REFLECTIVE PHOTOMASK BLANK AND REFLECTIVE PHOTOMASK
An object of the present disclosure is to provide a reflective photomask blank and a reflective photomask having high transferability by making the most use of a phase shift effect. The reflective photomask blank ( 10 ) according to an aspect of the present disclosure includes a substrate ( 1 ), a reflective layer ( 2 ) having a multi-layer film structure, formed on the substrate ( 1 ), and configured to reflect an EUV light, a protective layer ( 3 ) formed on the reflective layer ( 2 ) and configured to protect the reflective layer ( 2 ), and an absorption layer ( 4 ) formed on the protective layer ( 3 ) and configured to absorb the EUV light, in which the absorption layer ( 4 ) includes an absorption layer ( 4 a ) and an absorption layer ( 4 b ) having different functions from each other, and the absorption layer ( 4 ) has a phase difference in a range of 190 degrees or more and 270 degrees or less.
1 . A reflective photomask blank comprising:
a substrate;
a reflective layer having a multi-layer film structure, formed on the substrate, and configured to reflect an EUV light;
a protective layer formed on the reflective layer and configured to protect the reflective layer; and
an absorption layer formed on the protective layer and configured to absorb the EUV light,
wherein the absorption layer has a multi-layer structure of two or more layers having different functions, and
the absorption layer has a phase difference in a range of 190 degrees or more and 270 degrees or less.
2 . The reflective photomask blank according to claim 1 , wherein the absorption layer includes at least an absorption control film.
3 . The reflective photomask blank according to claim 2 , wherein the absorption layer includes the absorption control film and a phase control film.
4 . The reflective photomask blank according to claim 2 , wherein the absorption control film contains a material having an extinction coefficient k of 0.041 or more, and
a film thickness of the absorption layer is 60 nm or less.
5 . The reflective photomask blank according to claim 2 , wherein the absorption control film is configured with a material containing at least one or more elements of tin (Sn), indium (In), tantalum (Ta), silver (Ag), tellurium (Te), nickel (Ni), cobalt (Co), copper (Cu), platinum (Pt), palladium (Pd), iridium (Ir), gold (Au), or zinc (Zn).
6 . The reflective photomask blank according to claim 2 , wherein the absorption layer includes the absorption control film and a phase control film, and
the phase control film has a refractive index n with respect to the EUV light less than 0.93.
7 . The reflective photomask blank according to claim 2 , wherein the absorption layer includes the absorption control film and a phase control film, and
the phase control film has a refractive index n with respect to the EUV light less than 0.92.
8 . The reflective photomask blank according to claim 2 , wherein the absorption layer includes the absorption control film and a phase control film, and
the phase control film is configured with a material containing at least one or more elements of ruthenium (Ru), rhodium (Rh), molybdenum (Mo), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), osmium (Os), iridium (Ir), or rhenium (Re).
9 . The reflective photomask blank according to claim 1 , wherein the absorption layer has a phase difference in a range of 210 degrees or more and 265 degrees or less.
10 . The reflective photomask blank according to claim 1 , wherein the absorption layer has a phase difference in a range of 230 degrees or more and 260 degrees or less.
11 . A reflective photomask comprising:
a substrate;
a reflective layer having a multi-layer film structure, formed on the substrate, and configured to reflect an EUV light;
a protective layer formed on the reflective layer and configured to protect the reflective layer; and
an absorption pattern layer formed on the protective layer and configured to absorb the EUV light,
wherein the absorption pattern layer has a multi-layer structure of two or more layers having different functions, and
the absorption pattern layer has a phase difference in a range of 190 degrees or more and 270 degrees or less.
12 . The reflective photomask according to claim 11 , wherein the absorption pattern layer includes at least a patterned absorption control film.
13 . The reflective photomask according to claim 12 , wherein the absorption pattern layer includes the absorption control film and a patterned phase control film.
14 . The reflective photomask according to claim 12 , wherein the absorption control film contains a material having an extinction coefficient k of 0.041 or more, and
a film thickness of the absorption pattern layer is 60 nm or less.
15 . The reflective photomask according to claim 12 , wherein the absorption control film is configured with a material containing at least one or more elements of tin (Sn), indium (In), tantalum (Ta), silver (Ag), tellurium (Te), nickel (Ni), cobalt (Co), copper (Cu), platinum (Pt), palladium (Pd), iridium (Ir), gold (Au), or zinc (Zn).
16 . The reflective photomask according to claim 12 , wherein the absorption pattern layer includes the absorption control film and a patterned phase control film, and
the phase control film has a refractive index n with respect to the EUV light less than 0.93.
17 . The reflective photomask according to claim 12 , wherein the absorption pattern layer includes the absorption control film and a patterned phase control film, and
the phase control film has a refractive index n with respect to the EUV light less than 0.92.
18 . The reflective photomask according to claim 12 , wherein the absorption pattern layer includes the absorption control film and a patterned phase control film, and
the phase control film is configured with a material containing at least one or more elements of ruthenium (Ru), rhodium (Rh), molybdenum (Mo), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), osmium (Os), iridium (Ir), or rhenium (Re).
19 . The reflective photomask according to claim 11 , wherein the absorption pattern layer has a phase difference in a range of 210 degrees or more and 265 degrees or less.
20 . The reflective photomask according to claim 11 , wherein the absorption pattern layer has a phase difference in a range of 230 degrees or more and 260 degrees or less.