# US 2023/0273531 A1 · Spectrometric metrology systems based on multimode interference and lithographic apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0273531 A1 - Document ID: US20230273531A1 - Status: Published application - Kind: A1 - Application number: 18/016,225 - Filed: 2021-06-29 - Published: 2023-08-31 - Earliest claimed: 2020-07-16 - Assignees: ASML Holding N.V. - Applicants: ASML Holding N.V. - Inventors: Mohamed SWILLAM; Justin Lloyd KREUZER; Stephen ROUX - Web page: https://patentgrep.com/patent/US20230273531A1 ## CPC - G03F 7/70633: {Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching} - G03F 7/706845: {Calibration, e.g. tool-to-tool calibration, beam alignment, spot position or focus} - G03F 7/70233: {Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems} - G03F 7/706849: {Irradiation branch, e.g. optical system details, illumination mode or polarisation control} - G03F 7/706851: {Detection branch, e.g. detector arrangements, polarisation control, wavelength control or dark/bright field detection} - G03F 9/7088: {Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection} - G03F 9/7092: {Signal processing} - 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 metrology system comprises a radiation source, an optical element, first and second detectors, an integrated optical device comprising a multimode waveguide, and a processor. The radiation source generates radiation. The optical element directs radiation toward a target to generate scattered radiation from the target. The first detector receives a first portion of the scattered radiation and generates a first detection signal based on the received first portion. The multimode waveguide interferes a second portion of the scattered radiation using modes of the multimode waveguide. The second detector receives the interfered second portion and generates a second detection signal based on the received interfered second portion. The processor receives the first and second detection signals. The processor analyzes the received first portion, the received interfered second portion, and a propagation property of the multimode waveguide. The processor determines the property of the target based on the analysis. ## Claims ### Claim 1 A metrology system comprising: a radiation source configured to generate radiation; an optical element configured to direct the radiation toward a target to generate scattered radiation from the target; a first detector configured to receive a first portion of the scattered radiation and to generate a first detection signal based on the received first portion; an integrated optical device comprising a multimode waveguide configured to interfere a second portion of the scattered radiation using modes of the multimode waveguide; a second detector configured to receive the interfered second portion and to generate a second detection signal based on the received interfered second portion; and a processor configured to: receive the first and second detection signals; perform an analysis of the received first portion, the received interfered second portion, and a propagation property of the multimode waveguide; and determine a property of the target based on the analysis. ### Claim 2 (depends on 1) The metrology system of claim 1, wherein the processor is further configured to determine wavelength constituents of the received interfered second portion. ### Claim 3 (depends on 2) The metrology system of claim 2, wherein the determining the property of the target is further based on the determined wavelength constituents. ### Claim 4 (depends on 2) The metrology system of claim 2, wherein: the processor is configured to generate images; and each of the images respectively corresponds to each of the wavelength constituents. ### Claim 5 (depends on 1) The metrology system of claim 1, wherein the multimode waveguide comprises a semiconductor and/or dielectric material. ### Claim 6 (depends on 5) The metrology system of claim 5, wherein the semiconductor and/or dielectric material is Si-based, Ga-based, or Li-based. ### Claim 7 (depends on 5) The metrology system of claim 5, wherein the dielectric material comprises SiN and/or SiO2. ### Claim 8 (depends on 1) The metrology system of claim 1, further comprising a beam splitting element configured to receive and split the scattered radiation to generate the first and second portions. ### Claim 9 A lithographic apparatus comprising: an illumination system configured to illuminate a pattern of a patterning device; a projection system configured to project an image of the pattern onto a substrate; and a metrology system comprising: a radiation source configured to generate radiation; an optical element configured to direct the radiation toward a target on the substrate to generate scattered radiation from the target; a first detector configured to receive a first portion of the scattered radiation and to generate a first detection signal based on the received first portion; a multimode waveguiding device configured to interfere a second portion of the scattered radiation using modes of the multimode waveguiding device; a second detector configured to receive the interfered second portion and to generate a second detection signal based on the received interfered second portion; and a processor configured to: receive the first and second detection signals; perform an analysis of the received first portion, the received interfered second portion, and a propagation property of the multimode waveguiding device; and determine a property of the target based on the analysis. ### Claim 10 (depends on 9) The lithographic apparatus of claim 9, wherein the processor is further configured to determine wavelength constituents of the received interfered second portion. ### Claim 11 (depends on 10) The lithographic apparatus of claim 10, wherein the determining the property of the target is further based on the determined wavelength constituents. ### Claim 12 (depends on 10) The lithographic apparatus of claim 10, wherein: the processor is configured to generate images; and each of the images respectively corresponds to each of the wavelength constituents. ### Claim 13 (depends on 9) The lithographic apparatus of claim 9, wherein the multimode waveguiding device comprises a semiconductor and/or dielectric material. ### Claim 14 (depends on 13) The lithographic apparatus of claim 13, wherein the semiconductor and/or dielectric material is Si-based, Ga-based, or Li-based. ### Claim 15 (depends on 13) The lithographic apparatus of claim 13, wherein the dielectric material comprises SiN and/or SiO2. ### Claim 16 (depends on 9) The lithographic apparatus of claim 9, further comprising a beam splitting element configured to receive and split the scattered radiation to generate the first and second portions. ### Claim 17 (depends on 9) The lithographic apparatus of claim 9, wherein the multimode waveguiding device comprises a multimode waveguide integrated on a substrate. ### Claim 18 (depends on 9) The lithographic apparatus of claim 9, wherein the multimode waveguiding device comprises a multimode fiber. ### Claim 19 A metrology system comprising: a radiation source configured to generate radiation; an optical element configured to direct the radiation toward a target to generate scattered radiation from the target; an integrated optical device comprising a multimode waveguide configured to interfere the scattered radiation using modes of the multimode waveguide; a detector configured to receive the interfered scattered radiation and to generate a detection signal based on the received interfered scattered radiation; and a processor configured to: receive the detection signal; perform an analysis based on the received interfered scattered radiation and a propagation property of the multimode waveguide; and determine a property of the target based on the analysis. ### Claim 20 (depends on 19) The metrology system of claim 19, wherein the processor is further configured to determine wavelength constituents of the received interfered scattered radiation.