# US 12,191,112 B2 · System and method for defect inspection using voltage contrast in a charged particle system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,112 B2 - Document ID: US12191112B2 - Status: Granted - Kind: B2 - Application number: 17/786,190 - Filed: 2020-12-17 - Published: 2023-01-19 - Granted: 2025-01-07 - Earliest claimed: 2019-12-19 - Assignees: ASML Netherlands B.V. - Applicants: Asml Netherlands B.V. - Inventors: Wei Fang; Zhengwei Zhou; Lingling Pu - Web page: https://patentgrep.com/patent/US12191112B2 ## CPC - H01J 37/26: Electron or ion microscopes; Electron or ion diffraction tubes - H01J 37/28: with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} - H01J 37/02: Details - H01J 37/243: {Beam current control or regulation circuits (H01J37/241 takes precedence)} - H01J 37/244: Detectors; Associated components or circuits therefor - H01J 37/263: {Contrast, resolution or power of penetration} - H01J 37/265: {Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination} - H01J 37/3177: {Multi-beam, e.g. fly's eye, comb probe} - H01J 2237/0435: Multi-aperture - H01J 2237/2817: Pattern inspection - H01J 2237/31774: Multi-beam - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A system and method for defect inspection using voltage contrast in a charged particle system are provided. Some embodiments of the system and method include positioning the stage at a first position to enable a first beam of the plurality of beams to scan a first surface area of the wafer at a first time to generate a first image associated with the first surface area; positioning the stage at a second position to enable a second beam of the plurality of beams to scan the first surface area at a second time to generate a second image associated with the first surface area; and comparing the first image with the second image to enable detecting whether a defect is identified in the first surface area of the wafer. ## Claims ### Claim 1 A charged particle multi-beam system for generating a plurality of beams for inspecting a wafer positioned on a stage, the system comprising: a controller including circuitry configured to: position the stage at a first position to enable a first beam of the plurality of beams to scan a first surface area of the wafer at a first time to generate a first image associated with the first surface area; position the stage at a second position to enable a second beam of the plurality of beams to scan the first surface area at a second time to generate a second image associated with the first surface area; and compare the first image with the second image to enable detecting whether a defect is identified in the first surface area of the wafer. ### Claim 2 (depends on 1) The system of claim 1, wherein the wafer comprises a plurality of surface areas. ### Claim 3 (depends on 1) The system of claim 1, wherein the first and second images indicate voltage contrast levels. ### Claim 4 (depends on 3) The system of claim 3, wherein the controller includes circuitry to detect differences between the voltage contrast levels of the first and second images. ### Claim 5 (depends on 1) The system of claim 1, wherein the controller includes circuitry to adjust a time interval between the first and second times. ### Claim 6 (depends on 5) The system of claim 5, wherein adjusting the time interval between the first and second times comprises adjusting a speed of the stage. ### Claim 7 (depends on 1) The system of claim 1, further comprising: a detector, communicatively coupled to the controller, configured to produce detection data based on a detection of a plurality of secondary charged particles associated with the first and second beams impacting the first surface area. ### Claim 8 (depends on 1) The system of claim 1, wherein: the controller includes circuitry configured to: position the stage at a third position to enable a third beam of the plurality of beams to scan the first surface area at a third time to generate a third image associated with the first surface area; and compare the third image to the first image or the second image to enable detecting whether a defect is identified in the first surface area of the wafer. ### Claim 9 (depends on 8) The system of claim 8, wherein the controller includes circuitry to adjust a time interval between each of the first, second, and third times. ### Claim 10 (depends on 9) The system of claim 9, wherein adjusting the time interval between each of the first, second, and third times comprises adjusting a speed of the stage. ### Claim 11 (depends on 8) The system of claim 8, wherein the third image indicates voltage contrast levels. ### Claim 12 (depends on 11) The system of claim 11, wherein the controller includes circuitry configured to detect differences between the voltage contrast levels of the first, second, and third images. ### Claim 13 (depends on 7) The system of claim 7, wherein: the detector is configured to produce detection data based on a detection of a plurality of secondary charged particles associated with the first, second, and third beams impacting the first surface area. ### Claim 14 (depends on 8) The system of claim 8, wherein the first, second, and third beams are low-current beams. ### Claim 15 A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method for generating a plurality of beams for inspecting a wafer positioned on a stage, the method comprising: positioning the stage at a first position to enable a first beam of the plurality of beams to scan a first surface area of the wafer at a first time to generate a first image associated with the first surface area; positioning the stage at a second position to enable a second beam of the plurality of beams to scan the first surface area at a second time to generate a second image associated with the first surface area; and comparing the first image with the second image to enable detecting whether a defect is identified in the first surface area of the wafer.