# US 11,442,365 B1 · EUV photolithography system and methods of operating the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,365 B1 - Document ID: US11442365B1 - Status: Granted - Kind: B1 - Application number: 17/459,836 - Filed: 2021-08-27 - Granted: 2022-09-13 - Earliest claimed: 2021-08-27 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufacturing Co., Ltd. - Inventors: Yu-Kuang Sun; Ming-Hsun Tsai; Yu-Huan Chen; Wei-Shin Cheng; Cheng-Hao Lai; Hsin-Feng Chen; Chiao-Hua Cheng; Cheng-Hsuan Wu; Yu-Fa Lo; Shang-Chieh Chien; Li-Jui Chen; Heng-Hsin Liu - Web page: https://patentgrep.com/patent/US11442365B1 ## CPC - G03F 7/70033: {by plasma extreme ultraviolet [EUV] sources} - G03F 7/70891: {Temperature} - G03F 7/70908: {Hygiene, e.g. preventing apparatus pollution, mitigating effect of pollution or removing pollutants from apparatus} - G03F 7/70975: {Assembly, maintenance, transport or storage of apparatus} - H05G 2/0023: {Constructional details of the ejection system} - H05G 2/0027: {Arrangements for controlling the supply; Arrangements for measurements} - H05G 2/0092: {Housing of the apparatus for producing X-rays; Environment inside the housing} - 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) - H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321) ## Abstract A photolithography system utilizes tin droplets to generate extreme ultraviolet radiation for photolithography. The photolithography system irradiates the droplets with a laser. The droplets become energized and emit extreme ultraviolet radiation. A collector reflects the extreme ultraviolet radiation toward a photolithography target. The photolithography system isolates a source of droplets from oxidants to prevent the oxidation of the nozzle or the formation of metal oxides on the nozzle, both of which can adversely affect an ability of the nozzle to generate a sufficient amount of droplets and/or direct the droplets in a desired direction. ## Claims ### Claim 1 A method of operating an EUV photolithography system, the method comprising: outputting droplets from a nozzle of a droplet generator of the EUV photolithography system; exposing the droplets to a laser of the EUV photolithography system; receiving the droplets in a droplet receiver of the EUV photolithography system; stopping the outputting of the droplets from the nozzle; creating an inert gas environment around the nozzle by flowing an inert gas through the nozzle; isolating the nozzle from oxidants using the inert gas environment; cooling the nozzle using the inert gas forming the inert gas environment around the nozzle; maintaining the inert gas environment around the nozzle; and while maintaining the inert gas environment around the nozzle, performing maintenance on the EUV photolithography system. ### Claim 2 (depends on 1) The method of claim 1, wherein the inert gas environment includes an inert gas selected from argon, helium or nitrogen. ### Claim 3 (depends on 1) The method of claim 1, wherein creating an inert gas environment around the nozzle includes delivering an inert gas into a chamber including the nozzle. ### Claim 4 (depends on 3) The method of claim 3, wherein delivering the inert gas into the chamber including the nozzle includes maintaining a pressure of the inert gas within the chamber at 1 atm or greater. ### Claim 5 (depends on 1) The method of claim 1, wherein flowing an inert gas through the nozzle includes maintaining a pressure of the inert gas flowing through the nozzle at a pressure of 1 atm or greater. ### Claim 6 (depends on 5) The method claim 5, wherein creating an inert gas environment around the nozzle includes creating an argon gas environment around the nozzle. ### Claim 7 (depends on 1) The method of claim 1, wherein outputting droplets from a nozzle of a droplet generator includes pressurizing a droplet liquid with an inert gas from a first source of inert gas and creating an inert gas environment around the nozzle includes creating an inert gas environment around the nozzle using an inert gas from a second inert gas source, the second inert gas source being separate from the first inert gas source. ### Claim 8 (depends on 1) The method of claim 1, wherein maintaining the inert gas environment around the nozzle includes maintaining a humidity around the nozzle that is lower than the humidity around the nozzle during the outputting droplets from the nozzle. ### Claim 9 (depends on 1) The method claim 1, wherein the exposing the droplets to a laser includes exposing the droplets to a CO2 laser. ### Claim 10 A method comprising: outputting Sn droplets from a source of droplets of a droplet generator in an EUV photolithography system; irradiating the Sn droplets with a laser; receiving the Sn droplets in a droplet receiver; stopping the outputting of the Sn droplets from the source of droplets; establishing an inert gas environment around the source of droplets by flowing an inert gas through an outlet of the source of droplets; maintaining the inert gas environment around the source of the droplets; and while maintaining the inert gas environment around the source of the droplets, performing maintenance on the EUV photolithography system. ### Claim 11 (depends on 10) The method of claim 10, wherein the droplet generator is a Sn droplet generator. ### Claim 12 (depends on 10) The method of claim 10, further comprising absorbing, by the inert gas used to establish the inert gas environment, thermal energy from the source of the droplets. ### Claim 13 (depends on 10) The method of claim 10, wherein maintaining the inert gas environment around the source of the droplets includes isolating the source of the droplets from oxidants. ### Claim 14 (depends on 13) The method of claim 13, wherein isolating the source of the droplets from oxidants includes isolating the source of droplets from oxygen. ### Claim 15 (depends on 10) The method of claim 10, wherein irradiating the Sn droplets with a laser, includes irradiating the Sn droplets with a CO2 laser. ### Claim 16 (depends on 10) The method of claim 10, wherein establishing the inert gas environment around the source of droplets includes establishing an argon gas environment around the source of droplets. ### Claim 17 (depends on 10) The method of claim 10, wherein maintaining the inert gas environment around the source of droplets includes maintaining a humidity around the source of droplets that is lower than the humidity around the source of droplets during the outputting droplets from the source of droplets. ### Claim 18 A method of operating an EUV photolithography system, the method comprising: generating droplets from a source of droplets of the EUV photolithography system; stopping the generating droplets from the source of droplets; isolating the source of droplets from oxidants by flowing an inert gas through an outlet of the source of droplets and creating a cloud of inert gas around the outlet of the source of droplets; and while isolating the source of droplets from oxidants, performing maintenance on the EUV photolithography system. ### Claim 19 (depends on 18) The method of claim 18, wherein the isolating the source of droplets from oxidants includes forming an inert gas environment around the source of droplets. ### Claim 20 (depends on 19) The method of claim 19, further comprising cooling the source of droplets using an inert gas of the inert gas environment.