Master information carrier for magnetic transfer

Abstract

A master information carrier has a pattern of a magnetic layer representing information to be transferred to a high-density recording slave medium where the track width is not larger than 0.3 μm. The pattern is drawn by scanning a given track a plurality of times with an electron beam whose drawing diameter is smaller than the track width.

What is claimed is;  
     
         1 . A master information carrier having thereon a pattern of a magnetic layer representing information to be transferred to a high-density recording slave medium where the track width is not larger than 0.3 μm, wherein the improvement comprises that 
 the pattern is drawn by scanning a given track a plurality of times with an electron beam whose drawing diameter is smaller than the track width.  
 
     
     
         2 . A master information carrier as defined in  claim 1  in which, when it is assumed that W represents the track width, n represents the number of times by which one track is scanned by the electron beam, d represents the drawing diameter of the electron beam and k represents a coefficient representing the degree of overlap, W=[n−(n−1)k]×d, and the value of k is in the range of not smaller than 0 and not larger than 0.8.  
     
     
         3 . A master information carrier as defined in  claim 2  in which the value of k is in the range of not smaller than 0.2 and not larger than 0.8.  
     
     
         4 . A master information carrier as defined in  claim 1  in which the master information carrier is produced by drawing a pattern by scanning each track a plurality of times with an electron beam whose drawing diameter is smaller than the track width and which is modulated according to the information to be transferred while rotating a disc coated with photoresist, making a substrate having an irregularity pattern by mastering on the basis of the pattern drawn by the electron beam, and forming a magnetic layer on the substrate.