Patent ID: 8512916

Claim:
A photomask blank for producing a photomask to which an ArF excimer laser light is applied, wherein: a thin film having a multilayer structure is provided on a light transmissive substrate; the thin film has a light-shielding film in which a back-surface antireflection layer, a light-shielding layer and a front-surface antireflection layer are laminated in this order from the light transmissive substrate; the light-shielding layer comprises chromium and nitrogen, and the chromium content is more than 50 atomic %; the front-surface antireflection layer and the back-surface antireflection layer each has an amorphous structure made of a material comprising chromium, nitrogen, oxygen and carbon; the chromium content ratio of the front-surface antireflection layer and the back-surface antireflection layer is 40 atomic % or less; and a first sum of nitrogen content and oxygen content of the back-surface antireflection layer is less than a second sum of nitrogen content and oxygen content of the front-surface antireflection layer.