Reflective photomask substrate, reflective photomask, and manufacturing method of reflective photomask

Abstract

This invention provides a reflective photomask substrate that, after etching the absorber film, is less prone to the formation of a deteriorated layer on the exposed side of the absorber film, has a higher etching rate for the buffer layer, and exhibits lower crystallinity. The reflective photomask substrate of this invention sequentially comprises a substrate, a multilayer reflective film for reflecting EUV light, a buffer layer, and an absorber film. The absorber film contains platinum, and the buffer layer contains nitrogen, with the nitrogen content being less than 20 atomic percent relative to the total atoms of the buffer layer.

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