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

摘要

A mask blank for use in the manufacture of a transfer mask adapted to be applied with ArF excimer laser exposure light is disclosed. The mask blank has, on a transparent substrate, a light-shielding film for forming a transfer pattern. The light-shielding film has an at least two-layer structure including a lower layer and an upper layer from the transparent substrate side. 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. A surface layer of the upper layer contains oxygen and has a nitrogen content of 14 at % or more.