METHOD FOR MANUFACTURING MASTER DISK OF OPTICAL DISK AND OPTICAL DISK SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To manufacture a master disk of an optical disk capable of producing a high capacity optical disk substrate having a large taper angle of a groove. SOLUTION: Two photoresist films 2a, 2b are formed on a quartz substrate 1 and a groove 10 having a large taper angle is formed by using dry etching conditions vastly different from each other in etching rate. The resulting ruggedness is transferred to the substrate 1 by dry etching.