# US 7,609,455 B2 · Projection optical system and method for photolithography and exposure apparatus and method using same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,455 B2 - Document ID: US7609455B2 - Status: Granted - Kind: B2 - Application number: 11/907,907 - Filed: 2007-10-18 - Published: 2008-03-20 - Granted: 2009-10-27 - Earliest claimed: 2002-08-23 - Assignees: Nikon Corporation - Inventors: Yasuhiro Omura; Hironori Ikezawa - Web page: https://patentgrep.com/patent/US7609455B2 ## CPC - G02B 17/0892: {specially adapted for the UV} - G02B 17/08: Catadioptric systems {(used in non-imaging applications G02B19/00)} - G02B 21/33: Immersion oils {, or microscope systems or objectives for use with immersion fluids} - G03F 7/70225: {Optical aspects of catadioptric systems, i.e. comprising reflective and refractive elements} - G03F 7/70341: {Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply (chemical composition of immersion liquids G03F7/2041)} - G02B 13/22: Telecentric objectives or lens systems - 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) ## Abstract A lithographic projection apparatus is arranged to project a pattern from a patterning device onto a substrate using a projection system and has a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid. An element of the projection system through which the pattern is projected has, on a surface configured to be in contact with the liquid, a protective coating which is SiO2. ## Claims ### Claim 1 A lithographic projection apparatus arranged to project a pattern from a patterning device onto a substrate using a projection system and having a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid, wherein an element of the projection system through which the pattern is projected has, on a surface configured to be in contact with the liquid, a member which is SiO2. ### Claim 2 (depends on 1) The apparatus according to claim 1, wherein the member is a fused silica plate. ### Claim 3 (depends on 2) The apparatus according to claim 2, wherein the fused silica plate is attached to the element. ### Claim 4 A lithographic projection apparatus arranged to project a pattern from a patterning device onto a substrate using a projection system and having a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid, wherein an element of the projection system through which the pattern is to be projected and configured to be at least in part in contact with the liquid, comprises first and second components of CaF2, or SiO2, the components being arranged such that the projected pattern passes through the first component before passing through the second component. ### Claim 5 (depends on 4) The apparatus according to claim 4, wherein the second component is positioned substantially within a recess in the first component. ### Claim 6 (depends on 4) The apparatus according to claim 4, wherein elements of the projection system other than the element are made of a material other than CaF2. ### Claim 7 A device manufacturing method comprising projecting a patterned beam of radiation onto a substrate through a liquid provided in a space between an element of a projection system and the substrate, wherein a surface of the element in contact with the liquid comprises a member which is CaF2 or SiO2. ### Claim 8 (depends on 7) The method according to claim 7, wherein the member is SiO2. ### Claim 9 (depends on 7) The method according to claim 7, wherein the member is a fused silica plate. ### Claim 10 (depends on 9) The method according to claim 9, wherein the fused silica plate is attached to the element. ### Claim 11 A device manufacturing method comprising projecting a patterned beam of radiation onto a substrate through a first liquid and a second liquid provided in a space between an element of a projection system and the substrate, wherein the first liquid is in contact with the element and the second liquid is in contact with the substrate. ### Claim 12 (depends on 11) The method according to claim 11, wherein a membrane separates the first and second liquids. ### Claim 13 (depends on 12) The method according to claim 12, wherein the membrane is quartz. ### Claim 14 A device manufacturing method comprising projecting a patterned beam of radiation onto a substrate through a liquid provided in a space between an element of a projection system and the substrate, wherein the element is at least in part in contact with the liquid and comprises first and second components of CaF2, or SiO2, the components being arranged such that the patterned beam of radiation passes through the first component before passing through the second component. ### Claim 15 (depends on 14) The method according to claim 14, wherein elements of the projection system other than the element are made of a material other than CaF2. ### Claim 16 (depends on 14) The method according to claim 14, wherein the second component is positioned substantially within a recess in the first component.