# US 11,029,613 B2 · Droplet generator and method of servicing extreme ultraviolet radiation source apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,613 B2 - Document ID: US11029613B2 - Status: Granted - Kind: B2 - Application number: 16/933,872 - Filed: 2020-07-20 - Published: 2020-11-05 - Granted: 2021-06-08 - Earliest claimed: 2018-06-29 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufacturing Co., Ltd. - Inventors: Yen-Hsun Chen; Ming-Hsun Tsai; Shao-Hua Wang; Han-Lung Chang; Li-Jui Chen; Chia-Chen Chen - Web page: https://patentgrep.com/patent/US11029613B2 ## CPC - G03F 7/70925: {Cleaning, i.e. actively freeing apparatus from pollutants, e.g. using plasma cleaning} - G03F 7/70033: {by plasma extreme ultraviolet [EUV] sources} - H05G 2/0094: {Reduction, prevention or protection from contamination; Cleaning} - 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 An extreme ultraviolet radiation source apparatus includes a chamber including at least a droplet generator, a nozzle of the droplet generator, and a dry ice blasting assembly. The droplet generator includes a reservoir for a molten metal, and the nozzle has a first end connected to the reservoir and a second opposing end where molten metal droplets emerge from the nozzle. The dry ice blasting assembly includes a blasting nozzle, a blasting air inlet and a blaster carbon dioxide (CO2) inlet. The blasting nozzle is disposed inside the chamber. The blasting nozzle is arranged to direct a pressurized air stream and dry ice particles at the nozzle of the droplet generator. ## Claims ### Claim 1 A method of cleaning an extreme ultra violet (EUV) radiation source apparatus, wherein the EUV radiation source apparatus comprises: a target droplet generator for generating a metal droplet within a chamber; and a cleaner blasting assembly having a cleaner blasting nozzle and a cleaner supporting member, the method comprising: forming pressurized dry ice particles; ejecting the pressurized dry ice particles through the cleaner blasting nozzle toward a residual material at a nozzle of the target droplet generator, thereby removing the residual material from the target droplet generator; and adjusting microscopic shock waves to remove the residual material from the target droplet generator. ### Claim 2 (depends on 1) The cleaning method of claim 1, wherein forming the pressurized dry ice particles further comprises forming a pressurized air stream from the cleaner supporting member of the cleaner blasting assembly. ### Claim 3 (depends on 1) The cleaning method of claim 1, wherein cleaning the nozzle of the target droplet generator further comprises collecting the residual material and sublimated gaseous carbon dioxide from the pressurized dry ice particles. ### Claim 4 (depends on 1) The cleaning method of claim 1, further comprising: monitoring residual material in the droplet generator; adjusting valves of a blasting pump when an amount of the residual material in the droplet generator is more than a threshold amount; and regulating operating parameters of a blasting compressor and the blasting pump. ### Claim 5 (depends on 1) The cleaning method of claim 1, wherein a flow rate of the pressurized dry ice particles ejected through the cleaner blasting nozzle is in a range from 0.5 liters per minute to 500 liters per minute. ### Claim 6 (depends on 1) The cleaning method of claim 1, wherein a pressure of the pressurized dry ice particles ejected through the cleaner blasting nozzle is in a range of 1 kPa to 1000 kPa at the nozzle. ### Claim 7 (depends on 1) The cleaning method of claim 1, wherein the pressurized dry ice particles ejected through the cleaner blasting nozzle have a diameter in a range from about 10 μm to about 10 mm. ### Claim 8 An extreme ultra violet (EUV) radiation source apparatus, comprising: a target droplet generator for generating a metal droplet; a cleaner blasting assembly; and a chamber enclosing at least the target droplet generator and the cleaner blasting assembly, wherein the cleaner blasting assembly comprises: a supporting device configured to form pressurized dry ice particles; and a blasting device configured to eject the pressurized dry ice particles toward a residual material at a nozzle of the target droplet generator. ### Claim 9 (depends on 8) The EUV radiation source apparatus of claim 8, wherein the cleaner blasting assembly further comprises a monitoring device for monitoring residual material on the target droplet generator. ### Claim 10 (depends on 8) The EUV radiation source apparatus of claim 8, further comprising an exhaust device configured to collect the residual material and sublimated gaseous carbon dioxide from the pressurized dry ice particles. ### Claim 11 (depends on 10) The EUV radiation source apparatus of claim 10, wherein the blasting device further comprises a pulsation insert configured to generate a pulsation of pressurized air stream. ### Claim 12 (depends on 8) The EUV radiation source apparatus of claim 8, further comprising a supporting member including a blasting compressor. ### Claim 13 (depends on 8) The EUV radiation source apparatus of claim 8, further comprising an exhaust device configured to remove the residual material from the target droplet generator. ### Claim 14 (depends on 8) The EUV radiation source apparatus of claim 8, further comprising a controller configured to: monitor residual material on the nozzle of the droplet generator, adjust valves of a blasting pump when an amount of the residual material in the droplet generator is more than a threshold amount, and regulate ejecting parameters of a blasting compressor and the blasting pump, when pressurized dry ice particles are ejected from a cleaner blasting nozzle. ### Claim 15 (depends on 8) The EUV radiation source apparatus of claim 8, wherein the blasting device further adjusts microscopic shock waves to remove the residual material from the target droplet generator. ### Claim 16 (depends on 8) The EUV radiation source apparatus of claim 8, wherein the blasting device further adjusts cleaning modes and position of the cleaner blasting assembly in the chamber to enhance the cleaning effect. ### Claim 17 A method of cleaning an extreme ultra violet (EUV) radiation source apparatus, comprising: providing a cleaner blasting assembly having a cleaner blasting nozzle and a cleaner supporting member; forming pressurized dry ice particles from the cleaner supporting member; ejecting the pressurized dry ice particles through the cleaner blasting nozzle toward a residual material at a nozzle of a target droplet generator; and removing the residual material from the target droplet generator; and adjusting cleaning modes and position of the cleaner blasting assembly in a chamber to enhance the cleaning effect. ### Claim 18 (depends on 17) The cleaning method of claim 17, further comprising regulating the pressurized dry ice particles by: monitoring the residual material on the droplet generator, and comparing an amount of the residual material on the droplet generator with a threshold amount. ### Claim 19 (depends on 18) The cleaning method of claim 18, further comprising stopping the ejection of the pressurized dry ice particles when the amount of the residual material on the droplet generator is below the threshold amount. ### Claim 20 (depends on 17) The cleaning method of claim 17, further comprising collecting the residual material and sublimated gaseous carbon dioxide from the pressurized dry ice particles.