Mask blank, transfer mask, method of manufacturing a transfer mask, and method of manufacturing a semiconductor device

A mask blank for use in the manufacture of a binary mask adapted to be applied with ArF excimer laser exposure light, the mask blank comprising, on a transparent substrate, a light-shielding film for forming 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 transition metal and silicon, and having a refractive index n of 1.80 or less and an extinction coefficient k of 2.37 or more, and has a thickness of 30 nm or more,
• the upper layer is made of a material having a refractive index n of 2.00 or more and an extinction coefficient k of 1.00 or less, and has a thickness of 3 nm or more and 6 nm or less, 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 the thickness of the light-shielding film is 30 degrees or less.