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WO1989005362A1 - Disque magnetique a sous-couche de chrome a incidence elevee - Google Patents

Disque magnetique a sous-couche de chrome a incidence elevee Download PDF

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Publication number
WO1989005362A1
WO1989005362A1 PCT/US1987/003130 US8703130W WO8905362A1 WO 1989005362 A1 WO1989005362 A1 WO 1989005362A1 US 8703130 W US8703130 W US 8703130W WO 8905362 A1 WO8905362 A1 WO 8905362A1
Authority
WO
WIPO (PCT)
Prior art keywords
incidence
layer
chromium
magnetic
angle
Prior art date
Application number
PCT/US1987/003130
Other languages
English (en)
Inventor
Hudson A. Washburn
Philip L. Steiner
Eric K. Li
Original Assignee
Akashic Memories Corporation
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
Application filed by Akashic Memories Corporation filed Critical Akashic Memories Corporation
Priority to PCT/US1987/003130 priority Critical patent/WO1989005362A1/fr
Publication of WO1989005362A1 publication Critical patent/WO1989005362A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/225—Oblique incidence of vaporised material on substrate
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • 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
    • G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
    • G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
    • G11B5/656—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing Co
    • 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
    • G11B5/72—Protective coatings, e.g. anti-static or antifriction
    • G11B5/727—Inorganic carbon protective coating, e.g. graphite, diamond like carbon or doped carbon
    • 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
    • G11B5/7373—Non-magnetic single underlayer comprising chromium
    • 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
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • 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
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/8404—Processes or apparatus specially adapted for manufacturing record carriers manufacturing base 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
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/8408—Processes or apparatus specially adapted for manufacturing record carriers protecting the magnetic layer
    • 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
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/851—Coating a support with a magnetic layer by sputtering

Definitions

  • This invention concerns a method of producing sputtered magnetic disks, and more particularly, magnetic disks having a chromium under l ayer sputter deposited at a high incidence angle.
  • sputtered disks using a high incidence angle for the magnetic materials is known.
  • U.K. patents, No. 1,439,869 and No. 1,408,753 show a magnetic record member which has a substrate on which is deposited a metallic intermediate layer such as chromium. Subsequently, an iron-cobalt alloy is vapor deposited at an angle of incidence of about 60o to the substrate normal. The metallic undercoat is not obliquely deposited, however.
  • a thin film magnetic disk is produced by first sputtering a chromium undercoat onto a substrate at an oblique angle of about 60o and then a magnetic layer such as an FeCoCr alloy is sputtered at about the same oblique angle.
  • the magnetic layer is deposited at high incidence and particular attention is paid to the role of pressure variations in achieving the desired magnetic properties and of using complex shielding arrangements to achieve adequate uniformity.
  • the complex shielding employed in the prior patents tends to make them impractical for use in high throughput sputtering machines which usecylindrically symmetric sources such as the Varian Model MDP-1000 system. None of the prior art describes the role played by high incidence chromium in the undercoat in achieving the desired magnetic properties.
  • a method and apparatus for manufacturing a magnetic disk which has a very high circumferential coercivity and anisotropy.
  • the method is to sputter a chromium layer onto a disk substrate at a high angle of incidence, at least 45°, to set up the seed characteristics of the later-deposited magnetic layer.
  • the magnetic layer is then sputter-deposited over the chromium layer with a random incidence.
  • the disk is finished by depositing a protective layer over the magnetic layer.
  • the substrate with the high incidence chromium layer thereon is exposed to the air while it is transferred in preparation for sputtering of the magnetic and later layers.
  • a flash coat of chromium is deposited over the high incidence chromium layer before the magnetic layer is deposited in order to eliminate any effects of oxidation which may have been caused by the exposure.
  • the magnetic layer is begun within a short time thereafter, and without breaking vacuum to avoid any further oxidation.
  • the substrate is heated before deposition of the high incidence chromium and that temperature is maintained during that deposition.
  • the substrate with the high incidence angle chromium layer is directly sputtered onto by the magnetic layer without exposure to the atmosphere.
  • a method of achieving this high angle of incidence for the chromium deposition is to use an annular shield which blocks sputtered material from inpinging on the substrate which does not have an angle of incidence greater than 45°.
  • Fig. 1 shows a. disk according to the invention.
  • Fig. 2 shows a conventional S-Gun source.
  • Fig. 3 shows a disk standoff according to the invention.
  • Fig. 4 shows a disk standoff in position over an S-Gun for achieving high incidence chromium.
  • Fig. 5 shows the geometry of the disk and standoff during sputtering.
  • Fig. 6 is a graph illustrating the relationship between coercivity in the radial direction and in the circumferential direction with increasing angles of incidence.
  • FIG. 1 shown in FIG. 1 is a cross-section of a disk 1 such as might be used in a Winchester type drive.
  • the disk is a multilayered structure having a substrate 3 on which is sputter—deposited a chromium layer 5, a magnetic layer 7, and a protective layer 9.
  • the substrate is typically constructed of computer grade aluminum alloy 5086.
  • other materials such as pure aluminum, glass, silicon, or a Nickel-Phosphorous plated surface layer on aluminium may also be used.
  • the chromium layer is critical to the structure and acts to provide the seed characteristics for the later-deposited magnetic layer 7.
  • the substrate is first cleaned by standard techniques and is heated to a temperature of 200° C ⁇ 50o. While maintaining that temperature, the sputtering of the chromium layer 5 is begun, the layer then being sputter-deposited in a vacuum at a high angle of incidence, typically higher than 45°, with respect to the normal to the substrate, preferably higher than 55o, more preferably higher than 60°, and apparently the closer to 90o the better.
  • the minimum desired thickness for the chromium layer is about 1000 A and the maximum thickness is about 4500 A, with the preferred thickness being about, 2000 A ⁇ 20%.
  • the chromium layer should be quite pure, and preferably should contain less than 0. 5% by weight of other materials and should be free of cracks and bubbles.
  • the high angle of incidence can be produced by a number of methods, one approach is to use a sputtering source with a circular geometry such as a modified Varian Associates S-Gun which will be described later. With that modified source, and using a chromium grade A target such as that available from Varian Associates Specialty Metals Division, for a 95mm, outside diameter substrate, the chromium is deposited using an Argon gas pressure of 3 mTorr at a power rating of 3 kW for about 90 seconds.
  • the magnetic layer 7 is typically CoNiCr, or CoNi.
  • the angle of incidence for the deposition of the magnetic layer should be randomized, rather than at a high angle of incidence as was done for the chromium.
  • This can be achieved using a standard S-Gun configuration while rotating the substrate on a planetary at a distance from the source as is known in the art. Although the distance is not critical, it is generally about 12 to 20 inches in the 3125. According to this method of the invention, as soon as the chromium layer is deposited, the substrate with the high incidence chromium layer thereon is mounted on the planetary in the 3125.
  • a thin layer, or flash coat, of chromium (typically more than 50 A but less than 500 A) is deposited to cover any oxide layer that may have formed when transferring the substrate from the S-Gun to the planetary.
  • the magnetic layer is deposited on the flash coat of chromium.
  • a desired nominal thickness of 500 A to 700 A of CoNiCr can be deposited in about three minutes when operating at a power level of 3.0 kW at an Argon pressure of 3 mTorr.
  • a thickness of 450-650 A is obtained at these operating parameters.
  • the protective layer 9 is preferably carbon and can be sputtered according to methods well known in the art using a standard S-Gun configuration within the 3125 or using a planar magnetron.
  • the preferred thickness of the carbon layer is about 600 A, which can be achieved with the standard S-Gun configuration i n about 20 minutes using a power level of 1.2 kW at an Argon pressure of 8 mTorr.
  • the high incidence chromium layer is initially sputter-deposited as before in a modified S-Gun in the 3125. Then the substrate with the high incidence chromium layer thereon is transferred to a Varian Associates MDP-1000 Disk Sputtering System, described in detail in U.S. Patent 4,500,407.
  • the MDP-1000 also employs a plurality of sources with circular geometry but uses an M-Gun design such as described in U.S. Patents 4,500,408 and 4,500,409.
  • the sources in the MDP-1000 are typically arranged in pairs, hereinafter called stations, all connected to a common vacuum chamber, in addition to having individual vacuum systems for each pair of sources.
  • the substrate with the high incidence chromium layer thereon is placed between a pair of the circular sources, and both sides are simultaneously coated with a flash coat of chromium sputter-deposited at a random incidence angle to cover any oxide which might have formed, the thickness of this flash coat being about the same as before.
  • the substrate is then transferred within the vacuum housing to another sputtering station where a magnetic layer is deposited simultaneously on both sides of the substrate and then to a succession of other stations where a protective overcoat is sputtered over the magnetic layer on both sides of the substrate.
  • vacuum is maintained throughout the transfer of the substrate from one pair of sources to the next so that in the typical use with a short traverse time between stations (typically less than 80 seconds) oxide does not form to any significant degree between the flash coat of chromium and the deposition of the magnetic layer.
  • the pressure in the main vacuum chamber is first reduced to less than 2x10 -7 Tory, and preferably to below 1x10 -7 Torr, as measured on a Varian 860 cold cathode gauge, and the system is checked to ensure that the following readings are obtained on a residual gas analyzer such as Inficon Model 017-450-G1: O 2 (mass 32) less than 0.3x10 -9 , H 2 O (mass 18) less than 15x10 -9 , N 2 less than 2.0x10 -9 , and H 2 (mass 2) less than 10.0x10 -9
  • the individual sputtering stations are pumped by their individual cryopumps to achieve a gas pressure therein of less than 5x10 -7 Torr or lower, and all cryopumps are stabilized at a temperature of less than 15° K.
  • Standard procedures are used to ensure adequate cooling water to the station sputtering magnetrons; and gas lines for nitrogen, argon, and compressed air, are monitored to ensure adequate pressure.
  • the disk with the high incidence chromium is preheated for about 35 seconds to a temperature of 200o C to 330° C to help cause desorption of any adsorbed gases and to precondition the disk for the direct sputtering of the flash coat of chromium to follow.
  • the flash coat of chromium is sputter-deposited in the second station of the apparatus using an argon flow rate of 20 rnl/min. ⁇ 10% and argon pressure of less than 15 mTorr, with a cathode voltage of 550 volts and a target current of 11 amps.
  • the typical deposition rate is about 3000 A/min.., and the sputtering time is generally about 2 seconds, to achieve a nominal 100 A for the flash coat of chromium.
  • Other voltages, currents and times can be used to give the same thickness of chromium.
  • a typical target for the chromium deposition is part number 02000-24-000-00A, available from Varian Associates, which is of Grade A purity ( ⁇ 99.5% chromium by weight), having less than 250 parts per million of other materials therein, other than oxygen.
  • the magnetic layer is then sputter deposited in the next station, using an argon flow rate of 17ml /rain. ⁇ 10%, and an argon pressure of less than 15 mTorr, with a cathode voltage of 550 volts and a target current of 2.4 amps ⁇ 5%.
  • the sputtering time is typically about 22 seconds and the preferred deposition rate is about 1090 A/min.
  • a typical target for nickel-cobalt deposition is part number 03100-27-003-300 available from Varian Associates, having nominal nickel and cobalt atomic percentages of 20% and 80% respectively, with an admixture of impurities of less than 200 parts per million.
  • a typical target for CoNiCr has a preferred composition of 72% cobalt, 18% nickel, and 10% chromium (atomic percentages), and using the same process parameters with a sputtering time of 30 seconds results in a magnetic layer having a thickness of about 550 A.
  • the carbon deposition is typically performed in three successive stages in separate stations, since the carbon deposition rate is much lower than the metal deposition rates, only about 500 A/min.
  • the typical cathode voltage is 600 volts
  • the target current is 4.1 amps ⁇ 10%
  • the total sputtering time at each station is about 25 seconds to achieve a total preferred nominal thickness of 600 A.
  • the argon pressure is maintained below 15 mTorr in the stations, and the argon flow rate is maintained at about 20ml/min.
  • a typical target for the carbon deposition is Spectrographic grade carbon, having a purity of 99.999%, e.g., available from Sputtering Materials, Inc. in Santa Clara, California.
  • FIG. 2 Shown in FIG. 2 is a standard Varian Associates S-Gun sputtering source. It is made up of a disk-shaped anode 11, a concave annular cathode target 13 and an annular magnetic assembly 15. Also typically included is a ground shield 17, a removable plasma confinement shield 19, a water cooling jacket 21 and an anode cooling cavity 23.
  • a disk standoff 25 is constructed, typically of stainless steel.
  • the standoff 25 is made up of four portions as illustrated in FIG. 3.
  • the first portion is a sputtering shield 27 which restricts the angle of incidence of the sputtered material onto the disk.
  • shield 27 is typically constructed of 0.1 in. stainless steel and has an outer diameter of 5.6 in. and an inner diameter L1 typically of about 2.0 in. for a 95mm or 100mm diameter disk to be sputtered.
  • the second portion is a retaining ring 30 which holds the shield 27 in place inside the plasma shield 19 of the sputtering source as shown in FIG. 4.
  • the third portion is a standoff ring 29 having an inner diameter of 5.80 in. which is constructed typically of 0.06 in. to 0.10 in. thick stainless steel attached to retaining ring 30.
  • the height D of standoff ring 29 is typically 0.4 in.
  • the retaining ring 30 typically extends below standoff ring 29 a distance of about 0.1 in.
  • the fourth portion is a disk holder 26 which is constructed of a stainless steel annular ring having an outer diameter of 6.0 in. and a machined inner diameter L2 with a chamferred edge 28, the chamfer typically being about 30o.
  • the distance L2 varies depending on the size of the disk being sputtered. For example, for a 100mm diameter disk, L2 is about 3.90 in.
  • the typical disk has a chamferred edge which matches the 30° edge 28, thus assisting in precise centering of the disk over the concentric elements 27, 28, 29, and 30.
  • FIG. 5 illustrates how the incidence angle for the chromium deposition is achieved using the sputtering shield 27.
  • the cathode sputtering target 13 depletes primarily from the region 51.
  • the shield 27 tends to block the path of the sputtered material from the target to the closest side of the disk as illustrated by the dotted line 53.
  • the argon sputtering gas will cause some scattering of the sputtered chromium atoms.
  • the average angle of incidence will be close to that determined by the dotted lines 54 and 55.
  • substantially only the high incidence material is incident on the disk.
  • the typical geometry uses a distance L3 of 15 to 20mm and a distance L3 + L4 from the used portion 51 of the target to the disk of about 38mm.
  • the radii L5 and L6 are typically about 44.5mm and 64mm, respectively.
  • FIG. 6 shows the results of an experiment designed to show the results of increasing angles of incidence for the chromium deposition.
  • Hc coercivity
  • FIG. 6 shows the results of an experiment designed to show the results of increasing angles of incidence for the chromium deposition.
  • Such high values of the circumferential coercivity and am sotropy are very important in achieving a high quality recording medium.
  • the circumferential coercivity begins to increase at an angle A of about 30o and begins to rise much more steeply between 40o and 60o. Although it is not shown in FIG. 6, angles above 60o appear to be even better. Hence, in the preferred mode, the angle A should be greater than about 45o, preferably greater than 55o, an more preferably above 60o to achieve the desired circumferential coercivity and the desired am sotropy.
  • the second process i.e. first depositing the high angle chromium layer m an S-Gun in the 3125 and then depositing the magnetic layer and the overcoat in the MDP-1000, yields a track amplitude
  • an appropriate design change to sputter high incidence chromium within the MDP-1000 without breaking vacuum can eliminate the step of providing a flash coat to cover oxide formed on the high incidence chromium layer when transferring the substrate to the MDP-1000 from the 3125.
  • This design change to sputter high incidence chromium can be accomplished by providing an annular shield in the M-Gun source much like the shield used in Varian 3125.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)

Abstract

Sont décrits un procédé et un appareil de fabrication d'un disque magnétique (11) ayant une coercivité et une anisotropie de circonférence très élevées. Le procédé consiste à vaporiser une couche de chrome (5) sur un substrat se présentant sous la forme d'un disque (3), à un angle d'incidence élevé afin d'organiser les caractéristiques de grain de la couche magnétique (7) déposée ultérieurement. La couche magnétique (7) est ensuite déposée par vaporisation sur la couche de chrome (5) avec une incidence aléatoire. Puis le disque est fini par dépôt d'une couche protectrice (9) sur la couche magnétique (7). On utilise un agencement d'écran pour atteindre l'angle d'incidence élevée dans le dépôt de chrome.
PCT/US1987/003130 1987-12-07 1987-12-07 Disque magnetique a sous-couche de chrome a incidence elevee WO1989005362A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US1987/003130 WO1989005362A1 (fr) 1987-12-07 1987-12-07 Disque magnetique a sous-couche de chrome a incidence elevee

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1987/003130 WO1989005362A1 (fr) 1987-12-07 1987-12-07 Disque magnetique a sous-couche de chrome a incidence elevee

Publications (1)

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WO1989005362A1 true WO1989005362A1 (fr) 1989-06-15

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5037515A (en) * 1989-09-18 1991-08-06 Hmt Technology Corporation Method for making smooth-surfaced magnetic recording medium
EP0474348A3 (en) * 1990-08-31 1993-03-10 International Business Machines Corporation Sputtering apparatus and method for producing thin films of material
EP0588366A1 (fr) * 1992-09-17 1994-03-23 Kao Corporation Milieu d'enregistrement magnétique et dispositif et méthode pour sa fabrication

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4245008A (en) * 1978-10-30 1981-01-13 International Business Machines Corporation Corrosion resistant magnetic recording media
US4414086A (en) * 1982-11-05 1983-11-08 Varian Associates, Inc. Magnetic targets for use in sputter coating apparatus
US4416759A (en) * 1981-11-27 1983-11-22 Varian Associates, Inc. Sputter system incorporating an improved blocking shield for contouring the thickness of sputter coated layers
US4426265A (en) * 1981-04-11 1984-01-17 International Business Machines Corporation Method of producing a metallic thin film magnetic disk
US4503125A (en) * 1979-10-01 1985-03-05 Xebec, Inc. Protective overcoating for magnetic recording discs and method for forming the same
US4552820A (en) * 1984-04-25 1985-11-12 Lin Data Corporation Disc media
JPS6212923A (ja) * 1985-07-10 1987-01-21 Fujitsu Ltd 磁気記録媒体の製造方法
US4664976A (en) * 1984-05-30 1987-05-12 Victor Company Of Japan, Ltd. Magnetic recording medium comprising a protective carbon nitride layer on the surface thereof

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4245008A (en) * 1978-10-30 1981-01-13 International Business Machines Corporation Corrosion resistant magnetic recording media
US4503125A (en) * 1979-10-01 1985-03-05 Xebec, Inc. Protective overcoating for magnetic recording discs and method for forming the same
US4426265A (en) * 1981-04-11 1984-01-17 International Business Machines Corporation Method of producing a metallic thin film magnetic disk
US4416759A (en) * 1981-11-27 1983-11-22 Varian Associates, Inc. Sputter system incorporating an improved blocking shield for contouring the thickness of sputter coated layers
US4414086A (en) * 1982-11-05 1983-11-08 Varian Associates, Inc. Magnetic targets for use in sputter coating apparatus
US4552820A (en) * 1984-04-25 1985-11-12 Lin Data Corporation Disc media
US4664976A (en) * 1984-05-30 1987-05-12 Victor Company Of Japan, Ltd. Magnetic recording medium comprising a protective carbon nitride layer on the surface thereof
JPS6212923A (ja) * 1985-07-10 1987-01-21 Fujitsu Ltd 磁気記録媒体の製造方法

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5037515A (en) * 1989-09-18 1991-08-06 Hmt Technology Corporation Method for making smooth-surfaced magnetic recording medium
EP0474348A3 (en) * 1990-08-31 1993-03-10 International Business Machines Corporation Sputtering apparatus and method for producing thin films of material
EP0588366A1 (fr) * 1992-09-17 1994-03-23 Kao Corporation Milieu d'enregistrement magnétique et dispositif et méthode pour sa fabrication
US5593723A (en) * 1992-09-17 1997-01-14 Kao Corporation Magnetic recording medium manufacturing method and manufacturing apparatus and magnetic recording medium
US5723212A (en) * 1992-09-17 1998-03-03 Kao Corporation Magnetic recording medium manufacturing method and manufacturing apparatus and magnetic recording medium

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