# US 11,029,259 B2 · Detection device for detecting a structure on an area portion of a lithography mask, and apparatus comprising a detection device of this type > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,259 B2 - Document ID: US11029259B2 - Status: Granted - Kind: B2 - Application number: 16/707,391 - Filed: 2019-12-09 - Published: 2020-06-18 - Granted: 2021-06-08 - Earliest claimed: 2018-12-13 - Assignees: Carl Zeiss SMT GmbH - Applicants: Carl Zeiss SMT GmbH - Inventors: Ulrich Matejka; Sven Martin - Web page: https://patentgrep.com/patent/US11029259B2 ## CPC - G01N 21/956: Inspecting patterns on the surface of objects {(contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - G03F 1/84: Inspecting - G01N 21/21: Polarisation-affecting properties (G01N21/19 takes precedence) - G01N 2021/8867: {using sequentially two or more inspection runs, e.g. coarse and fine, or detecting then analysing} - G01N 2021/95676: {Masks, reticles, shadow masks} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - 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 A detection device serves for detecting a structure on an area portion of a lithography mask. The detection device has a first spatially resolving detector and also a further spatially resolving detector arranged separately therefrom. The first spatially resolving detector is embodied as a high-intensity (HI) detector and is arranged in an HI beam path of the detection light which emanates from the mask area portion. The further spatially resolving detector is embodied as a low-intensity (LI) detector and is arranged in an LI beam path of the detection light. The HI beam path on the one hand and the LI beam path on the other hand are embodied such that the HI detector is illuminated with a detection light intensity that is at least twice the magnitude of the detection light intensity with which the LI detector is illuminated. The two spatially resolving detectors are embodied for simultaneously detecting the detection light. The result is a detection device whose dynamic range is increased without limitations of a spatial resolution. Alternatively or additionally, the detection device, by way of the two spatially resolving detectors, can also be embodied for the polarization-resolved measurement of the detection light. ## Claims ### Claim 1 A detection device for detecting a structure on an area portion of a lithography mask, comprising a first spatially resolving detector, embodied as a high-intensity (HI) detector, arranged in an HI beam path of detection light which emanates from the mask area portion, and comprising a further spatially resolving detector, arranged separately from the first spatially resolving detector, embodied as a low-intensity (LI) detector, arranged in an LI beam path of the detection light, wherein the HI beam path on the one hand and the LI beam path on the other hand are embodied such that the HI detector is illuminated with a detection light intensity that is at least twice the magnitude of the detection light intensity with which the LI detector is illuminated, wherein the two spatially resolving detectors are embodied for simultaneously detecting the detection light, and the spatially resolving detectors are arranged such that a reflection at the HI detector is part of the LI beam path. ### Claim 2 (depends on 1) The detection device of claim 1, characterized by an arrangement in such a way that beam deflections in the HI beam path take place exclusively as a result of reflection. ### Claim 3 (depends on 1) The detection device of claim 1, wherein the HI detector has a multilayer coating. ### Claim 4 (depends on 1) The detection device of claim 1, comprising a beam splitter for splitting a detection beam path emanating from the area portion into the HI beam path and the LI beam path. ### Claim 5 (depends on 4) The detection device of claim 4, comprising an imaging optical unit for imaging the area portion, wherein the beam splitter is arranged in an image plane of the imaging optical unit. ### Claim 6 (depends on 4) The detection device of claim 4, wherein the beam splitter has a multilayer coating. ### Claim 7 (depends on 4) The detection device of claim 4, wherein the beam splitter has a diffractive structure. ### Claim 8 (depends on 7) The detection device of claim 7, wherein the beam splitter is embodied as a grating. ### Claim 9 (depends on 4) The detection device of claim 4, wherein an angle of reflection of a chief beam of the HI beam path after impinging on the beam splitter is less than 20°. ### Claim 10 (depends on 1) The detection device of claim 1, comprising at least one mirror in the LI beam path. ### Claim 11 A detection device for detecting a structure on an area portion of a lithography mask, comprising a first spatially resolving detector, embodied as a p-polarization (pPol) detector, arranged in a pPol beam path of detection light which emanates from the mask area portion, and comprising a further spatially resolving detector, arranged separately from the first spatially resolving detector, embodied as an s-polarization (sPol) detector, arranged in an sPol beam path of the detection light, wherein the two spatially resolving detectors are embodied for simultaneously detecting the detection light. ### Claim 12 (depends on 1) An apparatus for detecting a structure on an area portion of a lithography mask, comprising: the detection device of claim 1, a light source for the detection light, and a mask holder for mounting the lithography mask. ### Claim 13 A method for operating a detection device for detecting a structure on an area portion of a lithography mask or for operating an apparatus for detecting a structure on an area portion of a lithography mask, wherein the detection device comprises: a first spatially resolving detector, embodied as a high-intensity (HI) detector, arranged in an HI beam path of detection light which emanates from the mask area portion, and a further spatially resolving detector, arranged separately from the first spatially resolving detector embodied as a low-intensity (LI) detector, arranged in an LI beam path of the detection light, wherein the HI beam path on the one hand and the LI beam path on the other hand are embodied such that the HI detector is illuminated with a detection light intensity that is at least twice the magnitude of the detection light intensity with which the LI detector is illuminated, wherein the two spatially resolving detectors are embodied for simultaneously detecting the detection light, and the spatially resolving detectors are arranged such that a reflection at the HI detector is part of the LI beam path, wherein the apparatus comprises: the detection device, a light source for the detection light, and a mask holder for mounting the lithography mask, wherein the method comprises the following steps: recording images by simultaneously detecting the detection light by use of the detectors of the apparatus, and combining the recorded images to form an overall image. ### Claim 14 (depends on 13) The method of claim 13, wherein the combined overall image has an increased dynamic range in comparison with the individual images recorded. ### Claim 15 (depends on 11) The device of claim 11, comprising a diffractive structure that transmits s-polarized light to the s-polarization detector and reflects p-polarized light towards the p-polarization detector. ### Claim 16 (depends on 12) The apparatus of claim 12 in which the detection device is configured in such a way that beam deflections in the HI beam path take place exclusively as a result of reflection. ### Claim 17 (depends on 13) The method of claim 13 in which the detection device is configured in such a way that beam deflections in the HI beam path take place exclusively as a result of reflection. ### Claim 18 (depends on 13) The method of claim 13 in which combining the recorded images to form an overall image comprises coherent diffractive imaging. ### Claim 19 (depends on 13) The method of claim 13 in which combining the recorded images to form an overall image comprises iterative Fourier transformation. ### Claim 20 (depends on 1) The detection device of claim 1, comprising: a second spatially resolving detector, arranged separately from the first spatially resolving detector, embodied as a medium-intensity (MI) detector, wherein the HI detector is illuminated with a detection light intensity that is greater than the detection light intensity with which the MI detector is illuminated, and the MI detector is illuminated with a detection light intensity that is greater than the detection light intensity with which the LI detector is illuminated, and wherein the three spatially resolving detectors are embodied for simultaneously detecting the detection light.