Blank photomask and its manufacturing method

Abstract

[Problem] To provide a blank photomask that simplifies the steps for removing the hard mask film, thereby simplifying the mask manufacturing process. [Solution] A blank photomask characterized by having: a substrate, a pattern forming layer consisting of a single layer or multiple layers on the substrate, and a hard mask film on the pattern forming layer, the hard mask film being composed of a material containing chromium and at least one element selected from nitrogen, carbon and oxygen, the film density of the hard mask film being 6.0 g / cm3 or less, the aforementioned hard mask film having resistance to dry etching using a gas containing fluorine and not containing oxygen, and resistance to dry etching using a gas containing chlorine and not containing oxygen, when the film thickness reduction per minute of the hard mask film is set as v [nm / min] and the film thickness of the hard mask film is set as d [nm], it conforms to the following formula (1): d / v≦60 [min] (1).

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