# US 2024/0176249 A1 · Optical element, projection optical unit and projection exposure apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0176249 A1 - Document ID: US20240176249A1 - Status: Published application - Kind: A1 - Application number: 18/437,111 - Filed: 2024-02-08 - Published: 2024-05-30 - Earliest claimed: 2021-08-13 - Assignees: Carl Zeiss SMT GmbH - Applicants: Carl Zeiss SMT GmbH - Inventors: Marwene Nefzi; Jens Kugler; Matthias Fetzer - Web page: https://patentgrep.com/patent/US20240176249A1 ## CPC - G03F 7/70316: {Details of optical elements, e.g. of Bragg reflectors, extreme ultraviolet [EUV] multilayer or bilayer mirrors or diffractive optical elements} - G02B 7/1815: {with cooling or heating systems (cooling arrangements for laser mirrors H01S3/0401)} - G02B 7/182: for mirrors - G02B 17/06: using mirrors only {, i.e. having only one curved mirror (used in non-imaging applications G02B19/00)} - G03F 7/70233: {Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems} - G03F 7/70266: {Adaptive optics, e.g. deformable optical elements for wavefront control, e.g. for aberration adjustment or correction} - G03F 7/70833: {Mounting of optical systems, e.g. mounting of illumination system, projection system or stage systems on base-plate or ground} - G03F 7/7085: {Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load} - G03F 7/70891: {Temperature} - G03F 7/709: {Vibration, e.g. vibration detection, compensation, suppression or isolation} - 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) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract An optical element for a projection exposure apparatus comprises a mirror body having an optically active surface. The mirror body comprises a base portion which carries a sensor system. The mirror body comprises an edge portion on which actuator connectors for connecting actuators to the optical element are provided. The base portion has greater stiffness than the edge portion. A stiffening rib structure is attached to the back side of the edge portion, which faces away from the optically active surface. The rib structure supports the edge portion on the base portion. ## Claims ### Claim 1 An optical element, comprising: a mirror body, comprising an optically active surface, a base portion and an edge portion; a sensor system disposed on the base portion; actuator connectors disposed on the edge portion, the actuator connectors configured to connect actuators to the optical element; a stiffening rib structure attached to a back side of the edge portion, wherein: the base portion is stiffer than the edge portion; the backside of the edge portion faces away from the optically active surface; and the rib structure supports the edge portion on the base portion. ### Claim 2 (depends on 1) The optical element of claim 1, wherein the actuator connectors are disposed on the back side of the edge portion. ### Claim 3 (depends on 1) The optical element of claim 1, wherein the rib structure comprises a honeycomb geometry. ### Claim 4 (depends on 1) The optical element of claim 1, wherein the rib structure is connected to the actuator connectors to stiffen the actuator connectors. ### Claim 5 (depends on 1) The optical element of claim 1, wherein the sensor system comprises measurement targets configured to interact with a measuring beam. ### Claim 6 (depends on 1) The optical element of claim 1, wherein the actuator connectors are disposed on an edge of the edge portion. ### Claim 7 (depends on 1) The optical element of claim 1, wherein the edge portion is slab-shaped, and the base portion is block-shaped. ### Claim 8 (depends on 1) The optical element of claim 1, wherein the edge portion comprises a wall, the base portion comprises a wall, and the wall of the edge portion is thinner wall than the wall of the base portion. ### Claim 9 (depends on 1) The optical element of claim 1, wherein the mirror body is a monolithic component or a multi-part component. ### Claim 10 (depends on 1) The optical element of claim 1, wherein the mirror is a multi-part component, and the base portion and the edge portion are bonded to one another. ### Claim 11 (depends on 1) The optical element of claim 1, wherein the mirror body is configured to be actively cooled. ### Claim 12 (depends on 1) The optical element of claim 1, further comprising cooling channels through the mirror body, wherein the cooling channels are configured to actively cool the mirror body. ### Claim 13 (depends on 1) The optical element of claim 1, wherein the actuator connectors are disposed on the back side of the edge portion, the rib structure comprises a honeycomb geometry, and the rib structure is connected to the actuator connectors to stiffen the actuator connectors. ### Claim 14 (depends on 13) The optical element of claim 13, wherein the sensor system comprises measurement targets configured to interact with a measuring beam, and the actuator connectors are disposed on an edge of the edge portion. ### Claim 15 (depends on 14) The optical element of claim 14, further comprising cooling channels in the mirror body, wherein the cooling channels are configured to actively cool the mirror body. ### Claim 16 (depends on 13) The optical element of claim 13, further comprising cooling channels in the mirror body, wherein the cooling channels are configured to actively cool the mirror body. ### Claim 17 (depends on 1) An optical unit, comprising: an optical element according to claim 1; and a plurality of actuators connected to the actuator connectors, wherein the actuators are configured to adjust the optical element, and the optical unit is a lithography projection optical unit. ### Claim 18 (depends on 1) An apparatus, comprising: an illumination system; a projection optical unit; and an optical element according to claim 1, wherein the apparatus is a lithography projection exposure apparatus. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the projection optical unit comprises the optical element. ### Claim 20 (depends on 1) A method of using a lithography projection exposure apparatus comprising an illumination system and a projection optical unit, the method comprising: using the illumination system to illuminate a structure of a reticle; using the projection optical unit to project the illuminated structure of the reticle onto a light-sensitive material, wherein the projection optical unit comprises an optical element according to claim 1.