# US 12,111,565 B2 · Reflective photomask blank and reflective photomask > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,565 B2 - Document ID: US12111565B2 - Status: Granted - Kind: B2 - Application number: 17/615,083 - Filed: 2020-05-28 - Published: 2022-07-14 - Granted: 2024-10-08 - Earliest claimed: 2019-05-31 - Assignees: Toppan Inc. - Applicants: Toppan Inc. - Inventors: Ayumi Goda; Norihito Fukugami - Web page: https://patentgrep.com/patent/US12111565B2 ## CPC - G03F 1/24: Reflection masks; Preparation thereof - G03F 1/54: Absorbers, e.g. of opaque materials - G03F 1/58: having two or more different absorber layers, e.g. stacked multilayer absorbers - G03F 1/82: Auxiliary processes, e.g. cleaning or inspecting - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract There are provided a reflective photomask blank and a reflective photomask, which are compatibly capable of suppressing a shadowing effect and improving the life of a mask. A reflective photomask blank (10) includes a substrate (1), a reflection part (7) provided on the substrate (1) and configured to reflect incident light, and a low reflection part (8) provided on the reflection part (7) and configured to absorb incident light. The low reflection part (8) has a multi layer structure of at least two layers or more layers. An outermost layer (5) of the low reflection part (8) 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). ## Claims ### Claim 1 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 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. ### Claim 2 (depends on 1) The reflective photomask blank according to claim 1, wherein the compound material constituting the outermost layer contains one or more elements selected from boron (B), nitrogen (N), germanium (Ge), and hafnium (Hf). ### Claim 3 (depends on 1) The reflective photomask blank according to claim 1, wherein the outermost layer has a film thickness equal to or more than 1 nm and equal to or less than 20 nm. ### Claim 4 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. ### Claim 5 (depends on 4) The reflective photomask blank according to claim 4, wherein the absorption layer is constituted of the compound material in which an atomic number ratio of tin (Sn) to oxygen (O) is within a range of 1:1 to 1:2, and a total content of the tin and the oxygen is 75% by atom or more of a whole compound material. ### Claim 6 (depends on 4) The reflective photomask blank according to claim 4, wherein the absorption layer is constituted of the compound material in which an atomic number ratio of indium (In) to oxygen (O) is within a range of 1:1 to 1:1.5, and a total content of the indium and the oxygen is 80% by atom or more of a whole compound material. ### Claim 7 (depends on 4) The reflective photomask blank according to claim 4, wherein the compound material constituting the absorption layer contains one or more elements selected from boron (B), nitrogen (N), silicon (Si), germanium (Ge), and hafnium (Hf). ### Claim 8 (depends on 4) The reflective photomask blank according to claim 4, wherein the absorption layer has a film thickness equal to or more than 18 nm and equal to or less than 48 nm. ### Claim 9 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. ### Claim 10 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. ### Claim 11 (depends on 10) The reflective photomask according to claim 10, wherein the compound material constituting the outermost layer contains one or more elements selected from boron (B), nitrogen (N), germanium (Ge), and hafnium (Hf). ### Claim 12 (depends on 10) The reflective photomask according to claim 10, wherein the outermost layer has a film thickness equal to or more than 1 nm and equal to or less than 20 nm. ### Claim 13 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. ### Claim 14 (depends on 13) The reflective photomask according to claim 13, wherein the absorption layer is constituted of the compound material in which an atomic number ratio of tin (Sn) to oxygen (O) is within a range of 1:1 to 1:2, and a total content of the tin and the oxygen is 75% by atom or more of a whole compound material. ### Claim 15 (depends on 13) The reflective photomask according to claim 13, wherein the absorption layer is constituted of the compound material in which an atomic number ratio of indium (In) to oxygen (O) is within a range of 1:1 to 1:1.5, and a total content of the indium and the oxygen is 80% by atom or more of a whole compound material. ### Claim 16 (depends on 13) The reflective photomask blank according to claim 13, wherein the compound material constituting the absorption layer contains one or more elements selected from boron (B), nitrogen (N), silicon (Si), germanium (Ge), and hafnium (Hf). ### Claim 17 (depends on 13) The reflective photomask blank according to claim 13, wherein the absorption layer has a film thickness equal to or more than 18 nm and equal to or less than 48 nm. ### Claim 18 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.