Euv lithography reflective mask blank, and the substrate with a conductive film for the mask blank

Substrate with a conductive film for an EUV mask blank surface hardness is increased, as well as a multilayer reflective film coated substrate and EUV mask blank using the substrate with the conductive film. A substrate with a conductive film for use in the manufacture of reflective mask blank for EUV lithography, the material of the conductive film, than at least one selected Cr, Ti, Zr, Nb, from the group consisting of Ni and V becomes, the conductive film substrate with a conductive film which is characterized by containing a B (boron) at an average concentration of from 1 to 70 at%.