Systems and methods for region-adaptive defect detection
First Claim
Patent Images
1. A defect detection method comprising:
- acquiring a reference image;
selecting a target region of the reference image;
identifying, based on a matching metric, one or more comparative regions of the reference image corresponding to the target region;
acquiring a test image;
masking the test image with the target region of the reference image and the one or more comparative regions of the reference image to generate a masked test image;
defining a defect threshold based on a pixel value distribution including pixel values for pixels within the one or more comparative regions of the test image; and
determining whether the test image contains a defect by comparing a distribution of pixel values in the masked test image to the defect threshold.
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Abstract
A defect detection method includes acquiring a reference image; selecting a target region of the reference image; identifying, based on a matching metric, one or more comparative regions of the reference image corresponding to the target region; acquiring a test image; masking the test image with the target region of the reference image and the one or more comparative regions of the reference image; defining a defect threshold for the target region in the test image based on the one or more comparative regions in the test image; and determining whether the target region of the test image contains a defect based on the defect threshold.
23 Citations
54 Claims
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1. A defect detection method comprising:
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acquiring a reference image; selecting a target region of the reference image; identifying, based on a matching metric, one or more comparative regions of the reference image corresponding to the target region; acquiring a test image; masking the test image with the target region of the reference image and the one or more comparative regions of the reference image to generate a masked test image; defining a defect threshold based on a pixel value distribution including pixel values for pixels within the one or more comparative regions of the test image; and determining whether the test image contains a defect by comparing a distribution of pixel values in the masked test image to the defect threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A defect detection system comprising:
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an inspection sub-system comprising; an illumination source configured to generate a beam of illumination; a set of illumination optics to direct the beam of illumination to a sample; and a detector configured to collect illumination emanating from the sample; and a controller communicatively coupled to the detector, the controller including a memory device and one or more processors configured to execute program instructions configured to cause the one or more processors to; acquire a reference image; select a target region of the reference image; identify, based on a matching metric, one or more comparative regions of the reference image corresponding to the target region; acquire a test image; mask the test image with the target region of the reference image and the one or more comparative regions of the reference image to generate a masked test image; define a defect threshold based on a pixel value distribution including pixel values for pixels within the one or more comparative regions of the test image; and determine whether the test image contains a defect by comparing a distribution of pixel values in the masked test image to the defect threshold. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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53. A defect detection system comprising:
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an inspection sub-system comprising; an illumination source configured to generate a beam of illumination; a set of illumination optics to direct the beam of illumination to a sample; and a detector configured to collect illumination emanating from the sample; and a controller communicatively coupled to the detector, the controller including a memory device and one or more processors configured to execute program instructions configured to cause the one or more processors to; acquire a reference image; select a target pixel of the reference image; define a vicinity pattern including a defined layout of pixels; define a target vicinity in the reference image arranged according to the vicinity pattern, wherein the target vicinity includes the target pixel; identify, based on a matching metric, one or more comparative vicinities of the reference image corresponding to a target region, wherein the matching metric includes a pixel value distribution of the target vicinity; acquire a test image; mask the test image with the target region of the reference image and the one or more comparative vicinities of the reference image; calculate one or more pixel value distributions of the one or more comparative vicinities of the test image; estimate a pixel value distribution in the target vicinity of the test image based on the pixel value distributions of the one or more comparative vicinities of the test image; defining a defect threshold for the target pixel based on the estimated pixel value distribution in the target vicinity; and determine whether the target pixel of the test image contains a defect based on the defect threshold.
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54. A defect detection method comprising:
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acquiring a reference image; selecting a target region of the reference image; identifying, based on a matching metric, one or more comparative regions of the reference image corresponding to the target region; acquiring a test image; masking the test image with the target region of the reference image and the one or more comparative regions of the reference to generate a masked test image; determining a pixel value distribution including pixel values for pixels within the target region and one or more comparative regions in the test image; defining a defect threshold to identify outliers associated with a tail of the pixel value distribution; and determining whether the test image contains a defect by comparing a distribution of pixel values in the masked test image to the defect threshold.
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Specification