To prevent the occurrence of defects in a transparent substrate in the production of a phase shift mask by forming a light shielding film on the surface of the substrate and a protective film on the surface of the light shielding film.

A light shielding film 42 is formed on the surface of a substrate 40 comprising a material that is optically transparent to incident light, preferably a quartz substrate. The light shielding film is a film comprising a material that optically and substantially perfectly shields light incident on the substrate 40 and is preferably a chromium film. A protective film 44 is then formed on the surface of the light shielding film 42. The protective film 44 protects the light shielding film 42 from a gas that etches the substrate 40 in the production of a phase shift mask. The protective film 44 is preferably a volatile material film that is excellent in adhesiveness to the light shielding film 42, reacts with the etching gas and volatilizes. The volatile material film is preferably a molybdenum silicon oxynitride(MoSiON) film.