Patent ID: 7001698

Claim:
A chromium-containing half-tone phase-shift photomask comprising coarse and dense patterns coexisting in a plane which is prepared by performing a series of pattern-forming steps including a step for forming a resist layer on a photomask blank, a step for exposing and patterning said resist layer, a developing step, a step for etching said photomask blank and a step for removing said resist layer, wherein the photomask is characterized in that patterns to be transferred onto a wafer are formed on said photomask blank for the chromium-containing half-tone phase-shift photomask according to a dry-etching method comprising dry-etching a chromium-containing half-tone phase-shift film utilizing an etching gas comprised of a mixed gas including (a) a reactive ion etching gas, which contains an oxygen-containing gas and a hydrogen chloride gas, and (b) a reducing gas added to the gas component (a).