# US 2008/0187105 A1 · Gas Discharge Source, in Particular for Euv Radiation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0187105 A1 - Document ID: US20080187105A1 - Status: Published application - Kind: A1 - Application number: 11/914,773 - Filed: 2006-05-08 - Published: 2008-08-07 - Earliest claimed: 2005-05-19 - Assignees: Koninklijke Philips Electronics N.V. - Inventors: Jakob Willi Neff; Ralf Pruemmer - Web page: https://patentgrep.com/patent/US20080187105A1 ## CPC - H05G 2/002: {Supply of the plasma generating material} - G03F 7/70033: {by plasma extreme ultraviolet [EUV] sources} - 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) - 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 The present invention relates to a gas discharge source, in particular for EUV radiation and/or soft X-ray radiation, in which, in a vacuum chamber, at least two electrodes with an at least approximately circular periphery are rotatably mounted for rotation, wherein the electrodes at one spatial position have a small spacing for the ignition of a gas discharge and are in each case connected to a reservoir for a liquid, electrically conductive material in such a way that, during rotation, a liquid film of the electrically conductive material can form over the circular periphery of the electrodes and a flow of current to the electrodes is made possible via the reservoirs. In the present gas discharge source, the electrodes are in each case connected to the reservoirs via a connecting element, by means of which a gap is formed between the electrode and the connecting element over a partial section of the circular periphery of each electrode, into which gap the liquid material can penetrate from the reservoir during rotation of the electrode via at least one feed channel formed in the connecting element. ## Claims ### Claim 1 Gas discharge source, in particular for EUV radiation and/or soft X-ray radiation, in which, in a vacuum chamber (2), at least two electrodes (1) with an at least approximately circular periphery are rotatably mounted for rotation, wherein the electrodes (1) at one spatial position have a small spacing for the ignition of a gas discharge (6) and are in each case connected to a reservoir (15) for a liquid, electrically conductive material (5) in such a way that, during rotation, a liquid film (22) of the electrically conductive material (5) can form over the circular periphery of the electrodes (1) and a flow of current to the electrodes (1) is made possible via the reservoirs (15), characterized in that the electrodes (1) are in each case connected to the reservoirs (15) via a connecting element (14), by means of which a gap (19) is formed between the electrode (1) and the connecting element (14), said gap (19) extending over a partial section of the circular periphery of each electrode (1) to a length which is larger than a width of the gap (19), into which gap the liquid, electrically conductive material (5) can penetrate from the reservoir (15) during rotation of the electrode (1) via at least one feed channel (16) formed in the connecting element (14). ### Claim 2 (depends on 1) Gas discharge source according to claim 1, characterized in that the connecting element (14) is designed in such a way that the gap (19) tapers in a rotation direction of the electrode (1). ### Claim 3 (depends on 1) Gas discharge source according to claim 1, characterized in that the connecting element (14) also has at least one return channel (17) for the liquid, electrically conductive material (5), said return channel opening into the gap (19). ### Claim 4 (depends on 3) Gas discharge source according to claim 3, characterized in that the return channel (17) leads via a purification filter or a purifying antechamber into the reservoir (15). ### Claim 5 (depends on 1) Gas discharge source according to claim 1, characterized in that the gap (19) is dimensioned in such a way that the liquid, electrically conductive material (5) is drawn into the gap (19) and/or held in the gap (19) by means of capillary forces. ### Claim 6 (depends on 1) Gas discharge source according to claim 1, characterized in that the gap (19) is tapered at the ends of the gap. ### Claim 7 (depends on 1) Gas discharge source according to claim 1, characterized in that the gap (19) is dimensioned at least with respect to the width of the gap (19) and shaped in such a way that the liquid film (22) of the electrically conductive material (5), in the region of the small spacing of the electrodes (1), has a thickness at which an evaporated amount of the electrically conductive material (5) that is required for the gas discharge (6) is minimized for each discharge pulse. ### Claim 8 (depends on 1) Gas discharge source according to claim 1, characterized in that the reservoir (15) is formed in the connecting element (14). ### Claim 9 (depends on 1) Gas discharge source according to claim 1, characterized in that the reservoir (15) is connected to the feed channel (16) in the connecting element (14) via a supply line. ### Claim 10 (depends on 1) Gas discharge source according to claim 1, characterized in that the connecting element (14) has further channels which can be flowed through by a temperature control fluid. ### Claim 11 (depends on 1) Gas discharge source according to claim 1, characterized in that the electrodes (1) have a stepped contour on the circular periphery in cross section perpendicular to the rotation direction, wherein the contours of the two electrodes (1) are designed in a complementary manner so that they engage in one another in the region of the small spacing. ### Claim 12 (depends on 1) Gas discharge source according to claim 1, characterized in that a magnetic device is provided which prevents the electrically conductive material (5) from flowing out of the gap (19) counter to a rotation direction of the electrode (1). ### Claim 13 (depends on 12) Gas discharge source according to claim 12, characterized in that ferromagnetic materials are incorporated in regions of the electrodes (1) and/or connecting elements (14) for amplifying the magnetic forces of the magnetic device. ### Claim 14 (depends on 1) Gas discharge source according to claim 1, characterized in that the vacuum chamber (2) has an opening which allows the introduction of energetic radiation for evaporating material of the liquid film (22) in the region of the small spacing of the electrodes (1).