Methods for manufacturing reflective photomasks, reflective blank photomasks, and reflective photomasks

Abstract

[Solution] A reflective photomask comprising: a substrate; a multilayer reflective film that reflects extreme ultraviolet light, i.e., exposure light; a protective film with an extinction coefficient of 0.018 to 0.035 and a thickness of 1 to 6 nm; and a light-absorbing film with a reflectivity of 1 to 8% relative to the exposure light, a phase shift function with a phase difference of 190 to 240 degrees, which absorbs the exposure light and has a thickness of 32 to 38 nm; wherein the light-absorbing film is formed of a material containing 30 to 70 atomic% Ru and 30 to 70 atomic% Pt, and the total of Ru and Pt is 96 atomic% or more. [Effects] A reflective photomask with a thinner light-absorbing film is provided. The wafer transfer characteristics of the light-absorbing film are high (high NILS value), the difference in optimal focus value between lines and spacing patterns of different sizes (pitch) is small, the reflectivity is around 5%, the entire image can be removed by etching with fluorine-based gases, the pattern is easy to correct, and the influence of the shading effect is small.

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