Reflective mask blank, reflective mask, method for manufacturing reflective mask blank, and method for manufacturing semiconductor device

A reflective mask comprising:

• a substrate, and
• a multilayer reflective film, a protective film, and a phase-shift film pattern for shifting a phase of EUV light, which are formed in said order on the substrate,
• wherein the protective film is made of a material containing ruthenium as a main component, and
• wherein an anti-diffusion layer which contains ruthenium and oxygen is formed on a surface of the protective film, or as a part of the protective film on a side adjacent to the phase-shift film pattern, so as to inhibit counter diffusion in relation to the phase-shift film pattern.

A method for manufacturing a semiconductor device, comprising:

• setting a reflective mask in an exposure apparatus having an exposure light source for emitting EUV light, so as to transfer a transfer pattern onto a resist film formed on a transfer target substrate,
• wherein the reflective mask comprises:
• a substrate, and
• a multilayer reflective film, a protective film, and a phase-shift film pattern for shifting a phase of EUV light, which are formed in said order on the substrate,
• wherein the protective film is made of a material containing ruthenium as a main component, and
• wherein an anti-diffusion layer which contains ruthenium and oxygen is formed on a surface of the protective film, or as a part of the protective film on a side adjacent to the phase-shift film pattern, so as to inhibit counter diffusion in relation to the phase-shift film pattern.