# US 12,007,684 B2 · Mask blank, method of manufacturing imprint mold, method of manufacturing transfer mask, method of manufacturing reflective mask, and method of manufacturing semiconductor device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,684 B2 - Document ID: US12007684B2 - Status: Granted - Kind: B2 - Application number: 18/226,165 - Filed: 2023-07-25 - Published: 2023-11-16 - Granted: 2024-06-11 - Earliest claimed: 2017-02-27 - Assignees: Hoya Corporation - Applicants: Hoya Corporation - Inventors: Osamu Nozawa; Ryo Ohkubo; Hiroaki Shishido - Web page: https://patentgrep.com/patent/US12007684B2 ## CPC - G03F 1/24: Reflection masks; Preparation thereof - G03F 1/48: Protective coatings - G03F 1/80: Etching - H10P 76/405: {characterised by their composition, e.g. multilayer masks} - H10P 76/4085: {characterised by the processes involved to create the masks} - 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) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A light shielding film made up of a material containing one or more elements selected from silicon and tantalum and a hard mask film made up of a material containing chromium, oxygen, and carbon are laminated on a transparent substrate. The hard mask film is a single layer film having a composition gradient portion with increased oxygen content on the surface and on the neighboring region. The maximum peak for N1s in a narrow spectrum obtained via X-ray photoelectron spectroscopy analysis is the lower limit of detection or less. The portions excluding the composition gradient portion of the hard mask film have a 50 atom % or more chromium content, and the maximum peak for Cr2p in a narrow spectrum obtained via X-ray photoelectron spectroscopy analysis has a binding energy of 574 eV or less. ## Claims ### Claim 1 A mask blank comprising: a substrate; and a hard mask film formed on the substrate, wherein the hard mask film is a single layer film having a composition gradient portion formed on a surface of the hard mask film that faces away from the substrate and in a region adjacent to the surface, the hard mask film is made of a material containing chromium, oxygen, and carbon with a total content of chromium, oxygen, and carbon being 95 atomic % or more, a part of the hard mask film excluding the composition gradient portion has a chromium content of 50 atomic % or more, a ratio of a carbon content [atomic %] divided by a total content [atomic %] of chromium, carbon, and oxygen in the part of the hard mask film excluding the composition gradient portion is 0.1 or more, a ratio of a carbon content [atomic %] divided by a total content [atomic %] of chromium and carbon in the part of the hard mask film excluding the composition gradient portion is 0.14 or more, and a content of nitrogen in the hard mask film is equal to or less than a detection limit value in composition analysis of X-ray photoelectron spectroscopy. ### Claim 2 (depends on 1) The mask blank according to claim 1, wherein the part of the hard mask film excluding the composition gradient portion has a chromium content of 80 atomic % or less. ### Claim 3 (depends on 1) The mask blank according to claim 1, wherein the part of the hard mask film excluding the composition gradient portion has a carbon content of 10 atomic % or more and 20 atomic % or less. ### Claim 4 (depends on 1) The mask blank according to claim 1, wherein the part of the hard mask film excluding the composition gradient portion has an oxygen content of 10 atomic % or more and 35 atomic % or less. ### Claim 5 (depends on 1) The mask blank according to claim 1, wherein the hard mask film has a silicon content of 1 atomic % or less. ### Claim 6 (depends on 1) The mask blank according to claim 1, wherein the part of the hard mask film excluding the composition gradient portion has a difference in content of each constituent element, along a direction that is orthogonal to the surface, that is less than 10 atomic %. ### Claim 7 (depends on 1) The mask blank according to claim 1, wherein the hard mask film has a thickness of 15 nm or less. ### Claim 8 (depends on 1) The mask blank according to claim 1, wherein a light shielding film is formed between the substrate and the hard mask film, the light shielding film containing one or more elements selected from silicon and tantalum. ### Claim 9 (depends on 1) The mask blank according to claim 1, wherein a multilayer reflective film and an absorber film are formed between the substrate and the hard mask film, the absorber film being formed on the multilayer reflective film. ### Claim 10 (depends on 9) The mask blank according to claim 9, wherein the absorber film contains tantalum. ### Claim 11 (depends on 1) The mask blank according to claim 1, wherein the composition gradient portion of the hard mask film has a maximum peak of Cr2p narrow spectrum, obtained by analysis of X-ray photoelectron spectroscopy, at a binding energy of 576 eV or more. ### Claim 12 (depends on 1) The mask blank according to claim 1, wherein the hard mask film has a maximum peak of Si2p narrow spectrum, obtained by analysis of X-ray photoelectron spectroscopy, which is not higher than a lower detection limit. ### Claim 13 (depends on 1) A method of manufacturing an imprint mold using the mask blank according to claim 1, the method comprising: forming a pattern on the hard mask film by dry etching; and forming a mold pattern on a surface of the substrate by dry etching using the hard mask film provided with the pattern as a mask. ### Claim 14 (depends on 8) A method of manufacturing a transfer mask using the mask blank according to claim 8, comprising: forming a pattern on the hard mask film by dry etching; and forming a transfer pattern on the light shielding film by dry etching using the hard mask film provided with the pattern as a mask. ### Claim 15 (depends on 9) A method of manufacturing a reflective mask using the mask blank according to claim 9, the method comprising: performing a first dry etching to form a pattern on the hard mask film; and performing a second dry etching to form a transfer pattern on the absorber film, wherein a mask used for the second dry etching is the hard mask film provided with the pattern. ### Claim 16 (depends on 8) A method of manufacturing a semiconductor device, comprising exposure-transferring a transfer pattern of a transfer mask onto a resist film on a semiconductor substrate, the transfer mask having been manufactured from the mask blank according to claim 8. ### Claim 17 (depends on 9) A method of manufacturing a semiconductor device, comprising exposure-transferring a transfer pattern of a reflective mask onto a resist film on a semiconductor substrate, the reflective mask having been manufactured from the mask blank according to claim 9. ### Claim 18 A mask blank comprising: a substrate; and a hard mask film formed on the substrate, wherein the hard mask film is a single layer film having a composition gradient portion formed on a surface of the hard mask film that faces away from the substrate and in a region adjacent to the surface, the hard mask film is made of a material containing chromium, oxygen, and carbon, the hard mask film has a maximum peak of N1s narrow spectrum, obtained by analysis of X-ray photoelectron spectroscopy, which is not higher than a lower detection limit, a part of the hard mask film excluding the composition gradient portion has a maximum peak of Cr2p narrow spectrum, obtained by analysis of X-ray photoelectron spectroscopy, at a binding energy of 574 eV or less, and the composition gradient portion of the hard mask film has a maximum peak of Cr2p narrow spectrum, obtained by analysis of X-ray photoelectron spectroscopy, at a binding energy of 576 eV or more. ### Claim 19 (depends on 18) The mask blank according to claim 18, wherein, in the part of the hard mask film excluding the composition gradient portion, a ratio of carbon content [atomic %] to total content [atomic %] of chromium, carbon, and oxygen is 0.1 or more. ### Claim 20 (depends on 18) The mask blank according to claim 18, wherein the part of the hard mask film excluding the composition gradient portion has a chromium content of 50 atomic % or more. ### Claim 21 (depends on 18) The mask blank according to claim 18, wherein the hard mask film has a maximum peak of Si2p narrow spectrum, obtained by analysis of X-ray photoelectron spectroscopy, which is not higher than a lower detection limit. ### Claim 22 (depends on 18) The mask blank according to claim 18, wherein the part of the hard mask film excluding the composition gradient portion has a chromium content of 80 atomic % or less. ### Claim 23 (depends on 18) The mask blank according to claim 18, wherein the part of the hard mask film excluding the composition gradient portion has a carbon content of 10 atomic % or more and 20 atomic % or less. ### Claim 24 (depends on 18) The mask blank according to claim 18, wherein the part of the hard mask film excluding the composition gradient portion has an oxygen content of 10 atomic % or more and 35 atomic % or less. ### Claim 25 (depends on 18) The mask blank according to claim 18, wherein the part of the hard mask film excluding the composition gradient portion has a difference in content of each constituent element, along a direction that is orthogonal to the surface, that is less than 10 atomic %. ### Claim 26 (depends on 18) The mask blank according to claim 18, wherein the hard mask film has a thickness of 15 nm or less. ### Claim 27 (depends on 18) The mask blank according to claim 18, wherein a light shielding film is formed between the substrate and the hard mask film, the light shielding film containing one or more elements selected from silicon and tantalum. ### Claim 28 (depends on 18) The mask blank according to claim 18, wherein a multilayer reflective film and an absorber film are formed between the substrate and the hard mask film, the absorber film being formed on the multilayer reflective film. ### Claim 29 (depends on 28) The mask blank according to claim 28, wherein the absorber film contains tantalum. ### Claim 30 (depends on 18) A method of manufacturing an imprint mold using the mask blank according to claim 18, the method comprising: forming a pattern on the hard mask film by dry etching; and forming a mold pattern on a surface of the substrate by dry etching using the hard mask film provided with the pattern as a mask. ### Claim 31 (depends on 27) A method of manufacturing a transfer mask using the mask blank according to claim 27, comprising: forming a pattern on the hard mask film by dry etching; and forming a transfer pattern on the light shielding film by dry etching using the hard mask film provided with the pattern as a mask. ### Claim 32 (depends on 28) A method of manufacturing a reflective mask using the mask blank according to claim 28, the method comprising: performing a first dry etching to form a pattern on the hard mask film; and performing a second dry etching to form a transfer pattern on the absorber film, wherein a mask used for the second dry etching is the hard mask film provided with the pattern. ### Claim 33 (depends on 27) A method of manufacturing a semiconductor device, comprising exposure-transferring a transfer pattern of a transfer mask onto a resist film on a semiconductor substrate, the transfer mask having been manufactured from the mask blank according to claim 27. ### Claim 34 (depends on 28) A method of manufacturing a semiconductor device, comprising exposure-transferring a transfer pattern of a reflective mask onto a resist film on a semiconductor substrate, the reflective mask having been manufactured from the mask blank according to claim 28.