MASK BLANK, METHOD FOR PRODUCING PHOTO MASK, AND PHOTO MASK

摘要

PROBLEM TO BE SOLVED: To provide a mask blank which can definitely prevent an alkali metal from spreading to a surface of a glass substrate, a method for producing a photo mask, and a photo mask.;SOLUTION: A mask blank 10 comprises a glass substrate 1 containing an alkali metal, a diffusion prevention layer 2 formed on a surface of the glass substrate, a light-shielding layer 3 formed on the diffusion prevention layer 2, and an antireflection layer 4 formed on the light-shielding layer 3. The surface of the glass substrate is polished and its surface roughness Ra is no larger than 2 nm. Even if the surface roughness Ra is no larger than 2 nm, diffusion of alkali metal from the glass substrate 1 to other layers can be reduced and occurrence of mouse nip default can be reduced by providing the diffusion prevention layer 2.;COPYRIGHT: (C)2012,JPO&INPIT