US20130017413A1 - Discrete Track Media - Google Patents
Discrete Track Media Download PDFInfo
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- US20130017413A1 US20130017413A1 US13/620,499 US201213620499A US2013017413A1 US 20130017413 A1 US20130017413 A1 US 20130017413A1 US 201213620499 A US201213620499 A US 201213620499A US 2013017413 A1 US2013017413 A1 US 2013017413A1
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- magnetic
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- magnetic layers
- rod
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- 230000005291 magnetic effect Effects 0.000 claims abstract description 99
- 239000000463 material Substances 0.000 claims description 8
- 229910018979 CoPt Inorganic materials 0.000 claims description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 238000005530 etching Methods 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 239000010410 layer Substances 0.000 description 70
- 238000000151 deposition Methods 0.000 description 20
- 239000010408 film Substances 0.000 description 20
- 238000000034 method Methods 0.000 description 19
- 230000008021 deposition Effects 0.000 description 18
- 230000008569 process Effects 0.000 description 11
- 239000000758 substrate Substances 0.000 description 8
- 239000010409 thin film Substances 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- 239000011241 protective layer Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000000059 patterning Methods 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 239000000696 magnetic material Substances 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000000992 sputter etching Methods 0.000 description 2
- 238000005477 sputtering target Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001844 chromium Chemical class 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical group [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- UCNNJGDEJXIUCC-UHFFFAOYSA-L hydroxy(oxo)iron;iron Chemical compound [Fe].O[Fe]=O.O[Fe]=O UCNNJGDEJXIUCC-UHFFFAOYSA-L 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Images
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
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B26—HAND CUTTING TOOLS; CUTTING; SEVERING
- B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
- B26D3/00—Cutting work characterised by the nature of the cut made; Apparatus therefor
- B26D3/16—Cutting rods or tubes transversely
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
-
- 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
- G11B5/66—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers
- G11B5/676—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers having magnetic layers separated by a nonmagnetic layer, e.g. antiferromagnetic layer, Cu layer or coupling layer
- G11B5/678—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers having magnetic layers separated by a nonmagnetic layer, e.g. antiferromagnetic layer, Cu layer or coupling layer having three or more magnetic 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
- G11B5/74—Record carriers characterised by the form, e.g. sheet shaped to wrap around a drum
- G11B5/743—Patterned record carriers, wherein the magnetic recording layer is patterned into magnetic isolated data islands, e.g. discrete tracks
-
- 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
- G11B5/74—Record carriers characterised by the form, e.g. sheet shaped to wrap around a drum
- G11B5/82—Disk 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
- G11B5/86—Re-recording, i.e. transcribing information from one magnetisable record carrier on to one or more similar or dissimilar record carriers
- G11B5/865—Re-recording, i.e. transcribing information from one magnetisable record carrier on to one or more similar or dissimilar record carriers by contact "printing"
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T83/00—Cutting
- Y10T83/04—Processes
Definitions
- Thin film magnetic recording disks generally comprise a disk substrate having a magnetic layer and a number of underlayers and overlayers deposited thereon. The nature and composition of each layer is selected to provide desired magnetic recording characteristics, as generally recognized in the industry.
- An exemplary present day thin film disk comprises a non-magnetic disk substrate, typically composed of an aluminum alloy.
- An amorphous nickel phosphorous (Ni—P) underlayer is formed over each surface of the disk substrate, typically by plating and is subsequently polished and sometimes texturized prior to deposition of the additional films.
- the Ni—P layer is hard, and imparts rigidity to the aluminum substrate.
- glass and other non-metallic materials are now used to form highly rigid disk substrates.
- a second underlayer in the form of a chromium ground layer is formed over the Ni—P layer, typically by sputtering, and a magnetic layer is formed over the ground layer.
- the magnetic layer comprises a thin film of ferromagnetic material, such as a magnetic oxide or magnetic metal alloy.
- a protective layer such as a carbon film, is formed over the magnetic layer and a lubricating layer is formed over the protective layer.
- the presence of the Ni—P underlayer, together with the chromium ground layer, has been found to improve the recording characteristics of the magnetic layer.
- the chromium ground layer formed over a Ni—P layer provides enhanced coercivity and reduced noise characteristics. Such improvements are sometimes further enhanced when the Ni—P underlayer is treated by mechanical texturing to create a roughened surface prior to formation of the chromium ground layer.
- the texturing may be circumferential or crosswise, with the preferred geometry depending on the particular composition of the cobalt-containing magnetic layer.
- the outer carbon protective layer serves a very different purpose. This protective layer has been found to greatly extend the life of magnetic recording media by reducing disk wear. Carbon has been shown to provide a high degree of wear protection when a thin lubrication layer is subsequently, applied.
- Such magnetic recording disk constructions have been very successful and allow for high recording densities. As with all successes, however, it is presently desired to provide magnetic recording disks having even higher recording densities.
- One method for increasing the areal density on rigid magnetic disks involves patterning the surface of a thin film disk to form discrete data tracks.
- Such “discrete track media” typically include surface geometry data which are utilized by the hard disk drive servo mechanism, allowing specific recording tracks to be identified, and providing feedback to improve the accuracy of read/write head tracking.
- Discrete track media suffer from their own disadvantages.
- the surface patterns of discrete track media have generally been imposed using standard lithographic techniques to remove material from the magnetic recording layer or by creating recessed zones or valleys in the substrate prior to deposition of the magnetic material.
- the magnetic recording material is etched or ion milled through a resist mask to leave a system of valleys which are void of magnetic material.
- the magnetic film, subsequently applied is spaced far enough away from the recording head that the flux from the head does not sufficiently “write” the magnetic medium.
- Servo track information can be conveyed by the difference in magnetic flux at the boundary between the elevated patterns and the valleys.
- the boundary signals have at most 50% of the amplitude of conventionally recorded data.
- fabrication of production quantities of discrete track media has remained problematic, due in part to the expense of the required lithographic processes.
- a narrower track width corresponds to a higher areal density.
- the photo patterning of media helps separate tracks and also helps increase the areal density.
- the track width produced by photo patterning is greatly limited and does not achieve the desired narrow widths.
- the present invention is related to a method of fabricating a media for magnetic recording media.
- a base layer is provided onto which a magnetic film is deposited from a first magnetic sputtering target.
- a non-magnetic film is then deposited on top of the base-layer from a second sputtering target.
- the magnetic layer and non-magnetic layer are repeatedly deposited a predetermined number of times to produce a media source.
- the base layer comprises a cylindrical rod, such that the alternating magnetic and non-magnetic layers form radially around the rod. If the layers are deposited simultaneously, the layers can form a spiral extending outwardly from the center of the rod. Alternatively, the layers can form concentric circles around the rod.
- the resulting media layers can be sliced to form recording media discs.
- the rod can be used to stamp the discrete pattern onto other discs.
- FIG. 1 illustrates a top view of a disk made in accordance with an embodiment of the present invention
- FIG. 2 illustrates the process by which a disk is made in accordance with an embodiment of the present invention
- FIG. 3 illustrates a media rod during the formation process made in accordance with an embodiment of the present invention
- FIG. 4 illustrates a process by which the media rod is converted into disks in accordance with an embodiment of the present invention
- FIG. 5 illustrates a process by which the media rod is used to create disks in accordance with an embodiment of the present invention
- FIG. 6 illustrates a process by which the media rod is used to create disks in accordance with another embodiment of the present invention
- FIG. 7 illustrates a further media source in accordance with an embodiment of the present invention.
- FIG. 8 illustrates a process by which a media source is made in accordance with an embodiment of the present invention.
- the present invention relates generally to magnetic recording media, and more particularly to magnetic media formed where the tracks are created by film deposition and width of each tracks is controlled by the film deposition parameters.
- the present invention provides a new media for which the track-width (i.e., KTPI) is defined by the thickness of a sputter deposition/plating film.
- Film thickness can be controlled down to few angstroms. Therefore, the tracks can be controlled and produced having dimensions of similar size.
- the grain size of tracks produced in accordance with this invention will be well defined and small since narrow tracks require deposition of thin films. Such media will also enable high linear density.
- Narrow tracks also provide well defined grains in the down track direction by depositing magnetic films in a texture of a granular matrix.
- the present invention can produce discreet track media using magnetic layers that have different anisotropy fields (“Hk”) and exchange, and can include non-magnetic layers (e.g., metal or insulators).
- Disk 100 can include an open or hollow center 110 which is surrounded by multiple magnetic layers 120 and non-magnetic layers 130 .
- the magnetic layer 120 has a track width 140 of about 2 nm.
- the magnetic layer can be made of materials known in the art for such purposes (e.g., CoPt).
- the non-magnetic film can be an insulator or metallic. Further, the process used to deposit the non-magnetic film can be aqueous, for example by plating with a nonmagnetic metallic layer.
- the non-magnetic layer 130 preferably has a width of 2 nm and is made of alumina.
- FIG. 2 illustrates a process 200 by which disk 100 can be created.
- a cylindrical rod 210 made of a suitable material can be rotated about its axis in direction 240 .
- Two deposition targets are placed perpendicular to the rotational axis.
- the first target 220 deposits a magnetic layer, such as CoPt, on the rod 210 as it rotates about axis 240 .
- the second target 230 deposits an insulating, non-magnetic layer, such as alumina, on the rod 210 .
- the deposit parameters are preferable adjusted such that each target deposits a thin layer (e.g., 2 nm) of film on the rod 210 in a single revolution of the rod 210 .
- the films that result from this configuration spiral outwardly from the rod 210 .
- shutters can be used to control the exposure of the rod 210 to each target 220 and 230 such that only one of the targets is exposed during a single rotation of the rod 210 .
- the parameters of the deposition system can be adjusted to ensure that the thickness of the magnetic and/or non-magnetic layers is the same for each deposition layer.
- a material that can be etched selectively e.g., Cu
- Applying a magnetic field along the axis of the rod 210 can result in perpendicular anisotropy of the film layers deposited on the rod 210 .
- a layered structure “Media Rod” 310 is produced by the depositions of magnetic layer(s) from target 320 and depositions of non-magnetic layer(s) from target 330 , as illustrated in FIG. 3 .
- the media rod 310 has concentric (or spiral) layers of magnetic media separated by non-magnetic spacers.
- the top (or bottom) surface 340 of the media rod 310 exposes the concentric layers of deposited film.
- FIG. 4 illustrates one use of the media rod 410 to create media disks 430 .
- the media rod 410 can be cut (i.e., sliced) 420 into multiple individual disks 430 .
- the central Copper (Cu) can be etched into the disks 430 selectively, if necessary.
- the thickness of the magnetic film defines track-width in this particular method.
- the individual disks 430 can be placed on a support disk. Further, a highly permeable material can be deposited on the substrate of the disk 430 to create a soft underlayer (SUL).
- SUL soft underlayer
- the final disk 430 can be polished to smooth its surface.
- the anisotropy direction is preferably perpendicular to disk surface.
- the media rod 510 can be used to imprint circular tracks on a disk.
- a disk 520 preferably made of Silicon (“Si”) or an appropriate metal, can be heated to a predetermined temperature.
- the media rod 510 can then be used to stamp the heated disk 520 to imprint the concentric (or spiral) tracks on the media rod 510 onto the printed media disk 530 .
- the surface of the media rod 610 can be heated to a predetermined temperature such that when stamped onto a transfer disk 620 , the top surface of the media rod 620 is transferred to the printed media disk 630 .
- the media rod 620 can be heated with external agent (e.g., a laser) preferably to a temperature that liquefies the top surface.
- external agent e.g., a laser
- the surface of the printed media disk 630 can be polished for smoothness.
- the media layer 810 can be produced using process 800 illustrated in FIG. 8 .
- a conveyor-belt 850 or similar mechanism, can transport a media layer 810 through the manufacturing process.
- Multiple deposition targets are positioned relative to the conveyor belt such that a thin film will be deposited on the media layer 810 as it comes within proximity to the deposition target.
- conveyor-belt 850 can oscillate media layer 810 back and forth such that deposition target 820 sputter deposits a magnetic layer, deposition target 830 sputter deposits a non-magnetic layer, and deposition target 840 sputter deposits another magnetic layer.
- the convey-belt can then reverse directions such that deposition target 830 deposits a further non-magnetic layer, and deposition target 820 deposits a further magnetic layer. This process can be repeated until the desired number of magnetic layers have been deposited on the media layer 810 .
- the media layer 810 can then be cut into cylinders as described above, thereby producing cylindrical storage devices.
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- Mechanical Engineering (AREA)
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- Magnetic Record Carriers (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
Abstract
A method of fabricating a discrete track magnetic recording media. A base layer is provided onto which repeating and alternating magnetic layer and non-magnetic layers are deposited. The thickness of the magnetic layer corresponds to the width of the track of the recording media. A cylindrical rod can be used as the base layer, such that the alternating magnetic and non-magnetic layers spiraling or concentric layers around the rod. The resulting media layer can be cut or sliced into individual magnetic media or used to imprint other media discs with the discrete pattern of the media layer.
Description
- This application is a divisional of U.S. application Ser. No. 12/178,443 filed Jul. 23, 2008, which is incorporated herein by reference in its entirety.
- Thin film magnetic recording disks generally comprise a disk substrate having a magnetic layer and a number of underlayers and overlayers deposited thereon. The nature and composition of each layer is selected to provide desired magnetic recording characteristics, as generally recognized in the industry. An exemplary present day thin film disk comprises a non-magnetic disk substrate, typically composed of an aluminum alloy. An amorphous nickel phosphorous (Ni—P) underlayer is formed over each surface of the disk substrate, typically by plating and is subsequently polished and sometimes texturized prior to deposition of the additional films. The Ni—P layer is hard, and imparts rigidity to the aluminum substrate. Alternatively, glass and other non-metallic materials are now used to form highly rigid disk substrates. A second underlayer in the form of a chromium ground layer is formed over the Ni—P layer, typically by sputtering, and a magnetic layer is formed over the ground layer. The magnetic layer comprises a thin film of ferromagnetic material, such as a magnetic oxide or magnetic metal alloy. Usually, a protective layer, such as a carbon film, is formed over the magnetic layer and a lubricating layer is formed over the protective layer.
- The presence of the Ni—P underlayer, together with the chromium ground layer, has been found to improve the recording characteristics of the magnetic layer. In particular, the chromium ground layer formed over a Ni—P layer provides enhanced coercivity and reduced noise characteristics. Such improvements are sometimes further enhanced when the Ni—P underlayer is treated by mechanical texturing to create a roughened surface prior to formation of the chromium ground layer. The texturing may be circumferential or crosswise, with the preferred geometry depending on the particular composition of the cobalt-containing magnetic layer.
- The outer carbon protective layer serves a very different purpose. This protective layer has been found to greatly extend the life of magnetic recording media by reducing disk wear. Carbon has been shown to provide a high degree of wear protection when a thin lubrication layer is subsequently, applied.
- Such magnetic recording disk constructions have been very successful and allow for high recording densities. As with all successes, however, it is presently desired to provide magnetic recording disks having even higher recording densities. One method for increasing the areal density on rigid magnetic disks involves patterning the surface of a thin film disk to form discrete data tracks. Such “discrete track media” typically include surface geometry data which are utilized by the hard disk drive servo mechanism, allowing specific recording tracks to be identified, and providing feedback to improve the accuracy of read/write head tracking.
- The production of discrete track media and other magnetic recording media having patterned surfaces were described by S. E. Lambert et al. in Beyond Discrete Tracks: Other Aspects of Patterned Media, JOURNAL OF APPLIED PHYSICS, Vol. 69, 8:4724-26, Apr. 15, 1991. Each of the patterned media described were produced by sputter etching or ion milling a magnetic recording layer through a resist mask. The resist mask was written with an electron beam, as is known in the lithographic arts.
- The production of discrete track media with a pre-embossed rigid magnetic disk was described by D. Dericotte, et al., in Advancements in the Development of Plastic Hard Disks With Pre-embossed Servo Patterns, CORPORATE RESEARCH LABORATORIES, SONY CORPORATION. The disk is produced using an injection molding process between two stamping plates. The plates containing the media surface pattern are produced using lithographical techniques.
- Recording media having a selectively laser-textured surface and methods for their production are described in U.S. Pat. Nos. 5,062,021, and 5,108,781, respectively. A laser system for texturing a substrate, Ni—P layer, or a magnetic recording layer is also disclosed.
- Discrete track media, however, suffer from their own disadvantages. The surface patterns of discrete track media have generally been imposed using standard lithographic techniques to remove material from the magnetic recording layer or by creating recessed zones or valleys in the substrate prior to deposition of the magnetic material. In the former case, the magnetic recording material is etched or ion milled through a resist mask to leave a system of valleys which are void of magnetic material. In the latter case, the magnetic film, subsequently applied, is spaced far enough away from the recording head that the flux from the head does not sufficiently “write” the magnetic medium. Servo track information can be conveyed by the difference in magnetic flux at the boundary between the elevated patterns and the valleys. However, the boundary signals have at most 50% of the amplitude of conventionally recorded data. Additionally, fabrication of production quantities of discrete track media has remained problematic, due in part to the expense of the required lithographic processes.
- A narrower track width corresponds to a higher areal density. The photo patterning of media helps separate tracks and also helps increase the areal density. However, the track width produced by photo patterning is greatly limited and does not achieve the desired narrow widths.
- There is ever growing need for high areal densities. Sensor dimensions are reduced to read and writer small dimension tracks. In addition to the sensor, the magnetic media also plays a key role in enhancing areal densities. For these reasons, it would be desirable to provide an improved method for producing a discrete track patterned media. It would be particularly desirable if such a method provided the accuracy and reproducibility of lithography, but did not involve multiple process steps or the complex, dedicated tooling required for stamping. It would be best if such a method enhanced the improvements to the magnetic recording characteristics available using the conventional underlayers, magnetic recording layers, and overlayers of high density magnetic recording media.
- The present invention is related to a method of fabricating a media for magnetic recording media. A base layer is provided onto which a magnetic film is deposited from a first magnetic sputtering target. A non-magnetic film is then deposited on top of the base-layer from a second sputtering target. The magnetic layer and non-magnetic layer are repeatedly deposited a predetermined number of times to produce a media source.
- In a further aspect of the present invention, the base layer comprises a cylindrical rod, such that the alternating magnetic and non-magnetic layers form radially around the rod. If the layers are deposited simultaneously, the layers can form a spiral extending outwardly from the center of the rod. Alternatively, the layers can form concentric circles around the rod.
- In yet a further aspect of the present invention, if the base layer is a rod, the resulting media layers can be sliced to form recording media discs. Alternatively, the rod can be used to stamp the discrete pattern onto other discs.
- The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings of the illustrative embodiments of the invention wherein like reference numbers refer to similar elements throughout the views and in which:
-
FIG. 1 illustrates a top view of a disk made in accordance with an embodiment of the present invention; -
FIG. 2 illustrates the process by which a disk is made in accordance with an embodiment of the present invention; -
FIG. 3 illustrates a media rod during the formation process made in accordance with an embodiment of the present invention; -
FIG. 4 illustrates a process by which the media rod is converted into disks in accordance with an embodiment of the present invention; -
FIG. 5 illustrates a process by which the media rod is used to create disks in accordance with an embodiment of the present invention; -
FIG. 6 illustrates a process by which the media rod is used to create disks in accordance with another embodiment of the present invention; -
FIG. 7 illustrates a further media source in accordance with an embodiment of the present invention; and -
FIG. 8 illustrates a process by which a media source is made in accordance with an embodiment of the present invention. - The present invention relates generally to magnetic recording media, and more particularly to magnetic media formed where the tracks are created by film deposition and width of each tracks is controlled by the film deposition parameters.
- By way of overview, the present invention provides a new media for which the track-width (i.e., KTPI) is defined by the thickness of a sputter deposition/plating film. Film thickness can be controlled down to few angstroms. Therefore, the tracks can be controlled and produced having dimensions of similar size. Furthermore, the grain size of tracks produced in accordance with this invention will be well defined and small since narrow tracks require deposition of thin films. Such media will also enable high linear density. Narrow tracks also provide well defined grains in the down track direction by depositing magnetic films in a texture of a granular matrix. The present invention can produce discreet track media using magnetic layers that have different anisotropy fields (“Hk”) and exchange, and can include non-magnetic layers (e.g., metal or insulators).
- With reference to
FIG. 1 , anexemplary disk 100 is illustrated.Disk 100 can include an open orhollow center 110 which is surrounded by multiplemagnetic layers 120 andnon-magnetic layers 130. Preferably, themagnetic layer 120 has atrack width 140 of about 2 nm. The magnetic layer can be made of materials known in the art for such purposes (e.g., CoPt). - The non-magnetic film can be an insulator or metallic. Further, the process used to deposit the non-magnetic film can be aqueous, for example by plating with a nonmagnetic metallic layer. The
non-magnetic layer 130 preferably has a width of 2 nm and is made of alumina. -
FIG. 2 illustrates aprocess 200 by whichdisk 100 can be created. Acylindrical rod 210 made of a suitable material can be rotated about its axis indirection 240. Two deposition targets are placed perpendicular to the rotational axis. Thefirst target 220 deposits a magnetic layer, such as CoPt, on therod 210 as it rotates aboutaxis 240. Thesecond target 230 deposits an insulating, non-magnetic layer, such as alumina, on therod 210. The deposit parameters are preferable adjusted such that each target deposits a thin layer (e.g., 2 nm) of film on therod 210 in a single revolution of therod 210. The films that result from this configuration spiral outwardly from therod 210. However, if repeating concentric layers of film are preferred, shutters can be used to control the exposure of therod 210 to eachtarget rod 210. As the cylinder increases in diameter, the parameters of the deposition system can be adjusted to ensure that the thickness of the magnetic and/or non-magnetic layers is the same for each deposition layer. - Further, if it is desired that the center of the disk remain hollow, a material that can be etched selectively (e.g., Cu) can be used for the
rod 210. Applying a magnetic field along the axis of therod 210 can result in perpendicular anisotropy of the film layers deposited on therod 210. - Once the
rod 210 completely a predetermined number of rotations, a layered structure “Media Rod” 310 is produced by the depositions of magnetic layer(s) fromtarget 320 and depositions of non-magnetic layer(s) fromtarget 330, as illustrated inFIG. 3 . Themedia rod 310 has concentric (or spiral) layers of magnetic media separated by non-magnetic spacers. The top (or bottom)surface 340 of themedia rod 310 exposes the concentric layers of deposited film. - Once the media rod is produced, it can be used to create individual media disks.
FIG. 4 illustrates one use of themedia rod 410 to createmedia disks 430. Themedia rod 410 can be cut (i.e., sliced) 420 into multipleindividual disks 430. The central Copper (Cu) can be etched into thedisks 430 selectively, if necessary. The thickness of the magnetic film defines track-width in this particular method. Optionally, theindividual disks 430 can be placed on a support disk. Further, a highly permeable material can be deposited on the substrate of thedisk 430 to create a soft underlayer (SUL). Thefinal disk 430 can be polished to smooth its surface. - Because a disk made by slicing the
media rod 410 is thicker compare to deposited magnetic films (track-widths), the anisotropy direction is preferably perpendicular to disk surface. - Alternatively, once the
media rod 510 is produced, it can be used to imprint circular tracks on a disk. For example, as illustrated inFIG. 5 , adisk 520, preferably made of Silicon (“Si”) or an appropriate metal, can be heated to a predetermined temperature. Themedia rod 510 can then be used to stamp theheated disk 520 to imprint the concentric (or spiral) tracks on themedia rod 510 onto the printedmedia disk 530. - In a further alternative, as illustrated in
FIG. 6 , the surface of themedia rod 610 can be heated to a predetermined temperature such that when stamped onto atransfer disk 620, the top surface of themedia rod 620 is transferred to the printedmedia disk 630. Themedia rod 620 can be heated with external agent (e.g., a laser) preferably to a temperature that liquefies the top surface. Optionally, the surface of the printedmedia disk 630 can be polished for smoothness. - In accordance with yet a further aspect of the present invention, a
cylindrical drive 720 can be produced from the alternating deposition of magnetic and non-magnetic films. As illustrated inFIG. 7 , amedia layer 710 is created by depositing alternating layers of magnetic and non-magnetic layers. Preferably media plates are sputter deposited to create alternating layers corresponding to the track width. Cylindrical disks can be punched or cut out of themedia layer 710 to produce acylindrical drive 720. The thickness of the magnetic layer corresponds to the track-width and the non-magnetic thickness corresponds to the spacing between the tracks. - The
media layer 810 can be produced usingprocess 800 illustrated inFIG. 8 . A conveyor-belt 850, or similar mechanism, can transport amedia layer 810 through the manufacturing process. Multiple deposition targets are positioned relative to the conveyor belt such that a thin film will be deposited on themedia layer 810 as it comes within proximity to the deposition target. - For example, conveyor-
belt 850 can oscillatemedia layer 810 back and forth such thatdeposition target 820 sputter deposits a magnetic layer,deposition target 830 sputter deposits a non-magnetic layer, anddeposition target 840 sputter deposits another magnetic layer. The convey-belt can then reverse directions such thatdeposition target 830 deposits a further non-magnetic layer, anddeposition target 820 deposits a further magnetic layer. This process can be repeated until the desired number of magnetic layers have been deposited on themedia layer 810. Themedia layer 810 can then be cut into cylinders as described above, thereby producing cylindrical storage devices. - It is to be understood that even though numerous characteristics and advantages of various embodiments of the invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, the particular elements may vary depending on the particular application while maintaining substantially the same functionality without departing from the scope of the present invention. In addition, although the preferred embodiment described herein is directed to a magnetic data storage device, it will be appreciated by those skilled in the art that the teachings of the present invention can be applied to optical devices without departing from the scope of the present invention. The implementations described above and other implementations are within the scope of the following claims.
Claims (9)
1. An apparatus, comprising:
a base layer of a magnetic recording medium having a plurality of tracks, each track having a track width;
a plurality of magnetic layers; and
a plurality of non-magnetic layers interposed between the plurality of magnetic layers;
wherein the magnetic recording medium includes a first surface exposing the plurality of magnetic layers and the interposed plurality of non-magnetic layers, and a thickness of each of the magnetic layers corresponds to the track width of the magnetic recording medium.
2. The apparatus of claim 1 , wherein at least one of the plurality of magnetic layers comprises a sputtered magnetic film.
3. The apparatus of claim 1 , wherein the base layer comprises a cylindrical base layer, and each of the plurality of magnetic layers and each of the plurality of non-magnetic layers forms a cylindrical layer around the base layer.
4. The apparatus of claim 3 , wherein at least one of the plurality of magnetic layers has a magnetic anisotropy substantially parallel to a cylindrical axis of the base layer.
5. The apparatus of claim 1 , wherein the base layer comprises a material amenable to selective etching.
6. The apparatus of claim 1 , further comprising a soft underlayer comprising a permeable material on a surface of the magnetic recording medium.
7. The apparatus of claim 1 , wherein the magnetic layers comprise CoPt.
8. The apparatus of claim 1 , wherein the non-magnetic layers comprise alumina.
9. The apparatus of claim 1 , wherein the magnetic recording medium includes a cylindrical drive, and each of the plurality of magnetic layers and each of the plurality of non-magnetic layers form a substantially planar circular layer.
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US13/620,499 US20130017413A1 (en) | 2008-07-23 | 2012-09-14 | Discrete Track Media |
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US12/178,443 US8298611B2 (en) | 2008-07-23 | 2008-07-23 | Discrete track media |
US13/620,499 US20130017413A1 (en) | 2008-07-23 | 2012-09-14 | Discrete Track Media |
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US12/178,443 Division US8298611B2 (en) | 2008-07-23 | 2008-07-23 | Discrete track media |
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US20190236360A1 (en) * | 2018-01-30 | 2019-08-01 | Mashgin Inc. | Feedback loop for image-based recognition |
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US20060131270A1 (en) * | 2004-12-16 | 2006-06-22 | Asml Holding, N.V. | Method and system for making a nano-plate for imprint lithography |
US8049993B2 (en) * | 2007-05-14 | 2011-11-01 | Kabushiki Kaisha Toshiba | Magnetic recording medium and magnetic storage device |
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US3400328A (en) * | 1964-02-24 | 1968-09-03 | Texas Instruments Inc | Anisotropic ferromagnetic thin film magnetometer systems utilizing a modulator to perturb the field on the sensitive axis |
JPS5758226A (en) * | 1980-09-22 | 1982-04-07 | Toshiba Corp | Magnetic recording medium |
US5093192A (en) * | 1989-03-28 | 1992-03-03 | Konica Corporation | Magnetic recording medium |
US5066552A (en) * | 1989-08-16 | 1991-11-19 | International Business Machines Corporation | Low noise thin film metal alloy magnetic recording disk |
US5062021A (en) * | 1990-03-12 | 1991-10-29 | Magnetic Peripherals Inc. | Selectively textured magnetic recording media |
US5108781A (en) * | 1990-03-12 | 1992-04-28 | Magnetic Peripherals Inc. | Process for manufacturing selectively textured magnetic recording media |
US5815342A (en) * | 1992-07-13 | 1998-09-29 | Kabushiki Kaisha Toshiba | Perpendicular magnetic recording/reproducing apparatus |
US5723033A (en) * | 1995-09-06 | 1998-03-03 | Akashic Memories Corporation | Discrete track media produced by underlayer laser ablation |
TW340296B (en) * | 1997-02-21 | 1998-09-11 | Ricoh Microelectronics Kk | Method and apparatus of concave plate printing, method and apparatus for formation of wiring diagram, the contact electrode and the printed wiring nickel substrate |
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2008
- 2008-07-23 US US12/178,443 patent/US8298611B2/en active Active
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US20060131270A1 (en) * | 2004-12-16 | 2006-06-22 | Asml Holding, N.V. | Method and system for making a nano-plate for imprint lithography |
US8049993B2 (en) * | 2007-05-14 | 2011-11-01 | Kabushiki Kaisha Toshiba | Magnetic recording medium and magnetic storage device |
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US8298611B2 (en) | 2012-10-30 |
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