PHOTOMASK BLANK, PHOTOMASK PRODUCTION METHOD AND METHOD OF PRODUCING SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a photomask blank which achieves good pattern accuracy by optimizing the dry etching rate in the depth direction of a light-shielding film.SOLUTION: A photomask blank has a light-shielding film on a translucent substrate and is for a dry etching treatment corresponding to a method of forming a photomask by patterning the light-shielding film by a dry etching treatment with a mask pattern formed on the light-shielding film as a mask. The dry etching rate on the translucent substrate side of the light-shielding film is set to be lower than the dry etching rate on the front surface side of the light-shielding film.