Reflective mask blank for EUV lithography and substrate with conductive film

A reflective mask blank for EUV lithography, comprising:

• a substrate;
• a conductive film disposed on or above a back surface of the substrate;
• a reflective layer disposed on or above a front surface of the substrate, the reflective layer reflecting EUV light;
• and
• an absorption layer disposed on or above the reflective layer, the absorption layer absorbing the EUV light,
• wherein the conductive film has a refractive index nλ1000-1100 nm of 5.300 or less and has an extinction coefficient kλ1000-1100 nm of 5.200 or less, at a wavelength of 1000 nm to 1100 nm,
• the conductive film has a refractive index nλ600-700 nm of 4.300 or less and has an extinction coefficient kλ600-700 nm of 4.500 or less, at a wavelength of 600 nm to 700 nm, and
• the conductive film has a light transmittance at the wavelength of 1000 nm to 1100 nm of 2.0% or more, a light transmittance at the wavelength of 600 nm to 700 nm of 1.0% or more, and a light transmittance at a wavelength of 400 nm to 500 nm of less than 1.0%.