Method of recognizing wafer
First Claim
1. A method, comprising:
- obtaining image information including a first vector and a second vector by respectively capturing an image of a first wafer and an image of a second, wherein the first wafer is known to be a good product, wherein the second wafer is known to be a defective product;
calculating a projection vector based on a covariance matrix associated with the first vector and the second vector;
obtaining image information including a third vector by capturing an image of a third wafer under a test;
projecting each of the first vector, the second vector and the third vector onto the projection vector; and
classifying the third wafer as either the good product or the defective product based on the projected first vector, the projected second vector and the projected third vector.
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Abstract
A method includes obtaining image information including a first vector by capturing an image of a first wafer, wherein the first wafer is known to be a good product; obtaining image information including a second vector by capturing an image of a second wafer, wherein the second wafer is known to be a defective product; calculating a projection vector based on a covariance matrix associated with the first vector and the second vector; obtaining image information including a third vector by capturing an image of a third wafer under a test; projecting each of the first vector, the second vector and the third vector onto the projection vector; and classifying the third wafer as either the good product or the defective product based on the projected first vector, the projected second vector and the projected third vector.
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Citations
19 Claims
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1. A method, comprising:
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obtaining image information including a first vector and a second vector by respectively capturing an image of a first wafer and an image of a second, wherein the first wafer is known to be a good product, wherein the second wafer is known to be a defective product; calculating a projection vector based on a covariance matrix associated with the first vector and the second vector; obtaining image information including a third vector by capturing an image of a third wafer under a test; projecting each of the first vector, the second vector and the third vector onto the projection vector; and classifying the third wafer as either the good product or the defective product based on the projected first vector, the projected second vector and the projected third vector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method, comprising:
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obtaining image information including a first vector by capturing an image of a first wafer, wherein the first wafer is known to be a good product; obtaining image information including a second vector by capturing an image of a second wafer, wherein the second wafer is known to be a defect product; calculating a covariance matrix based on the first vector and the second vector; calculating a first eigenvalue and a second eigenvalue based on the covariance matrix; comparing the first eigenvalue and the second eigenvalue; calculating an eigenvector based on the first eigenvalue, instead of on both the first eigenvalue and the second eigenvalue when the first eigenvalue is greater than the second eigenvalue; obtaining a projection vector based on the eigenvector; projecting each of the first vector, the second vector and the third vector onto the projection vector; and classifying the third wafer as either the good product or the defective product based on the projected first vector, the projected second vector and the projected third vector. - View Dependent Claims (11, 12, 13, 14)
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15. An apparatus, comprising:
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an image capturing device configured to capture an image of a first wafer, an image of a second wafer and an image of a third wafer, wherein the first wafer is known to be a good product, the second wafer is known to be a defective product, and the third wafer is under a test; and a processing device configured to; obtain image information including a first vector and a second vector respectively based on the image of the first wafer and the image of the second wafer; obtain image information including a third vector based on the image of the third wafer; calculate a projection vector based on a covariance matrix associated with the first vector and the second vector; project each of the first vector, the second vector and the third vector onto the projection vector; and classify the third wafer as either the good product or the defective product based on the projected first vector, the projected second vector and the projected third vector. - View Dependent Claims (16, 17, 18, 19)
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Specification