PHASE SHIFT MASK BLANK, PRODUCTION METHOD THEREOF AND PRODUCTION METHOD OF PHASE SHIFT MASK

摘要

PROBLEM TO BE SOLVED: To provide a phase shift mask blank and its production method which enable patterning, by wet etching, of a phase shift film to a cross sectional shape capable of exerting a phase shift effect sufficiently and a production method of a phase shift mask having a phase shift film pattern capable of exerting a phase shift effect sufficiently.SOLUTION: A phase shift mask blank 1 consists of a phase shift film 3 formed on a transparent substrate 2 and containing chromium, oxygen and nitrogen. The phase shift film 3 has a main layer 3a and an outermost surface layer 3b composed of the same material. The refractive index of the upper part of the main layer on the side of the outermost surface layer 3b at the wavelength of 365 nm is smaller than the refractive index of the lower part of the main layer on the side of the transparent substrate 2 at the wavelength of 365 nm.