# US 2014/0190212 A1 · Mirror elements for euv lithography and production methods therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190212 A1 - Document ID: US20140190212A1 - Status: Published application - Kind: A1 - Application number: 14/204,009 - Filed: 2014-03-11 - Published: 2014-07-10 - Earliest claimed: 2009-12-22 - Assignees: Carl Zeiss SMT GmbH - Applicants: Carl Zeiss Smt GmbH - Inventors: Wilfried CLAUSS - Web page: https://patentgrep.com/patent/US20140190212A1 ## CPC - C03C 23/0005: {by irradiation} - C03B 32/005: {Hot-pressing vitrified, non-porous, shaped glass products} - C03C 17/00: Surface treatment of glass, not in the form of fibres or filaments, by coating (optical coatings of optical elements G02B1/10) - C03C 17/40: all coatings being metal coatings - G02B 1/12: by surface treatment, e.g. by irradiation - G02B 5/0891: {Ultraviolet [UV] mirrors (apparatus for microlithography exposure G03F7/70; X-ray multilayer structures G21K1/06)} - G02B 7/181: {with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation} - G03F 7/70316: {Details of optical elements, e.g. of Bragg reflectors, extreme ultraviolet [EUV] multilayer or bilayer mirrors or diffractive optical elements} - G03F 7/7095: {Materials, e.g. materials for housing, stage or other support having particular properties, e.g. weight, strength, conductivity, thermal expansion coefficient} - G21K 1/062: {Devices having a multilayer structure} - C03B 2201/42: doped with titanium - C03C 2218/31: Pre-treatment - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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) - G21K: HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES ## Abstract A method for the production of a mirror element (10) that has a reflective coating (10a) for the EUV wavelength range and a substrate (10b). The substrate (10b) is pre-compacted by hot isostatic pressing, and the reflective coating (10a) is applied to the pre-compacted substrate (10b). In the method, either the pre-compacting of the substrate (10b) is performed until a saturation value of the compaction of the substrate (10b) by long-term EUV irradiation is reached, or, for further compaction, the pre-compacted substrate (10b) is irradiated, preferably homogeneously, with ions (16) and/or with electrons in a surface region (15) in which the coating (10a) has been or will be applied. A mirror element (10) for the EUV wavelength range associated with the method has a substrate (10b) pre-compacted by hot isostatic pressing. Such a mirror element (10) is suitable to be provided in an EUV projection exposure system. ## Claims ### Claim 1 A method for producing a mirror element that has a substrate and a reflective coating for extreme ultraviolet wavelength radiation, comprising: pre-compacting the substrate by hot isostatic pressing, applying the reflective coating to a surface region of the pre-compacted substrate, and further compacting the pre-compacted substrate by irradiating the pre-compacted substrate with at least one of ions and electrons in a surface region of the substrate, wherein the pre-compacted substrate is irradiated until a density in the surface region is at least 0.5% higher than a density of a remainder of the substrate that is not in the irradiated region. ### Claim 2 (depends on 1) The method according to claim 1, wherein the pre-compacted substrate is irradiated homogeneously before the coating is applied in the surface region. ### Claim 3 (depends on 1) The method according to claim 1, wherein the coating is applied before the pre-compacted substrate is irradiated homogeneously. ### Claim 4 (depends on 1) The method according to claim 1, further comprising selecting a doped glass material or a glass ceramic as the material for the substrate. ### Claim 5 (depends on 1) The method according to claim 1, wherein the temperature during the hot isostatic pressing is selected to be between 1100° C. and 1300° C. ### Claim 6 (depends on 5) The method according to claim 5, wherein the temperature during the hot isostatic pressing is selected to be between 1150° C. and 1250° C. ### Claim 7 (depends on 1) The method according to claim 1, wherein the pressure during the hot isostatic pressing is selected to be between 20 MPa and 250 MPa. ### Claim 8 (depends on 7) The method according to claim 7, wherein the pressure during the hot isostatic pressing is selected to be between 50 MPa and 150 MPa. ### Claim 9 (depends on 1) The method according to claim 1, wherein the holding time during the hot isostatic pressing is selected to be between 0.5 hour and 5 hours. ### Claim 10 (depends on 9) The method according to claim 9, wherein the holding time during the hot isostatic pressing is selected to be between 2 hours and 4 hours. ### Claim 11 (depends on 1) The method according to claim 1, wherein the substrate is compacted by the hot isostatic pressing by at least 1%, preferably by at least 1.5%, in particular by at least 3%. ### Claim 12 (depends on 11) The method according to claim 11, wherein the substrate is compacted by the hot isostatic pressing by at least 3%. ### Claim 13 (depends on 1) The method according to claim 1, wherein at least one of: (a) the ions have an energy of between 0.2 MeV and 10 MeV at a total particle density of from 1014 to 1016 ions per cm2, and (b) the electrons have a dose of between 10 J/mm2 and 1000 J/mm2 at energies of between 10 KeV and 20 KeV. ### Claim 14 (depends on 1) The method according to claim 1, further comprising: carrying out the irradiation until there is obtained in the surface region a density that is at least 1% higher than the density of the remainder of the substrate. ### Claim 15 (depends on 14) The method according to claim 14, wherein the irradiation is carried out until there is obtained in the surface region a density that is at least 1.5% higher than the density of the remainder of the substrate. ### Claim 16 (depends on 14) The method according to claim 14, wherein the surface region extends to a depth of 5 μm from the surface of the substrate.