Reflective photomask blank and reflective photomask
There is provided a reflective photomask blank and a reflective photomask having good irradiation resistance and capable of obtaining good transfer performance. A reflective photomask blank ( 10 ) contains a reflective layer ( 2 ) reflecting incident light and an absorption layer ( 4 ) absorbing incident light, which are formed in this order on one surface side of a substrate ( 1 ). The absorption layer ( 4 ) contains a first material selected from the group consisting of tin, indium, and tellurium and a second material containing one or two or more kinds of materials selected from the group consisting of transition metals, bismuth (Bi), and silicon (Si) at least in the outermost layer. The content of the second material is more than 20 at and less than 50 at % in the same laver.
1. A reflective photomask blank comprising:
a reflective layer configured to reflect incident light; and
an absorption layer configured to absorb incident light,
the reflective layer and the absorption layer being formed in this order on one surface side of a substrate, wherein
the absorption layer contains a first material selected from the group consisting of tin, indium, and tellurium and a second material containing one or two or more of materials selected from the group consisting of transition metals, bismuth (Bi), and silicon (Si) at least in an outermost layer, and
a content of the second material is more than 20 at % and less than 50 at % in a same layer.
2. The reflective photomask blank according to claim 1 , wherein
the absorption layer further contains oxygen at least in the outermost layer, and
a ratio (B/A) of a number of atoms of the second material (B) to a total number of atoms of the first material and the oxygen (A) is in a range of more than ¼ and less than 1.
3. The reflective photomask blank according to claim 1 , wherein
the transition metals include one or two or more selected from the group consisting of tantalum, gold, osmium, hafnium, tungsten, platinum, iridium, rhenium, and zirconium.
4. The reflective photomask blank according to claim 1 , wherein
when intensity of reflected light from the reflective layer is defined as Rm, intensity of reflected light from the absorption layer is defined as Ra, and an optical density OD based on the reflective layer and the absorption layer is defined by Equation (1) below,
a value of the optical density OD is 1 or more,
OD=−log( Ra/Rm ) (1).
5. The reflective photomask blank according to claim 1 , wherein
a film thickness of the absorption layer is 18 nm or more and less than 45 nm.
6. The reflective photomask blank according to claim 1 , wherein
the reflective layer contains a multilayer reflective layer containing a multilayer structure and an intermediate layer formed on the multilayer reflective layer.
7. The reflective photomask blank according to claim 2 , wherein
the transition metals include one or two or more selected from the group consisting of tantalum, gold, osmium, hafnium, tungsten, platinum, iridium, rhenium, and zirconium.
8. The reflective photomask blank according to claim 2 , wherein
when intensity of reflected light from the reflective layer is defined as Rm, intensity of reflected light from the absorption layer is defined as Ra, and an optical density OD based on the reflective layer and the absorption layer is defined by Equation (1) below,
a value of the optical density OD is 1 or more,
OD=−log( Ra/Rm ) (1).
9. The reflective photomask blank according to claim 3 , wherein
when intensity of reflected light from the reflective layer is defined as Rm, intensity of reflected light from the absorption layer is defined as Ra, and an optical density OD based on the reflective layer and the absorption layer is defined by Equation (1) below,
a value of the optical density OD is 1 or more,
OD=−log( Ra/Rm ) (1).
10. The reflective photomask blank according to claim 2 , wherein
a film thickness of the absorption layer is 18 nm or more and less than 45 nm.
11. The reflective photomask blank according to claim 3 , wherein
a film thickness of the absorption layer is 18 nm or more and less than 45 nm.
12. The reflective photomask blank according to claim 4 , wherein
a film thickness of the absorption layer is 18 nm or more and less than 45 nm.
13. The reflective photomask blank according to claim 2 , wherein
the reflective layer contains a multilayer reflective layer containing a multilayer structure and an intermediate layer formed on the multilayer reflective layer.
14. The reflective photomask blank according to claim 3 , wherein
the reflective layer contains a multilayer reflective layer containing a multilayer structure and an intermediate layer formed on the multilayer reflective layer.
15. The reflective photomask blank according to claim 4 , wherein
the reflective layer contains a multilayer reflective layer containing a multilayer structure and an intermediate layer formed on the multilayer reflective layer.
16. The reflective photomask blank according to claim 5 , wherein
the reflective layer contains a multilayer reflective layer containing a multilayer structure and an intermediate layer formed on the multilayer reflective layer.
17. A reflective photomask comprising:
a reflective layer formed on one surface side of a substrate and configured to reflect incident light; and
an absorption layer formed by a predetermined pattern on the reflective layer and configured to absorb incident light, wherein
at least an outermost layer of the absorption layer contains a first material selected from the group consisting of tin, indium, and tellurium and a second material containing one or two or more of materials selected from the group consisting of transition metals, bismuth (Bi), and silicon (Si), and
a content of the second material is more than 20 at % and less than 50 at % in a same layer.