# US 12,007,693 B2 · Laser focussing module > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,693 B2 - Document ID: US12007693B2 - Status: Granted - Kind: B2 - Application number: 17/600,763 - Filed: 2020-04-03 - Published: 2022-06-30 - Granted: 2024-06-11 - Earliest claimed: 2019-04-04 - Assignees: ASML Netherlands B. V.; TRUMPF Lasersystems for Semiconductor Manufacturing GmbH - Applicants: ASML Netherlands B.V.; Trumpf Lasersystems For Semiconductor Manufacturing GmbH - Inventors: Ruud Antonius Catharina Maria Beerens; Nico Johannes Antonius Hubertus Boonen; Stefan Michael Bruno Bäumer; Tolga Mehmet Ergin; Andreas Kristian Hopf; Derk Jan Wilfred Klunder; Martin Anton Lambert; Stefan Piehler; Manisha Ranjan; Frank Bernhard Sperling; Andrey Sergeevich Tychkov; Jasper Witte; Jiayue Yuan - Web page: https://patentgrep.com/patent/US12007693B2 ## CPC - G03F 7/70033: {by plasma extreme ultraviolet [EUV] sources} - H01S 3/0071: {Beam steering, e.g. whereby a mirror outside the cavity is present to change the beam direction} - H05G 2/0086: {Optical arrangements for conveying the laser beam to the plasma generation location} - H01S 3/005: {Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping (shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B)} - 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) - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - 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 laser focusing system (330) for use in an EUV radiation source is described, the laser focusing system comprising: •—a first curved mirror (330.1) configured to receive a laser beam from a beam delivery system (320) and generate a first reflected laser beam (316); •—a second curved mirror (330.2) configured to receive the first reflected laser beam (316) and generate a second reflected laser beam (317), wherein the laser focusing system (330) is configured to focus the second reflected laser beam (317) to a target location (340) in a vessel (350) of the EUV radiation source (360). ## Claims ### Claim 1 A laser focusing system comprising: a first curved mirror configured to receive a laser beam from a beam delivery system and generate a first reflected laser beam; and a second curved mirror configured to receive the first reflected laser beam and generate a second reflected laser beam, wherein the second reflected laser beam is focused onto a target location in a vessel of an EUV radiation source, wherein the vessel comprises a collector mirror, wherein an angle between an optical axis of the second reflected laser beam and a horizontal axis is smaller than 25 degrees, wherein the horizontal axis is defined by the optical axis of the collector mirror, wherein the laser beam is received by one or more additional mirrors that redirect the laser beam towards the first curved mirror; and wherein the one or more additional mirrors are configured to overcome a difference in location between the received laser beam and the redirected laser beam, and to translate the laser beam in a substantially vertical direction. ### Claim 2 (depends on 1) The laser focusing system of claim 1, wherein: the first curved mirror is configured to receive the laser beam at an incidence angle that is smaller than 30 degrees; and the second curved mirror is configured to receive the laser beam at an incidence angle that is smaller than 30 degrees. ### Claim 3 (depends on 1) The laser focusing system of claim 1, wherein the one or more additional mirrors comprises a periscope system. ### Claim 4 (depends on 3) The laser focusing system of claim 3, wherein: the periscope system comprises a first periscope mirror configured to receive the laser beam and reflect the laser beam towards a second periscope mirror, and the second periscope mirror is configured to reflect the laser beam towards the first curved mirror. ### Claim 5 (depends on 3) The laser focusing system of claim 3, wherein the periscope system and the first and second curved mirror are configured so that the laser beam that is redirected towards the first curved mirror, the first reflected laser beam, and the second reflected laser beam are configured in substantially a same plane. ### Claim 6 (depends on 3) The laser focusing system of claim 3, wherein the periscope system and the first and second curved mirror are configured so that the laser beam that is redirected towards the first curved mirror, the first reflected laser beam, and the second reflected laser beam are configured in substantially a different plane. ### Claim 7 (depends on 1) The laser focusing system of claim 1, wherein the one or more curved additional mirrors form a telescope system configured to change a diameter of the laser beam and/or to change a divergence of the laser beam. ### Claim 8 (depends on 1) The laser focusing system of claim 1, wherein: the laser beam and the redirected laser beam define a first plane, and the first reflected laser beam and the second reflected laser beam define a second plane, the second plane being different from the first plane. ### Claim 9 (depends on 8) The laser focusing system of claim 8, wherein the first plane is substantially perpendicular to the second plane. ### Claim 10 (depends on 8) The laser focusing system of claim 8, wherein the second plane is non-perpendicular to the first plane. ### Claim 11 (depends on 8) The laser focusing system of claim 8, wherein the second plane is parallel to the first plane. ### Claim 12 (depends on 8) The laser focusing system of claim 8, wherein the laser beam that is redirected towards the first curved mirror is configured in both the first plane and the second plane. ### Claim 13 (depends on 8) The laser focusing system of claim 8, wherein the laser beam that is redirected towards the first curved mirror is not configured in the second plane. ### Claim 14 (depends on 1) The laser focusing system of claim 1, wherein the angle between the optical axis of the second reflected laser beam and the horizontal axis is smaller than 20 degrees. ### Claim 15 A laser source comprising: a laser focusing system configured to be used in the EUV radiation source, the laser focusing system comprising: a first curved mirror configured to receive a laser beam from a beam delivery system and generate a first reflected laser beam; and a second curved mirror configured to receive the first reflected laser beam and generate a second reflected laser beam, wherein the second reflected laser beam is focused onto a target location in a vessel of the EUV radiation source, wherein the vessel comprises a collector mirror, wherein an angle between an optical axis of the second reflected laser beam and a horizontal axis is smaller than 25 degrees, wherein the horizontal axis is defined by the optical axis of the collector mirror, wherein the laser beam is received by one or more additional mirrors that redirect the laser beam towards the first curved mirror; and wherein the one or more additional mirrors are configured to overcome a difference in location between the received laser beam and the redirected laser beam, and to translate the laser beam in a substantially vertical direction. ### Claim 16 (depends on 15) The laser source of claim 15, wherein the angle between the optical axis of the second reflected laser beam and the horizontal axis is smaller than 20 degrees. ### Claim 17 An EUV radiation source comprising: a laser source comprising: a laser focusing system configured to be used in the EUV radiation source, the laser focusing system comprising: a first curved mirror configured to receive a laser beam from a beam delivery system and generate a first reflected laser beam; and a second curved mirror configured to receive the first reflected laser beam and generate a second reflected laser beam, wherein the second reflected laser beam is focused onto a target location in a vessel of the EUV radiation source, wherein the vessel comprises a collector mirror, wherein an angle between an optical axis of the second reflected laser beam and a horizontal axis is smaller than 25 degrees, wherein the horizontal axis is defined by the optical axis of the collector mirror, wherein the laser beam is received by one or more additional mirrors that redirect the laser beam towards the first curved mirror; and wherein the one or more additional mirrors are configured to overcome a difference in location between the received laser beam and the redirected laser beam, and to translate the laser beam in a substantially vertical direction. ### Claim 18 (depends on 17) The EUV radiation source of claim 17, wherein the angle between the optical axis of the second reflected laser beam and the horizontal axis is smaller than 20 degrees.