Patent ID: 7981573

Claim:
A reflective mask blank comprising a substrate on which a reflective layer for reflecting exposure light in a short-wavelength region including an extreme ultraviolet region and an absorber layer for absorbing the exposure light are successively formed, the absorber layer having an at least two-layer structure including as a lower layer an exposure light absorbing layer comprising an absorber for the exposure light and as an upper layer a low-reflectivity layer comprising an absorber for inspection light used in inspection of a mask pattern, the upper layer being farther from the substrate than the lower layer, wherein the exposure light absorbing layer as the lower layer of the absorber layer is made of at least one substance selected from a lower layer substance group consisting of: one element selected from an element group consisting of chromium, manganese, cobalt, copper, zinc, gallium, germanium, molybdenum, palladium, silver, cadmium, tin, antimony, tellurium, iodine, hafnium, tantalum, tungsten, titanium, and gold; a substance comprising at least one of nitrogen and oxygen and said one element; an alloy comprising said one element; and a substance comprising at least one of nitrogen and oxygen and said alloy; wherein the low-reflectivity layer as the upper layer of the absorber layer is made of at least one substance selected from an upper layer substance group consisting of: one of nitride, oxide, and oxynitride of the substance forming the exposure light absorbing layer; one of the nitride, the oxide, and the oxynitride with silicon added thereto; and oxynitride of silicon; and wherein a contrast between reflected light reflected on a surface of the reflective layer and reflected light reflected on a surface of the absorber layer is 40% or more at the wavelength of light used in inspection of a pattern formed on the absorber layer.