METHODS FOR ACCURATE IDENTIFICATION OF AN EDGE OF A CARE AREA FOR AN ARRAY AREA FORMED ON A WAFER AND METHODS FOR BINNING DEFECTS DETECTED IN AN ARRAY AREA FORMED ON A WAFER

• US 20080205745A1
• Filed: 02/28/2007
• Published: 08/28/2008
• Est. Priority Date: 02/28/2007
• Status: Active Grant

• Current Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Original Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Inventors: Wang, Xiaoming, Shifrin, Eugene, Chen, Chien-Huei (Adam), Fang, Tsung-Pao
• Granted Patent: US 7,894,659 B2
• Time in Patent Office: Days
• US Class Current: 382/145
• CPC Class Codes: G06T 2207/10056 Microscopic image
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/187 involving region growing; involving region merging; involving connected component labelling

Abstract

Methods for identifying an edge of a care area for an array area formed on a wafer and/or for binning defects detected in the array area are provided. One method for identifying an edge of a care area for an array area formed on a wafer includes determining a value for a difference image as a function of position from a position known to be inside the array area to a position known to be outside of the array area. The method also includes identifying the position that is located closest to the inside of the array area and that has the value greater than a threshold as a position of the edge of the care area.

Claims

1. A computer-implemented method for identifying an edge of a care area for an array area formed on a wafer, comprising:

determining a value for a difference image as a function of position from a position known to be inside the array area to a position known to be outside of the array area; and

identifying the position that is located closest to the inside of the array area and that has the value greater than a threshold as a position of the edge of the care area.

2. The method of claim 1, wherein said identifying comprises expanding an original care area in x.

3. The method of claim 1, wherein the edge is a left edge of the care area, and wherein the method further comprises performing said determining and said identifying to identify a right edge of the care area.

4. The method of claim 1, wherein said identifying comprises expanding an original care area in x, and wherein the method further comprises expanding the original care area in y.

5. The method of claim 1, further comprising determining the threshold from an average of the values for the difference image known to be inside the array area.

6. The method of claim 1, wherein all steps of the method are performed during runtime of inspection of the wafer.

7. The method of claim 1, further comprising detecting defects in the array area by performing cell-to-cell comparisons in the care area.

8. The method of claim 1, further comprising performing the method for multiple array areas on the wafer on an individual array area basis.

9. A computer-implemented method for identifying an edge of a care area for an array area formed on a wafer, comprising:

determining a value for a difference image as a function of position from a position known to be inside the array area to a position known to be outside of the array area;

determining if a repeating pattern is formed at each of the positions; and

identifying the position that is located closest to the inside of the array area, that has the value greater than a threshold, and at which the repeating pattern is formed as a position of the edge of the care area.

10. The method of claim 9, wherein said identifying comprises expanding an original care area in y.

11. The method of claim 9, wherein the edge is a top edge of the care area, and wherein the method further comprises performing said determining the value, said determining if the repeating pattern is formed at each of the positions, and said identifying to identify a bottom edge of the care area.

12. The method of claim 9, wherein said identifying comprises expanding an original care area in y, and wherein the method further comprises expanding the original care area in x.

13. The method of claim 9, wherein said determining if the repeating pattern is formed at each of the positions is performed using a pattern recognition technique.

14. The method of claim 9, wherein said determining if the repeating pattern is formed at each of the positions is performed using a template matching technique.

15. The method of claim 9, further comprising determining the threshold from an average of the values for the difference image known to be inside the array area.

16. The method of claim 9, wherein all steps of the method are performed during runtime of inspection of the wafer.

17. The method of claim 9, further comprising detecting defects in the array area by performing cell-to-cell comparisons in the care area.

18. The method of claim 9, further comprising performing the method for multiple array areas on the wafer on an individual array area basis.

19. A computer-implemented method for binning defects detected in an array area formed on a wafer, comprising:

determining distances between positions of the defects and an edge of the array area; and

binning the defects in groups such that the distances determined for the defects in each of the groups are at least similar.

20. The method of claim 19, wherein the distances comprise distances in an x direction and a y direction, and wherein said binning comprises binning the defects in the groups such that the distances in the x direction determined for the defects in each of the groups are at least similar and such that the distances in the y direction determined for the defects in each of the groups are at least similar.

21. The method of claim 19, further comprising selecting the distances associated with each of the groups such that said binning comprises binning the defects into the groups such that each of the groups includes only nuisance defects or only defects of interest.