WO2002042511A2 - Method of coating smooth electroless nickel on magnetic memory disks and related memory devices - Google Patents
Method of coating smooth electroless nickel on magnetic memory disks and related memory devices Download PDFInfo
- Publication number
- WO2002042511A2 WO2002042511A2 PCT/US2001/043232 US0143232W WO0242511A2 WO 2002042511 A2 WO2002042511 A2 WO 2002042511A2 US 0143232 W US0143232 W US 0143232W WO 0242511 A2 WO0242511 A2 WO 0242511A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- substrate
- layer
- alloy
- magnetic
- nickel
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73923—Organic polymer substrates
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/7368—Non-polymeric layer under the lowermost magnetic recording layer
- G11B5/7369—Two or more non-magnetic underlayers, e.g. seed layers or barrier layers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73913—Composites or coated substrates
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73917—Metallic substrates, i.e. elemental metal or metal alloy substrates
- G11B5/73919—Aluminium or titanium elemental or alloy substrates
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
- G11B5/739—Magnetic recording media substrates
- G11B5/73911—Inorganic substrates
- G11B5/73921—Glass or ceramic substrates
Definitions
- This invention relates generally to thin film magnetic memory disks and related planar devices; and to a procedure for their manufacture which permits the use of less expensive materials than prior art, simultaneously greatly reduces the use of process water and chemicals, and also greatly reduces the need for the treatment and disposal of waste chemicals.
- Hard magnetic disks are used to store digital information utilized for data processing.
- An advantage of such a disk is that it can provide high-speed random access. That is, one can either write or retrieve information from any selected area on the magnetic memory surface without having to serially traverse the full memory space of the disk.
- a hard magnetic disk is mounted within a disk drive which is akin to a record turntable in that it includes means for rotation of the disk and means for translating a head across the surface of the disk to provide access to a selected annular track.
- a plurality of disks are mounted on a single spindle in spaced relationship to one another and heads are provided to interact through their magnetic fields with oppositely close planar surfaces of each of such disks. With high density data storage made possible by the use of newer design heads and close flying heights, a single head and single disk surface may suffice for some applications. For planar magnetic storage devices such as cards, direct sliding contact by the head may be preferred.
- the hard disks now available for memory applications are typically coated with a magnetic storage layer.
- Each of the disk surfaces which receives and stores information has a thin layer of magnetic material carried by a substrate.
- the heads which interact with each of the surfaces are so-called “flying" heads i.e., they do not touch the surface of the disk during its rotation-rather, they ride on an air film which acts as a bearing between the disk and the head.
- the head typically includes a magnetic coil to permit interacting with the magnetic film through the intervening air film space. The air film prevents wear of the head and the thin magnetic layer on the disk surface which would otherwise be caused by a contact between the head and the surface film.
- the basis metal of the disk is generally an aluminum alloy, typically 0.030 inches thick for 2 inch diameter disks or 0.050 inches for 3.5 inch diameter disks. Disk alloys generally contain about 4 to 5 weight percent magnesium to add strength to the disk.
- nickel-phosphorus alloy 88Ni— 12P, weight percent basis as a typical example
- the 88Ni ⁇ 12P layer is typically 300 microinches thick after polishing to obtain a smooth surface.
- the hard 88Ni— 12P layer is a firm base which provides support to much thinner subsequently added magnetic layers.
- the 88Ni ⁇ 12P resists mechanical damage which might be caused by inadvertent contact impacts between the head and disk surface, also known as "head slap".
- the aluminum alloy substrate itself has recently been given initial polishing to minimize surface roughness.
- the premise for pre-polishing of the substrate is that a smooth starting surface for the substrate will yield a smooth 88Ni ⁇ 12P deposit.
- the mechanical pre-polishing action tends to produce regions at the substrate surface which, although mechanically smooth, may respond unevenly in the wet chemical steps which condition the substrate for electroless nickel plating according to the prior art.
- the uneven response of the highly polished substrate has been termed "carpeting" or
- the present invention overcomes the problem of "carpeting" of electroless 88Ni— 12P and also serves to reduce the cost of memory disk manufacture by incorporating the results of experimentation and recent technical advances in materials science together with the general method described earlier by Nanis in US 5,405,646.
- FIG. 2 The major steps of coating a disk with the several layers necessary for a thin film memory disk in accordance with the prior art are shown in FIG. 2.
- the aluminum alloy substrate (disk) is degreased, washed in an alkaline soap solution and then rinsed in water. It is then etched in a dilute mineral acid bath and is then rinsed. The surface is then prepared for electroless nickel plating of the 88Ni— 12P layer by a double zincating process.
- the above-mentioned sequence is included for example only and has many variants such as single or triple zincating.
- 5,405,646 including materials for the initiation layer, method of sputtering to apply said initiation layers and subsequent electroless deposition of 88Ni ⁇ 12P.
- Electroless 88Ni— 12P has been found to be a useful top layer for glass substrates and it continues to be a practical choice for aluminum alloy substrates of the 5086 class.
- other strong, non-magnetic, polishable metal substrates may be considered for memory disk applications when coated according to the present invention, thus offering the opportunity for substantial cost saving.
- One advantage of the invention resides in the ability to accommodate artifacts, such as chemical and microstructural variations produced by the mechanical cold working, of pre-polished substrates as well as chemical variations due to inherent microstructural intermetallic inclusions.
- a magnetic disk or device which comprises a super- smooth substrate with a metallic sputtered binder layer, formed directly on the substrate and a second layer of sputtered metal, which nucleates the electroless plating of a nickel alloy which, after polishing, becomes the support for a thin sputtered magnetic layer.
- the novel procedure of this invention uses equipment already familiar in the prior art of the disk manufacturing industry.
- This invention also permits the use of pre-polished substrate materials, and avoids an unwanted prior art roughening ("carpeting") of electroless nickel deposited on a prepolished smooth aluminum having characteristics of a cold-worked surface.
- This invention thereby affords substantial savings in the polishing of electroless nickel to the degree of smoothness required for close head-disk spacing.
- the number of disks (and heads) required has decreased. For example, one head and only one disk surface may replace multi-disk stacks which use for example five disks and nine heads in a stack of the disk drive.
- the present invention provides a means to coat electroless nickel alloy selectively on only one side of a disk or planar card memory device.
- a thinner disk drive device low “form factor”
- the present invention provides a means to coat electroless nickel alloy selectively on only one side of a disk or planar card memory device.
- two target sources of sputtered material are provided, one for each side.
- Sputter deposition can readily be limited to one planar surface of a disk or card by control of the appropriate power supply as the substrate advances into the zone of sputter deposition activity. Only the surface with a sputtered nucleating layer will initiate electroless nickel deposition, thereby eliminating the unused material which otherwise would be added by prior art wet processing which requires total immersion of the disk or planar surface.
- one of the objects of the present invention is to reduce manufacturing costs by a rearrangement of the steps of prior art, following the teaching of US 5,405,646 supplemented by advances in materials science and in the understanding of the process of electroless deposition.
- 88Ni ⁇ 12P plating to accommodate the chemical and metallurgical structure of a specific class of aluminum alloys favored as a substrate for memory disks, typically alloys designated as 5086, 5186, 5585, CZ46 and the like.
- the present invention follows US 5,405,646 by adding a thin non-magnetic layer, preferably by sputtering, onto a substrate, thereby creating a surface of uniform chemistry by masking microscopic inclusions whose chemical and electrochemical behavior are substantially different from that of the aluminum alloy matrix.
- the added thin non-magnetic layer may itself serve as a nucleant (reactive or catalytic) to induce growth of 88Ni— 12P (or other compositions) upon immersion of the substrate into the wet chemistry of electroless deposition.
- a second layer may preferably be interposed by sputtering to serve as a binder between the substrate and the catalyst layer.
- Chakrabarti et al. in US 5,747,135 seek to reduce the cost of memory disk manufacture by eliminating the need for prior art zincating and chemical pre-treatment. Chakrabarti et al. propose to bypass these steps by adding to an aluminum alloy substrate a sputtered layer of non-magnetic nickel alloy whose purpose is to catalyze the electroless deposition of 88Ni ⁇ 12P. The sputtered nickel alloys examined by Chakrabarti et al.
- the present invention facilitates the replacement of prior art aluminum alloy substrates by less expensive high-strength aluminum alloys or by other materials selected mainly for their mechanical characteristics. By adding a layer of electroless nickel to new substrate materials, a dual advantage is possible.
- novel high strength substrates may permit higher rotational speeds and thinner disks with reduced mass, thus requiring less power for drive motors and/or an increased number of disks in a stack.
- the addition of a layer of electroless nickel affords the advantage of a well-tried and tested surface for prior art fine polishing with familiar technology and also a surface known to be compatible with the sputtering steps used for adding magnetic layers (e.g. chromium underlayer, cobalt alloy magnetic layer, carbon overcoat).
- the familiar second and third steps (WET-DRY) of prior art can be continued in use even with novel high-strength substrates, thus gaining an advantage in speeding novel substrate disk products to market.
- the burden is thus eliminated for defining best conditions for adhesion and orientation of said magnetic layers if they were to be sputtered directly onto the novel substrate.
- polishing and burnishing will recognize that a variety of techniques are available to produce super-smooth finishes on novel substrate materials.
- the binder and catalyst layers added by the present invention will preserve the finish of the substrate, which will in turn be preserved as the electroless nickel layer grows, thus requiring minimal polishing and thereby reduced cost.
- the smoother electroless nickel layer may be plated thinner than in prior art, conferring additional cost saving.
- the binder layer of the present invention such as chromium
- chromium is a suitable means to promote adhesion to metals which have thin naturally occurring protective oxide layers on their surface, such as titanium and its alloys. Chromium is also an effective binder layer to glass and ceramic materials.
- new improvements have generally been accompanied by new problems to be overcome.
- pre-polishing of aluminum alloy substrates to provide super- smooth substrates has provided smooth surfaces but has also mechanically induced non-uniform chemical behavior in the preparation and plating steps of the prior art.
- a super smooth substrate as the phrase is used herein refers to a substrate having an average surface roughness Ra in the range of about 30 Angstroms or smoother, or more preferably in the range of about 20 Angstroms or smoother. Measurements of average surface roughness at this level of smoothness are difficult, thus an Ra of about 30 Angstroms encompasses smoothness in a range of 30 Angstroms plus or minus measurement uncertainties of around 15% to 25%. Similar or even greater measurement uncertainties apply to smoother results.
- the super smooth substrate is manufactured, for example, by a fixed-pad abrasive polishing, with a resultant cold-working of the surface.
- the present invention masks artifacts of the processes used to provide a substrate having a super smooth surface, such as mechanically induced chemical variations believed to be induced by cold-working, which result in uneven patchy 88Ni ⁇ 12P plating ("carpeting" or "wall effect") and also masks the inherent microstructural chemical differences attributed to intermetallic compound particles in prior art aluminum alloys.
- the present invention also avoids roughness as induced by the etch baths of the first WET step of prior art.
- the present invention permits the zincate surface preparation steps of the prior art to be completely bypassed, thereby conferring cost savings from
- polishing step A major component of cost in the prior art is the polishing step (second WET step).
- Present practice favors the use of two polishing stages, with a first abrasive of alumina slurry and a second stage of fine polishing with colloidal silica.
- the positioning of plated disks on polishing pads is labor intensive as is also their removal and thorough rinsing at the end of polishing.
- An estimate of the cost of two-stage prior art polishing indicates it is 20 to 25 % of processing costs, or even greater when yields are factored into the estimate.
- the present invention offers a good opportunity for significant reduction of the polishing cost.
- the multiple steps of the prior art surface preparation are eliminated in the present invention and are replaced by a single step, increasing the opportunity for greater yields.
- soap rinse and mild acid etches are considered to remove or neutralize the effect of intermetallic inclusion before double zincate steps.
- the first alkaline zincate solution chemically dissolves aluminum oxide from the surface of the aluminum alloy disk, exposing aluminum which automatically receives a partial deposit of zinc through an electrochemical replacement reaction. Surface roughening can occur in these stages of pre-treatment plus the additional roughening associated with "carpeting" on pre-polished aluminum alloy substrates.
- the disk is rinsed in water, placed in a nitric acid solution to remove the first zinc deposit, is again rinsed in water and is then again immersed in an alkaline zincate solution. The surface becomes more completely covered by zinc in the second zincate immersion.
- the disk is then rinsed in water and immersed in an electroless nickel plating solution to grow a 88Ni— 12P layer.
- the time-temperature-concentration parameters of the pre-treatment etch and double zincate steps are tailored to the chemical nature of the aluminum alloy substrate. Inadequate rinsing and cross contamination of baths can lead to imperfect prior art 88Ni ⁇ 12P plating such as the formation of non-adherent blister regions.
- the 88Ni— 12P layer is plated extra thick and the rough nodular surface is then partially removed by polishing in the second WET step so that the remaining layer is completely dense, with a smooth surface.
- WET— WET— DRY comprising WET substrate preparation (pre-treatment), WET electroless plating and polishing and DRY (vacuum-sputtered) magnetic layer
- the present invention replaces WET substrate preparation with DRY vacuum sputtering of a nucleating layer, making a new sequence of DRY— WET— DRY.
- the second and third steps remain identical to prior art.
- FIG. 1 is an enlarged cross sectional view of a portion of a thin film magnetic disk in accordance with the prior art
- FIG. 2 is a flow chart showing the WET- WET-DRY steps of manufacturing the prior art disk of FIG. 1;
- FIG. 3 is a flow chart showing the DRY- WET-DRY steps of manufacturing a disk or planar device in accordance with the invention
- FIG. 4 is an enlarged cross-sectional view of a portion of a disk or planar device manufactured in accordance with one embodiment of the invention; wherein the thin sputtered layer is a dual purpose single material, serving both as binder and also as catalyst to nucleate a 88M--12P deposit;
- FIG. 5 is an enlarged cross sectional view of a portion of a disk manufactured in accordance with another embodiment of the invention in which a binder layer is first sputtered onto the disk or planar device, followed by a sputtered layer which has catalytically nucleated a 88 -12P deposit;
- FIG. 6 is an enlarged cross sectional view of a portion of a disk manufactured in accordance with another embodiment of the invention in which a reactive layer such as zinc sputtered onto a first sputtered binder layer has sacrificially reacted to nucleate a 88Ni ⁇ 12P deposit;
- FIG. 7 is a simplified diagram of a disk drive system including a motor and head assembly with a super smooth magnetic disk according to the present invention.
- FIG. 3 a super smooth aluminum alloy substrate (disk or planar device) is first degreased by organic solvents, as in the prior art.
- the substrate is then moved into a vacuum sputtering system designated by the dotted block.
- Vacuum sputter deposition systems are well known. Suffice to say that in such systems, the substrate is placed in an evacuated enclosure for processing.
- the first step may be to further clean the surface by reverse sputter etching.
- a first layer, 21, FIG. 5, of material selected to bind with the aluminum surface is vacuum sputter deposited onto the surface. This is followed by vacuum sputter deposition of a second layer 22 which serves as the catalytic or reactive nucleating layer for the subsequent electroless plating of a 88Ni— 12P layer.
- Pure chromium, pure titanium or tungsten—titanium alloy are preferred for the binder layer materials.
- Zirconium, vanadium, niobium, molybdenum, tantalum, tungsten, copper and rhenium as well as alloy combinations of these and other elements may also be vacuum sputter deposited onto the aluminum disk as a first layer.
- the first (binder) layer covers over the chemical non-uniformities associated with cold-worked pre-polished aluminum alloy and also the imbedded inclusions of intermetallic particles.
- the binder layer adheres firmly to the aluminum and also to the second sputtered nucleating layer.
- the second or nucleating vacuum sputtered layer is selected to:
- resist oxidation during storage preferably be non-magnetic or
- the most important requirements are the ability to nucleate 88Ni— 12P plating upon immersion in the electroless nickel bath and to be non-magnetic.
- a thin catalytic layer of nickel-phosphorus alloy with from 8.5 to 12 weight percent phosphorous is a preferred material for sputtering onto either bare aluminum or onto a first sputtered binder layer such as chromium.
- Sputtering targets of nickel- phosphorus alloy may be prepared by the prior art process or, more preferably, by powder metallurgical techniques, available, for example, from Heraeus MTD Specialty Products Group, Chandler AZ.
- Zinc is also a preferred material for sputtering as a reactive thin layer onto either bare aluminum or onto a first sputtered binder layer such as chromium, recognizing, however, that reacted and dissolved zinc will accumulate in the electroless nickel bath.
- Pure nickel is an effective catalytic nucleating layer and, if the aluminum alloy surface is smooth, the growth of 88Ni— 12P will continue as a smooth surface. Although pure nickel is magnetic, the sputtered nucleating layer may be made sufficiently thin and remote from the field of the read-write head so as to be of negligible influence.
- the thin nucleating and binder layers may be deposited by other techniques such as chemical vapor deposition and physical chemical vapor deposition, evaporation and the like.
- the first and second layers cover and mask the chemical and physical non-uniformities of the substrate and reduce their tendency to produce non-uniform 88Ni— 12P deposition.
- the chemistry of the aluminum alloy has minimal influence on subsequent 88Ni— 12P deposition. Since the invention masks the chemical and metallurgical differences in the aluminum alloy, such as those which produce the "carpeting effect" , it may be possible to use less expensive alloy grades.
- glass, ceramic and polymeric substrates can be coated with 88Ni— 12P by the present invention.
- the first (binder) layer may be chromium or titanium, each of which each bonds well to both glass and ceramic materials.
- US 5,405,646 provides a way to use available metals as new substrate materials, selected for their mechanical strength and ability to be polished to a very smooth surface, thus permitting the use of thinner disks.
- Lightweight titanium or magnesium or beryllium or their alloys may also find use as substrates (disk or planar device), as well as non-magnetic austenitic stainless steel compositions, manganese steel and beryllium copper or other high-strength, non-magnetic materials known to skilled practitioners of materials arts and sciences.
- the electroless 88Ni-12P deposit continues to grow uniformly with a smooth surface.
- the as-deposited surface may be sufficiently smooth so as to require minimum polishing, thus requiring less waste treatment of spent polishing slurry and rinse water.
- Waste water treatment is reduced by eliminating rinse stations in the WET surface preparation sequence of prior art. Waste treatment of spent etch, concentrated alkaline zincate and concentrated nitric acid solutions is also eliminated.
- the DRY— WET— DRY sequence of vacuum sputter deposition of a thin nucleating layer followed by improved wet process electroless nickel plating and polishing followed by prior art vacuum sputter deposition of the magnetic layer provides an improved process for the manufacture of magnetic disks with the possibility of cost savings.
- a further advantage of the novel DRY- WET-DRY process permits the use of prior art equipment to add well-proven electroless nickel to a wide variety of disk or planar substrates including glass, metal, ceramic and polymer plastics as well as to highly polished aluminum alloys or other suitable metals.
- Yet a further advantage is the capability to selectively coat a disk or planar card on one side only with a nucleating layer by vacuum sputter deposition and thus provide a device with a single-sided electroless nickel to be then followed by single-sided polishing, if required, and single-sided addition of magnetic layers (final DRY step).
- amorphous, non-magnetic sputtered 88Ni— 12P acts as a catalytic nucleating layer to trigger the electroless deposition of 88Ni— 12P, and adhesion is enhanced by bonding with a first sputtered binder layer such as chromium.
- a first sputtered binder layer such as chromium.
- Super-smooth disks of alloy 5585, 3.5 inch diameter, 0.050 inch thick were first sputtered with a binder layer of chromium, 300 Angstrom thick, followed by 300 Angstrom of 88Ni ⁇ 12P in an Intevac disk coating system. After sputtering, the disks were immersed in a standard electroless nickel plating bath (OMG-Fidelity), with no special attempt to activate the surface.
- OMG-Fidelity electroless nickel plating bath
- the sputtered layer of 88Ni— 12P smoothly nucleated the growth of electroless 88Ni— 12P, which achieved a thickness of 375 microinches in one hour.
- the plated layer had excellent adhesion, as tested by bending a sample disk about a diameter line (without a supporting mandrel) to an angle of 180 degrees.
- a control substrate, treated by the prior art, had a comparable adhesion.
- the roughness (or micro-waviness) of disk surfaces was measured by doppler laser vibrometry (THoT Technologies, Inc. model 4224M) and also by a MicroXAM (Phase Shift Technology, Inc.) optical device and is conveniently represented by the parameter Ra, the arithmetic average deviation of the surface profile.
- Ra the arithmetic average deviation of the surface profile.
- Another related embodiment of the present invention has a sputtered chromium binder layer thickness of 1000 Angstrom with a sputtered 300 Angstrom nucleating layer of 88Ni ⁇ 12P. Yet another related embodiment has a sputtered chromium binder layer 300 Angstrom thick with a 1000 Angstrom thick sputtered nucleating layer of 88Ni-12P.
- surface roughness was essentially unchanged after electroless deposition of 375 microinches of 88Ni ⁇ 12P, as determined by doppler laser vibrometry (THoT Technologies, Campbell CA, model 4224M). Nucleation of growth occurred smoothly, without delay when the present invention substrates were immersed in the identical plating bath used for prior art control substrates.
- a uniform thin layer of zinc is added to the aluminum substrate by a DRY process of vacuum sputtering. After removal of the substrate from the vacuum apparatus and subsequent immersion in the electroless nickel solution, the zinc layer serves to reactively nucleate the growth of 88 -12P.
- zinc may also be added by other processes such as vacuum vaporization.
- vacuum sputtering is preferred because it offers close control of thickness and also because disk sputtering systems can readily be arranged to deposit a binder layer between the aluminum and the zinc layer.
- An initial sputtered binder layer such as chromium will serve to bond the sputtered zinc layer and also to cover over the chemical and physical variations of the aluminum substrate.
- the sputtered layer is comprised of pure nickel with thickness less than 100 Angstroms, preferably, on a binder layer of chromium. Upon immersion in the electroless nickel solution, the sputtered nickel layer or partial layer catalytically nucleates deposition of 88Ni— 12P layers.
- FIG. 4 illustrates the layers of material on one side of a magnetic storage device going to one embodiment of the invention.
- the substrate 100 comprising aluminum magnesium alloy which has been processed to create a super smooth surface 101, such as by a fixed-pad polishing process.
- a nucleating and binding layer 102 is formed on the super smooth surface 101 of the substrate.
- the nucleating and binding layer has a surface 103 on which a electroless nickel layer 104 is formed.
- the electroless nickel layer 104 has a super smooth surface 105 as deposited.
- a chromium layer 106 followed by a magnetic cobalt alloy layer 107 and a thin chromium layer 108 are formed on the device.
- a carbon overcoat layer 109 and a lubricant layer 110 complete the device.
- FIG. 5 illustrates the layers of material on one side of a magnetic storage device going to a second embodiment of the invention.
- the substrate 100 comprises an aluminum magnesium alloy which has been processed to create a super smooth surface 101, such as by a fixed-pad polishing process.
- a binding layer 21 is formed on the super smooth surface 101 of the substrate.
- a nucleating layer 22, is formed on the binding layer.
- the nucleating layer 22 has a surface 103 on which a electroless nickel layer 104 is formed.
- the electroless nickel layer 104 has a super smooth surface 105 as deposited.
- a chromium layer 106 followed by a magnetic cobalt alloy layer 107 and a thin chromium layer 108 are formed on the device.
- a carbon overcoat layer 109 and a lubricant layer 110 complete the device.
- the substrate 100 comprises an aluminum magnesium alloy which has been processed to create a super smooth surface 101, such as by a fixed-pad polishing process.
- a binding layer 21 is formed on the super smooth surface 101 of the substrate.
- a sacrificial nucleating layer 23 is formed on the binding layer.
- the nucleating layer 23 is essentially consumed in this example in the electroless nickel deposition process, which results in a surface 103 on which a electroless nickel layer 104 is formed.
- the electroless nickel layer 104 has a super smooth surface 105 as deposited.
- a chromium layer 106 followed by a magnetic cobalt alloy layer 107 and a thin chromium layer 108 are formed on the device.
- a carbon overcoat layer 109 and a lubricant layer 110 complete the device.
- the data storage system 220 typically includes a disk drive motor and head assembly, and one or more rigid data storage disks 224 which are stacked coaxially in a tandem spaced relationship, and rotate about a spindle motor 226 at a relatively high rate of rotation.
- the disk 224 is manufactured according to the process described above, using a super smooth substrate, and which after the plating of electroless nickel, is given a final polish to achieve a final surface roughness Ra of 5 Angstroms or less, in preferred embodiments.
- Each disk 224 is typically formatted to include a plurality of spaced concentric tracks 250, with each track being partitioned into a series of sectors 252 which, in turn, are further divided into individual information fields.
- One or more of the disks 224 may alternatively be formatted to include a spiraled track configuration. In one embodiment, only one disk, and one surface of the disk, are used.
- An actuator typically includes an actuator arm 228, with the arm having one or more transducer and slider body assemblies 235, known as heads, for reading and writing information to and from the data storage disks 224.
- Alternative embodiment include a plurality of interleaved head assemblies for a corresponding plurality of disk surfaces.
- the assembly 235 is typically designed as an aerodynamic lifting body that lifts the transducer to hover above the disk 224 on an air bearing or airflow patterns produced by high-speed disk rotation.
- a conformal lubricant is typically designed as an aerodynamic lifting body that lifts the transducer to hover above the disk 224 on an air bearing or air
- (110 in FIGS. 4 and 5) may alternatively be disposed on the surface of the disk 224 to reduce static and dynamic friction between the head assembly 235 and the disk 224.
- a typical data storage system includes one or more data storage disks coaxially mounted on a hub of spindle motor 226.
- the spindle motor rotates the disks at speeds typically on the order of several thousand revolutions-per-minute.
- Digital information representing various types of data, is typically written to and read from the data storage disks by one or more transducers, or read/write heads, which are mounted to an actuator and passed over the surface of the rapidly rotating disks.
- the actuator typically includes one or a plurality of outwardly extending arms with one or more transducers being mounted resiliently or rigidly on the extreme end of the arms.
- the actuator arms are interleaved into and out of the stack of rotating disks, typically by means of a coil assembly mounted to the actuator.
- the coil assembly generally interacts with a permanent magnet structure, and the application of current to the coil in one polarity causes the actuator arms and transducers to shift in one direction, while current of the opposite polarity shifts the actuator arms and transducers in an opposite direction.
- digital data is stored in the form of magnetic transitions on a series of concentric, closely spaced tracks comprising the surface of the magnetizable rigid data storage disks.
- the tracks are generally divided into a plurality of sectors, with each sector comprising a number of information fields.
- One of the information fields is typically designated for storing data, while other fields contain sector identification and synchronization information, for example.
- Data is transferred to, and retrieved from, specified track and sector locations by the transducers being shifted from track to track, typically under the control of a controller.
- the transducer assembly typically includes a read element and a write element.
- Other transducer assembly configurations incorporate a single transducer element used to write data to the disks and read data from the disks.
- Writing data to a data storage disk generally involves passing a current through the write element of the transducer assembly to produce magnetic lines of flux which magnetize a specific location of the disk surface. Reading data from a specified disk location is typically accomplished by a read element of the transducer assembly sensing the magnetic field or flux lines emanating from the magnetized locations of the disk. As the read element passes over the rotating disk surface, the interaction between the read element and the magnetized locations on the disk surface results in the production of electrical signals in the read element. The electrical signals correspond to transitions in the magnetic field.
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Metallurgy (AREA)
- Ceramic Engineering (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
- Magnetic Record Carriers (AREA)
- Chemically Coating (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2002232414A AU2002232414A1 (en) | 2000-11-21 | 2001-11-20 | Method of coating smooth electroless nickel on magnetic memory disks and related memory devices |
GB0310475A GB2384788B (en) | 2000-11-21 | 2001-11-20 | Method of coating smooth electroless nickel on magnetic memory disks and related memory devices |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US25236500P | 2000-11-21 | 2000-11-21 | |
US60/252,365 | 2000-11-21 | ||
US09/894,375 US6977030B2 (en) | 2000-11-21 | 2001-06-27 | Method of coating smooth electroless nickel on magnetic memory disks and related memory devices |
US09/894,375 | 2001-06-27 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2002042511A2 true WO2002042511A2 (en) | 2002-05-30 |
WO2002042511A3 WO2002042511A3 (en) | 2002-09-06 |
Family
ID=26942266
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2001/043232 WO2002042511A2 (en) | 2000-11-21 | 2001-11-20 | Method of coating smooth electroless nickel on magnetic memory disks and related memory devices |
Country Status (4)
Country | Link |
---|---|
US (2) | US6977030B2 (en) |
AU (1) | AU2002232414A1 (en) |
GB (1) | GB2384788B (en) |
WO (1) | WO2002042511A2 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6689413B2 (en) * | 2000-09-15 | 2004-02-10 | Seagate Technology Llc | Using plated surface for recording media without polishing |
US7005751B2 (en) * | 2003-04-10 | 2006-02-28 | Formfactor, Inc. | Layered microelectronic contact and method for fabricating same |
US7882616B1 (en) * | 2004-09-02 | 2011-02-08 | Seagate Technology Llc | Manufacturing single-sided storage media |
US7651794B2 (en) * | 2005-04-28 | 2010-01-26 | Hitachi Global Storage Technologies Netherlands B.V. | Adhesion layer for thin film magnetic recording medium |
US20080308425A1 (en) * | 2007-06-12 | 2008-12-18 | Honeywell International, Inc. | Corrosion and wear resistant coating for magnetic steel |
JP5006145B2 (en) * | 2007-09-19 | 2012-08-22 | 株式会社リコー | Manufacturing method of developer regulating member |
US8404369B2 (en) | 2010-08-03 | 2013-03-26 | WD Media, LLC | Electroless coated disks for high temperature applications and methods of making the same |
US20120111360A1 (en) * | 2010-11-10 | 2012-05-10 | Helmuth Treichel | Method and Apparatus for Cleaning a Substrate |
US20120247223A1 (en) * | 2011-03-30 | 2012-10-04 | Canada Pipeline Accessories, Co. Ltd. | Electroless Plated Fluid Flow Conditioner and Pipe Assembly |
WO2018191485A1 (en) * | 2017-04-14 | 2018-10-18 | Cabot Microelectronics Corporation | Chemical-mechanical processing slurry and methods for processing a nickel substrate surface |
DE102017213170A1 (en) | 2017-07-31 | 2019-01-31 | Infineon Technologies Ag | SOLDERING A LADDER TO ALUMINUM METALLIZATION |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4929499A (en) * | 1988-04-20 | 1990-05-29 | Magnetic Peripherals Inc. | Use of nickel-phosphorous undercoat for particulate media in magnetic storage devices |
WO1994015720A1 (en) * | 1993-01-07 | 1994-07-21 | Akashic Memories Corporation | Magnetic recording media on non-metallic substrates and methods for their production |
US5405646A (en) * | 1992-10-14 | 1995-04-11 | Nanis; Leonard | Method of manufacture thin film magnetic disk |
US5569506A (en) * | 1993-10-06 | 1996-10-29 | International Business Machines Corporation | Magnetic recording disk and disk drive with improved head-disk interface |
Family Cites Families (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5082747A (en) * | 1985-11-12 | 1992-01-21 | Hedgcoth Virgle L | Magnetic recording disk and sputtering process and apparatus for producing same |
DE69027053T2 (en) * | 1989-01-28 | 1996-12-12 | Canon Kk | Multi-color ink jet recording method and device |
US5250339A (en) * | 1989-10-09 | 1993-10-05 | Nihon Shinku Gijutsu Kabushiki Kaisha | Magnetic recording medium |
US5316844A (en) * | 1990-04-16 | 1994-05-31 | Hoya Electronics Corporation | Magnetic recording medium comprising an aluminum alloy substrate, now magnetic underlayers, magnetic layer, protective layer, particulate containing protective layer and lubricant layer |
JPH05114127A (en) * | 1991-10-23 | 1993-05-07 | Hitachi Ltd | Magnetic disk and production thereof and magnetic disk device |
JPH05225560A (en) * | 1992-02-12 | 1993-09-03 | Nkk Corp | Production of magnetic disk substrate made of titanium |
JPH06162493A (en) * | 1992-11-18 | 1994-06-10 | Nec Ibaraki Ltd | Substrate for magnetic disk |
JP3107480B2 (en) * | 1993-06-16 | 2000-11-06 | 日本鋼管株式会社 | Titanium substrate for magnetic disk |
WO1996027878A1 (en) * | 1995-03-08 | 1996-09-12 | Migaku Takahashi | Magnetic recording medium and method of manufacturing the same |
GB2299991B (en) * | 1995-04-20 | 1998-09-09 | Ag Technology Corp | Glass substrate for magnetic disk |
US5871810A (en) * | 1995-06-05 | 1999-02-16 | International Business Machines Corporation | Plating on nonmetallic disks |
US5747135A (en) | 1995-12-08 | 1998-05-05 | Aluminum Company Of America | Thin film pretreatment for memory disks and associated methods |
US5980997A (en) * | 1996-06-03 | 1999-11-09 | Komag, Incorporated | Method for preparing a substrate for a magnetic disk |
US6152976A (en) * | 1996-08-30 | 2000-11-28 | Showa Denko Kabushiki Kaisha | Abrasive composition for disc substrate, and process for polishing disc substrate |
MY124578A (en) * | 1997-06-17 | 2006-06-30 | Showa Denko Kk | Magnetic hard disc substrate and process for manufacturing the same |
US6030681A (en) * | 1997-07-10 | 2000-02-29 | Raychem Corporation | Magnetic disk comprising a substrate with a cermet layer on a porcelain |
US6106927A (en) * | 1998-02-03 | 2000-08-22 | Seagate Technology, Inc. | Ultra-smooth as-deposited electroless nickel coatings |
US6316097B1 (en) * | 1998-09-28 | 2001-11-13 | Seagate Technology Llc | Electroless plating process for alternative memory disk substrates |
US6143375A (en) * | 1999-01-28 | 2000-11-07 | Komag, Incorporated | Method for preparing a substrate for a magnetic disk |
US6687197B1 (en) * | 1999-09-20 | 2004-02-03 | Fujitsu Limited | High density information recording medium and slider having rare earth metals |
-
2001
- 2001-06-27 US US09/894,375 patent/US6977030B2/en not_active Expired - Fee Related
- 2001-11-20 GB GB0310475A patent/GB2384788B/en not_active Expired - Fee Related
- 2001-11-20 AU AU2002232414A patent/AU2002232414A1/en not_active Abandoned
- 2001-11-20 WO PCT/US2001/043232 patent/WO2002042511A2/en not_active Application Discontinuation
-
2003
- 2003-05-01 US US10/427,158 patent/US6986956B2/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4929499A (en) * | 1988-04-20 | 1990-05-29 | Magnetic Peripherals Inc. | Use of nickel-phosphorous undercoat for particulate media in magnetic storage devices |
US5405646A (en) * | 1992-10-14 | 1995-04-11 | Nanis; Leonard | Method of manufacture thin film magnetic disk |
WO1994015720A1 (en) * | 1993-01-07 | 1994-07-21 | Akashic Memories Corporation | Magnetic recording media on non-metallic substrates and methods for their production |
US5569506A (en) * | 1993-10-06 | 1996-10-29 | International Business Machines Corporation | Magnetic recording disk and disk drive with improved head-disk interface |
Also Published As
Publication number | Publication date |
---|---|
AU2002232414A1 (en) | 2002-06-03 |
US6986956B2 (en) | 2006-01-17 |
US20020061424A1 (en) | 2002-05-23 |
US6977030B2 (en) | 2005-12-20 |
WO2002042511A3 (en) | 2002-09-06 |
US20030198836A1 (en) | 2003-10-23 |
GB2384788A (en) | 2003-08-06 |
GB2384788B (en) | 2004-10-20 |
GB0310475D0 (en) | 2003-06-11 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6316097B1 (en) | Electroless plating process for alternative memory disk substrates | |
JP2816472B2 (en) | Magnetic recording media | |
US5405646A (en) | Method of manufacture thin film magnetic disk | |
US6977030B2 (en) | Method of coating smooth electroless nickel on magnetic memory disks and related memory devices | |
JPH07122933B2 (en) | Magnetic recording disk and manufacturing method thereof | |
WO2008047609A1 (en) | Glass substrate for information recording medium, magnetic recording medium, and method for manufacturing glass substrate for information recording medium | |
US5091225A (en) | Magnetic disc member and process for manufacturing the same | |
EP0534624B1 (en) | Magnetic recording disk | |
JPH08102033A (en) | Thin-film magnetic recording disk and manufacture thereof | |
JP2000506300A (en) | Sputter texture magnetic recording media | |
JPH0520658A (en) | Substrate for magnetic recording medium and production thereof | |
US6689413B2 (en) | Using plated surface for recording media without polishing | |
JP3657196B2 (en) | Magnetic recording medium and magnetic disk device | |
JPH11161933A (en) | Plated substrate, magnetic recording medium and their production | |
JP2952967B2 (en) | Magnetic recording media | |
JPS6018817A (en) | Magnetic storage medium | |
JPH0315254B2 (en) | ||
JP2547994B2 (en) | Magnetic recording media | |
JP3492908B2 (en) | Magnetic recording / reproducing method | |
JP2873702B2 (en) | Magnetic recording medium and magnetic recording / reproducing method | |
JPH04295614A (en) | Magnetic recording medium | |
KR920010488B1 (en) | Fixed magnetic disk and the magnetic manufacturing method | |
JPH0352130B2 (en) | ||
JPH05282668A (en) | Substrate for perpendicular magnetic recording, magnetic disk and its production | |
JPH09231561A (en) | Production of magnetic recording medium |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US US UZ VN YU ZA ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
ENP | Entry into the national phase |
Ref document number: 0310475 Country of ref document: GB Kind code of ref document: A Free format text: PCT FILING DATE = 20011120 Format of ref document f/p: F |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
122 | Ep: pct application non-entry in european phase | ||
NENP | Non-entry into the national phase |
Ref country code: JP |
|
WWW | Wipo information: withdrawn in national office |
Country of ref document: JP |