| 摘要 |
By increasing the dry etching rate of a light shielding film, the dry etching time can be shortened so that loss of a resist film is reduced. As a result, a reduction in thickness (to 300 nm or less) of the resist film becomes possible so that pattern resolution and pattern accuracy (CD accuracy) can be improved. Further, by shortening the dry etching time, a photomask blank and a photomask manufacturing method are provided, which can form a pattern of the light shielding film having an excellent sectional shape. In a photomask blank having a light shielding film on an optically transparent substrate, the photomask blank being a mask blank for a dry etching process adapted for a photomask producing method of patterning the light shielding film by the dry etching process using as a mask a pattern of a resist formed on the light shielding film, the light shielding film is made of a material having a selectivity exceeding 1 with respect to the resist in the dry etching process.
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