Patent ID: 7989124

Claim:
A photomask blank from which is produced a photomask comprising a transparent substrate and a mask pattern formed thereon including transparent regions and effectively opaque regions to exposure light, said photomask blank comprising: a transparent substrate; a light-shielding film having a single layer structure or a multilayer structure, said light-shielding film disposed on the substrate, optionally with another film intervening therebetween, said light-shielding film consisting essentially of a metal or metal compound susceptible to fluorine dry etching, and said metal and metal compound being selected from the group consisting of silicon alone, a silicon compound comprising silicon and at least one element selected from the group consisting of oxygen, nitrogen and carbon, and a material comprising a transition metal and silicon; an etching mask film contiguously laminated on said light-shielding film, said etching mask film consisting essentially of a metal or metal compound resistant to fluorine dry etching, and said metal or metal compound being selected from the group consisting of chromium alone, a chromium compound comprising chromium and at least one element selected from the group consisting of oxygen, nitrogen and carbon, and free of silicon, tantalum alone, and a tantalum compound comprising tantalum and free of silicon; and an antireflective film contiguously laminated on said etching mask film, said antireflective film consisting essentially of a metal or metal compound selected from the group consisting of chromium alone, and a chromium compound comprising chromium and at least one element selected from the group consisting of oxygen, nitrogen and carbon, and free of silicon, wherein said transition metal is at least one element selected from the group consisting of titanium, vanadium, cobalt, nickel, zirconium, niobium, molybdenum, hafnium, tantalum and tungsten.