Patent ID: 8293435
Filing Date: 2012-10-23
Classification: G03F

Abstract:
1. A photomask blank for manufacturing a phase shift mask having a light-transmitting substrate provided with a phase shift portion adapted to give a predetermined phase difference to transmitted exposure light, wherein the phase shift portion is a phase shift film adapted to give a predetermined phase change amount to the transmitted exposure light, and the photomask blank comprises: an etching mask film, on a surface of the phase shift film, that is made of a material being dry-etchable with a chlorine-based gas, but not dry-etchable with a fluorine-based gas, and serves as an etching mask at least until a transfer pattern is formed in the phase shift film by dry etching; and a light-shielding film, on a surface of the etching mask film, that is made of a material mainly containing tantalum and has a thickness so as to be removable during the dry etching for forming the transfer pattern in the phase shift film.