# US 2019/0244336 A1 · Defect inspection apparatus and defect inspection method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0244336 A1 - Document ID: US20190244336A1 - Status: Published application - Kind: A1 - Application number: 16/125,946 - Filed: 2018-09-10 - Published: 2019-08-08 - Earliest claimed: 2018-02-06 - Assignees: Toshiba Memory Corporation - Applicants: Toshiba Memory Corporation - Inventors: Kenji WAKISAKA; Osamu NAGANO - Web page: https://patentgrep.com/patent/US20190244336A1 ## CPC - G06T 7/001: {using an image reference approach} - G01N 21/88: Investigating the presence of flaws or contamination - G01N 21/8803: {Visual inspection (measuring projectors G01B9/08)} - G01N 21/8806: {Specially adapted optical and illumination features} - G01N 21/8851: {Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges (G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002)} - G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - G01N 21/95607: {using a comparative method} - G06T 7/0002: {Inspection of images, e.g. flaw detection} - G06T 7/0004: {Industrial image inspection} - G06T 7/0006: {using a design-rule based approach} - G06T 7/90: Determination of colour characteristics - H04N 23/56: provided with illuminating means - H10P 74/203: {Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects} - H10P 74/23: {characterised by multiple measurements, corrections, marking or sorting processes} - G01N 2021/8809: {Adjustment for highlighting flaws} - G06T 2207/10148: Varying focus - G06T 2207/10152: Varying illumination - G06T 2207/30148: Semiconductor; IC; Wafer - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract An imaging portion acquires first sample-images of a first sample under optical-conditions, the first sample having a defect, and acquires second sample-images of a second sample under optical-conditions, the second sample having no defects. An arithmetic portion calculates a first difference between a first sample-image taken under a first optical-condition and the first sample-image taken under a second optical-condition, calculates a second difference between a second sample-image taken under the first optical-condition and a second sample-image taken under the second optical-condition, and selects the first and second optical-conditions under which a difference between the first and second differences becomes largest, as a first and a second inspection-condition. The imaging portion takes images of the target to be inspected under the first and second inspection-conditions to acquire a first and second inspection-images. The arithmetic portion performs inspection based on the difference between the first and second inspection-images. ## Claims ### Claim 1 A defect inspection apparatus comprising: an illuminating portion emitting light to a pattern; an imaging portion acquiring a plurality of first sample images by taking images of the pattern in a first sample under a plurality of optical conditions, the first sample having a defect in a first area of the pattern, and acquiring a plurality of second sample images by taking images of the pattern in a second sample under a plurality of optical conditions, the second sample having no defects in the first area of the pattern; and an arithmetic portion calculating a first difference between a first sample image taken under a first optical condition and a first sample image taken under a second optical condition, among the plurality of optical conditions, calculating a second difference between a second sample image taken under the first optical condition and a second sample image taken under the second optical condition, and selecting the first and second optical conditions under which a difference between the first and second differences becomes largest, as a first and a second inspection condition, wherein the imaging portion takes images of the pattern in a target to be inspected under the first and second inspection conditions to acquire a first and a second inspection image, and the arithmetic portion determines whether there is a defect in the first area of the pattern in the target based on a difference between the first and second inspection images. ### Claim 2 (depends on 1) The defect inspection apparatus according to claim 1, wherein the arithmetic portion determines that there is no defect in the first area if the difference between the first and second inspection images is smaller than a threshold value, whereas determines that there is a defect in the first area if the difference between the first and second inspection images is equal to or larger than the threshold value. ### Claim 3 (depends on 1) The defect inspection apparatus according to claim 1, wherein the plurality of optical conditions are different from one another in any one of a wavelength of the light from the illuminating portion, polarization of the illuminating portion, an aperture of a lens provided to the illuminating portion, and an imaging plane location. ### Claim 4 (depends on 2) The defect inspection apparatus according to claim 2, wherein the plurality of optical conditions are different from one another in any one of a wavelength of the light from the illuminating portion, polarization of the illuminating portion, an aperture of a lens provided to the illuminating portion, and an imaging plane location. ### Claim 5 (depends on 1) The defect inspection apparatus according to claim 1, wherein the first and second optical conditions are different from each other in height of a stage on which the target to be inspected is placed. ### Claim 6 (depends on 2) The defect inspection apparatus according to claim 2, wherein the first and second optical conditions are different from each other in height of a stage on which the target to be inspected is placed. ### Claim 7 (depends on 1) The defect inspection apparatus according to claim 1, wherein the first and second differences are calculated based on a brightness difference between the first and second sample images. ### Claim 8 (depends on 2) The defect inspection apparatus according to claim 2, wherein the first and second differences are calculated based on a brightness difference between the first and second sample images. ### Claim 9 A defect inspection method using a defect inspection apparatus comprising an illuminating portion emitting light to a pattern, an imaging portion taking an image of the pattern, and an arithmetic portion inspecting a defect of the pattern, comprising: acquiring a plurality of first sample images by taking images of the pattern in a first sample under a plurality of optical conditions, the first sample having a defect in a first area of the pattern; acquiring a plurality of second sample images by taking images of the pattern in a second sample under a plurality of optical conditions, the second sample having no defects in the first area of the pattern; calculating a first difference between a first sample image taken under a first optical condition and a first sample image taken under a second optical condition, among the plurality of optical conditions; calculating a second difference between a second sample image taken under the first optical condition and a second sample image taken under the second optical condition; selecting the first and second optical conditions under which a difference between the first and second differences becomes largest, as a first and a second inspection condition; taking images of a location of the target to be inspected under the first and second inspection conditions to acquire a first and a second inspection image, and determining whether there is a defect in the first area of the pattern in the target based on a difference between the first and second inspection images. ### Claim 10 (depends on 9) The defect inspection method according to claim 9, wherein the arithmetic portion determines that there is no defect in the first area if the difference between the first and second inspection images is smaller than a threshold value, whereas determines that there is a defect in the first area if the difference between the first and second inspection images is equal to or larger than the threshold value. ### Claim 11 (depends on 9) The defect inspection apparatus according to claim 9, wherein the plurality of optical conditions are different from one another in any one of a wavelength of the light from the illuminating portion, polarization of the illuminating portion, an aperture of a lens provided to the illuminating portion, and an imaging plane location. ### Claim 12 (depends on 10) The defect inspection method according to claim 10, wherein the plurality of optical conditions are different from one another in any one of a wavelength of the light from the illuminating portion, polarization of the illuminating portion, an aperture of a lens provided to the illuminating portion, and an imaging plane location. ### Claim 13 (depends on 9) The defect inspection method according to claim 9, wherein the first and second optical conditions are different from each other in height of a stage on which the target to be inspected is placed. ### Claim 14 (depends on 10) The defect inspection method according to claim 10, wherein the first and second optical conditions are different from each other in height of a stage on which the target to be inspected is placed. ### Claim 15 (depends on 11) The defect inspection method according to claim 11, wherein the first and second optical conditions are different from each other in height of a stage on which the target to be inspected is placed. ### Claim 16 A semiconductor device manufacturing method using a defect inspection apparatus comprising an illuminating portion emitting light to a pattern formed with a mask on a semiconductor substrate, an imaging portion taking an image of the pattern, and an arithmetic portion inspecting a defect of the pattern, comprising: acquiring a plurality of first sample images by taking images of the pattern in a first sample under a plurality of optical conditions, the first sample having a defect in a first area of the pattern; acquiring a plurality of second sample images by taking images of the pattern in a second sample under a plurality of optical conditions, the second sample having no defects in the first area of the pattern; calculating a first difference between a first sample image taken under a first optical condition and a first sample image taken under a second optical condition, among the plurality of optical conditions; calculating a second difference between a second sample image taken under the first optical condition and a second sample image taken under the second optical condition; selecting the first and second optical conditions under which a difference between the first and second differences becomes largest, as a first and a second inspection condition; taking images of a location of the target to be inspected under the first and second inspection conditions to acquire a first and a second inspection image, and determining whether there is a defect in the first area of the pattern in the target based on a difference between the first and second inspection images.