# US 11,307,507 B2 · Method to obtain a height map of a substrate having alignment marks, substrate alignment measuring apparatus 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 11,307,507 B2 - Document ID: US11307507B2 - Status: Granted - Kind: B2 - Application number: 16/630,668 - Filed: 2018-06-05 - Published: 2021-04-22 - Granted: 2022-04-19 - Earliest claimed: 2017-07-14 - Assignees: ASML Netherlands B.V. - Applicants: ASML Netherlands B.V. - Inventors: Bram Van Hoof; Arjan Hölscher; Alex Pascal Ten Brink; Petrus Franciscus Van Gils - Web page: https://patentgrep.com/patent/US11307507B2 ## CPC - G03F 9/7034: {Leveling} - G03F 7/70625: {Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness} - G03F 7/70683: {Mark designs} - 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 The present invention provides a method to obtain a height map of a substrate having alignment marks, the method comprising the steps: determining a height of one or more locations or areas of the substrate, and determining the height map of the substrate on the basis of the determined height of the one or more locations or areas of the substrate and a shape model of the substrate. ## Claims ### Claim 1 A method to obtain a height map of a substrate having alignment marks, the method comprising the steps of: determining a height of one or more locations or areas of the substrate; and determining the height map of the substrate based on the determined height of the one or more locations or areas of the substrate and a shape model of the substrate; wherein the shape model of the substrate is determined based on at least a single scan height map of the substrate by a level sensor, a low resolution height map of the substrate, and height measurements by a substrate stage position measurement system. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the height of the one or more locations or areas of the substrate comprises: measuring positions of one or more alignment marks at different tilted and/or offset positions of the substrate; and determining a height of the one or more alignment marks on the basis of the measured positions of the one or more alignment marks. ### Claim 3 (depends on 2) The method of claim 2, wherein the determining a height of the one or more alignment marks comprises determining differences in the measured positions of the one or more alignment marks between the different tilted and/or offset positions of the substrate, and calculating the height of the one or more alignment marks on the basis of the differences in the measured positions of the one or more alignment marks. ### Claim 4 (depends on 3) The method of claim 3, wherein the calculating the height of the one or more alignment marks on the basis of the differences in the measured positions of the one or more alignment marks is based on a calibration between the differences in the measured positions of the one or more alignment marks and the height of the one or more alignment marks. ### Claim 5 (depends on 3) The method of claim 3, wherein the method further comprises the step of calibrating a relationship between the differences in the measured positions of the one or more alignment marks and the associated height of the one or more alignment marks. ### Claim 6 (depends on 1) The method of claim 1, wherein the determining the height map of the substrate using the shape model comprises using a shape model of the substrate comprising a higher order fit extrapolation of the measured height of the one or more areas of a part of the substrate, in combination with an edge roll off profile and/or a mean intrafield pattern. ### Claim 7 (depends on 1) A method to measure positions of multiple alignment marks on a substrate, comprising: in a first station, obtaining a height map of a substrate having alignment marks using the method of claim 1; and in a second station, adapting a height and/or tilt position of the substrate on the basis of the height map. ### Claim 8 (depends on 7) The method of claim 7, further comprising a step of determining positions of the multiple alignment marks in the second station and adapting the height and/or tilt position of the substrate for each alignment mark. ### Claim 9 (depends on 8) The method of claim 8, wherein the one or more alignment marks are X alignment marks, wherein the multiple alignment marks are Y alignment marks, and wherein Y>X. ### Claim 10 (depends on 1) A method to project a patterned radiation beam on multiple target portions of a substrate, comprising: in a first station, obtaining a height map of a substrate having alignment marks using the method of claim 1; and in a second station, projecting successively a patterned radiation beam on multiple target portions of the substrate, comprising adapting, for each target portion, a height and/or tilt position of the substrate on the basis of the height map. ### Claim 11 An alignment measuring apparatus to measure positions of multiple alignment marks on a substrate, comprising: a first station, comprising a first alignment sensor system to measure positions of one or more alignment marks at different tilted and/or offset positions of the substrate; and a processing unit to determine a height of the one or more alignment marks on the basis of the measured positions of the one or more alignment marks, and to determine the height map of the substrate on the basis of the determined height of the one or more alignment marks and a shape model of the substrate; wherein the shape model of the substrate is determined on the basis of a single scan height map of the substrate by a level sensor and/or a low resolution height map of the substrate. ### Claim 12 (depends on 11) The alignment measuring apparatus according to claim 11, further comprising: a second station, comprising a second alignment sensor system to measure positions of at least one of the multiple alignment marks, wherein the alignment measuring apparatus is arranged to adapt, in the second station, for each measurement of an alignment mark, a height and/or tilt position of the substrate on the basis of the height map provided by the processing unit. ### Claim 13 (depends on 11) A lithographic system, comprising: the alignment measuring apparatus of claim 11; and a lithographic apparatus comprising a projection system to project successively a patterned radiation beam on multiple target portions of the substrate, wherein the lithographic apparatus is arranged to adapt, in a second station, for each target portion, a height and/or tilt position of the substrate on the basis of the height map provided by the processing unit. ### Claim 14 A lithographic apparatus, comprising: a first station, comprising an alignment sensor system to measure positions of one or more alignment marks at different tilted and/or offset positions of the substrate; a processing unit to determine a height of the one or more alignment marks on the basis of the measured positions of the one or more alignment marks, and to determine the height map of the substrate on the basis of the determined height of the one or more alignment marks and a shape model of the substrate; and a second station, comprising a projection system to project successively a patterned radiation beam on multiple target portions of the substrate, wherein the lithographic apparatus is arranged to adapt, in the second station, for each target portion, a height and/or tilt position of the substrate on the basis of the height map provided by the processing unit.