To manufacture a master optical disk which has high reliability and high tracking performance in a method of forming a fine pattern by forming a mixed film smaller than the diameter of a light beam spot at the boundary between a substrate and a metallic film and forming a pattern having a guide groove of a rectangular shape.
A metallic film is formed on the surface of the substrate and the mixed film consisting of the metallic film and the substrate is formed at the boundary of the metallic film and the substrate heated up to a prescribed temperature or above by condensing and irradiating the prescribed position of the metallic film with the light beam from above the metallic film, by which only the metallic film is selectively removed. The substrate of the regions where the mixed films are not formed is etched by a prescribed amount in such a manner that the mixed film and the substrate below the same are made to remain.
MORI TAKESHI
SAEGUSA MICHINOBU
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