# US 9,752,807 B2 · Lithographic apparatus and to a reflector apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,807 B2 - Document ID: US9752807B2 - Status: Granted - Kind: B2 - Application number: 14/773,120 - Filed: 2014-02-18 - Published: 2016-01-14 - Granted: 2017-09-05 - Earliest claimed: 2013-03-15 - Assignees: ASML Netherlands B.V. - Applicants: ASML Netherlands B.V. - Inventors: Andani Alhassan Osuman - Web page: https://patentgrep.com/patent/US9752807B2 ## CPC - F25B 21/04: reversible - G02B 7/181: {with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation} - G03F 7/70891: {Temperature} - H10N 10/13: characterised by the heat-exchanging means at the junction - H10N 10/17: characterised by the structure or configuration of the cell or thermocouple forming the device - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP 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) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract Disclosed is a reflector apparatus comprising a reflector and an array of thermoelectric heat pumps each having a first end proximal to and in thermal contact with the reflector and having a second end distal from the reflector, a lithography tool having such a reflector apparatus, and a method of using the same. ## Claims ### Claim 1 A reflector apparatus comprising: a reflector and an array of thermoelectric heat pumps, wherein each thermoelectric heat pump is electrically insulated from another and comprises a first and a second semiconductor block and an electrical insulation layer disposed between the first and second semiconductor blocks; and a controller configured to independently control each thermoelectric heat pump of the array of thermoelectric heat pumps, whereby the controller is configured to determine a temperature of the reflector from a voltage measured across at least one of the thermoelectric heat pumps. ### Claim 2 (depends on 1) The reflector apparatus according to claim 1, wherein the controller is configured to control a supply voltage applied across the thermoelectric heat pumps. ### Claim 3 (depends on 2) The reflector apparatus according to claim 2, further comprising a power source configured to supply a supply voltage across the thermoelectric heat pumps. ### Claim 4 (depends on 2) The reflector apparatus according to claim 2, wherein the controller is configured to alternatingly apply the supply voltage to at least one of the thermoelectric heat pumps in order to heat or cool the reflector and disconnect the at least one of the thermoelectric heat pumps from the supply voltage to enable a measurement of the voltage across the at least one of the thermoelectric heat pumps. ### Claim 5 (depends on 1) The reflector apparatus according to claim 1, wherein the controller is configured to periodically determine the temperature of the reflector from the voltage measured across the at least one of the thermoelectric heat pumps. ### Claim 6 (depends on 1) The reflector apparatus of claim 1, wherein the controller is configured to use feed-forward correction to control the thermoelectric heat pumps. ### Claim 7 (depends on 1) The reflector apparatus of claim 1, wherein the controller is configured to use feed-back correction to control the thermoelectric heat pumps. ### Claim 8 (depends on 7) The reflector apparatus of claim 7, wherein the feed-back correction is based on the determined temperature of the reflector. ### Claim 9 (depends on 1) The reflector apparatus of claim 1, wherein the first semiconductor block is positively doped and the second semiconductor block is negatively doped. ### Claim 10 (depends on 1) The reflector apparatus of claim 1, wherein the array of thermoelectric heat pumps is a two-dimensional array. ### Claim 11 (depends on 1) The reflector apparatus of claim 1, wherein the thermoelectric heat pumps are individually controllable. ### Claim 12 (depends on 11) The reflector apparatus of claim 11, wherein the controller is configured to adjust a wavefront of radiation reflected by the reflector, by maintaining a temperature difference between mirror areas connected to adjacent thermoelectric heat pumps. ### Claim 13 (depends on 11) The reflector apparatus of claim 11, wherein the controller is configured to maintain a substantially equal temperature across the reflector using the thermoelectric heat pumps. ### Claim 14 (depends on 1) The reflector apparatus of claim 1, wherein the controller is configured to reverse the polarity of current supplied to the thermoelectric heat pumps if radiation ceases to be incident upon the reflector. ### Claim 15 (depends on 1) A laser or beam delivery system comprising the reflector of claim 1. ### Claim 16 (depends on 1) A lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a substrate table constructed to hold a substrate; and a projection system configured to project the radiation beam onto a target portion of the substrate, wherein a reflector of the illumination system or the projection system is a reflector apparatus according to claim 1. ### Claim 17 A method of controlling the temperature of a reflector, the method comprising: supplying power to an array of thermoelectric heat pumps, wherein each thermoelectric heat pump is electrically insulated from another and comprises a first and a second semiconductor block and an electrical insulation layer disposed between the first and second semiconductor blocks, the power supplied to the array of thermoelectric heat pumps causing the thermoelectric heat pumps to remove heat from or transfer heat to the reflector; independently controlling each thermoelectric heat pump of the array of thermoelectric heat pumps; and determining a temperature of the reflector from a voltage measured across at least one of the thermoelectric heat pumps. ### Claim 18 (depends on 17) The method of claim 17, wherein a temperature difference is maintained between mirror areas connected to adjacent thermoelectric heat pumps, thereby adjusting a wavefront of radiation reflected by the reflector. ### Claim 19 (depends on 18) The method of claim 18, wherein the spatial intensity of the radiation is adjusted to more closely correspond to a distribution of fuel upon which the radiation is incident. ### Claim 20 A support for supporting an object, the support comprising; a support surface configured to receive the object, the support further comprising: an array of thermoelectric heat pumps, wherein each thermoelectric heat pump is electrically insulated from another and comprises a first and a second semiconductor block and an electrical insulation layer disposed between the first and second semiconductor blocks; and a controller configured to independently control each thermoelectric heat pump of the array of thermoelectric heat pumps, whereby the controller is configured to, in use, determine a temperature of the object from a voltage measured across at least one of the thermoelectric heat pumps.