# US 2014/0192335 A1 · Euv exposure apparatus, euv mask, and method of measuring distortion > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192335 A1 - Document ID: US20140192335A1 - Status: Published application - Kind: A1 - Application number: 13/798,301 - Filed: 2013-03-13 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: Kabushiki Kaisha Toshiba - Applicants: Kabushiki Kaisha Toshiba - Inventors: Yoshinori HAGIO; Yosuke OKAMOTO - Web page: https://patentgrep.com/patent/US20140192335A1 ## CPC - G03F 1/22: Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof - G03F 1/24: Reflection masks; Preparation thereof - G03F 1/44: Testing or measuring features, e.g. grid patterns, focus monitors, sawtooth scales or notched scales - G03F 1/72: Repair or correction of mask defects - G03F 7/70258: {Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system} - G03F 7/70783: {Handling stress or warp of chucks, masks or workpieces, e.g. to compensate for imaging errors or considerations related to warpage of masks or workpieces due to their own weight} - G03F 7/7085: {Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load} - 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 An EUV exposure apparatus according to embodiments includes a reticle stage which suctions a rear surface side of an EUV mask to retain the EUV mask. In addition, the EUV exposure apparatus includes a detection unit which detects a position of a measurement mark formed on the rear surface of the EUV mask in the state where the EUV mask is suctioned on the reticle stage. In addition, the EUV exposure apparatus includes a control unit which calculates a distortion amount of the EUV mask based on the position of the measurement mark and performs exposure control on a wafer while correcting the distortion amount. ## Claims ### Claim 1 An EUV exposure apparatus comprising: a reticle stage which suctions a rear surface side of an EUV mask to retain the EUV mask; a detection unit which detects a position of a measurement mark formed on a rear surface of the EUV mask in the state where the EUV mask is suctioned on the reticle stage; and a control unit which calculates a distortion amount of the EUV mask based on the position of the measurement mark and performs exposure control on a wafer while correcting the distortion amount. ### Claim 2 (depends on 1) The EUV exposure apparatus according to claim 1, wherein the detection unit detects the position of the measurement mark on a plane parallel to the rear surface of the EUV mask. ### Claim 3 (depends on 2) The EUV exposure apparatus according to claim 2, further comprising a light source which illuminates the EUV mask with an inspection light beam from a front surface of the EUV mask, wherein the detection unit detects the position of the measurement mark by detecting the inspection light beam which is reflected by the rear surface of the EUV mask and is emitted from the front surface of the EUV mask. ### Claim 4 (depends on 3) The EUV exposure apparatus according to claim 3, wherein the inspection light beam is a laser beam having a wavelength of 900 nm or more. ### Claim 5 (depends on 2) The EUV exposure apparatus according to claim 2, further comprising a light source which illuminates the EUV mask with an inspection light beam from a side surface of the EUV mask, wherein the detection unit detects the position of the measurement mark by detecting the inspection light beam which is reflected by the rear surface of the EUV mask and is emitted from the side surface of the EUV mask. ### Claim 6 (depends on 5) The EUV exposure apparatus according to claim 5, wherein the light source includes a first light source which illuminates the rear surface of the EUV mask with a first inspection light beam from a first direction and a second light source which illuminates the rear surface of the EUV mask with a second inspection light beam from a second direction, wherein the detection unit includes a first detection unit which detects the first inspection light beam reflected by the rear surface of the EUV mask and a second detection unit which detects the second inspection light beam reflected by the rear surface of the EUV mask, and wherein the first and second directions are perpendicular to each other on a plane parallel to the rear surface of the EUV mask. ### Claim 7 (depends on 5) The EUV exposure apparatus according to claim 5, wherein the inspection light beam is a laser beam having a wavelength of 200 nm or more. ### Claim 8 (depends on 2) The EUV exposure apparatus according to claim 2, further comprising a light source which illuminates the EUV mask with an inspection light beam from the rear surface of the EUV mask, wherein the light source and the detection unit are arranged on an suctioning surface side of the reticle stage, and wherein the detection unit detects the position of the measurement mark by detecting the inspection light beam which is reflected by the rear surface of the EUV mask. ### Claim 9 (depends on 1) The EUV exposure apparatus according to claim 1, wherein the detection unit detects the position of the measurement mark by measuring a focus value with respect to the measurement mark in a direction perpendicular to the rear surface of the EUV mask. ### Claim 10 An EUV mask comprising: a circuit pattern which is formed on a front surface side of the EUV mask opposite to a surface side of the EUV mask suctioned on a reticle stage; and a measurement mark which is formed on a rear surface side of the EUV mask that is the surface side suctioned on the reticle stage and of which position is detected in the state where the EUV mask is suctioned on the reticle stage. ### Claim 11 (depends on 10) The EUV mask according to claim 10, further comprising a metal film which is formed on the rear surface side of the EUV mask and is suctioned on the reticle stage, wherein the measurement mark is formed by cutting the metal film. ### Claim 12 (depends on 10) The EUV mask according to claim 10, further comprising a suction portion which is formed in an outer periphery portion of the rear surface side of the EUV mask to be suctioned on the reticle stage, wherein the measurement mark is arranged inside the suction portion. ### Claim 13 (depends on 12) The EUV mask according to claim 12, wherein the measurement mark is formed on an outer layer side from the metal film by using a member different from that of the metal film. ### Claim 14 (depends on 10) The EUV mask according to claim 10, wherein the measurement mark has a shape of a combination of one or more pairs of two perpendicular straight-line patterns. ### Claim 15 A method of measuring distortion, comprising: allowing a reticle stage to suction a rear surface side of an EUV mask to retain the EUV mask; detecting a position of a measurement mark which is formed on a rear surface of the EUV mask in the state where the EUV mask is suctioned on the reticle stage; and calculating a distortion amount of the EUV mask based on the position of the measurement mark. ### Claim 16 (depends on 15) The method of measuring distortion according to claim 15, wherein at the time of detecting the position of the measurement mark, the position of the measurement mark is detected by measuring the position of the EUV mask on a plane parallel to the rear surface of the EUV mask. ### Claim 17 (depends on 16) The method of measuring distortion according to claim 16, wherein at the time of detecting the position of the measurement mark, the position of the measurement mark is detected by illuminating the EUV mask with an inspection light beam from a front surface of the EUV mask and by detecting the inspection light beam which is reflected by the rear surface of the EUV mask and is emitted from the front surface of the EUV mask. ### Claim 18 (depends on 16) The method of measuring distortion according to claim 16, wherein at the time of detecting the position of the measurement mark, the position of the measurement mark is detected by illuminating the EUV mask with an inspection light beam from a side surface of the EUV mask and by detecting the inspection light beam which is reflected by the rear surface of the EUV mask and is emitted from the side surface of the EUV mask. ### Claim 19 (depends on 16) The method of measuring distortion according to claim 16, wherein at the time of detecting the position of the measurement mark, the position of the measurement mark is detected by illuminating the rear surface of the EUV mask with an inspection light beam from a light source which is arranged on a suction surface side of the reticle stage and by detecting the inspection light beam reflected by the rear surface of the EUV mask on the suction surface of the reticle stage. ### Claim 20 (depends on 16) The method of measuring distortion according to claim 16, wherein at the time of detecting the position of the measurement mark, the position of the measurement mark is detected by measuring a focus value of the measurement mark in a direction perpendicular to the rear surface of the EUV mask.