# US 12,222,640 B2 · Reflective mask blank, reflective mask, method of manufacturing reflective mask blank, and method of manufacturing reflective mask > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,640 B2 - Document ID: US12222640B2 - Status: Granted - Kind: B2 - Application number: 18/382,269 - Filed: 2023-10-20 - Published: 2024-05-23 - Granted: 2025-02-11 - Earliest claimed: 2021-08-27 - Assignees: AGC Inc. - Applicants: AGC Inc. - Inventors: Shunya Taki; Hiroaki Iwaoka; Daijiro Akagi; Ichiro Ishikawa - Web page: https://patentgrep.com/patent/US12222640B2 ## CPC - G03F 1/26: Phase shift masks [PSM]; PSM blanks; Preparation thereof - G03F 1/24: Reflection masks; Preparation thereof - G03F 1/32: Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof - G03F 1/48: Protective coatings - G03F 1/54: Absorbers, e.g. of opaque materials - G03F 1/80: Etching - 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 A reflective mask blank containing a substrate, a multilayer reflective film that reflects EUV light, and a phase shift film that shifts a phase of the EUV light, the substrate, the multilayer reflective film, and the phase shift film being arranged in this order. The phase shift film contains a compound containing Ru and Cr, an element ratio between Cr and Ru (Cr:Ru) in the phase shift film is 5:95 to 42:58, and a melting point MP1 of an oxide of the compound and a melting point MP2 of a fluoride or an oxyfluoride of the compound satisfy the following relation (1): 0.625MP1+MP2≤1000 (1). ## Claims ### Claim 1 A reflective mask blank comprising: a substrate; a multilayer reflective film that reflects EUV light; and a phase shift film that shifts a phase of the EUV light, the substrate, the multilayer reflective film, and the phase shift film being arranged in this order, wherein the phase shift film contains a compound containing Ru and Cr, an element ratio between Cr and Ru (Cr:Ru) in the phase shift film is 5:95 to 42:58, and a melting point MP1 of an oxide of the compound and a melting point MP2 of a fluoride or an oxyfluoride of the compound satisfy the following relation (1): 0.625MP1+MP2≤1000 (1). ### Claim 2 (depends on 1) The reflective mask blank according to claim 1, wherein the element ratio between Cr and Ru (Cr:Ru) in the phase shift film is 1:9 to 42:58. ### Claim 3 (depends on 1) The reflective mask blank according to claim 1, wherein a refractive index of the phase shift film is 0.925 or less. ### Claim 4 (depends on 1) The reflective mask blank according to claim 1, wherein an extinction coefficient k of the phase shift film is 0.024 or more. ### Claim 5 (depends on 1) The reflective mask blank according to claim 1, wherein the melting point MP1 of the oxide of the compound and the melting point MP2 of the fluoride or the oxyfluoride of the compound satisfy the following relation (2): −0.500MP1+MP2≤400 (2). ### Claim 6 (depends on 1) The reflective mask blank according to claim 1, wherein the phase shift film further contains, in addition to Ru and Cr, at least one element selected from the group consisting of B, C, O, and N. ### Claim 7 (depends on 1) The reflective mask blank according to claim 1, wherein a film thickness of the phase shift film is 50 nm or less. ### Claim 8 (depends on 1) The reflective mask blank according to claim 1 further comprising: a protection film that protects the multilayer reflective film from an etching gas for etching the phase shift film, the protection film being arranged between the multilayer reflective film and the phase shift film, wherein a ratio of an etching rate of etching the phase shift film using the etching gas to an etching rate of etching the protection film using the etching gas is 10 or more. ### Claim 9 (depends on 1) The reflective mask blank according to claim 1, wherein the protection film contains Rh, or the protection film contains Rh and at least one element selected from the group consisting of Ru, Si, Al, Hf, Y, Ta, Nb, Mo, and Ir. ### Claim 10 (depends on 1) The reflective mask blank according to claim 1 further comprising: a protection film that protects the multilayer reflective film from an etching gas for etching the phase shift film, the protection film being arranged between the multilayer reflective film and the phase shift film; and a buffer film that protects the protection film from the etching gas, the buffer film being arranged between the protection film and the phase shift film, wherein a ratio of an etching rate of etching the phase shift film using the etching gas to an etching rate of etching the buffer film using the etching gas is 3 or more. ### Claim 11 (depends on 10) The reflective mask blank according to claim 10, wherein the buffer film contains Ta, or the buffer film contains Ta and at least one element selected from the group consisting of O and N. ### Claim 12 (depends on 1) The reflective mask blank according to claim 1 further comprising: an etching mask film on the phase shift film, wherein the etching mask film contains at least one element selected from the group consisting of Al, Hf, Y, Cr, Nb, Ti, Mo, Ta, Ru, and Si. ### Claim 13 (depends on 1) A reflective mask provided with the reflective mask blank according to claim 1, wherein the phase shift film includes an opening pattern. ### Claim 14 A method of manufacturing a reflective mask blank, the method comprising: forming a multilayer reflective film on a substrate, the multilayer reflective film reflecting EUV light; and forming a phase shift film over the multilayer reflective film, the phase shift film shifting a phase of the EUV light, wherein the phase shift film contains a compound containing Ru and Cr, an element ratio between Cr and Ru (Cr:Ru) in the phase shift film is 5:95 to 42:58, and a melting point MP1 of an oxide of the compound and a melting point MP2 of a fluoride or an oxyfluoride of the compound satisfy the following relation (1): 0.625MP1+MP2≤1000 (1). ### Claim 15 (depends on 14) A method of manufacturing a reflective mask, the method comprising: preparing a reflective mask blank manufactured by using the method according to claim 14; and forming an opening pattern in the phase shift film in the reflective mask blank. ### Claim 16 (depends on 15) The method of manufacturing a reflective mask according to claim 15, wherein an etching gas used for forming the opening pattern in the phase shift film is a mixed gas of a fluorine-based gas and an oxygen-based gas. ### Claim 17 (depends on 16) The method of manufacturing a reflective mask according to claim 16, wherein the fluorine-based gas is a CF4 gas, a CHF3 gas, a SF6 gas, a BF3 gas, a XeF2 gas, or a mixture thereof. ### Claim 18 (depends on 17) The method of manufacturing a reflective mask according to claim 17, wherein a volume ratio between the oxygen-based gas and the fluorine-based gas, (oxygen-based gas):(fluorine-based gas), is 10:90 to 50:50.