Master carrier for magnetic transfer
View Patent ↗To improve the quality of transfer signal by reducing loss of azimuth when the magnetic transfer is performed by bringing a master carrier and a slave medium into close contact with each other and applying transfer magnetic field thereto, even if the width of track is narrowed. The master carrier 3 has a pattern which corresponds to a transfer information for high density recording and is formed of a soft magnetic layer 32 with a width W of track of 3 μm or less, wherein the pattern is written and formed by scanning with an electron beam EB of which a writing diameter d is smaller than the width W of track, on a same track over plural times. Writing is performed approximately to a rectangular shape, whereby the loss of azimuth can be reduced and the accuracy of transfer can be enhanced.
1. A method of manufacturing a master carrier for magnetic transfer comprising a substrate having an unevenness pattern which corresponds to a transfer information for high density recording, and which master carrier comprises a soft magnetic layer with a track width of 0.3 μm or less, said method comprising:
writing said master carrier for magnetic transfer by illuminating a disc coated with an electron beam resist while rotating the disc and scanning at least twice with an electron beam which has been modulated in accordance with a transfer information and has a writing diameter smaller than the width of a track on a same track over plural times, whereby said electron beam scans partially overlap within a given track to write and form a pattern;
producing said substrate having an unevenness pattern by mastering based on the writing; and
coating a layer of soft magnetic substance on said substrate,
wherein a coefficient k, which satisfies a formula of W=[n−(n−1)k]xd is set to be not less than 0 and not more than 0.8, provided that k is a degree of overlap of the electron beam in writing a given track, W is the width of a given track in μm, n is the number of times that a given track is scanned by the electron beam, and d is the diameter of the electron beam in μtm.
2. The method as claimed in claim 1 , wherein the unevenness pattern of the master carrier is the same as or opposite the pattern written by the scanning electron beam.