically-conductive thermoplastic adhesive, or type CB8130, PS8090, ME8456, ME8550-SMT or ME8650, all available from AI Technology, which may serve as conductors 32, 36, 37, 38, 39, 50, 52, 54 as well as the contacts
52, 54 adhesive that attaches and electrically connects electronic device 40 to substrate 20. As previously described, it is preferred that the contacts of an etched or otherwise patterned metal loop 30A be coated or plated with a precious or other suitable metal to preserve the conductive and adhesion properties thereof, in addition, a suitable dielectric underfill may be employed to strengthen the attachment of electronic device 40 to substrate 20 as described above.
Articles having conductors, including articles having a plural-turn loop antenna, on both surfaces of a substrate may be formed by at least the two following methods. A substrate is provided of a conventional high-strength thermoplastic film material, such as an acrynitrile-butadiene-styrene (ABS), polyester, polyimide, polyphynylene sulfide, polysulfone, polyether sulfone, or other high-temperature resin or other suitable material. Usually, processing a sheet of substrate material of size sufficient to form an array of substrates 20 is preferred over processing substrates 20 individually, but either is acceptable. An about 25 mm by 50 mm (about 10 inch by 20 inch) or larger sheet is convenient for screen printing deposition of adhesive and is conveniently diced or cut into individual substrates, such as by rotary dicing. A pattern of holes or vias 22, 24 are cut in the substrates 20 and may be of sufficient size, e.g., about 1 mm (about 40 mils) or larger (which is comparable to the 1 mm width commonly utilized for antenna 30 conductors), as can be readily cut or punched out with suitable conventional tools, such as punches, drills and dies. Commonly available electrically-conductive inks and adhesives may then be deposited, such as by screen printing or stenciling, onto both surfaces of the sheet of substrates 20 to cover and fill holes 22, 24 as well as deposit the plural turn loop patterns of antenna portions 30A, 30B and antenna 30. After one surface of the substrate or the sheet of substrates is printed with its pattern (or geometric pattern) of conductive adhesive, the substrate or sheet is heated to dry, B-stage or cure the conductive adhesive before the other surface thereof is printed with a related pattern (or geometric pattern) of the same conductive adhesive. The printed conductive adhesive patterns on the two surfaces of the substrate or sheet are electrically connected by the conductive adhesive filling holes 22, 24, and provide suitable contact bumps or strips 52, 54 corresponding to the contacts of an electronic device 40 that provide the input and output (I/O) connections thereto. Electronic device 40 is attached to substrate 20 either while the conductive adhesive of contacts 52, 54 is wet or after it is dry or B-staged and heated to a melt-flow condition, as described above. Electrically-conductive adhesives types PSS8090, CB8130, PSS8150, ESS8450, ME8456, ME8550-SMT and ME8650 available from AI Technology are suitable for screening and/or stenciling to produce the described conductive patterns.
Alternatively, antenna portion 30A on one surface of the substrate 20 may be formed of a stamped or etched metal foil. A substrate 20 preferably of a sheet of a laminatable B-staged epoxy or other suitable laminatable structural adhesive substrate material, typically having a thickness of about 25 - 250 m (about 1 - 10 mils) is provided, again preferably in a sheet of sufficient size to form an array of substrates 20. Preferably the sheet of substrate material is formed with a pattern of holes or vias 22, 24 therein, but holes 22, 24 may be cut with suitable conventional tools. The sheet of substrate 20 material is laminated with a sheet of a thin metal foil, for example, a thin metal foil of about 2.5 - 12.5 m (about 0.1 - 0.5 mils) thickness, such as by heat-stamped transfer of a copper, aluminum or silver foil. Alternatively, a metal foil of about 25 - 125 m (about 1 - 5 mils) thickness is laminated to the substrate 20 and is then patterned by photo-etching to form antenna 30, or antenna portion 30A using conventional photo-etching, with the ends thereof in place over and either partially or completely covering holes 22, 24. The material of substrate 20 is a material that is, when B-staged or cured, as the case may be, not adversely affected by such processing as the photo-etching and plating of the metal foil. At least the portion of the remaining metal foil at holes 22, 24 is spot plated or coated with a precious or other metal, such as silver, nickel, nickel-gold, nickel palladium, to preserve its conductivity and adhesion against degradation by oxidation, for example. An electrically- conductive ink adhesive is then printed on the second surface of the sheet of substrate material to form the pattern of antenna portion 30B, contacts 52, 54 and other conductive features thereon, as described above. Holes 22, 24 may be filled with the deposited conductive adhesive or the metal foil may be built up by plating metal thereon to fill or partially fill holes 22, 24 before the spot plating or coating of a precious or other metal thereon and deposition of the conductive adhesive, to complete a conductive connection from antenna 30, 30A to the second surface of the sheet of substrates, as described above. Electronic device 40 is attached to substrate 20 either while the conductive adhesive of contacts 52, 54 is wet or after it is dry or B- staged and heated to a melt-flow condition, as described above. Insulating thermosetting epoxy adhesive types MB7100, CB7200-E, LESP7450, ESP7450 and
ME7850 are suitable for the substrate 20 material, either directly in liquid or paste form or in the form of a laminatable B-staged sheet, and electrically-conductive adhesives types PSS8090, CB8130, PSS8150, ESS8450, ME8456, ME8550-SMT and ME8650 are suitable for screening and/or stenciling to produce the described conductive patterns, which adhesives are available from AI Technology.
Optionally, and for articles likely to encounter moisture and other potentially detrimental environments, an article according to the present invention may be covered with a layer of protective material. For example, as shown in FIGURE 6, a layer 56 of an insulating adhesive may be applied to one surface of substrate to cover and protect antenna portion 30A and/or a layer 58 of an insulating adhesive may be applied to the other surface of substrate to cover and protect antenna portion 30B and electronic device 40. Layers 56, 58 may be applied by roll coating, screening, laminating or other suitable method, and may be covered by a layer of ABS, PVC, PET or other material, preferably a material similar to the material of substrate 20. Suitable insulating adhesives include, for example, insulating thermoplastic adhesives such as types MB7100, TP7090 and MB7100, and insulating thermosetting adhesives such as types CB-7200-E, MEE7650 and ESP7450-SC, all available from AI Technology.
FIGURES 7 and 8 are plan views of opposing surfaces of an alternative exemplary embodiment of a wireless article 100 according to the present invention that includes, in addition to a plural turn antenna 130 for wireless communication with an external card reader by electromagnetic waves, a pattern 110 of contacts 112 located in a predetermined location on substrate 120 for making physical electrical connection to the contacts of an external card reader. The pattern 110 of metal contacts 112 are formed on one surface of substrate 120 which may be of any of the aforementioned substrate materials, but which is preferably a sheet of insulating adhesive such as type MB7100 thermoplastic or type, CB7200-E, ESP7250 or ESP7450 thermosetting insulating epoxy adhesive available from AI Technology. Contacts 112 are preferably of hot stamped thin copper, aluminum or silver foil, or of laminated copper applied to substrate 120 and photo-etched into pattern 110, and plated with one or more layers of protective metal, such as nickel and gold layers or nickel and palladium layers, all as described above. Substrate 120 has at least two holes 122, 124 therethrough at which are located the ends or terminals 132, 134 of plural-turn antenna 130 formed on the same surface of substrate as is pattern 110 of contacts 112, and has an additional hole (not visible in FIGURE 7) located beneath each of contacts 112 for making electrical connection thereto. Preferably, plural-turn antenna 130 is located towards the edges of substrate to the extent practicable in view of the required predetermined position of contact pattern 110. Antenna 130 may be formed of hot stamped thin metal foil or of photo-etched metal in like manner to contacts 112 or may be deposited electrically conductive material, such as plated copper, aluminum or silver metal or an electrically-conductive adhesive, for example, types CB8130 PSS8090, PSS8150, ME8456, ME8550-SMT and ME8650 adhesives available from AI Technology, all as described above.
A pattern of conductors 152, 154, 156, 158 is formed on the other surface of substrate 120 by hot-stamping a copper, aluminum, silver or other metal foil thereon or depositing a pattern of electrically conductive material, such as copper, aluminum, silver, gold, and/or an electrically-conductive adhesive, for example, types CB8130 PSS8090, PSS8150, ME8456, ME8550-SMT and ME8650 adhesives available from AI Technology, all as described above. In depositing the electrically-conductive material onto substrate 120, electrically-conductive material fills holes 122, 124, which are typically about 75 - 250 m (about 3 - 10 mils) in diameter, to form conductive connections or vias 150 to terminals 132, 134, respectively, of antenna 130 and fills the holes beneath contacts 112, which holes are typically about 250 - 1000 m (about 10 - 40 mils) in diameter, to form conductive connections or vias thereto providing contacts 156. Conductor 152 provides electrical connection between terminal 132 of antenna 130 and one of the contacts 158 and conductor 154 provides electrical connection between terminal 134 of antenna 130 and the other of the contacts 158. One or more additional deposits of conductive material may be made in the locations of contacts 156, 158 to increase the height thereof for facilitating attachment of an electronic device 140 thereto. Where a thin metal foil, such as a hot-stamped silver, copper, aluminum or gold foil, is utilized, the thickness of the conductor provided thereby may be increased by plating conductive metal thereon, such a electroless silver, silver, nickel-gold, copper and the like, to decrease the electrical resistance of the conductor, as may be important for proper antenna performance.
Electronic device 140 has a pattern of contacts and is attached to the other surface of substrate 120 with its pattern of contacts facing the surface of substrate 120 and adhering thereto by a plurality of electrically conductive adhesive connections to the corresponding contacts 156, 158 on substrate 120, i.e. in a flip-chip mounting manner. Certain of the contacts of electronic device 140, i.e. those arranged in two parallel rows of three contacts each, are connected through vias 156 to the contacts 112 of article 100, which are likewise arranged in two parallel rows of three contacts each. Two other contacts of electronic device 140, i.e. those not in the 2-row by 3- contact arrangement, are connected by conductors 152, 154 to plural-turn antenna 130 thereof.
As a result, if article 100 is inserted into a contact-type card reader, communication between the card reader and electronic device 140 is via external contacts 112 of contact pattern 110, however, if article 100 is within communication range of a wireless-type card reader, communication between the card reader and electronic is via signals transmitted and/or received via plural-turn loop antenna 130. The electronic devices referred to herein are conventional and may be obtained form plural commercial sources, including but not limited to Philips Electronics located in the Netherlands, Siemens and Infineon located in Germany, and Inside Technology located in France.
It is noted that the arrangements of articles described herein may be employed in any of the articles and may be made by the methods described in U.S. Patent Application Serial Number 09/412,058 (AI-TECH-11) entitled "Article Having An Embedded Electronic Device, And Method Of Making Same" filed by Kevin Kwong-
Tai Chung on October 4, 1999, which application is hereby incorporated herein by reference in its entirety. For example, any of the articles of FIGURES 1 - 8 herein may be coated with a layer 56, 58 of insulating adhesive to cover and protect the antenna 30, 130 and the electronic device 40, 140 attached to substrate 20, 120, on either one or both sides of substrate 20, 120, and whether or not a card blank is or is not employed. Such wireless articles may be employed as an identification tag, an identification badge, a luggage tag, a pallet identification tag, a laundry tag, an access card, a credit card, a debit card, a cash card, a phone card, or like article.
In applications requiring high durability, such as laundering and industrial processes, the wireless article is preferably of flexible adhesive substrate, e.g., type
ESP7450 flexible dielectric adhesive, on a polyester film, such as Mellinex polyester film available from E.I. duPont de Nemoirs located in Delaware. The electronic devices preferably connected to the substrate with a flexible electrically-conductive adhesive and a similar high-strength flexible dielectric underfill adhesive, e.g., types MEE7650 and MEE7660, respectively. The completed wireless tag is preferably laminated with a melt-bondable flexible adhesive that melts almost instantly and that withstands immersion in boiling water and other high-temperature and high-moisture conditions, so as to encapsulate and protect the substrate and electronic device.. A preferred such adhesive is type ESP7450 flexible dielectric thermoplastic adhesive. The encapsulated wireless article is then hot-pressed into the cloth, clothing article or other object to be processed so that the melt-bondable adhesive permanently attached the wireless article to the object.
FIGURE 9 is a side view of an exemplary article 200 according to the invention. Tamper-resistant wireless article 200 includes a substrate 220 that is an adhesive that also serves for attaching article 200 to the object to be identified.
Suitable adhesives include thermoplastic adhesive that may be bonded to the object by either heat or a solvent or thermosetting adhesive that is attached to the object and cured, such as by application of heat. Suitable strong dielectric adhesives for tamper- resistant articles include, for example, type MB7100 thermoplastic dielectric adhesive, type CB7200-E thermosetting dielectric adhesive, and type ESP7450 thermosetting flexible adhesive, all available from AI Technology, Inc. The adhesive may comprise the entire substrate 220 or may be an outer layer or layers of a laminated substrate 220. A "strong" adhesive will have a "peel strength" that is at least 1000 gm/inch of width (about 400 gm/cm of width), and preferably more than 2000 gm inch (about 800 gm cm) of width, measured by a conventional pull test. Antenna 230 is, for example, an etched copper pattern, and is preferably passivated by a layer of precious metal, such as silver or gold, to resist oxidation, at least at the contacts thereof at connections 252, 254. The plated metal layer also desirably serves to increase the height of the contacts and to reduce the resistance of antenna 230. The shape and size of substrate 220 and antenna 230 are established to fit the desired physical size requirements, if any, for article 200 in conjunction with the number of turns or loops of antenna 230 for receiving sufficient electromagnetic flux for operability with electronic device 240.
Contacts on electronic device 240 are attached to antenna terminals on substrate 220 in a flip-chip manner by connections 252, 254, such as by a relatively weakly bonding flexible electrically-conductive adhesive, so as to easily separate (de- bond) if article 200 is tampered with. "Weakly bonding" adhesives have a bond strength that is less than about 1000 psi (about 70 kg/m2) measured by a conventional shear strength test. Suitable conductive adhesives include type PSS8090 where device 240 is not encapsulated and type CB8130 where device is covered or encapsulated, such as by type MB7100 thermoplastic adhesive. Preferably, the contacts of device 240 and the antenna 230 terminals are passivated by a precious metal, such as gold on nickel ("nickel-gold"), to resist oxidation.
Article 200 may be made to "tamper destruct" rather than to be just tamper resistant as follows. Antenna 230 is a heat stamped transfer of a thin foil of copper or aluminum or silver foil, and may retain the weakened feature about 25 μm (about 1 mil) in size. Typically, very thin metal foil, e.g., 2.5 to 12.5 μm (about 0.1 to 0.5 mil) thick is employed, and is plated with electroless silver, gold, palladium or platinum, or a combination thereof, typically to about the same thickness as is the hot-stamped metal foil, to reduce its resistance A typical loop or turn of a hot stamped metal foil antenna 230 exhibits a resistance of about 10 to 100 ohms, which is reduced to less than 10 ohms, and typically to 0 2 to 2 ohms, by the plated precious metal layer so as to be effective with a typical electronic device 240, such as a "smart tag" type integrated circuit operating at a frequency of about 245 GHz available from Single Chip Systems Corporation located in California An added benefit is that the metal plating also provides a desirable oxidation resistant coating for the antenna 230 and its terminals Alternatively or additionally, antenna 230 may be an etched copper pattern having a thin portion 231, e g , less than about 25 μm (about 1 mil) in thickness, so as to be fragile and not withstand an attempt to remove the substrate from the object to which it is attached
Antenna 230 of a tamper-destruct article 200 may also be provided by depositing an electroless activatable thermoplastic such as ABS plastic on substrate
220 ABS plastic may be deposited, for example, by dissolving it in a solvent and printing, screening or stenciling it in the desired pattern of antenna 30 on substrate 220 The patterned ABS is plated with electroless silver or gold or combination of precious metals (plating will only adhere to the activatable ABS) to reduce the resistance to less than about 10 ohms, all as descπbed above
Electronic device 240 is connected to antenna 230 terminals by a relatively strong electπcally-conductive adhesive, e g , an adhesive having a strength m excess of about 1000 psi (about 70 kg/m2), and preferably in excess of about 2000 psi (about 140 kg/m2) A strong adhesive will tend to cause the thin antenna 230 to be pulled away from substrate 220 with device 240 and break Suitable strongly bonding adhesives include, for example, AI Technology types ME8456, ME8550-SMT and ME8650 which may be encapsulated with type MEE7660 thermosetting dielectπc adhesive for tamper resistant applications
Typically, pressure sensitive (non-cured) adhesives have a peel strength of about 200-500 gm inch of width, and are considered to relatively weakly bond Cured adhesives typically have a peel strength of 1000 gm/inch of width and are considered to relatively strongly bond.
FIGURE 10 is a side v_ f an exemplary article 200' according to the invention which is similar to article 200 of FIGURE 9 described above. Article 200' differs from FIGURE 9 in that antenna 230' has one or more small gaps 233 or discontinuities along its length that are filled or bridged by an electrically conductive adhesive 235 that strongly bonds to substrate 220 and will separate from the plated copper portions of antenna 230' so that antenna 230' is destroyed if article 200' is tampered with. Typically, the electrically-conductive gap-filling adhesive 235 utilizes the same type resin binders as the dielectric adhesive utilized for substrate 220. For example, type CB8130 electrically conductive adhesive is utilized with type MB7100 thermoplastic adhesive substrate and type CB8205-E electrically conductive adhesive is utilized with type CB7200-E thermosetting adhesive substrate. Antenna 230' may also include thin or narrow frangible portions 231. In addition, electronic device 240 is encapsulated to substrate 220 by an epoxy encapsulant 245, such as AI Technology type MEE7650 or MEE7660.
FIGURES 11A and 11B are side and plan views, respectively, of another exemplary article 300 according to the invention which differs from articles 200 and 200' in that electronic device 340 is on a surface of substrate 320 opposite antenna 330. Substrate 320 is like substrate 220 in structure and materials, except that electrically-conductive vias 350 are formed in holes 250 through substrate 320 to connect to the underside of antenna 330 and to connect to electronic device 340 by means of conductors 352, 354. Preferably, the holes in which conductive vias 350 are disposed are formed contemporaneously with substrate 320, such as by features on the mask, stencil or screen utilized in printing the dielectric adhesive forming substrate 320. Preferably, conductive vias 350 are of electrically-conductive adhesive deposited into the holes in substrate 320. Connections 352, 354 between conductive vias 350 and contacts of electronic device 340 are preferably also of electrically- conductive adhesive and are deposited contemporaneously with conductive vias 350 in a single screen printing, stenciling or mask printing operation. Suitable electrically-conductive adhesives include types PSS8090, CB8130 and PSS8150, and may be deposited, for example, in a width of 50 - 500 μm (about 2 - 20 mils) and at a thickness of 25 - 100 μm (about 1 - 4 mils).
Alternatively, connections 352, 354 may be of like structure and material as is antenna 330 which is like antenna 230 and/or 230' in structure and materials, e.g., is of etch-patterned copper, hot-stamped copper foil with electroless silver plating, hot- stamped silver foil or electroless silver plated on an activated plastic such as ABS plastic. Antenna 330 may be plated with silver, electroless silver, copper, aluminum and the like to increase its thickness and to decrease the resistance thereof, e.g., to less than five ohms, and typically to about two ohms. Conductors 352, 354 are preferably bonded to substrate 320 and at least partially encapsulated so as to be frangible and tend to break easily if article 300 is attempted to be removed from the object to which it is attached or is otherwise tampered with.
The embodiments of FIGURES 9-1 IB in particular lend themselves to inexpensive fabrication and to have tamper resistant and tamper destruct properties, as desired. Accordingly, such an electronic article is adapted for attachment to a utilization object (e.g., an object to which the electronic article is attached for identification, inventory, cleaning, laundering, processing or other purpose) and comprises a layer of electrically insulating adhesive providing a substrate adapted for adhering to a utilization object. The adhesive preferably has an adhesive bond strength to the utilization object that substantially exceeds the intrinsic shear strength of the adhesive, whereby attempting to remove the substrate from a utilization object results in damage to the substrate before separation of the substrate from a utilization object. Substantially exceeds or substantially less than generally refers to a difference of about a factor of two or more. The intrinsic strength or shear strength of a material, such as an adhesive, is a measure of the physical force necessary to damage or destroy the sheet of material, such as by it tearing, breaking or otherwise suffering a loss of physical integrity or function. An electronic device is either mounted to or embedded in the adhesive substrate and is electrically connected to an antenna on a surface of an adhesive layer of the adhesive substrate.
Typical adhesives having greater bond strength than intrinsic strength have a peel strength greater than about 1000 gm/inch of width and a shear strength greater than about 2000 psi (about 140 kg/cm2), and preferably greater than about 1000 psi (about 70 kg/cm2). Suitable adhesives include, for example, thermoplastic and thermoset adhesives types CB7130 and ESP7450.
At least a portion of the antenna is preferably a frangible region having a strength substantially less than the mtπnsic strength of the adhesive of the substrate, whereby attempting to remove the electronic article from the utilization object by physical force tends to damage the antenna. The frangible region includes either a thm region, a narrowed region, a notch, a thin foil of copper, aluminum or silver, electroless plated silver on activated plastic, electroless plated silver on activated ABS, or electπcally-conductive adhesive bπdgmg a gap in the pattern of electπcally- conductive material. Preferably, the frangible region has a thickness less than about
0.025 mm or a width less than about 0.10 mm. The antenna preferably includes alternatively either a patterned metal foil of copper, aluminum or silver, having a thickness of at least about 0.01 mm, and typically about 0.025 mm, and a width at least in part of at least about 0.10 mm, or a pattern of electroless plated silver on activated plastic or electroless plated silver on activated ABS, wherein the electroless silver has a thickness of less than about 0.025 mm, and typically about 0.01 mm, and a width at least in part of at least about 0.10 mm.
The electronic device is electrically connected to the antenna by electπcally- conductive adhesive that is either (a) of substantially lower intrinsic strength than the intπnsic strength of the adhesive of said substrate, or (b) soluble in a solvent that dissolves the adhesive of said substrate, whereby attempting to remove the electronic article from a utilization object by physical force or solvent tends to damage the electπcal connection of the antenna to the electronic device. Preferably and alternatively, the antenna includes a patterned metal foil of one of copper, aluminum and silver, and has electroless silver plating thereon for providing an antenna having a resistance of less than about 2 ohms.
FIGURES 12 and 13 are plan and side view schematic diagrams, respectively, of an exemplary substrate 402 for a contact-less card 400 having an electronic device therem. Substrate 402 is formed of a thin sheet of substrate mateπal, such as thermoplastic or thermosetting dielectπc adhesive, PVC, PET, ABS or HIPS, polyimide, polymer film, or other plastic, or paper film, or other suitable mateπal, on which is deposited an elongated electπcal conductor 404 that serves as an RF loop antenna 404. Antenna 404 is formed of a thermoplastic or thermosetting polymer adhesive that is made electrically conductive by the inclusion of electπcally conductive particles therein, and which may include one or more regions of reduced width and/or thickness to provide frangible areas that break easily to provide tamper- destruct properties, or of a hot-stamped metal foil or the like. Electronic device 410 is attached to substrate 402 in a flip-chip manner by electπcal connections 406 that bond the contact pads thereof to the ends of the elongated conductive pattern 404 of conductive adhesive that serve as the contacts of RF loop antenna 404. Connections 406 to electronic device 410 at the ends of conductive pattern 404 may be made while the conductive adhesive thereof is wet by placing electronic device 410 thereon or conductive adhesive pattern 404 may be dπed or B-staged before electronic device
410 is placed to contact the ends thereof by melting or cuπng the conductive adhesive. As a result, and beneficially, the substrate is made in a single deposition rather than requiπng the deposition of a thick-film mk to form the antenna conventionally and conductive bumps to form interconnections between the antenna and the electronic device.
A stencil, screen or mask defining the pattern of antenna 404 is employed to deposit electπcally conductive adhesive on substrate 402 in the pattern of antenna 404. Typically, the substrate 402 is between about 0.025 mm and 1 mm thick (about 1 - 40 mils thick), and the conductors forming antenna 404 are about 250 m (about 10 mils) wide and are within the range of about 25 m to 125 m thick (about 0.5 to 5 mils thick). In most cases, the conductors of antenna 404 are about 50 - 100 m thick (about 2 - 4 mils thick) when wet and about 12.5 - 75 m thick (about 0.5 - 3 mils thick) after drying or B-staging. Suitable conductive adhesives include, for example, type PSS8150 thermosetting conductive adhesive filled with silver particles which is available from AI Technology, Inc. and type CB025 silver-filled conductive ink available from E.I. duPont de Nemoirs located in Delaware. The deposited conductive adhesive is dπed or B-staged by heating in an oven. Electronic devices 410 may be positioned to the substrate 402 either when the adhesive is still wet from being deposited or after the conductive adhesive is dπed or B-staged
Where antenna 402 has plural turns and electronic device 410 bπdges one or more turns of antenna 404 or other conductors formed of electπcally-conductive adhesive, and particularly where the width or spacing of such conductors is small, i.e. less than about 0.25 - 0.5 mm (about 10 - 20 mils), the deposited conductive adhesive is preferably dπed or B-staged before attachment of electronic device 410 A second deposition of the same electπcally-conductive adhesive is made to deposit a second layer of adhesive on bumps 406 to which electronic device 410 may be attached while the second layer of adhesive is wet or after drying or B-stagmg. However, where the conductor width or spacing is small, it is preferred that attachment of electronic device 410 be after the second deposition of conductive adhesive on bumps 406 has been dπed or B-staged Optionally, but m certain applications, preferably, an insulating adhesive underfill in liquid form may be applied along the edges of electronic device 410 from where it flows by capillary action to substantially fill the remaining volume between electronic device 410 and substrate 402 that is not filled by conductive adhesive. Such adhesive underfill provides additional mechanical strength to the attachment of electronic device 410 to substrate 402 and resistance to moisture and other potential contaminants, as is desirable in a tamper-resistant article. Where the electπcally- conductive adhesive is a flexible adhesive such as type PSS8150, as is desirable where the substrate 402 is somewhat flexible, a flexible adhesive underfill, such as type MEE7650 or type MEE7650-5 thermoplastic epoxy adhesive, is preferably utilized.
FIGURE 14 is a cross-sectional side view of another alternative exemplary embodiment of a contact-less card 400' according to the present invention Card 400', like card 400 descπbed above, includes a prepared substrate 402 with loop antenna 404 and electronic device 410 mounted thereon as descπbed in relation to FIGURES 12 and 13 Substrate 402 is encapsulated by roll coating a layer 424 or laminating a sheet 424 of melt-flowable adhesive thereto Adhesive layer 424 has a thickness greater than the height (thickness) of electronic device 410 above substrate 402 so that it is sufficient to cover and encapsulate electronic device 410. It is noted that the adhesive of which layer 424 is formed is preferably selected to be of a different type than is the conductive adhesive of which loop antenna 402 and contacts 406 are formed so as to avoid the smearing thereof, such as an adhesive based upon a different chemistry of its molecular and physical structure, such as one being a thermosetting adhesive and the other being a thermoplastic adhesive or two adhesives employing different solvent so that the solvent of the one adhesive does not affect or dissolve the other adhesive. Smearing is also avoided if layer 424 is formed by laminating a sheet of dried or B-staged, i.e. solvent-free, adhesive to substrate 402.
Substrate 402 may be attached or laminated to an object to be identified by placing them together between heated flat plates or heated rollers, at a temperature and for a time appropriate for adhesive layer 424 to melt flow and form a permanent bond between substrate 402 and the object, thereby to attach the complete contact-less card 400' with electronic device 410 positioned and encapsulated between substrate 402 and the object by melt-flowable adhesive 424.
FIGURE 15 is a plan view of a substrate 402 as for cards 400, 400' above in which an alternative arrangement for mounting an electronic device 410' to substrate 402 is employed. Electronic device 410', for example, a semiconductor die, which is illustrated apart from substrate 402, has two contact pads 412' located, for example, spaced apart along opposing edges thereof. RF loop antenna 404' of suitable width and conductivity is deposited, as by screen printing, stenciling or other suitable method of depositing an electrically-conductive adhesive, onto substrate 402 and has at the ends thereof contacts 406' of RF loop antenna 404' spaced apart the same distance as are contact pads 412' of electronic device 410' for making electrical connection thereto. In addition, a support 408 is deposited onto substrate 402 for supporting a part of electronic device 410' apart from contact pads 412' thereof. Support 408 may be deposited at the same time and of the same material as is antenna 404' if the surface of electronic device 410' to which it will be attached is passivated or coated so that the function of electronic device 410' will not be compromised by having electrically-conductive adhesive attached thereto, or support 408 may be deposited separately or of a different mateπal, such as an electπcally insulating adhesive. Alternatively, a second deposit of electπcally-conductive adhesive may be made onto contacts 406' to increase the height thereof, and a second deposit of adhesive may be made onto support 408 to similarly increase the height thereof. Electronic device 40' is flipped over and mounted to substrate 402, as is shown in FIGURE 16, with contact pads 412' connecting to antenna contacts 406' and with electronic device 410 also being supported by support 408. Electronic device 410' can be attached to substrate 402 while the adhesive deposited to form contacts 406' and support 408 are still wet, or the adhesives forming contacts 406' and support 408 may be dπed or B-staged prior to attachment of electronic device
410' thereto. Where a thermoplastic adhesive is utilized for contacts 406' and support 408, electronic device 410' may be attached to substrate 402 by heating substrate 402 and/or electronic device 410' to an elevated temperature sufficient to melt flow the thermoplastic adhesive (i.e. make it wettable for bonding and cuπng) when substrate 402 and device 410' are pressed together. Where a thermosetting adhesive is utilized for contacts 406' and support 408, electronic device 410' may be attached to substrate 402 by pressing device 410' into the wet thermosetting adhesive or by heating substrate 402 and/or electronic device 410' to an elevated temperature sufficient to melt flow the B-staged thermosetting adhesive (i.e. make it wettable for bonding and cuπng) and pressing substrate 402 and device 410' together. The thermosetting adhesive may then be cured by heating for a sufficient time at an appropπate elevated temperature.
The preferred adhesive for card 400, 400' is a type PSS8150 electπcally- conductive, flexible thermosetting adhesive also available from AI Technology, which may be pπnted with a suitable width and thickness, e.g., about 1 mm wide and 0.1 mm thick, to provide suitable conductivity and quality factor Q of antenna 404'. An underfill may be employed to better secure electronic device 410' to substrate 402 after it is attached thereto by contacts 406' and support 408'. Where electronic device 410' is of small size, e.g., less than about 5 mm along its edge, an underfill of πgid mateπal or of flexible mateπal may be employed, with a flexible underfill mateπal being employed where substrate 402 is flexible. If device 410' is larger, however, than about 5 mm along any edge and a rigid substrate such as an FR4 substrate is employed, or if substrate 402 is flexible, or if the adhesive employed for contacts 406' and/or support 408 is a flexible adhesive, then a flexible adhesive underfill is preferred. The underfill adhesive provides additional strength for the bond between device 410' and substrate 402, and also provides additional insulation and resistance to intrusion of contaminants, including migration of silver from the conductive particles that might be employed to impart conductivity to an electrically-conductive adhesive. The preferred adhesive for flexible underfill is a type MEE7650-5 electrically-insulating, flexible thermosetting adhesive also available from AI Technology, which may be applied along the edges of electronic device 410' and is drawn between device 410' and substrate 402 by capillary action. In addition, the same flexible insulating adhesive material may be employed as a protective coating for substrate 402 and card 400, 400' to resist mechanical abrasion of RF loop antenna 404' and contact of contaminants and other environments therewith. Because the size of the electronic devices usually utilized in these types of cards, rigid adhesive underfill may be utilized if additional mechanical protection is desired.
The method of making an exemplary card 400' is as follows. A 7-mil thick (0.178 mm) sheet of annealed, highly-printable PVC is obtained. Preferably, the sheet is of sufficient size that a plurality of substrates 402 may be made contemporaneously. For example, an 11-inch by 11-inch (about 28 mm by 28 mm) sheet is convenient for making a panel containing a 3 by 4 array of 12 substrates, or an 11-inch by 18-inch (about 28 mm by 46 mm) sheet is convenient for making a panel containing a 3 by 8 array of 24 substrates, each with sufficient unused peripheral area of the sheet remaining for the placement of guide holes or other indexing and alignment indicia that facilitate placement and alignment of the sheet, for example, with respect to screens and stencils, pick-and-place equipment, laminating equipment, die-cutting equipment, and the like. An electrically-conductive adhesive, such as type PSS8090 thermoplastic highly-electrically-conductive (e.g., <0.001 ohm-cm conductivity) adhesive available from AI Technology, is screen printed onto the PVC sheet at a thickness of about 2 mils (about 0.05 mm) to form the conductive loop antenna 404 and contacts 406 to which electronic devices 410 are to be attached in a single step, although stenciling, masking, ink-jet printing or other suitable deposition method could also be utilized. While the conductive adhesive is still wet, electronic devices 410 are placed onto the PVC sheet substrate in the proper positions for contacts thereon to make electrical contact and bond with the wet conductive adhesive at the ends of the 24 elongated patterns of conductive adhesive loop antenna by pick-and- place equipment. The substrates 402 with electronic devices 410 thereon are then dried or B-staged in an oven at about 60 C, and may be inspected and electrically tested, if desired. If the conductive adhesive is dried before placement of electronic device 410, substrate 402 and/or device 410 are/is heated to a temperature sufficient to melt-flow the conductive adhesive before device 410 is placed on substrate 402. A
10-mil thick (0.25 mm) sheet 424 of dried type MB7060-W melt-flowable white- pigmented adhesive is laminated to substrate 402 at a temperature of about 75 C. Preferably, this adhesive sheet 424 is of like size to that of which the plurality of substrates 402 are made, i.e. an 11-inch by 18-inch (about 28 mm by 46 mm) sheet for making a 3 by 8 array of 24 cards 400' with sufficient unused peripheral area of the sheet remaining for the placement of guide holes or other indexing and alignment indicia corresponding to those on the sheet of substrates 402 that facilitate placement and alignment of these two sheets. With proper indexing and sufficient precision of size, individual panels can be laminated to a web form for ease of subsequent die cutting and further processing. The sheet of substrates 402 and the sheet of adhesive
424 are roll laminated together at a temperature and speed selected to raise the adhesive 424 to about 65 - 75 C, which may be facilitated by pre-heating the two sheets to about 50 - 60 C and also by employing heated pinch rollers spaced apart by a distance equal to the thickness of the finished card 400'. The pinch rollers also tend to eliminate trapping of air in pockets between the substrate and the adhesive, which would tend to weaken the card. The combined sheet of laminated cards 400' are then cut by a suitable rotary die cutter into individual cards , e.g., 24 cards, 400' each having an electronic device 410 embedded therein.
In like manner, cards 400, 400' of PET and other materials may be made by the foregoing method where PET sheets and suitable melt-flowable adhesives, such as types MB7100 from AI Technology, and temperatures consistent therewith, are employed therein. For example, for substrates of PET material, electronic devices 410 may be attached with conductive adhesives at a melt-flow temperature of either 120 C or 200 C, such as types PSS8090 and PSS8150, respectively, as is convenient, because with the PET heated to about 120 C and the electronic device heated to about 200 C, the adhesive will melt flow and bond instantly without heating the PET appreciably above 120 C. Lamination of the card thereafter requires a temperature in the range of about 60 - 120 C, and preferably about 80 C, depending on the particular melt-flowable adhesive employed, which does not disturb the connections attaching the electronic device embedded therein. If an optional adhesive underfill is desired between electronic device 410 and substrate 402, a flexible adhesive, such as types
MEE7650, MEE7650-5 and MEE7850 thermosetting epoxy adhesives available from AI Technology, which cure at a temperature of less than about 80 C, is suitable. Where the size of the electronic device is small, conventional rigid adhesive underfill may be employed. It is noted that the arrangement of FIGURE 14 is particularly advantageous because no cavity is required to be machined or otherwise formed in the card blank to receive the electronic device therein. This not only saves time and reduces cost, but also simplifies processing, and in addition permits thin substrate 402 material, e.g., about 5 mils (about 0.127 mm) thick, to be employed with a relatively thicker adhesive layer 424, e.g., about 10 - 15 mils (about 0.25 - 0.38 mm) thick, to easily accommodate standard thickness electronic devices. Thus, the melt flowable adhesive layer, such as type MB7070 thermoplastic adhesive which flows at a low temperature of about 70 - 90 C, serves as the core of card 400' and flows around electronic device 410 to "form in place" the cavity therefor with precise size and location. As a result, there is no need for an underfill of insulating adhesive under electronic device 410, thereby avoiding additional processing.
In fact, the foregoing method advantageously lends itself to being employed in a continuous process to produce a large number of cards having an electronic device embedded therein. As shown in FIGURE 17, instead of being provided in sheet form, the material from which substrates 402 are made is provided as a long strip in roll form, i.e. on roll 510, as is the melt-flowable adhesive on roll 520 to be laminated therewith. The conductive loops 404 and contacts 406 are roll printed onto the moving substrate strip 402 at printing station 512, the electronic devices 410 are placed thereon as substrate strip 402 moves past a pick-and-place equipment station 515, and the moving strip is dried as it passes through a drying oven station 518. Then the prepared substrate strip 402 and the melt-flowable adhesive strip 424 420 are brought together, preferably after pre-heating, and roll laminated in a set of pinch rollers 535 heated to a suitable elevated temperature and spaced apart a fixed distance that is the final card thickness, to form a strip of completed cards. Alternatively, panels having suitable sprocket holes may be butted together end-to-end and driven by a sprocket drive so as to be driven together with strips of adhesives. Finally the individual cards 400 are cut from the strip by a suitable rotary die cutter or other cutter 540.
Further, the arrangement of FIGURE 17 may be employed with a roll 530 providing a strip 420 of release liner 420 which is interposed between adhesive 424 and pinch rollers 535 when substrate 402 is laminated with a strip of adhesive 424 by heated pinch rollers 535 so that adhesive 424 does not adhere to rollers 535.
Suitable pick-and-place equipment that is employed in the method described herein and in conventional surface mount technology is widely available commercially and typically has a placement inaccuracy of about 0.12 mm (about 5 mils) or less. Suitable pick-and-place equipment is commercially available from
Mydata Automation located in Peabody, Massachusetts, from Universal Instrument located in Binghamton, New York, from Zevatech Inc. located in Morrisville, North Carolina, and from Manncorp, and can place components onto substrates with a positional inaccuracy of one one-thousandth of an inch (about 25 μm) or less and at a rate greater than one component per second.
As is known, the contact pads on the substrates and those on the electronic devices are preferably passivated with an oxidation-resistant conductive material to further their making low resistance and reliable electrical connections. For example, copper contacts may be tinned with solder or plated, as are aluminum and other semiconductor contacts, or otherwise coated with layers of nickel, gold, nickel-gold, palladium, nickel-palladium, platinum or other precious metal, and combinations and alloys thereof.
Where electronic devices are attached or bonded to the article substrate by deposited bumps of an electrically conductive adhesive, preferred adhesives are thermoplastic and thermosetting adhesives that are "flexible" when cured, i.e. molecularly flexible. Molecularly flexible adhesives have a modulus of elasticity that is less than about 500,000 psi (about 35,000 kg/cm2) over most of the range of temperatures that the bonded electronic device is specified to operate over. Suitable conductive adhesives include types PSS8090 and PSS8150 thermosetting paste adhesives which are melt-flow bondable at temperatures of about 120 C and 200 C, respectively. Type PSS8090 may be melt-flow bonded at a lower temperature, such as 100 C, if a higher pressure is utilized, as is the case for type PSS8150 as well. If it is desired to employ an adhesive underfill between the electronic device and the substrate, an insulating adhesive that will be drawn under the electronic device when dispensed and having a modulus of elasticity no greater than that of the conductive adhesive utilized for the conductive electrical connections should be employed. For example, type MEE7650 flexible insulating thermosetting epoxy adhesive, which has a modulus of elasticity of about 10,000 psi (about 700 kg/cm2), is suitable for use with types PSS8090 and PSS8150 conductive adhesives, as is type MEE7650-5 which is more flexible.
Attachment of wireless articles according to the invention to objects to be identified or tracked may be by a layer of adhesive or by an adhesive that is the substrate of the article. One suitable thermoplastic adhesive that melts and bonds instantly when pressed against PVC under a pressure of about 5 psi (about 0.35 kg/cm2) at a temperature of 70 C is type MB7060 adhesive which is available commercially in sheet form. Where the article is of PET which has a deformation temperature of about 120 C, an adhesive that bonds at a temperature below 120 C is preferred. Suitable thermoplastic adhesives that melt and bond instantly when pressed against PET under a pressure of about 5 psi (about 0.35 kg/cm2) include type MB7060 which bonds at a temperature of about 65 - 75 C, type MB7070 which bonds at a temperature of about 70 - 90 C, and type MB7100 which bonds at a temperature of about 110 C, all of which are commercially available in sheet form. Type MB7060 may be bonded at a lower temperature, such as 60 C if a higher pressure is utilized, as is the case with types MB7070 and MB 7100 as well. Further, where a high temperature and high-strength bond is desired, an epoxy adhesive, such as type ESP7450-SC thermosetting epoxy adhesive available from AI Technology, may be employed. Type ESP7450-SC has a high bond strength up to temperatures of about 125 - 150 C, yet is flowable (under a pressure of about 5 psi (about 0.35 kg/cm2)) and curable in less than 30 minutes at a temperature of about 80 C. Each of these adhesives has a die-shear strength greater than 500 - 1000 psi (35 - 70 kg/cm2) at temperatures below about 45 C, although a bond strength of about 200 psi (about 14 kg/cm2) at temperatures below about 45 C is sufficient for many applications. In addition, these adhesives are insensitive to exposure to moisture as is desirable for cards to be used in tropical climates, or to track items being laundered or otherwise processed.
The adhesives identified in the foregoing paragraphs are commercially available from AI Technology, Inc.
Where the substrate of a wireless article, card or tag includes sheet material, either as the substrate or as a layer in a substrate, such sheet material is typically formed of a suitable electronic substrate material, such as conventional printed wiring circuit board material (e.g., FR4 material), PVC, PET, acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS), polyimide, polyester, polyimide or other plastic material, and the like.
In addition to RF identification tag applications, cards and other articles according to the invention may be utilized in other applications and in special environments, such as remotely identifiable tagging devices used to keep track of, identify, and/or account for personnel, animals, tools, equipment, laundry, and other items, or as smart-card type credit cards and the like. For example, the articles described in U.S. Patent Applications Number 09/411,849 entitled "Wireless Article Including a Plural-Turn Loop Antenna" and Number 09/412,058, entitled "Article having an Embedded Electronic Device, And Method For Making Same," both filed by Kevin K-T Chung on October 4, 1999, each of which applications is hereby incorporated herein by reference it its entirety, may be employed. In certain of these applications, the cards and the electronic devices therein may be exposed to a totally different environment that requires the substrate to be of a material other than those described above in relation to typical applications. For example, in the case of cleaning or laundry tags, the card and embedded device is washed and cleaned along with the clothing or other article to which it is attached and so is exposed to various chemical solvents, soaps, detergents and water, as well as to high temperatures of up to about 250 C. In such applications, the substrate and materials are selected to withstand the higher temperature and the chemical environment, and so may be polyimide film, such as Kapton® film, or other high temperature thermoplastics and thermoset materials. Further, to protect the electronic device, the attached semiconductor die may be encapsulated with a resin that exhibits satisfactory resistance to the expected chemicals and solvents to which the card will be exposed, such as type MEE7650. Different layering and thicknesses of adhesives may also be utilized. For example, types ESP7450-SC or TP7205-E pressure sensitive adhesives may be pre-applied as an outer layer of an article and may subsequently be utilized to bond the article onto the object that the article is to identify. The foregoing adhesives are also commercially available from AI Technology.
While the present invention has been described in terms of the foregoing exemplary embodiments, variations within the scope and spirit of the present invention as defined by the claims following will be apparent to those skilled in the art. For example, the loop antenna pattern and other features may be deposited by hot-stamping, screening, stenciling and/or masking as described, or other methods of application such as printing, ink-jet printing, preform lamination and the like may be used. Further, it is likewise suitable to employ flexible or rigid electrically- conductive adhesives and flexible or rigid insulating adhesives, in addition to the preferred conductive and insulating adhesives described herein.
While the exemplary embodiments herein are described in relation to one electronic device, plural electronic devices of like or differing kinds may be attached to a single substrate, e.g., in a flip-chip manner by either electrically-conductive adhesive or solder, or with conventional wire bonding. A single deposition of solder or conductive adhesive can provide contact bumps or strips for all the electronic devices as well as any interconnections therebetween.
By way of further example, the electronic devices may be single or plural semiconductor devices such as integrated circuits, memories, microprocessors and the like, and can include networks of conductors and/or diodes for providing continuity and the lack thereof between particular contacts, or networks of resistors and/or capacitors and/or inductors, as may be necessary or convenient in any particular application. Such devices are attached to substrates by solder or conductive adhesive connections, and suitable adhesive underfill materials may also be employed to fill the thin space between the electronic device and the substrate. Where the connections are formed by a flexible conductive adhesive, for example, a suitable underfill is a flexible insulating adhesive having a modulus of elasticity that is no greater than that of the flexible conductive adhesive. Adhesive underfill may be applied as a preform or by capillary action, screening, stenciling, masking, ink-jet printing or other suitable method. Where the electronic device is less than about 5 mm along any edge, conventional rigid adhesive underfill may be employed.
Further, contact-less cards as described herein may employ etched metal or wire conductive loops on the card substrate to serve as the RF antenna therefor. While not as advantageous as certain embodiments, wire loops may facilitate a multiple turn antenna having higher gain. A loop antenna having a small number of turns may be employed where the electronic device has spaced apart contacts that bridge over or straddle the intermediate turns of the antenna.
In any case, the antenna contacts to which the electronic devices electrically connect may be deposited onto the substrate or may be deposited onto the electronic devices, either at the individual semiconductor chip level or at the semiconductor wafer level, to make connect the loop antenna when the electronic device is attached to the substrate.

Claims

WHAT IS CLAIMED IS:
1. A tamper-resistant article comprising: a substrate including at least one layer of a strong dielectric adhesive having an exposed surface adapted for attaching said substrate to an object; a pattern of electrically-conductive material including an elongated electrical conductor on one surface of said substrate and having at least one electrical contact; and at least one electronic device attached to said substrate by a strong adhesive and having at least one contact electrically connected to the contact of said pattern of electrically-conductive adhesive, whereby at least one of the strong dielectric adhesive of said substrate and the strong adhesive attaching said electronic device render said article resistant to tampering.
2. The tamper-resistant article of claim 1 wherein said elongated electrical conductor includes at least one of a deposited electrically-conductive adhesive and a metal foil.
3. The tamper-resistant article of claim 2 wherein said metal foil is laminated to the one surface of said substrate and is patterned to define said elongated electrical conductor.
4. The tamper-resistant article of claim 1 wherein at least one of said pattern of electrically conductive material and the electrical connection of the contact of said electronic device to said substrate includes at least one frangible region.
5. The tamper-resistant article of claim 4 wherein said frangible region includes at least one of a thin region, a narrowed region, a notch, a thin foil of copper or silver, electroless plated silver on activated plastic, and electrically-conductive adhesive bridging a gap in the pattern of electrically-conductive material.
6. The tamper-resistant article of claim 1 wherein said elongated electrical conductor includes a spiral conductor having at least one turn.
7. The tamper-resistant article of claim 1 wherein at least the at least one electrical contact of said pattern of electrically-conductive material is coated with an oxidation-resistant metal.
8. The tamper-resistant article of claim 1 wherein said pattern of electrically- conductive material is formed by one of (a) roll coating, screen printing, stenciling, mask printing, ink jet printing and laminating an electrically conductive adhesive, and (b) hot stamping and electroless plating a conductive metal.
9. The tamper-resistant article of claim 1 wherein the at least one contact of said electronic device is electrically connected to the contact of said pattern of electrically conductive adhesive by one of solder and an electrically- conductive adhesive.
10. The tamper-resistant article of claim 1 wherein the strong adhesive by which said electronic device is attached to said substrate includes at least one of a strong electrically-conductive adhesive connecting the contact of said electronic circuit to the contact of said pattern of electrically-conductive material and a strong dielectric adhesive underfill.
11. The tamper-resistant article of claim 1 wherein the electronic device is attached to said substrate one of (a) while the electrically-conductive adhesive is wet, and (b) after the electrically-conductive adhesive is dried or B-staged and wherein one of said substrate and said electronic device is heated to melt flow said electrically-conductive adhesive.
12. The tamper-resistant article of claim 1 wherein said substrate further comprises a sheet of one of poly- vinyl-chloride (PVC), polyimide, polyethylene terephthallate (PET), FR4 material, acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS), polyimide, polybutylene terephthallate, polyester, polyester terephthallate, polymer blends, polyphynylene sulfide, polysulfone, polyether sulfone, paper film, dried insulating adhesive, B-staged insulating adhesive, and cured insulating adhesive.
13. The tamper-resistant article of claim 1 further comprising an insulating adhesive underfill attaching said electronic device to said substrate.
14. The tamper-resistant article of claim 1 wherein said substrate has at least two holes, further comprising a second pattern of electrically-conductive material having at least two additional electrical contacts on a second surface of said substrate, each of said at least two additional contacts being electrically connected to said pattern of electrically-conductive material on the one surface of said substrate through the at least two holes, respectively, wherein said electronic device has at least two contacts electrically connected respectively to the at least two additional contacts of the electrically-conductive material.
15. The tamper-resistant article of claim 14 wherein said second pattern of electrically-conductive material includes electrically-conductive adhesive extending into the at least two holes of said substrate to provide electrical connection between the contacts of said electronic device and said pattern of electrically-conductive material on the one surface of said substrate.
16. The tamper-resistant article of claim 1 wherein said at least one layer of strong dielectric adhesive of said substrate encapsulates said electronic device.
17. A tamper-destruct article comprising: a substrate including at least one layer of a dielectric adhesive having an exposed surface adapted for attaching said substrate to an object; a pattern of electrically-conductive material including an elongated electrical conductor on one surface of said substrate and having at least one electrical contact; and at least one electronic device attached to said substrate by an adhesive and having at least one contact electrically connected to the contact of said pattern of electrically-conductive adhesive; wherein at least one of said pattern of electrically conductive material and the electrical connection of the contact of said electronic device to said substrate includes at least one frangible region, whereby tampering with said article tends to break at least one of the frangible regions of said pattern of electrically-conductive material and the adhesive attaching said electronic device.
18. The tamper-destruct article of claim 17 wherein said frangible region includes at least one of a thin region, a narrowed region, a notch, a thin foil of copper or silver, electroless plated silver on activated plastic, and electrically-conductive adhesive bridging a gap in the pattern of electrically-conductive material.
19. The tamper-destruct article of claim 17 wherein said elongated electrical conductor includes at least one of a deposited electrically-conductive adhesive and a metal foil.
20. The tamper-destruct article of claim 19 wherein said metal foil is laminated to the one surface of said substrate and is patterned to define said elongated electrical conductor.
21. The tamper-destruct article of claim 17 wherein said elongated electrical conductor includes a spiral conductor having at least one turn.
22. The tamper-destruct article of claim 17 wherein at least the at least one electrical contact of said pattern of electrically-conductive material is coated with an oxidation-resistant metal.
23. The tamper-destruct article of claim 1 wherein said pattern of electrically- conductive material is formed by one of (a) roll coating, screen printing, stenciling, mask printing, ink jet printing and laminating an electrically conductive adhesive, and (b) hot stamping and electroless plating a conductive metal.
24. The tamper-destruct article of claim 17 wherein the at least one contact of said electronic device is electrically connected to the contact of said pattern of electrically conductive adhesive by one of solder and an electrically- conductive adhesive.
25. The tamper-destruct article of claim 17 wherein the adhesive by which said electronic device is attached to said substrate includes at least one of a electrically-conductive adhesive connecting the contact of said electronic circuit to the contact of said pattern of electrically-conductive material and a dielectric adhesive underfill.
26. The tamper-destruct article of claim 17 wherein the electronic device is attached to said substrate one of (a) while the electrically-conductive adhesive is wet, and (b) after the electrically-conductive adhesive is dried or B-staged and wherein one of said substrate and said electronic device is heated to melt flow said electrically-conductive adhesive.
27. The tamper-destruct article of claim 17 wherein said substrate further comprises a sheet of one of poly-vinyl-chloride (PVC), polyimide, polyethylene terephthallate (PET), FR4 material, acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS), polyimide, polybutylene terephthallate, polyester, polyester terephthallate, polymer blends, polyphynylene sulfide, polysulfone, polyether sulfone, paper film, dried insulating adhesive, B-staged insulating adhesive, and cured insulating adhesive.
28. The tamper-destruct article of claim 17 further comprising an insulating adhesive underfill attaching said electronic device to said substrate.
29. The tamper-destruct article of claim 17 wherein said substrate has at least two holes, further comprising a second pattern of electrically-conductive material having at least two additional electrical contacts on a second surface of said substrate, each of said at least two additional contacts being electrically connected to said pattern of electrically-conductive material on the one surface of said substrate through the at least two holes, respectively, wherein said electronic device has at least two contacts electrically connected respectively to the at least two additional contacts of the electrically-conductive material.
30. The tamper-destruct article of claim 29 wherein said second pattern of electrically-conductive material includes electrically-conductive adhesive extending into the at least two holes of said substrate to provide electrical connection between the contacts of said electronic device and said pattern of electrically-conductive material on the one surface of said substrate.
31. The tamper-destruct article of claim 17 wherein said at least one layer of dielectric adhesive of said substrate encapsulates said electronic device.
32. A wireless article having an electronic device embedded therein and adapted to evidence tampering therewith comprising: a substrate having first and second opposing surfaces; an electronic device mounted on the first surface of said substrate; a patterned electrically-conductive material on said substrate and electrically coupled to said electronic device, at least one of said patterned electrically-conductive material and said electrical coupling including a frangible region susceptible to breaking upon tampering therewith; and a layer of melt-flowable adhesive on the first surface of said substrate covering said electronic device, whereby said electronic device is encapsulated by said layer of melt-flowable adhesive, said layer of melt-flowable adhesive being adapted for attaching said substrate to a utilization object.
33. The wireless article of claim 32 wherein said frangible region includes at least one of a thin region, a narrowed region, a notch, a thin foil of copper or silver, electroless plated silver on activated plastic, and electrically-conductive adhesive bridging a gap in the pattern of electrically-conductive material.
34. The wireless article of claim 32 wherein said patterned electrically-conductive material is on the first surface of said substrate and includes an elongated electrical conductor having first and second ends electrically connected to said electronic device.
35. The wireless article of claim 34 wherein said elongated electrical conductor is a loop antenna of one of (a) a deposited pattern of conductive adhesive and (b) a hot-stamped foil of copper or silver on the first surface of said substrate.
36. The wireless article of claim 34 wherein said elongated electrical conductor is a loop antenna of one of (a) a deposited pattern of conductive adhesive and (b) a hot-stamped foil of copper or silver on the second surface of said substrate, and electrically connected to said electronic device by electrically-conductive adhesive vias through said substrate
37. The wireless article of claim 32 wherein said layer of melt-flowable adhesive is one of a laminated sheet and a deposited layer, wherein the deposited layer is deposited by one of roll coating, screen printing, stenciling, masking, and ink-jet printing.
38. The wireless article of claim 32 wherein said melt-flowable adhesive has a bond strength greater than about 200 psi (14 kg/cm2) at temperatures less than about 45 C.
39. The wireless article of claim 32 wherein said substrate is of a material selected from the group consisting of polyvinyl chloride, acrylonitrile-butadiene- styrene polymer, high-impact polystyrene, polyester, and polyimide.
40. The wireless article of claim 32 further comprising a layer of adhesive on the second surface of said substrate adapted for attaching said wireless article to a utilization object.
41. A wireless article having an electronic device embedded therein and adapted to evidence tampering therewith comprising: a substrate having first and second opposing surfaces; an electronic device mounted on the first surface of said substrate; a patterned electrically-conductive material on said substrate and electrically coupled to said electronic device, at least one of said patterned electrically-conductive material and said electrical coupling including a frangible region susceptible to breaking upon tampering therewith; and a layer of melt-flowable adhesive on the second surface of said substrate, said layer of melt-flowable adhesive being adapted for attaching said substrate to a utilization object.
42. The wireless article of claim 41 wherein said frangible region includes at least one of a thin region, a narrowed region, a notch, a thin foil of copper or silver, electroless plated silver on activated plastic, and electrically-conductive adhesive bridging a gap in the pattern of electrically-conductive material.
43. The wireless article of claim 41 wherein said patterned electrically-conductive material is on the first surface of said substrate and includes an elongated electrical conductor having first and second ends electrically connected to said electronic device.
44. The wireless article of claim 43 wherein said elongated electrical conductor is a loop antenna of one of (a) a deposited pattern of conductive adhesive and (b) a hot-stamped foil of copper or silver on the first surface of said substrate.
45. The wireless article of claim 43 wherein said elongated electrical conductor is a loop antenna of one of (a) a deposited pattern of conductive adhesive and (b) a hot-stamped foil of copper or silver on the second surface of said substrate, and electrically connected to said electronic device by electrically-conductive adhesive vias through said substrate
46. The wireless article of claim 41 wherein said layer of melt-flowable adhesive is one of a laminated sheet and a deposited layer, wherein the deposited layer is deposited by one of roll coating, screen printing, stenciling, masking, and ink-jet printing.
47. The wireless article of claim 41 wherein said melt-flowable adhesive has a bond strength greater than about 200 psi (14 kg/cm2) at temperatures less than about 45 C.
48. The wireless article of claim 41 wherein said substrate is of a material selected from the group consisting of polyvinyl chloride, acrylonitrile-butadiene- styrene polymer, high-impact polystyrene, polyester, and polyimide.
49. The wireless article of claim 41 further comprising a layer of melt-flowable adhesive on the first surface of said substrate covering said electronic device and adapted for attaching said wireless article to a utilization object, whereby said electronic device is encapsulated by said layer of melt-flowable adhesive.
50. An electronic article adapted for attachment to a utilization article comprising: a layer of electrically insulating adhesive providing a substrate adapted for adhering to a utilization object, the adhesive having an adhesive bond strength to a utilization object that substantially exceeds the intrinsic strength of the adhesive, whereby attempting to remove the substrate from a utilization object results in damage to the substrate before separation of the substrate from a utilization object; an electronic device that is one of mounted to and embedded in said adhesive substrate; and an antenna on a surface of said adhesive substrate and electrically connected to said electronic device.
51. The electronic article of claim 50 wherein at least a portion of said antenna is a frangible region having a strength substantially less than the intrinsic strength of the adhesive of said substrate, whereby attempting to remove the electronic article from a utilization object by physical force tends to damage the antenna.
52. The electronic article of claim 51 wherein said frangible region includes at least one of a thin region, a narrowed region, a notch, a thin foil of copper, aluminum or silver, electroless plated silver on activated plastic, electroless plated silver on activated ABS, and electrically-conductive adhesive bridging a gap in the pattern of electrically-conductive material.
53. The electronic article of claim 52 wherein at least said frangible region has at least one of a thickness less than about 0.025 mm and a width less than about 0.10 mm.
54. The electronic article of claim 51 wherein said antenna includes a patterned metal foil of copper, aluminum or silver, having a thickness of at least about 0.025 mm and a width at least in part of at least about 0.10 mm.
55. The electronic article of claim 51 wherein said antenna includes a pattern of one of electroless plated silver on activated plastic and electroless plated silver on activated ABS, the electroless silver having a thickness of less than about 0.025 mm and a width at least in part of at least about 0.10 mm.
56. The electronic article of claim 50 wherein said electronic device is electrically connected to said antenna by electrically-conductive adhesive that is one of (a) of substantially lower intrinsic strength than the intrinsic strength of the adhesive of said substrate, and (b) soluble in a solvent that dissolves the adhesive of said substrate, whereby attempting to remove the electronic article from a utilization object by physical force or solvent tends to damage the electrical connection of the antenna to the electronic device.
57. The electronic article of claim 50 wherein said antenna includes a patterned metal foil of one of copper, aluminum and silver, and electroless silver plating thereon for providing an antenna having a resistance of less than about 2 ohms.
PCT/US2000/027227 1999-10-04 2000-10-03 Tamper-resistant wireless article including an antenna WO2001026180A1 (en)

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
US09/411,849 US6353420B1 (en) 1999-04-28 1999-10-04 Wireless article including a plural-turn loop antenna
US09/411,849 1999-10-04
US09/412,058 US6404643B1 (en) 1998-10-15 1999-10-04 Article having an embedded electronic device, and method of making same
US09/412,058 1999-10-04
US16979099P 1999-12-09 1999-12-09
US60/169,790 1999-12-09
US21240100P 2000-06-19 2000-06-19
US60/212,401 2000-06-19

Publications (1)

Publication Number Publication Date
WO2001026180A1 true WO2001026180A1 (en) 2001-04-12

Family

ID=27496879

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2000/027227 WO2001026180A1 (en) 1999-10-04 2000-10-03 Tamper-resistant wireless article including an antenna

Country Status (1)

Country Link
WO (1) WO2001026180A1 (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003092073A2 (en) * 2002-04-23 2003-11-06 Alien Technology Corporation Electrical contacts for flexible displays
EP1467315A2 (en) * 2003-04-11 2004-10-13 Eastman Kodak Company Medium having data storage and communication capabilities and method for forming same
WO2005083836A1 (en) * 2004-02-20 2005-09-09 3M Innovative Properties Company Field-shaping shielding for radio frequency identification (rfid) system
US7102522B2 (en) 2002-12-24 2006-09-05 3M Innovative Properties Company Tamper-indicating radio frequency identification antenna and sticker, a radio frequency identification antenna, and methods of using the same
US7259678B2 (en) 2003-12-08 2007-08-21 3M Innovative Properties Company Durable radio frequency identification label and methods of manufacturing the same
WO2013100607A1 (en) * 2011-12-29 2013-07-04 전자부품연구원 Miniature antenna apparatus
WO2016168423A1 (en) * 2015-04-14 2016-10-20 Capital One Services, LLC. Tamper-resistant dynamic transaction card and method of providing a tamper-resistant dynamic transaction card
US9710744B2 (en) 2015-04-14 2017-07-18 Capital One Services, Llc Tamper-resistant dynamic transaction card and method of providing a tamper-resistant dynamic transaction card
US11177809B2 (en) 2018-01-09 2021-11-16 Inteva Products France Sas Ripple count circuit

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5463404A (en) * 1994-09-30 1995-10-31 E-Systems, Inc. Tuned microstrip antenna and method for tuning
US5574470A (en) * 1994-09-30 1996-11-12 Palomar Technologies Corporation Radio frequency identification transponder apparatus and method
US5892661A (en) * 1996-10-31 1999-04-06 Motorola, Inc. Smartcard and method of making
US5903239A (en) * 1994-08-11 1999-05-11 Matsushita Electric Industrial Co., Ltd. Micro-patch antenna connected to circuits chips
US5936305A (en) * 1997-11-20 1999-08-10 Micron Technology, Inc. Stacked leads-over chip multi-chip module
US6018299A (en) * 1998-06-09 2000-01-25 Motorola, Inc. Radio frequency identification tag having a printed antenna and method
US6161761A (en) * 1998-07-09 2000-12-19 Motorola, Inc. Card assembly having a loop antenna formed of a bare conductor and method for manufacturing the card assembly

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5903239A (en) * 1994-08-11 1999-05-11 Matsushita Electric Industrial Co., Ltd. Micro-patch antenna connected to circuits chips
US5463404A (en) * 1994-09-30 1995-10-31 E-Systems, Inc. Tuned microstrip antenna and method for tuning
US5574470A (en) * 1994-09-30 1996-11-12 Palomar Technologies Corporation Radio frequency identification transponder apparatus and method
US5892661A (en) * 1996-10-31 1999-04-06 Motorola, Inc. Smartcard and method of making
US5936305A (en) * 1997-11-20 1999-08-10 Micron Technology, Inc. Stacked leads-over chip multi-chip module
US6018299A (en) * 1998-06-09 2000-01-25 Motorola, Inc. Radio frequency identification tag having a printed antenna and method
US6161761A (en) * 1998-07-09 2000-12-19 Motorola, Inc. Card assembly having a loop antenna formed of a bare conductor and method for manufacturing the card assembly

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6864435B2 (en) 2001-04-25 2005-03-08 Alien Technology Corporation Electrical contacts for flexible displays
WO2003092073A3 (en) * 2002-04-23 2004-05-27 Alien Technology Corp Electrical contacts for flexible displays
WO2003092073A2 (en) * 2002-04-23 2003-11-06 Alien Technology Corporation Electrical contacts for flexible displays
US7102522B2 (en) 2002-12-24 2006-09-05 3M Innovative Properties Company Tamper-indicating radio frequency identification antenna and sticker, a radio frequency identification antenna, and methods of using the same
EP1467315A2 (en) * 2003-04-11 2004-10-13 Eastman Kodak Company Medium having data storage and communication capabilities and method for forming same
EP1467315A3 (en) * 2003-04-11 2006-02-15 Eastman Kodak Company Medium having data storage and communication capabilities and method for forming same
US7051429B2 (en) 2003-04-11 2006-05-30 Eastman Kodak Company Method for forming a medium having data storage and communication capabilities
US7259678B2 (en) 2003-12-08 2007-08-21 3M Innovative Properties Company Durable radio frequency identification label and methods of manufacturing the same
WO2005083836A1 (en) * 2004-02-20 2005-09-09 3M Innovative Properties Company Field-shaping shielding for radio frequency identification (rfid) system
US7421245B2 (en) 2004-02-20 2008-09-02 3M Innovative Properties Company Field-shaping shielding for radio frequency identification (RFID) system
WO2013100607A1 (en) * 2011-12-29 2013-07-04 전자부품연구원 Miniature antenna apparatus
WO2016168423A1 (en) * 2015-04-14 2016-10-20 Capital One Services, LLC. Tamper-resistant dynamic transaction card and method of providing a tamper-resistant dynamic transaction card
US9710744B2 (en) 2015-04-14 2017-07-18 Capital One Services, Llc Tamper-resistant dynamic transaction card and method of providing a tamper-resistant dynamic transaction card
US9965715B2 (en) 2015-04-14 2018-05-08 Capital One Services, Llc Tamper-resistant transaction card and method of providing a tamper-resistant transaction card
US10474939B2 (en) 2015-04-14 2019-11-12 Capital One Services, Llc Tamper-resistant transaction card and method of providing a tamper-resistant transaction card
US10929740B2 (en) 2015-04-14 2021-02-23 Capital One Services, Llc Tamper-resistant transaction card and method of providing a tamper-resistant transaction card
US11354554B2 (en) 2015-04-14 2022-06-07 Capital One Services, Llc Tamper-resistant transaction card and method of providing a tamper-resistant transaction card
US11177809B2 (en) 2018-01-09 2021-11-16 Inteva Products France Sas Ripple count circuit
US11838023B2 (en) 2018-01-09 2023-12-05 Inteva France Ripple count circuit

Similar Documents

Publication Publication Date Title
US6421013B1 (en) Tamper-resistant wireless article including an antenna
US6353420B1 (en) Wireless article including a plural-turn loop antenna
US6886246B2 (en) Method for making an article having an embedded electronic device
US6288905B1 (en) Contact module, as for a smart card, and method for making same
US6259408B1 (en) RFID transponders with paste antennas and flip-chip attachment
EP1399881B1 (en) A smart label and a smart label web
US6940408B2 (en) RFID device and method of forming
US6973716B2 (en) Electronic circuit construction method, as for a wireless RF tag
US6140146A (en) Automated RFID transponder manufacturing on flexible tape substrates
KR100770193B1 (en) Ic card
EP1976060B1 (en) Antenna built-in module, card type information device and methods for manufacturing them
US8284117B2 (en) Antenna device and method of manufacturing the same
KR20030060894A (en) Method for assembling components and antennae in radio frequency identification devices
CN101432926A (en) Electronic circuit module with built-in antenna and method for manufacturing the same
EP1272285A1 (en) High speed flip chip assembly process
WO2001026180A1 (en) Tamper-resistant wireless article including an antenna
US6281048B1 (en) Method of making an electronic component, and an electronic component
JP4675184B2 (en) IC tag
KR100846236B1 (en) A smart card web and a method for its manufacture
US20060057763A1 (en) Method of forming a surface mountable IC and its assembly
WO2001003188A1 (en) Integrated circuit attachment process and apparatus
JP2003256798A (en) Non-contact data carrier and method of manufacturing the data carrier
JP3463539B2 (en) Flexible circuit board with anisotropic conductive adhesive and manufacturing method
JP2002183696A (en) Method of manufacturing coil of ic card

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CN JP KR SG US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP