System and method for patterning a master disk for nanoimprinting patterned magnetic recording disks

Abstract

A system and method for patterning a master disk or “stamper” to be used for nanoimprinting magnetic recording disks uses an air-bearing slider that supports an aperture structure within the optical near-field of a resist layer on a rotating master disk substrate. Laser pulses directed to the input side of the aperture are output to the resist layer. The aperture structure includes a metal film reflective to the laser radiation with the aperture formed in it. The aperture has a size less than the wavelength of the incident laser radiation and is maintained by the air-bearing slider near the resist layer to within the radiation wavelength. The timing of the laser pulses is controlled to form a pattern of exposed regions in the resist layer, with this pattern ultimately resulting in the desired pattern of data islands and nondata islands in the magnetic recording disks when they are nanoimprinted by the master disk.

1 - 12 . (canceled) 
   
   
       13 . A method for patterning a master disk for nanoimprinting magnetic recording disks, the method comprising:
 providing a master disk to be patterned comprising a substantially rigid substrate having a substantially planar surface, a resist layer on said substrate surface and comprising a material whose etching properties are changed when heated by laser radiation, a protective overcoat on the resist layer, and a layer of liquid lubricant on the overcoat;   providing an aperture structure comprising material substantially reflective to laser radiation at a specified wavelength and having an aperture therein, said aperture having a size less than said specified wavelength;   rotating the master disk about an axis substantially perpendicular to the substrate;   supporting the aperture structure on an air-bearing slider having an air-bearing surface (ABS) facing the rotating master disk, the aperture being maintained less than said specified wavelength from the resist layer during rotation of the master disk;   directing pulses of laser radiation at said specified wavelength through the aperture, through the liquid lubricant and protective overcoat, and to the resist layer to heat regions of the resist layer to thereby change the etching properties in said heated regions;   using said heated regions as an etch mask, etching the resist layer and underlying substrate in regions of the resist not exposed to said laser radiation to remove substrate material underlying regions of the resist not exposed to said laser radiation; and   after said etching, removing the remaining resist material from the substrate.   
   
   
       14 . The method of  claim 13  wherein providing an aperture structure comprising material having an aperture therein comprises providing a metallic film having periodic corrugations surrounding the aperture. 
   
   
       15 . The method of  claim 13  wherein providing an aperture structure comprising material having an aperture therein comprises providing a metallic film having an aperture with a shape selected from the group consisting of a C-shape, an E-shape, an H-shape and a bowtie shape. 
   
   
       16 . The method of  claim 13  system of claim  1  wherein providing a master disk having a layer of resist comprises providing a master disk having a bilayer of bismuth on indium. 
   
   
       17 . The method of  claim 13  wherein directing laser pulses comprises directing laser pulses at a rate to generate between about 0.5 million to 1 million heated regions of resist per inch. 
   
   
       18 . The method of  claim 13  wherein directing laser pulses comprises generating laser pulses having a pulse length in the range of about 10 picoseconds to about 10 nanoseconds. 
   
   
       19 . The method of  claim 13  wherein etching the resist layer comprises exposing the resist layer to an acid selected from hydrochloric acid and nitric acid. 
   
   
       20 . The method of  claim 13  wherein etching the resist layer comprises reactive-ion-etching (RIE) the resist layer.