Photomask blank and production method thereof, and photomask production method, and semiconductor device production method

A method for producing a photomask blank, comprising the step of forming a shielding film on a translucent substrate by sputtering, wherein:

• the photomask blank is a dry etching photomask blank suitable for use with the method for producing a photomask wherein the shielding film is patterned by dry etching using the mask pattern formed on the shielding film as a mask;
• the shielding film being formed in such a manner that a film formation rate of the layer at a surface side is lower than a film formation rate of a layer at a translucent substrate side of the shielding film.

A photomask blank, comprising a translucent substrate having thereon a shielding film, wherein:

• the photomask blank is a dry etching photomask blank suitable for use with the method for producing a photomask wherein the shielding film is patterned by dry etching using a mask pattern formed on the shielding film as a mask;
• the dry etching rate of the shielding film being lower at a translucent substrate side than at a surface side.

A photomask blank, comprising a translucent substrate having thereon a shielding film, wherein:

• the photomask blank is a dry etching photomask blank suitable for use with the method for producing a photomask wherein the shielding film is patterned by dry etching using the mask pattern formed on the shielding film as a mask;
• the shielding film containing nitrogen in almost all regions along a depth direction from a surface side toward a translucent substrate side of the shielding film, an oxygen content in the shielding film decreasing from a surface side toward a translucent substrate side.