DEFECT CLASSIFICATION USING TOPOGRAPHICAL ATTRIBUTES

• US 20130279791A1
• Filed: 04/19/2012
• Published: 10/24/2013
• Est. Priority Date: 04/19/2012
• Status: Active Grant

• Current Assignee: Applied Materials Israel Limited (Applied Materials Incorporated)
• Original Assignee: Applied Materials Israel Limited (Applied Materials Incorporated)
• Inventors: Kaizerman, Idan, Rozenman, Efrat, Schwarzband, Ishai
• Granted Patent: US 9,595,091 B2
• Time in Patent Office: Days
• US Class Current: 382/145
• CPC Class Codes: G06T 2207/10061 from scanning electron microscope
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

A method for classification includes receiving an image of an area of a semiconductor wafer on which a pattern has been formed, the area containing a location of interest. At least one value for one or more attributes of the location of interest are computed based upon topographical features of the location of interest in a three-dimensional (3D) map of the area.

Claims

1. A method for classification, comprising:

receiving, by a computer system, a three-dimensional (3D) map of an area of a semiconductor wafer containing a location of interest; and

computing, by the computer system, at least one value for one or more attributes of the location of interest based upon topographical features of the location of interest in the map.

2. The method of claim 1, wherein the location of interest contains at least one feature, wherein the at least one feature is selected from a plurality of features, the plurality of features comprising a defect, a process variation, and a design of interest.

3. The method of claim 2, further comprising:

automatically classifying the defect at the location of interest based on the at least one value for the one or more attributes.

4. The method of claim 1, wherein receiving the 3D map comprises deriving the 3D map from images captured by a scanning electron microscope (SEM).

5. The method of claim 1, wherein computing the respective values comprises calculating one or more 3D shape parameters of the location of interest.

6. The method of claim 5, wherein calculating the 3D shape parameters comprises:

fitting a parametric surface to the location of interest in the 3D map; and

deriving the 3D shape parameters from the fitted surface.

7. The method of claim 5, wherein calculating the 3D shape parameters comprises finding an orientation of a plane corresponding to a surface of the location of interest.

8. The method of claim 5, wherein calculating the 3D shape parameters comprises finding a measure of curvature of a surface of the location of interest.

9. The method of claim 1, wherein computing the at least one value comprises calculating one or more texture parameters of the location of interest.

10. The method of claim 9, wherein calculating the texture parameters comprises:

computing a gradient over a surface of the location of interest; and

finding a measure of roughness of the surface based on the gradient.

11. The method of claim 9, wherein calculating the texture parameters comprises computing a directional order of a plurality of edges in the location of interest.

12. An apparatus comprising:

a memory; and

a processing device coupled with the memory wherein the processing device is configured to

receive a three-dimensional (3D) map of an area of a semiconductor wafer containing a location of interest; and

compute at least one value for one or more attributes of the location of interest based upon topographical features of the location of interest in the map.

13. The apparatus of claim 12, wherein the location of interest comprises at least one feature, wherein the at least one feature is selected from a group of features, the plurality of features comprising a defect, a process variation, and a design of interest.

14. The apparatus of claim 13, wherein the processor is further configured to automatically classify the defect at the location of interest based on the at least one value for the one or more attributes.

15. The apparatus of claim 12, wherein the 3D map is derived from a plurality of images captured by a scanning electron microscope (SEM).

16. The apparatus of claim 12, wherein the at least one value comprises one or more 3D shape parameters of the location of interest.

17. The apparatus of claim 16, wherein the processor is configured to compute the 3D shape parameters by:

fitting a parametric surface to the location of interest in the map; and

deriving the 3D shape parameters from the fitted surface.

18. The apparatus of claim 16, wherein the processor is configured to compute the 3D shape parameters by finding an orientation of a plane corresponding to a surface of the location of interest.

19. The apparatus of claim 16, wherein the 3D shape parameters comprise a measure of curvature of a surface of the location of interest.

20. The apparatus of claim 12, wherein the at least one value comprises one or more texture parameters of the location of interest.

21. The apparatus of claim 20, wherein the processor is configured to calculate the texture parameters by:

computing a gradient over a surface of the location of interest; and

finding a measure of roughness of the surface responsively to the gradient.

22. The apparatus of claim 20, wherein the processor is configured to calculate the texture parameters by computing a directional order of edges in the location of interest.

23. A non-transitory computer readable storage medium having instructions that, when executed by a processing device, cause the processing device to perform operations comprising:

receiving a three-dimensional (3D) map of an area of a semiconductor wafer containing a location of interest; and

computing one or more values for one or more attributes of the location of interest based upon topographical features of the location of interest in the map.

24. The non-transitory computer readable storage medium of claim 23, wherein the location of interest contains at least one feature, wherein the at least one feature is selected from a plurality of features, the plurality of features comprising a defect, a process variation, and a design of interest.

25. The non-transitory computer readable storage medium of claim 24, wherein the processing device performs operations further comprising:

automatically classifying the location of interest based on the at least one value for the one or more attributes.

26. The non-transitory computer readable storage medium of claim 23, wherein the at least one value comprises one or more 3D shape parameters or texture parameters of the location of interest.