# US 2017/0255104 A1 · Metrology Apparatus, Method of Measuring a Structure 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 2017/0255104 A1 - Document ID: US20170255104A1 - Status: Published application - Kind: A1 - Application number: 15/444,765 - Filed: 2017-02-28 - Published: 2017-09-07 - Earliest claimed: 2016-03-01 - Assignees: ASML Netherlands B.V. - Applicants: ASML Netherlands B.V. - Inventors: Alessandro POLO; Simon Gijsbert Josephus Mathijssen - Web page: https://patentgrep.com/patent/US20170255104A1 ## CPC - G03F 9/7046: {Strategy, e.g. mark, sensor or wavelength selection} - G01B 11/00: Measuring arrangements characterised by the use of optical techniques - G01B 11/02: for measuring length, width or thickness (G01B11/08 takes precedence) - G01B 11/24: for measuring contours or curvatures - G01B 11/272: {using photoelectric detection means} - G01B 11/303: {using photoelectric detection means} - G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - 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 7/70625: {Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness} - 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 7/70775: {Position control, e.g. interferometers or encoders for determining the stage position} - 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 9/7069: {Alignment mark illumination, e.g. darkfield, dual focus} - G03F 9/7088: {Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection} - G01B 2210/56: Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth - G02B 2207/129: Coded aperture imaging - 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) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - 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) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Disclosed is a metrology apparatus and method for measuring a structure formed on a substrate by a lithographic process. The metrology apparatus comprises an illumination system operable to provide measurement radiation comprising a plurality of wavelengths; and a hyperspectral imager operable to obtain a hyperspectral representation of a measurement scene comprising the structure, or a part thereof, from scattered measurement radiation subsequent to the measurement radiation being scattered by the structure. ## Claims ### Claim at position 1 1-26. (canceled) ### Claim 27 A metrology apparatus for measuring a structure formed on a substrate by a lithographic process, said metrology apparatus comprising: an illumination system operable to provide measurement radiation comprising a plurality of wavelengths; and a hyperspectral imager operable to obtain a hyperspectral representation of a measurement scene comprising the structure, or a part thereof, from scattered measurement radiation subsequent to said measurement radiation being scattered by said structure. ### Claim 28 (depends on 27) The metrology apparatus of claim 27, wherein said hyperspectral representation comprises a three-dimensional data cube having two spatial dimensions and one spectral dimension. ### Claim 29 (depends on 28) The metrology apparatus of claim 28, wherein the hyperspectral imager is a compressive sensing hyperspectral imager operable to directly acquire an optically compressed representation of said three-dimensional data cube. ### Claim 30 (depends on 28) The metrology apparatus of claim 28, wherein the hyperspectral imager is a snapshot hyperspectral imager operable to capture the three-dimensional data cube without scanning. ### Claim 31 (depends on 30) The metrology apparatus of claim 30, wherein the hyperspectral imager is a coded aperture snapshot spectral imager comprising a coded aperture element and at least one wavelength dispersive element, being operable to capture a two-dimensional coded spatio-spectral projection of the three-dimensional data cube. ### Claim 32 (depends on 31) The metrology apparatus of claim 31 wherein the coded aperture element is operable to modulate spatial information of the measurement scene over all wavelengths comprised within the three-dimensional data cube with a coded pattern to obtain a coded signal; and said wavelength dispersive element is operable to disperse this coded signal spatially as a function of wavelength to obtain said two-dimensional coded spatio-spectral projection. ### Claim 33 (depends on 31) The metrology apparatus of claim 31, comprising a processing unit operable to perform a sparse reconstruction method to estimate the three-dimensional data cube from the two-dimensional coded spatio-spectral projection and knowledge of the encoding of the coded aperture element. ### Claim 34 (depends on 33) The metrology apparatus of claim 33, wherein said sparse reconstruction method aims to find an estimate of the three-dimensional data cube having a sparse representation. ### Claim 35 (depends on 31) The metrology apparatus of claim 31, wherein the coded aperture snapshot spectral imager is a singer disperser coded aperture snapshot spectral imager comprising only a single wavelength dispersive element. ### Claim 36 (depends on 31) The metrology apparatus of claim 31, wherein the wavelength dispersive element comprises a prism. ### Claim 37 (depends on 31) The metrology apparatus of claim 31, wherein the coded aperture element comprises a binary glass mask, programmable micromirror array or a liquid crystal on Silicon Spatial light modulator. ### Claim 38 (depends on 27) The metrology apparatus of claim 27, wherein the hyperspectral imager comprises a sensor for sensing said hyperspectral representation of a measurement scene. ### Claim 39 (depends on 27) The metrology apparatus of claim 27, wherein said illumination system is configured such that said measurement radiation comprises a continuous spectrum. ### Claim 40 (depends on 27) The metrology apparatus of claim 27, wherein said illumination system is configured such that said measurement radiation comprises a plurality of discrete wavelengths. ### Claim 41 (depends on 27) The metrology apparatus of claim 27, operable to measure overlay from the hyperspectral representation of the structure, said structure comprising a metrology target for the measurement of overlay. ### Claim 42 An alignment sensor comprising a metrology apparatus for measuring an alignment structure formed on a substrate by a lithographic process, said metrology apparatus comprising: an illumination system operable to provide measurement radiation comprising a plurality of wavelengths; and a hyperspectral imager operable to obtain a hyperspectral representation of a measurement scene comprising the structure, or a part thereof, from scattered measurement radiation subsequent to said measurement radiation being scattered by said structure. ### Claim 43 A method of measuring a structure formed on a substrate by a lithographic process comprising: illuminating the structure with measurement radiation comprising a plurality of wavelengths, such that the measurement radiation is scattered by the structure; spatially modulating the scattered measurement radiation with a coded pattern to obtain coded measurement radiation; spectrally dispersing the coded measurement radiation to obtain a two-dimensional coded spatio-spectral projection; sensing the two-dimensional coded spatio-spectral projection; and estimating a hyperspectral representation of the structure from the two-dimensional coded spatio-spectral projection and knowledge of the coded pattern. ### Claim 44 (depends on 43) The method of claim 43, wherein said two-dimensional coded spatio-spectral projection is sensed during a single or few snapshot(s). ### Claim 45 (depends on 43) The method of claim 43, wherein said hyperspectral representation comprises a three-dimensional data cube having two spatial dimensions and one spectral dimension. ### Claim 46 The lithography apparatus, arranged to transfer a pattern from a patterning device onto a substrate, comprising an alignment sensor with a metrology apparatus for measuring an alignment structure formed on the substrate, said metrology apparatus comprising: an illumination system operable to provide measurement radiation comprising a plurality of wavelengths; and a hyperspectral imager operable to obtain a hyperspectral representation of a measurement scene comprising the structure, or a part thereof, from scattered measurement radiation subsequent to said measurement radiation being scattered by said structure.