Claims
- 1. A method of inspecting a patterned substrate, comprising:a) obtaining a first image of a first portion of said substrate; b) obtaining a second image of a second portion of said substrate; c) converting said first image and said second image into a frequency domain; d) aligning said first image with said second image in said frequency domain; e) converting said first image and said second image to a spatial domain; and f) comparing said first image to said second image in said spatial domain.
- 2. The method of claim 1, wherein said first and second images are compared in said spatial domain to determine whether defects are present in said substrate.
- 3. The method of claim 1, wherein said conversion of said first and second images into said frequency domain is performed by use of a mathematical operation.
- 4. The method of claim 3, wherein said mathematical operation is a sinusoidal transform.
- 5. The method of claim 3, wherein said first image and said second image are each divided into a plurality of sub-images, and said mathematical operation is performed independently and simultaneously on each of said sub-images.
- 6. A method of inspecting a patterned substrate, comprising:a) obtaining a first image of a first portion of said substrate; b) obtaining a second image of a second portion of said substrate; c) mathematically converting at least one of said first image and said second image into a frequency domain; d) analyzing said converted image to detect repeating elements within said pattern; and e) comparing said first image to said second image in a spatial domain.
- 7. The method of claim 6, wherein said first and second images are compared in said spatial domain to determine whether defects are present in said substrate.
- 8. The method of claim 7, wherein said mathematical conversion comprises a sinusoidal transform.
- 9. The method of claim 7, wherein at least one of said first image and said second image is divided into a plurality of sub-images, and said mathematical operation is performed independently and simultaneously on each of said sub-images.
Parent Case Info
This is a continuation of application Ser. No. 08/524,608, filed on Sep. 7, 1995, now U.S. Pat. No. 6,021,214, which is a divisional of application Ser. No. 08/129,341, filed on Sep. 30, 1993, now U.S. Pat. No. 5,537,669.
US Referenced Citations (2)
Number |
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Date |
Kind |
5537669 |
Evans et al. |
Jul 1996 |
A |
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Continuations (1)
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Number |
Date |
Country |
Parent |
08/524608 |
Sep 1995 |
US |
Child |
09/496013 |
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US |