Patent ID: 8021806
Filing Date: 2011-09-20
Classification: G03F

Abstract:
1. A photomask blank for manufacturing a phase shift mask having a light-transmitting substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure light, wherein the phase shift part is a dug-down part that is dug down from a surface of the light-transmitting substrate to a digging depth adapted to produce the predetermined phase difference with respect to exposure light transmitted through the light-transmitting substrate at a portion where the phase shift part is not provided, the photomask blank comprising: an etching mask film, on the digging-side surface of the light-transmitting substrate, 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 the digging depth is reached when forming the dug-down part; and a light-shielding film, on an opposite-side surface of the light-transmitting substrate, that forms, by etching, a light-shielding part adapted to shield exposure light transmitted through the light-transmitting substrate in a region other than a transfer pattern region, wherein the light-shielding film comprises a portion that contacts with the opposite-side surface of the light-transmitting substrate and that is formed by a material having an etch resistance with respect to the light-transmitting substrate.