Patent ID: 6630408
Filing Date: 2003-10-07
Classification: G03F,Y10S

Abstract:
A method of forming an attenuating phase shifting mask having a chrome border on a semiconductor substrate, comprising the steps of:providing a attenuating phase shifting mask substrate having a primary surface; forming a layer of attenuating phase shifting material on the primary surface of said attenuating phase shifting mask substrate; forming a layer of opaque material on said layer of attenuating phase shifting material; patterning said layer of opaque material by forming a resist pattern on the surface of said opaque material, said resist pattern comprising a first exposure creating a first resist pattern, said first resist pattern being a mask pattern and an alignment mark pattern, and a second, low energy exposure, creating a second resist pattern, said second resist pattern being a guard ring pattern, said guard ring pattern being interspersed between said mask pattern and said alignment mark pattern; forming said first resist pattern in said layer of opaque material and in said layer of attenuating phase shifting material, using said first resist pattern in said pattern region of said layer of opaque material as a mask; placing a radiation interceptor over said resist pattern, said radiation interceptor not covering said mask pattern, said radiation interceptor partially covering said guard ring pattern; exposing said resist pattern through said radiation interceptor; removing said exposed resist pattern, leaving an unexposed resist pattern having a thickness in place surrounding said guard ring pattern; reducing said thickness of said resist pattern surrounding said guard ring pattern, creating a resist pattern of reduced and uniform thickness surrounding said guard ring pattern; etching said layer of opaque material in accordance with said resist pattern of reduced and uniform thickness; and removing said resist pattern of reduced and uniform thickness surrounding said guard ring region.