Contact printing of magnetic media with mechanically reinforced and/or gas venting stamper

Abstract

An apparatus for performing contact printing of a magnetic transition pattern in a magnetic recording medium, comprising: (a) a stamper/imprinter including a body formed of at least one magnetic material having a high saturation magnetization B sat and a high permeability, including an imprinting surface adapted to be placed in intimate contact with a surface of a magnetic layer, the imprinting surface comprised of a plurality of patterned areas which separate a plurality of areas which are not patterned, each of the areas which is not patterned being provided with at least one of: (i) mechanical reinforcing means for preventing deformation of the body when the imprinting surface is urged into contact with the surface of the magnetic layer; and (ii) gas venting means for facilitating removal of air or other gas from between the imprinting surface and the surface of the magnetic layer when the former is urged into contact with the latter.

1 - 13 . (canceled)  
     
     
         14 . A method of forming a magnetic transition pattern in a surface of a magnetic material, comprising the sequential steps of: 
 providing a workpiece having a surface comprised of the magnetic material, the magnetic material including a plurality of magnetic domains extending from the surface;    unidirectionally aligning the magnetic domains of the magnetic material in a first unidirectional DC magnetic field having a first direction;    contacting the surface of the magnetic material with an imprinting surface of a stamper, the stamper including a body formed of at least one magnetic material having a high saturation magnetization B sat ≧about 0.5 Tesla and a high permeability μ≧about 5, the imprinting surface adapted to be placed in contact with the surface of the magnetic material, the imprinting surface comprised of a plurality of projections and a plurality of depressions arranged in a pattern corresponding to the magnetic transition pattern to be formed in the surface of the magnetic material and including a plurality of patterned areas separating a plurality of unpatterned areas, and each of the plurality of unpatterned areas being provided with at least one of:    a plurality of spaced-apart projections, and    spaced-apart parallel channels    selectively re-aligning the plurality of magnetic domains in a second unidirectional DC magnetic field having a second direction opposite of the first direction where the plurality of magnetic domains which are in contact with the plurality of projections or which face the plurality of depressions of the imprinting surface of the stamper, forming a pattern replicating the pattern of the plurality of projections and plurality of depressions with aligned magnetic domains and re-aligned magnetic domains; and    removing the stamper from contact with the surface of the magnetic material.    
     
     
         15 . The method according to  claim 14 , wherein contacting the surface of the magnetic material includes each of the patterned areas of the imprinting surface having a plurality of projections forming plurality of images of a plurality of servo sectors to be formed in the magnetic layers and 
 each of the unpatterned areas corresponds to a data zone to be formed in the magnetic layer.    
     
     
         16 . The method according to  claim 15 , wherein each of the plurality of unpatterned areas corresponding to the data zones are recessed relative to the plurality of projections forming the images of the servo sectors, 
 each of the recessed areas corresponding to the data zones comprises a plurality of spaced-apart projections, and    areas adjacent to the plurality of spaced-apart projections comprise channels in the data zones.    
     
     
         17 . The method according to  claim 16 , wherein the imprinting surface is annular disk-shaped with an inner diameter and an outer diameter, each of the plurality of patterned areas forming the servo sectors comprises a plurality of spaced-apart parallel projections extending radially in partial spirals originating at the inner diameter and extending to the outer diameter, and 
 the plurality of spaced-apart projections in the data zones form as a plurality of spaced-apart parallel extending radially in partial spirals originating at the inner diameter and extending to the outer diameter.    
     
     
         18 . The method according to  claim 15 , wherein each of the plurality of unpatterned areas corresponding to the data extends to a height approximately equal to a height of the projections forming the images of the servo sectors; and 
 the imprinting surface is annular disk-shaped with an inner diameter and an outer diameter, each of the plurality of patterned areas forming the servo sectors comprises a plurality of spaced-apart parallel projections extending radially in partial spirals originating at the inner diameter and extending to the outer diameter, and each of the plurality of data zones comprises a plurality of spaced-apart parallel channels extending radially in partial spirals originating at the inner diameter and extending to the outer diameter.    
     
     
         19 . The method according to  claim 14 , further comprising: 
 erasing any magnetic transition patterns formed in portions of the magnetic layer corresponding to the plurality of unpatterned areas of the imprinting surface of the stamper.    
     
     
         20 . The method according to  claim 14 , wherein providing the workpiece comprises providing a disk-shaped workpiece for a magnetic recording medium, the workpiece including a non-magnetic substrate with a layer of a magnetic recording material overlying a surface thereof, and the substrate comprised of a non-magnetic material selected from the group consisting of Al, NiP-plated Al, Al—Mg alloys, other Al-based alloys, other non-magnetic metals, other non-magnetic metal-based alloys, glass, ceramics, polymers, glass-ceramics, and composites and/or laminates thereof; 
 aligning the plurality of magnetic domains comprises placing the workpiece in a first unidirectional DC magnetic field having a first direction and a second unidirectional DC magnetic field having a second direction opposite the first direction and a strength sufficient to align each of the plurality of magnetic domains in the first direction;    providing the stamper formed of at least one magnetic material having high saturation magnetization and high permeability, selected from the group consisting of Ni, NiFe, CoNiFe, CoSiFe, CoFe, and CoFeV, and the imprinting surface of the stamper including a plurality of projections and depressions arranged in a pattern corresponding to a servo pattern to be formed in the surface of the magnetic material; and    placing the workpiece with the imprinting surface of the stamper in contact with the second unidirectional DC magnetic field having a to a strength lower than the first unidirectional DC magnetic field to selectively reverse the alignment of said the plurality of magnetic domains of the portions of the magnetic material which are in contact with the projections or face the depressions of the imprinting surface of the stamper, while retaining the first direction alignment of the plurality of magnetic domains of the portions of the magnetic material facing the depressions or the projections, respectively, of the imprinting surface of the stamper.    
     
     
         21 . The method according to  claim 14 , wherein providing the workpiece includes a layer of a perpendicular magnetic recording material; 
 placing the workpiece in the first unidirectional DC magnetic field having the first direction perpendicular to the surface of the layer of perpendicular magnetic recording material and a strength sufficient to align each of the plurality of magnetic domains along the first direction; and    placing the workpiece with the imprinting surface of the stamper in contact with the second unidirectional DC magnetic field and a strength lower than the first unidirectional DC magnetic field to selectively reverse the alignment of the plurality of magnetic domains of the portions of the magnetic material in contact with the projections of the imprinting surface of the stamper, while retaining the first direction alignment of the plurality of magnetic domains of the portions of the magnetic material facing the depressions of the imprinting surface of the stamper, the stamper having an imprinting surface including a plurality of projections and depressions arranged in a pattern corresponding to a servo pattern to be formed in the surface of the layer of perpendicular magnetic recording material.    
     
     
         22 . The method according to  claim 14 , wherein. providing the workpiece includes a layer of a longitudinal magnetic recording material; 
 placing the workpiece in the first direction parallel to the surface of the layer of longitudinal magnetic recording material and a high strength to align each of the plurality of magnetic domains along the first direction; and    step (c) comprises placing the workpiece with the imprinting surface of the stamper in the second unidirectional DC magnetic field parallel to the surface of the longitudinal magnetic recording layer and a lower strength than the strength of the first direction to selectively reverse the alignment of the plurality of magnetic domains of the portions of the magnetic recording layer facing the depressions of the imprinting surface of the stamper, while aligning the plurality of magnetic domains of the portions of the magnetic recording layer in contact with the projections of the imprinting surface of the stamper in the first direction, and the stamper having an imprinting surface including a plurality of projections and depressions arranged in a pattern corresponding to a servo pattern to be formed in the surface of the longitudinal magnetic recording material.    
     
     
         23 . (canceled)  
     
     
         24 . A method of forming a magnetic transition pattern on a surface of a magnetic material provided on a workpiece, the magnetic material including a plurality of magnetic domains extending from the surface, comprising the sequential steps of: 
 aligning the plurality of magnetic domains of the magnetic material in a first unidirectional DC magnetic field having a first direction;    contacting the surface of the magnetic material with an imprinting surface of a stamper, the imprinting surface comprised of a plurality of projections and plurality of depressions arranged in a pattern corresponding to the magnetic transition pattern to be formed in the surface of the magnetic material and including a plurality of patterned areas separating a plurality of unpatterned areas, and each of the unpatterned areas being provided with at least one spaced-apart projections and at least one spaced-apart parallel channel;    selectively re-aligning the plurality of magnetic domains which are in contact with the plurality of projections in a second unidirectional DC magnetic field having a second direction opposite the first direction; and    forming a pattern replicating the magnetic transition of the plurality of projections and plurality of depressions with aligned magnetic domains and re-aligned magnetic domains.    
     
     
         25 . The method according to  claim 24 , wherein the stamper further comprises: 
 a body formed of at least one magnetic material having a high saturation magnetization B sat ≧about 0.5 Tesla.    
     
     
         26 . The method according to  claim 24 , wherein the stamper further comprises: 
 a body formed of at least one magnetic material having a high permeability μ≧about 5.    
     
     
         27 . The method according to  claim 24 , wherein the imprinting surface is adapted to be placed in contact with the surface of the magnetic material.  
     
     
         28 . The method according to  claim 24 , wherein the stamper further comprises: 
 a body formed of at least one magnetic material having a high saturation magnetization B sat ≧about 0.5 Tesla and a high permeability μ≧about 5, and    the body including the imprinting surface adapted to be placed in contact with the surface of the magnetic material.    
     
     
         29 . The method according to  claim 24 , wherein contacting the surface of the magnetic material includes each of the patterned areas of the imprinting surface having a plurality of projections forming a plurality of images of a plurality of servo sectors to be formed in the magnetic layer, and 
 each of the unpatterned areas correspond to a data zone to be formed in the magnetic layer.    
     
     
         30 . The method according to  claim 29 , wherein each of the unpatterned areas corresponding to the data zones are recessed relative to the projections forming the plurality of images of the plurality of servo sectors, 
 each of the recessed areas corresponding to the data zones comprises a plurality of spaced-apart projections, and    areas adjacent to the plurality of spaced-apart projections comprise channels in the data zones.    
     
     
         31 . A method of forming a magnetic transition pattern on a surface of a magnetic recording layer having a plurality of magnetic domains extending from the surface, comprising: 
 aligning the plurality of magnetic domains in a first unidirectional DC magnetic field having a first direction;    contacting the surface of the magnetic recording layer with an imprinting surface of a stamper, the imprinting surface having a plurality of projections and plurality of depressions arranged in a pattern corresponding to the magnetic transition pattern to be formed in the surface of the magnetic recording layer;    re-aligning the plurality of magnetic domains in a second unidirectional DC magnetic field having a second direction opposite the first direction; and    forming a pattern replicating the magnetic transition pattern of the plurality of projections and plurality of depressions with the aligned magnetic domains and the re-aligned magnetic domains.    
     
     
         32 . The method according to  claim 31 , wherein the stamper further comprises: 
 a body formed of at least one magnetic material having a high saturation magnetization B sat ≧about 0.5 Tesla and a high permeability μ≧about 5, and    the body including the imprinting surface adapted to be placed in contact with the surface of the magnetic recording layer.    
     
     
         33 . The method according to  claim 31 , wherein the imprinting surface further comprises: 
 a plurality of patterned areas separating a plurality of unpatterned areas, and each of the unpatterned areas being provided with at least one spaced-apart projection and at least one spaced-apart parallel channel.    
     
     
         34 . The method according to  claim 33 , comprising: 
 forming a plurality of images having a plurality of servo sectors in the magnetic recording layer and each of the unpatterned areas,    wherein the plurality of servo sectors has a plurality of spaced-apart parallel projections extending radially in partial spirals originating at an inner diameter of each of the servo sectors and extending to an outer diameter of each of the servo sectors.    
     
     
         35 . The method according to  claim 34 , comprising: 
 each of the plurality of unpatterned areas corresponds to a data zone to be formed in the magnetic recording layer, and are recessed relative to the spaced-apart parallel projections forming the plurality of images of the plurality of servo sectors.