High density magnetic information storage medium
AssigneeThe Board of Trustees of the Leland Stanford Jr. University
InventorRobert L. White
Life of this patent
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Abstract
Magnetic recording media comprising an ordered, ultra-high density array of 500 .ANG. diameter circular magnetic thin film islands on a substrate. The magnetic material supports magnetization perpendicular to the film plan, and each circular island comprises a single magnetic domain and a single information storage bit. An areal bit density of 10.sup.11 bits/in.sup.2 can be achieved by such an array. The magnetic array is generated using a single level mask comprised of a self-ordering polymer array, either an array of polymer spheres or a regular array of polymeric blocks in a phase-separating polymer film.
Claims14
A magnetic information storage medium comprising:
- a substrate;
- and
- a plurality of discrete, generally disk-shaped, spaced apart bodies of magnetic material disposed on said substrate with a density in excess of 10.sup.9 bodies/in.sup.2, each said body being magnetizable independent of its neighboring bodies and each said body having a maximum diameter of between 200 .ANG. and 500 .ANG., said bodies being formed by
- (a) providing a layer of magnetic material on said substrate, said layer being at least 100 .ANG. thick and no greater than 500 .ANG. thick, said magnetic material having uniaxial anisotropy;
- (b) providing a layer of photoresist over the layer of magnetic material;
- (c) providing a primary mask over said layer of photoresist, said primary mask being formed by an ordered array of discrete generally spherical polymeric particles having a diameter no greater than 750 .ANG.;
- (d) exposing said photoresist through said primary mask by flooding it with electrons, said polymeric particles causing generally disk-shaped regions of said layer of photoresist to remain unexposed;
- (e) removing said primary mask;
- (f) developing said photoresist to leave a plurality of discrete photoresist disks on said layer of magnetic material which form a secondary mask;
- (g) subjecting the secondarily masked magnetic film to an etchant to remove magnetic material not covered by said disks;
- and
- (h) stripping away the photoresist disks to leave said plurality of disk-shaped bodies of magnetic material disposed on said substrate.
A magnetic information storage medium comprising:
- a substrate;
- and
- a plurality of discrete, spaced apart generally disk-shaped bodies of magnetic material disposed on said substrate with a density in excess of 10.sup.9 bodies/in.sup.2, each said body being magnetizable independent of its neighboring bodies and being between 200 .ANG. and 500 .ANG. in diameter, said bodies being formed of a thin film with no significant jaggedness in its edges.
Dependencies are inferred from the claim text.