US3901770A - Method for the production of microscopically small metal or metal alloy structures - Google Patents

Method for the production of microscopically small metal or metal alloy structures Download PDF

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US3901770A
US3901770A US436513A US43651374A US3901770A US 3901770 A US3901770 A US 3901770A US 436513 A US436513 A US 436513A US 43651374 A US43651374 A US 43651374A US 3901770 A US3901770 A US 3901770A
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    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/108—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by semi-additive methods; masks therefor
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C19/00—Digital stores in which the information is moved stepwise, e.g. shift registers
    • G11C19/02—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements
    • G11C19/08—Digital stores in which the information is moved stepwise, e.g. shift registers using magnetic elements using thin films in plane structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
    • H01B5/14—Non-insulated conductors or conductive bodies characterised by their form comprising conductive layers or films on insulating-supports
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/32—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying conductive, insulating or magnetic material on a magnetic film, specially adapted for a thin magnetic film
    • H01F41/34—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying conductive, insulating or magnetic material on a magnetic film, specially adapted for a thin magnetic film in patterns, e.g. by lithography
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/702—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof of thick-or thin-film circuits or parts thereof
    • H01L21/707—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof of thick-or thin-film circuits or parts thereof of thin-film circuits or parts thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
    • 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
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
    • H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
    • H05K3/067—Etchants
    • 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
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • 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
    • H01L2924/095—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00 with a principal constituent of the material being a combination of two or more materials provided in the groups H01L2924/013 - H01L2924/0715
    • H01L2924/097—Glass-ceramics, e.g. devitrified glass
    • H01L2924/09701—Low temperature co-fired ceramic [LTCC]
    • 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
    • H05K1/03—Use of materials for the substrate
    • H05K1/0306—Inorganic insulating substrates, e.g. ceramic, glass
    • 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
    • H05K2203/07—Treatments involving liquids, e.g. plating, rinsing
    • H05K2203/0703—Plating
    • H05K2203/0723—Electroplating, e.g. finish plating
    • 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
    • H05K2203/07—Treatments involving liquids, e.g. plating, rinsing
    • H05K2203/0703—Plating
    • H05K2203/073—Displacement plating, substitution plating or immersion plating, e.g. for finish plating
    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
    • H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
    • H05K3/061—Etching masks
    • H05K3/062—Etching masks consisting of metals or alloys or metallic inorganic compounds
    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
    • H05K3/388—Improvement of the adhesion between the insulating substrate and the metal by the use of a metallic or inorganic thin film adhesion layer

Definitions

  • ABSTRACT This invention deals with the deposition of a microscopically small metal or metal alloy structure in which a relatively thin metal or metal alloy such as a nickel-iron alloy is vapor deposited upon a carrier after which a photoresist layer is applied over the thin layer. Channels in the form desired in the ultimate pattern are then produced using the conventional photographic technique, to leave the desired pattern exposed in the previously deposited thin layer. A thin layer of gold is then applied to the exposed layer and a thicker metal or metal alloy layer is then galvanically deposited on the gold layer. The remaining photoresist layer is then removed, followed by the removal of the remaining thin layer of metal or metal alloy. The process may also include the deposition of a thin layer of gold over the thicker layer of alloy.
  • a relatively thin metal or metal alloy such as a nickel-iron alloy
  • Field of the Invention This invention is in the field of producing microscopically small metal or metal alloy structures by successive deposition of a thin metal layer, followed by a gold layer, and a relatively thick metalor metal alloy layer. The conditions are such that the lateral erosion of the structure is minimized.
  • Microscopically small metal or metal alloy structures are required, for example, in the production of manipulation patterns for cylindrical magnetic domainsand for the micro-wiring of integrated circuits. If the required line width of these structures, such as occur in the aforementioned manipulation patterns amounts to approximately 3 to 20 microns, it has proven to be extremely difficult when using the photo-etching method to keep the sub-etching, that is, the lateral erosion of the structure sufficiently small in the zone of the structure protected by the photo lacquers. In order to avoide these difficulties, a number of other prior art methods have been used heretofore such as described, for example, in Al? Conference Proceedings No. 5, 1971, page 215 in Appl. Phys. Letter Vol. 17, page 328 (1970) and in the Journal Appl. Phys, Vol. 42, page 1,362 (1971).
  • This invention is directed to a relatively simplified method for preventing sub-etching of the structures when using the conventional photo lacquer techniques in the production of microscopically small metal or metal alloy structures.
  • a thin continuous metal or metal alloy layer vapor deposited on a carrier such as a glass carrier.
  • a photo lacquer layer is applied onto the metal or metal alloy layer and channels corresponding to the desired metal or metal alloy structure are formed in the photo lacquer layer in the usual manner, that is, by exposing the lacquer to a light source through a mask having the desired pattern formed therein and then removing the exposed portions by means of a suitable solvent, leaving the unexposed photoresist layer. The removal of the exposed channels of the photoresist material exposes the underlying thin continuous layer in these areas.
  • a thin gold layer is galvanically deposited on the exposed metal or metal alloy layer.
  • a thicker deposit of the same metal or metal alloy is galvanically deposited onto the gold layer.
  • the remaining photo lacquer layer is then removed, followed by the removal of the originally deposited thin metal or metal alloy layer.
  • the method of the present invention can be carried out without significant difficulty.
  • the edge sharpness of the structures which result is quite precise.
  • the dimensions of the structures are not significantly affected by etching treatments.
  • small nonhomogenities in the photo lacquer which can otherwise lead to an unwanted etching of the layers do not interfere. It is possible by means of the method of the present invention to produce structures with close dimensional tolerances, having dimensions on the order of 5 to 20 microns, and to produce structures reproducibly in conformity to the mask in the required layer thicknesses.
  • the uniform thickness and edge sharpness of the structures are insured primarily by the thin'gold layer.
  • the preferred method according to the present invention is suitable for the production of manipulation patterns for cylindrical magnetic domains, utilizing a magnetostriction-free nickel-iron alloy such as an alloy containing about 79 to 83 weight percent nickel, and 21 to 17 weight percent iron.
  • This nickel-iron alloy is vapor deposited onto a substrate such as glass to a thickness of approximately 100 to 500 Angstroms and, more preferably, to a thickness of about'300' Angstroms.
  • I f v The photoresist layer is'then applied and exposed through a mask and developed photographically to provide the configuration of channels desired in the final product. The exposed portions of the photoresist layer are removed by a suitable solvent in accordance with the usual photomask technique.
  • a thin gold layer measuring several hundred Angstroms in thickness (200-800) and preferably 600 Anstroms is deposited over the thin nickel-iron alloy.
  • a relatively thick nickel-iron layer measuring several thousand Angstroms in thickness, usually about 10,000 Anstrorns in thickness, is galvanically deposited over the exposed portions of the gold layer.
  • a second thin gold layer is then preferably galvanically deposited onto the thicker nickel-iron layer, the gold layer acting as a protective layer during the subsequent etching away of the thin nickel-iron layer.
  • the gold is preferably galvanically deposited on the iron-nickellayer to a thickness of several hundred Angstroms, usually about 600 Angstroms.
  • the entire nickel-iron layer is dissolved in a few minutes and is replaced by a gold layer of comparable dimensions.
  • the gold layer can be etched away be means of a suitable gold etching means such as a dilute potassium cyanide solution with a concentration of about 20 grams KCN/liter H O to grams KCN/liter H O, for example, 60 grams KCN/Liter H O.
  • nickel-iron etching solutions such as solutions of ferric chloride attack the galvanically reinforced nickel-iron layer and also the thicker nickel-iron layer to a substantial extent when the 200 to 300 Angstrom thick nickel-iron layer is being removed.
  • ferric chloride attack the galvanically reinforced nickel-iron layer and also the thicker nickel-iron layer to a substantial extent when the 200 to 300 Angstrom thick nickel-iron layer is being removed.
  • gold bath according to the present invention only the 200 to 300 Angstrom nickel-iron layer is removed from the thicker nickel-iron layer.
  • FIG. 1 is a greatly enlarged view illustrating the structure after the channels have been formed by the photographic process
  • FIG. 2 illustrates the structure after the deposition of the two gold layers and the intermediate metal alloy layer
  • FIG. 3 is a view of the structure after removal of the residual photoresist layer.
  • a nickel-iron layer 2 which is approximately 200 to 300 Angstroms thick is vapor deposited upon a carrier 1 composed of glass, ceramic or other insulating material.
  • a photo lacquer layer 3 is applied onto the nickeliron layer 2.
  • Channels 7 having the configuration of the desired nickel-iron structure are then provided in the usual way by exposing the surface to the light through a suitable mask and removing the exposed areas in which the channels are to appear, leaving the underlying nickel-iron layer 2 exposed in those areas.
  • a gold layer 4 measuring several hundred Angstroms in thickness, and usually around 600 Angstroms is galvanically deposited on the exposed nickel-iron layer 2, using an suitable commercial gold bath.
  • a relatively thick nickel-iron layer 5 whose thickness is measured in thousands of Angstrom units, preferably about 10,000 Angstrom units galvanically deposited over the predeposited gold layer 4.
  • the remaining photo lacquer layer 3 is subsequently dissolved as illustrated in FIG. 3 and the structure this produced is placed into a slightly acid gold bath, whereby after a few minutes the entire non-reinforced nickel-iron layer 2 of approximately 300 Angstroms in thickness, is removed and replaced by a correspondingly thick gold layer.
  • This gold layer can be easily etched away by a gold etching means such as a dilute potassium cyanide solution.
  • the removal of the unreinforced nickel-iron layer in certain areas by means of the exchange reaction in the gold bath and the subsequent gold etching is particularly desirable in the manufacture of signal detectors for cylindrical magnetic domains.
  • a method for the production of microscopically small metal or metal alloy structures comprising vapor depositing a thin continuous layer of metal or metal alloy on a substrate, applying a photoresist layer over the thus deposited layer, forming channels in said photoresist layer corresponding to the desired pattern thereby exposing said continuous layer in the channels, galvanically depositing a thin gold layer on the exposed portions of said layer, galvanically depositing a thicker metal or metal alloy on said thin gold layer, removing the remaining photoresist layer, treating the remaining thin metal or metal alloy to replace the metal or metal alloy layer with a gold layer, and etching away the lastnamed gold layer.
  • a method for the production of microscopically small metal structures which comprises vapor depositing a thin continuous layer of a nickel-iron alloy onto a substrate, applying a photoresist layer over the thus deposited layer, forming channels in said photoresist layer corresponding to the desired pattern thereby exposing said continous layer in said channels, galvanically depositing a first thin layer of gold over the exposed portions of said layer, galvanically depositing a thicker layer of nickel-iron alloy over said first thin layer of gold, removing the remaining photoresist layer, treating the remaining structure in a slightly acid gold bath to replace said thin nickel-iron layer with a gold layer, and etching away the last-named gold layer.

Abstract

This invention deals with the deposition of a microscopically small metal or metal alloy structure in which a relatively thin metal or metal alloy such as a nickel-iron alloy is vapor deposited upon a carrier after which a photoresist layer is applied over the thin layer. Channels in the form desired in the ultimate pattern are then produced using the conventional photographic technique, to leave the desired pattern exposed in the previously deposited thin layer. A thin layer of gold is then applied to the exposed layer and a thicker metal or metal alloy layer is then galvanically deposited on the gold layer. The remaining photoresist layer is then removed, followed by the removal of the remaining thin layer of metal or metal alloy. The process may also include the deposition of a thin layer of gold over the thicker layer of alloy.

Description

United States Patent [1 1 [111 3,901,770
Littwin 1 Aug. 26, 1975 METHOD FOR THE PRODUCTION OF MICROSCOPICALLY SMALL METAL OR METAL ALLOY STRUCTURES [75] Inventor: Burkhard Littwin, Munich, Germany [73] Assignee: Siemens Aktiengesellschaft, Berlin & Munich, Germany [22] Filed: Jan. 25, 1974 [21] Appl. No.: 436,513
[30] Foreign Application Priority Data Jan. 31, 1973 Germany 2304685 [52] US. Cl. 204/15; 156/8; 156/18 [51] Int. Cl C23b 5/48 [58] Field of Search 204/15; 117/212; 156/8, 156/18 [56] References Cited UNITED STATES PATENTS 3,306,830 2/1967 Bittrich et al 204/15 3,575,824 4/1971 Eide 204/15 3,576,722 4/1971 Fennirnore et al 204/15 OTHER PUBLICATIONS Plating, May 1969 pgs. 505-510.
Primary ExaminerT. M. Tufariello Attorney, Agent, or Firml-lill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT This invention deals with the deposition of a microscopically small metal or metal alloy structure in which a relatively thin metal or metal alloy such as a nickel-iron alloy is vapor deposited upon a carrier after which a photoresist layer is applied over the thin layer. Channels in the form desired in the ultimate pattern are then produced using the conventional photographic technique, to leave the desired pattern exposed in the previously deposited thin layer. A thin layer of gold is then applied to the exposed layer and a thicker metal or metal alloy layer is then galvanically deposited on the gold layer. The remaining photoresist layer is then removed, followed by the removal of the remaining thin layer of metal or metal alloy. The process may also include the deposition of a thin layer of gold over the thicker layer of alloy.
6 Claims, 3 Drawing Figures It SI/Z 1 I METHOD FOR THE PRODUCTION OF MICROSCOPICALLY SMALL METAL OR METAL ALLOY STRUCTURES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is in the field of producing microscopically small metal or metal alloy structures by successive deposition of a thin metal layer, followed by a gold layer, and a relatively thick metalor metal alloy layer. The conditions are such that the lateral erosion of the structure is minimized.
2. Description of the Prior Art Microscopically small metal or metal alloy structures are required, for example, in the production of manipulation patterns for cylindrical magnetic domainsand for the micro-wiring of integrated circuits. If the required line width of these structures, such as occur in the aforementioned manipulation patterns amounts to approximately 3 to 20 microns, it has proven to be extremely difficult when using the photo-etching method to keep the sub-etching, that is, the lateral erosion of the structure sufficiently small in the zone of the structure protected by the photo lacquers. In order to avoide these difficulties, a number of other prior art methods have been used heretofore such as described, for example, in Al? Conference Proceedings No. 5, 1971, page 215 in Appl. Phys. Letter Vol. 17, page 328 (1970) and in the Journal Appl. Phys, Vol. 42, page 1,362 (1971).
This invention is directed to a relatively simplified method for preventing sub-etching of the structures when using the conventional photo lacquer techniques in the production of microscopically small metal or metal alloy structures.
SUMMARY OF THE INVENTION In the process of the present invention, a thin continuous metal or metal alloy layer vapor deposited on a carrier such as a glass carrier. A photo lacquer layer is applied onto the metal or metal alloy layer and channels corresponding to the desired metal or metal alloy structure are formed in the photo lacquer layer in the usual manner, that is, by exposing the lacquer to a light source through a mask having the desired pattern formed therein and then removing the exposed portions by means of a suitable solvent, leaving the unexposed photoresist layer. The removal of the exposed channels of the photoresist material exposes the underlying thin continuous layer in these areas. A thin gold layer is galvanically deposited on the exposed metal or metal alloy layer. Next, a thicker deposit of the same metal or metal alloy is galvanically deposited onto the gold layer. The remaining photo lacquer layer is then removed, followed by the removal of the originally deposited thin metal or metal alloy layer.
The method of the present invention can be carried out without significant difficulty. The edge sharpness of the structures which result is quite precise. The dimensions of the structures are not significantly affected by etching treatments. In addition, small nonhomogenities in the photo lacquer which can otherwise lead to an unwanted etching of the layers do not interfere. It is possible by means of the method of the present invention to produce structures with close dimensional tolerances, having dimensions on the order of 5 to 20 microns, and to produce structures reproducibly in conformity to the mask in the required layer thicknesses. The uniform thickness and edge sharpness of the structures are insured primarily by the thin'gold layer.
The preferred method according to the present invention is suitable for the production of manipulation patterns for cylindrical magnetic domains, utilizing a magnetostriction-free nickel-iron alloy such as an alloy containing about 79 to 83 weight percent nickel, and 21 to 17 weight percent iron. This nickel-iron alloy is vapor deposited onto a substrate such as glass to a thickness of approximately 100 to 500 Angstroms and, more preferably, to a thickness of about'300' Angstroms. I f v The photoresist layer is'then applied and exposed through a mask and developed photographically to provide the configuration of channels desired in the final product. The exposed portions of the photoresist layer are removed by a suitable solvent in accordance with the usual photomask technique. Following this, a thin gold layer measuring several hundred Angstroms in thickness (200-800) and preferably 600 Anstroms is deposited over the thin nickel-iron alloy. Next, a relatively thick nickel-iron layer measuring several thousand Angstroms in thickness, usually about 10,000 Anstrorns in thickness, is galvanically deposited over the exposed portions of the gold layer. A second thin gold layer is then preferably galvanically deposited onto the thicker nickel-iron layer, the gold layer acting as a protective layer during the subsequent etching away of the thin nickel-iron layer. The gold is preferably galvanically deposited on the iron-nickellayer to a thickness of several hundred Angstroms, usually about 600 Angstroms.
For the removal of the non-reinforced thin nickeliron layer, it is advisable and preferred to immerse the carriers processed in the manner described above when freed from the residual photo lacquer layer in a slightly acid gold bath, for instance Autronex C1 bath of Sel- Rex International containing 8 grams gold/liter and having a pH of 3.5, whereby the nickel-iron thin layer is removed and replaced by a correspondingly thin gold layer which can be easily etched by means of conventional gold etching means. An exchange reaction takes place in the bath which is caused by the potential differences occuring between the nickel-iron and the gold layers, whereby the nickel-iron goes into solution and is replaced by an equivalent amount of gold. The entire nickel-iron layer, usually 200 to 300 angstroms thick, is dissolved in a few minutes and is replaced by a gold layer of comparable dimensions. Without affecting the galvanically applied nickel-iron layer, the gold layer can be etched away be means of a suitable gold etching means such as a dilute potassium cyanide solution with a concentration of about 20 grams KCN/liter H O to grams KCN/liter H O, for example, 60 grams KCN/Liter H O.
Presently used nickel-iron etching solutions such as solutions of ferric chloride attack the galvanically reinforced nickel-iron layer and also the thicker nickel-iron layer to a substantial extent when the 200 to 300 Angstrom thick nickel-iron layer is being removed. In the gold bath according to the present invention, however, only the 200 to 300 Angstrom nickel-iron layer is removed from the thicker nickel-iron layer.
BRIEF DESCRIPTION OF THE DRAWINGS A further description of the present invention will be made in connection with the attached drawings in which:
FIG. 1 is a greatly enlarged view illustrating the structure after the channels have been formed by the photographic process;
FIG. 2 illustrates the structure after the deposition of the two gold layers and the intermediate metal alloy layer; and
FIG. 3 is a view of the structure after removal of the residual photoresist layer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A nickel-iron layer 2 which is approximately 200 to 300 Angstroms thick is vapor deposited upon a carrier 1 composed of glass, ceramic or other insulating material. A photo lacquer layer 3 is applied onto the nickeliron layer 2. Channels 7 having the configuration of the desired nickel-iron structure are then provided in the usual way by exposing the surface to the light through a suitable mask and removing the exposed areas in which the channels are to appear, leaving the underlying nickel-iron layer 2 exposed in those areas.
In the next step of the procedure, a gold layer 4 measuring several hundred Angstroms in thickness, and usually around 600 Angstroms is galvanically deposited on the exposed nickel-iron layer 2, using an suitable commercial gold bath. Subsequently, a relatively thick nickel-iron layer 5, whose thickness is measured in thousands of Angstrom units, preferably about 10,000 Angstrom units galvanically deposited over the predeposited gold layer 4. Next, a second gold layer 6 serving as a protective layer, and measuring several hundred Angstrom units in thickness, usually about 600 Angstroms, is galvanically deposited on the relatively thick nickel-iron layer 5.
The remaining photo lacquer layer 3 is subsequently dissolved as illustrated in FIG. 3 and the structure this produced is placed into a slightly acid gold bath, whereby after a few minutes the entire non-reinforced nickel-iron layer 2 of approximately 300 Angstroms in thickness, is removed and replaced by a correspondingly thick gold layer. This gold layer can be easily etched away by a gold etching means such as a dilute potassium cyanide solution. The removal of the unreinforced nickel-iron layer in certain areas by means of the exchange reaction in the gold bath and the subsequent gold etching is particularly desirable in the manufacture of signal detectors for cylindrical magnetic domains.
It should be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
I claim as my invention:
1. A method for the production of microscopically small metal or metal alloy structures comprising vapor depositing a thin continuous layer of metal or metal alloy on a substrate, applying a photoresist layer over the thus deposited layer, forming channels in said photoresist layer corresponding to the desired pattern thereby exposing said continuous layer in the channels, galvanically depositing a thin gold layer on the exposed portions of said layer, galvanically depositing a thicker metal or metal alloy on said thin gold layer, removing the remaining photoresist layer, treating the remaining thin metal or metal alloy to replace the metal or metal alloy layer with a gold layer, and etching away the lastnamed gold layer.
2. The method of claim 1 in which said metal is a nickel-iron alloy.
'3. The method of claim 1 in which said thin continuous layer of metal or metal alloy has a thickness of about to 500 Angstroms.
4. The method of claim 1 in which the second layer of gold has a thickness of several hundred Angstroms.
5. A method for the production of microscopically small metal structures which comprises vapor depositing a thin continuous layer of a nickel-iron alloy onto a substrate, applying a photoresist layer over the thus deposited layer, forming channels in said photoresist layer corresponding to the desired pattern thereby exposing said continous layer in said channels, galvanically depositing a first thin layer of gold over the exposed portions of said layer, galvanically depositing a thicker layer of nickel-iron alloy over said first thin layer of gold, removing the remaining photoresist layer, treating the remaining structure in a slightly acid gold bath to replace said thin nickel-iron layer with a gold layer, and etching away the last-named gold layer.
'6. The method of claim 5 in which the gold etching is carried out by means of a dilute potassium cyanide solution.

Claims (6)

1. A METHOD FOR THE PRODUCTION OF MICROCOPIALLY SMALL METAL OR METAL ALLOY STRUCTURES COMPRISING VAPOR DEPOSITING A THIN CONTINUOUS LAYER OF METAL OR METAL ALLOY ON A SUBSTRATE, APPLYING A PHOTORESIST LAYER OVER THE THUS DEPOSITE LAYER, FORMING CHANNELS IN SAID PHOTORESIST LAYER CORRESPONDING TO THE DESIRED PATTERN THEREBY EXPOSING SAID CONTINUOUS LAYER IN THE CHANNELS, GALVANICALLY DEPOSITING A THIN GOLD LAYER ON THE
2. The method of claim 1 in which said metal is a nickel-iron alloy.
3. The method of claim 1 in which said thin continuous layer of metal or metal alloy has a thickness of about 100 to 500 Angstroms.
4. The method of claim 1 in which The second layer of gold has a thickness of several hundred Angstroms.
5. A method for the production of microscopically small metal structures which comprises vapor depositing a thin continuous layer of a nickel-iron alloy onto a substrate, applying a photoresist layer over the thus deposited layer, forming channels in said photoresist layer corresponding to the desired pattern thereby exposing said continous layer in said channels, galvanically depositing a first thin layer of gold over the exposed portions of said layer, galvanically depositing a thicker layer of nickel-iron alloy over said first thin layer of gold, removing the remaining photoresist layer, treating the remaining structure in a slightly acid gold bath to replace said thin nickel-iron layer with a gold layer, and etching away the last-named gold layer.
6. The method of claim 5 in which the gold etching is carried out by means of a dilute potassium cyanide solution.
US436513A 1973-01-31 1974-01-25 Method for the production of microscopically small metal or metal alloy structures Expired - Lifetime US3901770A (en)

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Cited By (10)

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Publication number Priority date Publication date Assignee Title
US4043877A (en) * 1975-03-19 1977-08-23 Siemens Aktiengesellschaft Method for the manufacture of microscopically small metal or metal-alloy structures
US4075757A (en) * 1975-12-17 1978-02-28 Perstorp Ab Process in the production of a multilayer printed board
US4179802A (en) * 1978-03-27 1979-12-25 International Business Machines Corporation Studded chip attachment process
US4193849A (en) * 1977-03-18 1980-03-18 Nippon Mining Co., Ltd. Method for making a raw board for use in printed circuits
US4454014A (en) * 1980-12-03 1984-06-12 Memorex Corporation Etched article
FR2627003A1 (en) * 1988-02-04 1989-08-11 Canon Kk MAGNETIC BUBBLE RECORDING DEVICE
US4878294A (en) * 1988-06-20 1989-11-07 General Dynamics Corp., Pomona Division Electroformed chemically milled probes for chip testing
US5027062A (en) * 1988-06-20 1991-06-25 General Dynamics Corporation, Air Defense Systems Division Electroformed chemically milled probes for chip testing
US5140547A (en) * 1987-12-01 1992-08-18 Canon Kabushiki Kaisha Magnetic bubble recording element
WO1997029223A1 (en) * 1996-02-09 1997-08-14 Board Of Supervisors Of Louisiana State University And Agricultural And Mechanical College High aspect ratio, microstructure-covered, macroscopic surfaces

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3957552A (en) * 1975-03-05 1976-05-18 International Business Machines Corporation Method for making multilayer devices using only a single critical masking step
US4001061A (en) * 1975-03-05 1977-01-04 International Business Machines Corporation Single lithography for multiple-layer bubble domain devices
DE2637652A1 (en) * 1976-08-20 1978-02-23 Siemens Ag Microscopic cylindrical domain store - has nickel- iron layer applied on storage layer, processed and non-magnetic layer subsequently applied on top

Citations (3)

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Publication number Priority date Publication date Assignee Title
US3306830A (en) * 1963-06-13 1967-02-28 Bell Telephone Labor Inc Printed circuit boards and their fabrication
US3575824A (en) * 1968-12-23 1971-04-20 Gen Electric Method of making a thin magnetic film storage device
US3576722A (en) * 1969-03-26 1971-04-27 Bendix Corp Method for metalizing ceramics

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3306830A (en) * 1963-06-13 1967-02-28 Bell Telephone Labor Inc Printed circuit boards and their fabrication
US3575824A (en) * 1968-12-23 1971-04-20 Gen Electric Method of making a thin magnetic film storage device
US3576722A (en) * 1969-03-26 1971-04-27 Bendix Corp Method for metalizing ceramics

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4043877A (en) * 1975-03-19 1977-08-23 Siemens Aktiengesellschaft Method for the manufacture of microscopically small metal or metal-alloy structures
US4075757A (en) * 1975-12-17 1978-02-28 Perstorp Ab Process in the production of a multilayer printed board
US4193849A (en) * 1977-03-18 1980-03-18 Nippon Mining Co., Ltd. Method for making a raw board for use in printed circuits
US4179802A (en) * 1978-03-27 1979-12-25 International Business Machines Corporation Studded chip attachment process
US4454014A (en) * 1980-12-03 1984-06-12 Memorex Corporation Etched article
US5140547A (en) * 1987-12-01 1992-08-18 Canon Kabushiki Kaisha Magnetic bubble recording element
FR2627003A1 (en) * 1988-02-04 1989-08-11 Canon Kk MAGNETIC BUBBLE RECORDING DEVICE
US5142491A (en) * 1988-02-04 1992-08-25 Canon Kabushiki Kaisha Magnetic bubble recording device
US4878294A (en) * 1988-06-20 1989-11-07 General Dynamics Corp., Pomona Division Electroformed chemically milled probes for chip testing
US5027062A (en) * 1988-06-20 1991-06-25 General Dynamics Corporation, Air Defense Systems Division Electroformed chemically milled probes for chip testing
WO1997029223A1 (en) * 1996-02-09 1997-08-14 Board Of Supervisors Of Louisiana State University And Agricultural And Mechanical College High aspect ratio, microstructure-covered, macroscopic surfaces
US6197180B1 (en) 1996-02-09 2001-03-06 Board Of Supervisors Of Louisiana State University And Agricultural And Mechanical College High aspect ratio, microstructure-covered, macroscopic surfaces

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DE2304685A1 (en) 1974-08-15
JPS5842276B2 (en) 1983-09-19
GB1414947A (en) 1975-11-19
DE2304685B2 (en) 1974-11-28
NL7316471A (en) 1974-08-02
FR2216369B1 (en) 1979-06-01
FR2216369A1 (en) 1974-08-30
DE2304685C3 (en) 1975-07-17
JPS49106442A (en) 1974-10-09

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