# US 2021/0241449 A1 · Metrology data correction using image quality metric > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0241449 A1 - Document ID: US20210241449A1 - Status: Published application - Kind: A1 - Application number: 17/268,863 - Filed: 2019-08-14 - Published: 2021-08-05 - Earliest claimed: 2018-08-17 - Assignees: ASML Netherlands B.V. - Applicants: Asml Netherlands B.V. - Inventors: Fuming WANG; Stefan HUNSCHE; Wei FANG - Web page: https://patentgrep.com/patent/US20210241449A1 ## CPC - G03F 7/7065: {Defects, e.g. optical inspection of patterned layer for defects} - G03F 7/70616: {Monitoring the printed patterns} - 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 7/70641: {Focus} - G06F 18/214: Generating training patterns; Bootstrap methods, e.g. bagging or boosting - G06T 7/0004: {Industrial image inspection} - G06T 7/73: using feature-based methods - G06T 2207/10061: from scanning electron microscope - G06T 2207/20081: Training; Learning - G06T 2207/30148: Semiconductor; IC; Wafer - G06T 2207/30168: Image quality inspection - H01J 37/28: with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} - 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) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A method for correcting metrology data of a patterning process. The method includes obtaining (i) metrology data of a substrate subjected to the patterning process and (ii) a quality metric (e.g., a focus index) that quantifies a quality of the metrology data of the substrate; establishing a correlation between the quality metric and the metrology data; and determining a correction to the metrology data based on the correlation between the quality metric and the metrology data. ## Claims ### Claim 1 A method for correcting metrology data of a patterning process, the method comprising: obtaining (i) metrology data of a substrate subjected to the patterning process and (ii) an image quality metric that quantifies a quality of the metrology data of the substrate; establishing, via a hardware computing system, a correlation between the image quality metric and the metrology data; and determining, via the computing system, a correction to the metrology data based on the correlation between the image quality metric and the metrology data. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the correction comprises determining a corrected value of the metrology data based on a correction model, wherein the metrology data is obtained via a metrology tool. ### Claim 3 (depends on 2) The method of claim 2, wherein the corrected value is determined based on a slope of the correlation between the image quality metric and the metrology data, and a difference between a maximum value of the image quality metric across the substrate and a value of the image quality metric at a point of interest on the substrate. ### Claim 4 (depends on 1) The method of claim 1, wherein the image quality metric is a focus index of an image of the substrate captured via the metrology tool. ### Claim 5 (depends on 4) The method of claim 4, wherein the focus index is determined based on a local phase coherence map that reveals a phase relationship, in a vicinity of a feature location on the substrate, between neighbouring wavelet coefficients in a scale-space. ### Claim 6 (depends on 4) The method of claim 4, wherein the focus index is determined based on a sample selected from the image that has a relatively higher gradient compared to other locations on the image. ### Claim 7 (depends on 6) The method of claim 6, wherein the sample is an area of the image that has a relatively high gradient compared to remaining areas of the image. ### Claim 8 (depends on 1) The method of claim 1, wherein the image quality metric is independent of variations in a dose used in the patterning process. ### Claim 9 (depends on 1) The method of claim 1, wherein the metrology data comprises an image of a printed substrate, or a parameter of the patterning process. ### Claim 10 (depends on 1) The method of claim 1, wherein the metrology data comprises a parameter of the patterning process and the parameter of the patterning process is a critical dimension, an edge placement error, or an overlay. ### Claim 11 (depends on 1) The method of claim 1, further comprising generating a map of a parameter of the patterning process based on the correction applied to the metrology data. ### Claim 12 (depends on 11) The method of claim 11, wherein the map is a dose map, a focus map, a critical dimension (CD) map, an overlay map, or an edge placement error map. ### Claim 13 (depends on 1) The method of claim 1, wherein the metrology data is a scanning electron microscope image, or an e-beam image. ### Claim 14 (depends on 1) The method of claim 1, further comprising training a correction model based on the correlation between the image quality metric and the metrology data, wherein the correction model is configured to determine real-time corrections to metrology data collected during the patterning process. ### Claim 15 A computer program product comprising a non-transitory computer readable medium having instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least: obtain (i) metrology data of a substrate subjected to a patterning process and (ii) an image quality metric that quantifies a quality of the metrology data of the substrate; establish a correlation between the image quality metric and the metrology data; and determine a correction to the metrology data based on the correlation between the image quality metric and the metrology data. ### Claim 16 (depends on 15) The computer program product of claim 15, wherein the instructions configured to cause the computer system to determine the correction are further configured to cause the computer system to determine the correction based on a slope of the correlation between the image quality metric and the metrology data, and a difference between a maximum value of the image quality metric across the substrate and a value of the image quality metric at a point of interest on the substrate. ### Claim 17 (depends on 15) The computer program product of claim 15, wherein the image quality metric is a focus index of an image of the substrate captured via the metrology tool. ### Claim 18 (depends on 15) The computer program product of claim 15, wherein the image quality metric is independent of variations in a dose used in the patterning process. ### Claim 19 (depends on 15) The computer program product of claim 15, wherein the instructions are further configured to cause the computer system to generate a map of a parameter of the patterning process based on the correction applied to the metrology data. ### Claim 20 (depends on 15) The computer program product of claim 15, wherein the instructions are further configured to cause the computer system to train a correction model based on the correlation between the image quality metric and the metrology data, wherein the correction model is configured to determine real-time corrections to metrology data collected during the patterning process.