Patent ID: 8574793

Claim:
A mask blank adapted to manufacture a transfer mask 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 an at least two-layer structure comprising a lower layer and an upper layer from a side of the transparent substrate, the lower layer is made of a material composed of a transition metal, silicon, and nitrogen and having a nitrogen content of 21 at % or more and a refractive index n of 1.9 or less, the upper layer is made of a material composed of a transition metal, silicon, and nitrogen and having a refractive index n of 2.1 or less, and a surface layer of the upper layer contains oxygen and has a nitrogen content of 14 at % or more.