Reflective photomask blank and reflective photomask

A reflective photomask blank comprising:

• a substrate;
• a reflection part provided on the substrate and configured to reflect incident light;
• and
• a low reflection part provided on the reflection part and configured to absorb incident light,
• wherein the low reflection part has a multi-layer structure including at least two or more layers, and
• an outermost layer of the low reflection part has a refractive index n equal to or more than 0.90 and an extinction coefficient k equal to or less than 0.02 with respect to extreme ultraviolet (EUV) light (where a wavelength is 13.5 nm),
• wherein the low reflection part has an absorption layer provided between the outermost layer and the reflection part and configured to absorb incident light, and
• the absorption layer is constituted of a compound material having a refractive index n equal to or less than 0.95 and an extinction coefficient k equal to or more than 0.06 with respect to the EUV light.

A reflective photomask blank comprising:

• a substrate;
• a reflection part provided on the substrate and configured to reflect incident light;
• and
• a low reflection part provided on the reflection part and configured to absorb incident light,
• wherein the low reflection part has a multi-layer structure including at least two or more layers, and
• an outermost layer of the low reflection part has a refractive index n equal to or more than 0.90 and an extinction coefficient k equal to or less than 0.02 with respect to extreme ultraviolet (EUV) light (where a wavelength is 13.5 nm),
• wherein the low reflection part has an optical density (an OD value) equal to or more than 1.5 with respect to the reflection part.

A reflective photomask comprising:

• a substrate;
• a reflection part provided on the substrate and configured to reflect incident light;
• and
• a low reflection part provided on the reflection part and configured to absorb incident light,
• wherein the low reflection part has a multi-layer structure including at least two or more layers, and
• an outermost layer of the low reflection part has a refractive index n equal to or more than 0.90 and an extinction coefficient k equal to or less than 0.02 with respect to extreme ultraviolet (EUV) light (where a wavelength is 13.5 nm),
• wherein the outermost layer is constituted of a compound material in which an atomic number ratio of silicon (Si) to oxygen (O) is within a range of 1:1.5 to 1:2, and a total content of the silicon and the oxygen is 50% by atom or more of a whole compound material.

A reflective photomask comprising:

• a substrate;
• a reflection part provided on the substrate and configured to reflect incident light;
• and
• a low reflection part provided on the reflection part and configured to absorb incident light,
• wherein the low reflection part has a multi-layer structure including at least two or more layers, and
• an outermost layer of the low reflection part has a refractive index n equal to or more than 0.90 and an extinction coefficient k equal to or less than 0.02 with respect to extreme ultraviolet (EUV) light (where a wavelength is 13.5 nm),
• wherein the low reflection part has an absorption layer provided between the outermost layer and the reflection part and configured to absorb incident light, and
• the absorption layer is constituted of a compound material having a refractive index n equal to or less than 0.95 and an extinction coefficient k equal to or more than 0.06 with respect to the EUV light.

A reflective photomask comprising:

• a substrate;
• a reflection part provided on the substrate and configured to reflect incident light;
• and
• a low reflection part provided on the reflection part and configured to absorb incident light,
• wherein the low reflection part has a multi-layer structure including at least two or more layers, and
• an outermost layer of the low reflection part has a refractive index n equal to or more than 0.90 and an extinction coefficient k equal to or less than 0.02 with respect to extreme ultraviolet (EUV) light (where a wavelength is 13.5 nm),
• wherein the low reflection part has an optical density (an OD value) equal to or more than 1.5 with respect to the reflection part.