Defect discovery and inspection sensitivity optimization using automated classification of corresponding electron beam images

Patent metadata

Field	Value
Publication number	US-9293298-B2
Application number	US-201414528941-A
Country	US
Kind code	B2
Filing date	Oct 30, 2014
Priority date	Dec 23, 2013
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

Various embodiments for classifying defects detected on a wafer are provided. One method includes acquiring an electron beam image generated by a defect review tool for a location of a defect detected on a wafer by a wafer inspection tool. The method also includes determining a classification of the defect based on at least the electron beam image and without input from a user. The method may also include feeding back the classification results to the wafer inspection tool and optimizing the parameters of the tool to maximize sensitivity to the defects of interest.

First claim

What is claimed is:

1. A computer-implemented method for classifying defects detected on a wafer, comprising:
acquiring an electron beam image generated by a defect review tool for a location of a defect detected on a wafer by a wafer inspection tool, wherein an inspection process used by the wafer inspection tool to detect the defect is setup to detect defects having sizes that are below a resolution limit of the wafer inspection tool; and
determining a classification of the defect based on at least the electron beam image and without input from a user, wherein said acquiring and said determining are performed using a computer system.

2. The method of claim 1 , wherein the wafer inspection tool is a light-based wafer inspection tool.

3. The method of claim 1 , wherein a sensitivity of the wafer inspection tool used to detect the defect is a highest sensitivity achievable by the wafer inspection tool.

4. The method of claim 1 , wherein the inspection process used by the wafer inspection tool to detect the defect is further setup to detect unknown defect types on the wafer.

5. The method of claim 1 , wherein acquiring the electron beam image comprises automatically generating the electron beam image at the location of the defect with the defect review tool based on the location of the defect determined by the wafer inspection tool included in an inspection results file generated by the wafer inspection tool.

6. The method of claim 1 , wherein determining the classification comprises performing a defect detection method on the electron beam image.

7. The method of claim 1 , wherein determining the classification comprises determining one or more attributes of the defect based on the electron beam image.

8. The method of claim 1 , wherein determining the classification comprises correlating the electron beam image of the defect with an optical image of the defect generated by the wafer inspection tool.

9. The method of claim 8 , wherein said correlating comprises scaling one or more of the electron beam image and the optical image to a common resolution.

10. The method of claim 8 , wherein said correlating comprises aligning the electron beam image to the optical image based on one or more patterned features in the electron beam and optical images having a unique geometry within the electron beam and optical images.

11. The method of claim 8 , wherein determining the classification further comprises determining a location of the defect in the optical image based on results of correlating the electron beam image with the optical image.

12. The method of claim 1 , further comprising displaying, to the user, the determined classification, one or more images for the defect, and any attributes of the defect determined by the method.

13. The method of claim 1 , wherein determining the classification comprises processing the electron beam image using one or more methods selected based on a design for the wafer, defect types of interest, or a combination thereof.

14. The method of claim 1 , wherein determining the classification comprises determining if the defect is a defect of interest, a nuisance defect, or a defect that cannot be detected by the defect review tool.

15. The method of claim 1 , further comprising altering one or more parameters of the inspection process used to detect the defect based on the determined classification.

16. The method of claim 1 , further comprising combining results of the method with an inspection results file generated for the wafer by the wafer inspection tool.

17. The method of claim 1 , further comprising altering an inspection results file generated for the wafer by the wafer inspection tool based on the determined classification.

18. A non-transitory computer-readable medium containing program instructions stored therein for causing a computer system to perform a computer-implemented method for classifying defects detected on a wafer, wherein the computer-implemented method comprises:
acquiring an electron beam image generated by a defect review tool for a location of a defect detected on a wafer by a wafer inspection tool, wherein an inspection process used by the wafer inspection tool to detect the defect is setup to detect defects having sizes that are below a resolution limit of the wafer inspection tool; and
determining a classification of the defect based on at least the electron beam image and without input from a user.

19. A system configured to classify defects detected on a wafer, comprising:
an electron beam defect review subsystem configured to acquire an electron beam image for a location of a defect detected on a wafer by a wafer inspection tool, wherein an inspection process used by the wafer inspection tool to detect the defect is setup to detect defects having sizes that are below a resolution limit of the wafer inspection tool; and
a computer subsystem configured to determine a classification of the defect based on at least the electron beam image and without input from a user.

20. The system of claim 19 , wherein the wafer inspection tool is a light-based wafer inspection tool.

21. The system of claim 19 , wherein a sensitivity of the wafer inspection tool used to detect the defect is a highest sensitivity achievable by the wafer inspection tool.

22. The system of claim 19 , wherein the inspection process used by the wafer inspection tool to detect the defect is further setup to detect unknown defect types on the wafer.

23. The system of claim 19 , wherein the electron beam defect review subsystem is further configured to acquire the electron beam image by automatically generating the electron beam image at the location of the defect based on the location of the defect determined by the wafer inspection tool included in an inspection results file generated by the wafer inspection tool.

24. The system of claim 19 , wherein the computer subsystem is further configured to determine the classification of the defect by performing a defect detection method on the electron beam image.

25. The system of claim 19 , wherein the computer subsystem is further configured to determine the classification of the defect by determining one or more attributes of the defect based on the electron beam image.

26. The system of claim 19 , wherein the computer subsystem is further configured to determine the classification of the defect by correlating the electron beam image of the defect with an optical image of the defect generated by the wafer inspection tool.

27. The system of claim 26 , wherein said correlating comprises scaling one or more of the electron beam image and the optical image to a common resolution.

28. The system of claim 26 , wherein said correlating comprises aligning the electron beam image to the optical image based on one or more patterned features in the electron beam and optical images having a unique geometry within the electron beam and optical images.

29. The system of claim 26 , wherein the computer subsystem is further configured to determine the classification of the defect by determining a location of the defect in the optical image based on results of correlating the electron beam image with the optical image.

30. The system of claim 19 , wherein the computer subsystem is further configured for displaying, to the user, the determined classification, one or more ima

Assignees

• Kla Tencor Corp
• Kla Tencor Corp

Inventors

• Lauber Jan A

Classifications

• H10P74/203 Primary

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H01J37/261 Primary

  Details · CPC title

• H01J2237/2817

  Pattern inspection · CPC title