Patent ID: 8715892

Claim:
A mask blank for manufacturing a binary mask adapted to be applied with ArF excimer laser exposure light, comprising: a transparent substrate; and a light-shielding film formed on the transparent substrate, the light-shielding film serving to form a transfer pattern; wherein the light-shielding film has a laminated structure of a lower layer and an upper layer and has an optical density of 2.8 or more for the exposure light, the lower layer is made of a material containing tantalum and nitrogen and has a thickness of 33 nm or more, the upper layer is made of a material containing tantalum and oxygen and has a thickness of 3 nm or more, and a phase difference between the exposure light transmitted through the light-shielding film and the exposure light transmitted in air for a distance equal to a thickness of the light-shielding film is 60 degrees or less.