Patent ID: 6060220
Filing Date: 2000-05-09
Classification: G11B,Y10S

Abstract:
A method for making a master for making optical information carriers having a relief structure, said relief structure representing data, said method comprising the following steps:a) depositing a first photoresist layer on a metal layer;b) exposing said first photoresist layer to a first radiation pattern;c) developing said first photoresist layer, thereby exposing screen portions of said metal layer;d) depositing by anodization an oxide screen layer on said screen portions of said metal layer, said screen layer having a thickness s.sub.0 ;e) removing said first photoresist layer from said metal layer, thereby creating a blank master comprising said metal layer and said screen layer, wherein said screen layer covers said screen portions of said metal layer and leaves a superset of open regions of said metal layer exposed, said superset comprising a first set of open regions and other open regions;f) depositing a first selector layer of photoresist on said blank master;g) exposing said selector layer to a second radiation pattern;h) developing said first selector layer, thereby exposing said first set of open regions of said metal layer;i) depositing by anodization a first oxide data layer of thickness s on said first set of open regions of said metal layer, said thickness s representing a first data value; andj) removing said first selector layer;wherein said step of depositing said first oxide data layer comprises the step of applying a constant anodization voltage V until an anodization current density falls to a value j.