Detection of defects on wafer during semiconductor fabrication

Patent metadata

Field	Value
Publication number	US-9466101-B2
Application number	US-201313951243-A
Country	US
Kind code	B2
Filing date	Jul 25, 2013
Priority date	May 1, 2013
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

Among other things, systems and techniques are provided for detecting defects on a wafer based upon non-correctable error data yielded from a scan of the wafer to determine a topology of the wafer. The non-correctable error data is reconstructed to generate a non-correctable error image map, which is transformed to generate a projection. In some embodiments, the non-correctable error image map is transformed via a feature extraction transform such as a Hough transform or a Radon transform. In some embodiments, the projection is compared to a set of rules to identify a signature in the non-correctable error image map indicative of a defect.

First claim

What is claimed is:

1. A method for detecting defects on a wafer, comprising:
scanning a wafer to acquire a non-correctable error image map indicative of non-correctable errors on the wafer, wherein a pixel of the non-correctable error image map indicates a presence and a magnitude of a non-correctable error at a location on the wafer represented by the pixel, wherein the magnitude of the non-correctable error corresponds to a difference between a height of the wafer at the location and an expected height of the wafer at the location;
applying an image transform to the non-correctable error image map to generate a projection; and
reviewing the projection based upon a set of rules to identify a signature in the non-correctable error image map that corresponds to a defect on the wafer.

2. The method of claim 1 , comprising:
reducing a fingerprint, in the non-correctable error image map, of a tool used during a fabrication process.

3. The method of claim 2 , the tool comprising at least one of a mask or a chuck used during a photolithographic process.

4. The method of claim 1 , comprising:
applying a sigma filter to the non-correctable error image map to reduce noise in the non-correctable error image map.

5. The method of claim 1 , the image transform comprising a Hough transform.

6. The method of claim 1 , the image transform comprising a Radon transform.

7. The method of claim 1 , comprising:
applying a second image transform to the non-correctable error image map to generate a second projection.

8. The method of claim 7 , the image transform comprising a Hough transform and the second image transform comprising a Radon transform.

9. The method of claim 7 , the reviewing comprising:
reviewing the projection and the second projection based upon the set of rules to identify the signature.

10. The method of claim 1 , the image transform comprising a feature extraction transform.

11. The method of claim 1 , the defect comprising at least one of a coating defect, column defocus, or a scratch defect.

12. A non-transitory computer readable medium comprising processor executable instructions that when executed perform a method for detecting defects on a wafer, the method comprising:
scanning a wafer to acquire a non-correctable error image map indicative of non-correctable errors on the wafer, wherein a pixel of the non-correctable error image map indicates a presence and a magnitude of a non-correctable error at a location on the wafer represented by the pixel, wherein the magnitude of the non-correctable error corresponds to a difference between a height of the wafer at the location and an expected height of the wafer at the location;
applying an image transform to the non-correctable error image map to generate a projection, the image transform comprising a feature extraction transform; and
reviewing the projection based upon a set of rules to identify a signature in the non-correctable error image map that corresponds to a defect on the wafer.

13. The non-transitory computer readable medium of claim 12 , the method comprising:
reducing noise in the non-correctable error image map introduced by a tool used during a photolithographic process.

14. The non-transitory computer readable medium of claim 12 , the method comprising:
applying a sigma filter to the non-correctable error image map to reduce noise in the non-correctable error image map.

15. The non-transitory computer readable medium of claim 12 , the image transform comprising a Hough transform.

16. The non-transitory computer readable medium of claim 12 , the image transform comprising a Radon transform.

17. The non-transitory computer readable medium of claim 12 , the method comprising:
applying a second image transform to the non-correctable error image map to generate a second projection, and the reviewing comprising:
reviewing the projection and the second projection based upon the set of rules to identify the signature.

18. The non-transitory computer readable medium of claim 17 , the image transform comprising a Hough transform and the second image transform comprising a Radon transform.

19. The non-transitory computer readable medium of claim 12 , the signature corresponding to a substantially linear line having a magnitude greater than a specified threshold.

20. A method for detecting defects on a wafer during formation of a photoresist layer, comprising:
scanning a wafer to acquire a non-correctable error image map indicative of non-correctable errors on the wafer, wherein a pixel of the non-correctable error image map indicates a presence and a magnitude of a non-correctable error at a location on the wafer represented by the pixel, wherein the magnitude of the non-correctable error corresponds to a difference between a height of the wafer at the location and an expected height of the wafer at the location;
applying an image transform to the non-correctable error image map to generate a projection, the image transform comprising at least one of a Hough transform or a Radon transform; and
reviewing the projection based upon a set of rules to identify a signature in the non-correctable error image map that corresponds to a defect on the wafer.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Lin Chun-Hsien
• Bo-Tsun Liu
• Ko Chin-Ti
• Cheng-Hung Wu
• Chao Kuo-Hung
• Jui-Chun Peng
• Tsai Fei-Gwo
• Liu Heng-Hsin
• Mou Jong-I

Classifications

• G06T2207/20061

  Hough transform · CPC title

• G06T7/0006 Primary

  using a design-rule based approach · CPC title

• G06T2207/30148

  Semiconductor; IC; Wafer · CPC title