To provide a transparent substrate with excellent appearance and with high visibility when observed from a predetermined direction, and a process for producing it. A transparent substrate comprising a substrate having a curved surface on at least a part of its front surface, and an antiglare layer formed on the center region and the edge region of the curved surface, wherein the absolute value of the difference between the 60 specular glossiness at the center region and the 60 specular glossiness at the edge region is higher than 20%.

To provide a transparent substrate with excellent appearance and with high visibility when observed from a predetermined direction, and a process for producing it. A transparent substrate comprising a substrate having a curved surface on at least a part of its front surface, and an antiglare layer formed on the center region and the edge region of the curved surface, wherein the absolute value of the difference between the 60 specular glossiness at the center region and the 60 specular glossiness at the edge region is higher than 20%.

A photomask blank has on a transparent substrate, an optional first film, a second film, a third film, and a fourth film. The first and third films are formed of silicon-containing materials which are resistant to chlorine base dry etching and removable by fluorine base dry etching. The second and fourth films are formed of chromium-containing materials which are resistant to fluorine base dry etching and removable by chlorine base dry etching. An etching clear time of the fourth film is longer than an etching clear time of the second film, on chlorine base dry etching.

A photomask blank has on a transparent substrate, an optional first film, a second film, a third film, and a fourth film. The first and third films are formed of silicon-containing materials which are resistant to chlorine base dry etching and removable by fluorine base dry etching. The second and fourth films are formed of chromium-containing materials which are resistant to fluorine base dry etching and removable by chlorine base dry etching. An etching clear time of the fourth film is longer than an etching clear time of the second film, on chlorine base dry etching.

A mask for semiconductor manufacturing includes a mask substrate, a shifter layer over the mask substrate, a stop layer over and in contact with the shifter layer, and an absorber layer over the stop layer. The shifter layer includes each material of a set of materials, the materials being combined in a first proportion in the shifter layer. The stop layer includes each material of the set of materials, the materials being combined in a second proportion in the stop layer that is different from the first proportion.

A mask for semiconductor manufacturing includes a mask substrate, a shifter layer over the mask substrate, a stop layer over and in contact with the shifter layer, and an absorber layer over the stop layer. The shifter layer includes each material of a set of materials, the materials being combined in a first proportion in the shifter layer. The stop layer includes each material of the set of materials, the materials being combined in a second proportion in the stop layer that is different from the first proportion.

A reflection mode photomask includes a substrate. The reflection mode photomask further includes a reflective multilayer over the substrate. The reflection mode photomask further includes a plurality of absorber stacks over the reflective multilayer, wherein each absorber stack of the plurality of absorber stacks has an etch stop layer, an absorber layer and an ARC layer, wherein a ratio of a thickness of the ARC layer to that of the etch stop layer is in a range from about 1:1 to about 1:2.5, and a sidewall roughness of each absorber stack of the plurality of absorber stacks is smaller than 3 nanometers (nm).

A reflection mode photomask includes a substrate. The reflection mode photomask further includes a reflective multilayer over the substrate. The reflection mode photomask further includes a plurality of absorber stacks over the reflective multilayer, wherein each absorber stack of the plurality of absorber stacks has an etch stop layer, an absorber layer and an ARC layer, wherein a ratio of a thickness of the ARC layer to that of the etch stop layer is in a range from about 1:1 to about 1:2.5, and a sidewall roughness of each absorber stack of the plurality of absorber stacks is smaller than 3 nanometers (nm).

A photomask blank (1) having: a transparent substrate (10); a first film (11) etched by chlorine/oxygen-based dry etching and made of a material having resistance against fluorine-based dry etching; and a second film (12) formed adjacent to the first film and made of a material which comprises silicon and oxygen or silicon, oxygen, and nitrogen and has an SiSi bond and which is substantially not etched by chlorine/oxygen-based dry etching, wherein: the photoresist adhesive performance is improved; the resist pattern is stably maintained without degrading, collapsing, or peeling even when a fine resist pattern is formed from a photoresist film; and an excellent shape and dimensional accuracy is obtained in regard to etching of a lower layer film in which the resist pattern is used.

A photomask blank (1) having: a transparent substrate (10); a first film (11) etched by chlorine/oxygen-based dry etching and made of a material having resistance against fluorine-based dry etching; and a second film (12) formed adjacent to the first film and made of a material which comprises silicon and oxygen or silicon, oxygen, and nitrogen and has an SiSi bond and which is substantially not etched by chlorine/oxygen-based dry etching, wherein: the photoresist adhesive performance is improved; the resist pattern is stably maintained without degrading, collapsing, or peeling even when a fine resist pattern is formed from a photoresist film; and an excellent shape and dimensional accuracy is obtained in regard to etching of a lower layer film in which the resist pattern is used.