Patent ID: 6228562
Filing Date: 2001-05-08
Classification: G03F,G11B,Y10S

Abstract:
A method of manufacturing a recording original disc for optical information recording media comprising the steps of:forming a lower layer of a first etching-applied material onto a surface of a substrate, the first etching-applied material being one of Si, Si.sub.3 N.sub.4, Cr and Al;forming an intermediate layer of a second etching-applied material on said lower layer, the second etching-applied material being SiO.sub.2 ;forming an upper layer of positive type photoresist on said intermediate layer;exposing said upper layer of positive type photoresist to light to form a pattern corresponding to recording information, a shape of a latent image being formed on said upper layer, and first side walls defining said image in said upper layer being slanted with respect to a vertical axis of said disc, and decreasing in width in a direction from said upper layer towards said intermediate layer;developing said upper layer of positive type photoresist to remove said latent image formed in said upper layer, thus forming a first opening portion in said upper layer having said slanted first side walls;etching said intermediate layer while using as a mask said upper layer of positive type photoresist which has been exposed to light and developed, thus forming a second opening portion in said intermediate layer having second side walls, said second side walls being slanted from a perpendicular and decreasing in width in a direction from said intermediate layer towards said lower layer; andetching said lower layer while using as a mask said intermediate layer, thus forming a third opening portion in said lower layer, with side walls of said third opening portion being substantially perpendicular to said surface of said substrate, thus forming a recording original disc;wherein a material used for said substrate and said first etching-applied material are the same material, and thus said substrate and said lower layer are formed simultaneously in a single step.