Systems and Methods for Sample Inspection and Review

• US 20130271596A1
• Filed: 02/27/2013
• Published: 10/17/2013
• Est. Priority Date: 04/12/2012
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Lewis, Isabella T., Bobrov, Yakov
• Granted Patent: US 9,939,386 B2
• Time in Patent Office: Days
• US Class Current: 348/126
• CPC Class Codes: G01N 2021/8845 Multiple wavelengths of illumination or detection
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10

Abstract

The disclosure is directed to systems and methods for sample inspection and review. In some embodiments, images are collected and/or defects are located utilizing separately addressable red, green, and blue (RGB) illumination sources to improve image quality. In some embodiments, illumination sources are pulse width modulated for substantially consistent light intensity in presence of variable sample motion. In some embodiments, a stage assembly is configured to support the sample without blocking access to the supported surface of the sample, and further configured to reduce oscillations or vibrations of the sample. In some embodiments, an illumination system includes an imaging path and a focusing path to allow full field of view focusing.

Claims

1. A system for analyzing a sample, comprising:

an inspection module including one or more illumination sources configured to sequentially illuminate a surface of the sample with red, green, and blue illumination, and one or more monochromic detectors configured to receive illumination reflected from the surface of the sample in response to the sequential illumination by the one or more illumination sources;

a review module including one or more illumination sources configured to illuminate the surface of the sample, and one or more detectors configured to receive illumination reflected from the surface of the sample in response to the illumination by the one or more illumination sources; and

at least one computing system in communication with the inspection module and the review module, the at least one computing system configured to determine a location of a defect of the sample utilizing information associated with the illumination received by the one or more monochromic detectors of the inspection module, and further configured to collect an image of a portion of the surface of the sample including the defect utilizing the one or more detectors of the review module and the determined location of the defect.

2. The system of claim 1, wherein the review module further includes:

a platform configured to support the one or more detectors and collection optics of the review module, wherein the collection optics are configured to direct illumination received from the surface of the sample along a collection path to the one or more detectors of the review module; and

at least one actuator mechanically coupled to the platform, the at least one actuator configured to actuate the platform to a selected location.

3. The system of claim 2, wherein the at least one actuator is configured to translate the platform along a first axis and at least a second axis.

4. The system of claim 1, wherein the one or more illumination sources of the review module are configured to sequentially illuminate the surface of the sample with red, green, and blue illumination, and the at least one computing system is configured to reconstruct a color image of the portion of the surface of the sample from a first image associated with the red illumination, a second image associated with the green illumination, and a third image associated with the blue illumination collected utilizing the one or more detectors of the review module.

5. The system of claim 4, wherein the one or more detectors of the review module include a monochrome camera.

6. The system of claim 4, wherein the one or more detectors of the review module are configured to collect the first, second, and third images at different focus levels from one another.

7. The system of claim 4, wherein the one or more illumination sources of the review module are configured to provide illumination according to a selected integration time.

8. The system of claim 1, wherein the one or more illumination sources of the review module comprise one or more pulse width modulated light emitting diodes (LEDs).

9. The system of claim 8, wherein the one or more LEDs are configured to provide a plurality of illumination pulses according to a collection time of the one or more detectors of the review module.

10. The system of claim 8, wherein the one or more LEDs are configured to provide the plurality of illumination pulses over a selected number of integration lines associated with the collection time of the one or more detectors of the review module.

11. The system of claim 8, wherein the one or more LEDs are configured to provide a first plurality of illumination pulses and at least a second plurality of illumination pulses sequentially delayed with respect to one another according to the collection time of the one or more detectors of the review module.

16. The system of claim 1, wherein the one or more illumination sources of the review module are configured to strobe illumination to compensate for motion of the sample.

17. The system of claim 1, wherein the one or more illumination sources of the review module include:

a first illumination source configured to provide illumination along a first illumination path to the surface of the sample; and

a second illumination source configured to provide illumination along a second illumination path to the surface of the sample, the second illumination path including a grid mask, wherein the at least one computing system is configured to determine a focus position based upon a portion of illumination from the second illumination source reflected from the surface of the sample to the one or more detectors of the review module.

18. The system of claim 17, wherein the first illumination path and the second illumination path merge into a common illumination path leading to the surface of the sample.

19. The system of claim 17, wherein the first illumination path is an imaging path and the second illumination path is an image based autofocus path.

20. The system of claim 1, further comprising a frame configured to support the inspection module, the review module, and the at least one computing system.

25. The system of claim 1, wherein the one or more illumination sources comprise one or more pulse width modulated light emitting diodes (LEDs).

26. The system of claim 25, wherein the one or more LEDs are configured to provide a plurality of illumination pulses according to a collection time of the one or more detectors.

27. The system of claim 25, wherein the one or more LEDs are configured to provide the plurality of illumination pulses over a selected number of integration lines associated with the collection time of the one or more detectors.

28. The system of claim 25, wherein the one or more LEDs are configured to provide a first plurality of illumination pulses and at least a second plurality of illumination pulses sequentially delayed with respect to one another according to the collection time of the one or more detectors.

12. The system of claim 12, further comprising:

a stage assembly configured to support the wafer by contacting a selected number of points on a backside of the wafer and a selected number of points along an edge of the wafer, wherein the backside of the wafer is substantially accessible to illumination associated with at least one of the inspection module and the review module.

13. The system of claim 12, wherein the stage assembly includes at least one sidearm configured to contact the selected number of points along the edge of the wafer.

14. The system of claim 13, wherein the at least one sidearm includes a reciprocating mechanism configured to reduce motion of the sample.

15. The system of claim 12, further comprising:

an actuator configured to actuate the stage assembly to contact the selected number of points at one or more selected locations on the backside of the wafer.

21. A system for analyzing a sample, comprising:

one or more illumination sources configured to sequentially illuminate a surface of the sample with red, green, and blue illumination;

one or more detectors configured to receive illumination reflected from the surface of the sample in response to the illumination by the one or more illumination sources; and

at least one computing system in communication the one or more detectors, the at least one computing system configured to reconstruct a color image of a portion of the surface of the sample from a first image associated with the red illumination, a second image associated with the green illumination, and a third image associated with the blue illumination collected utilizing the one or more detectors of the review module.

22. The system of claim 21, wherein the one or more detectors include a monochrome camera.

23. The system of claim 21, wherein the one or more detectors are configured to collect the first, second, and third images at different focus levels from one another.

24. The system of claim 21, wherein the one or more illumination sources are configured to provide illumination according to a selected integration time.

29. A system for analyzing a sample, comprising:

a stage assembly configured to support the wafer by contacting a selected number of points on a surface of the sample and a selected number of points along an edge of the sample;

one or more illumination sources configured to illuminate the surface of the sample;

one or more detectors configured to receive illumination reflected from the surface of the sample in response to the illumination by the one or more illumination sources; and

at least one computing system in communication the one or more detectors, the at least one computing system configured to determine information associated with a defect of the sample utilizing information associated with the illumination received by the one or more detectors.

30. The system of claim 29, wherein the surface of the sample comprises a backside of a wafer, wherein the backside of the wafer is substantially accessible to illumination from the one or more illumination sources.

31. The system of claim 29, wherein the stage assembly includes at least one sidearm configured to contact the selected number of points along the edge of the sample.

32. The system of claim 31, wherein the at least one sidearm includes a reciprocating mechanism configured to reduce motion of the sample.

33. The system of claim 31, wherein the at least one sidearm comprises a first sidearm and a second sidearm.

34. The system of claim 29, further comprising:

an actuator configured to actuate the stage assembly to contact the selected number of points at one or more selected locations of the surface of the sample.

35. The system of claim 29, wherein the one or more illumination sources are configured to strobe illumination to compensate for motion of the sample.

36. A system for analyzing a sample, comprising:

a first illumination source configured to provide illumination along a first illumination path to a surface of the sample;

a second illumination source configured to provide illumination along a second illumination path to the surface of the sample, the second illumination path including a grid mask;

one or more detectors configured to receive illumination reflected from the surface of the sample in response to the illumination at least one of the first illumination source and the second illumination source; and

at least one computing system in communication the one or more detectors, the at least one computing system configured to determine a focus position based upon a portion of illumination from the second illumination source reflected from the surface of the sample to the one or more detectors.

37. The system of claim 36, wherein the first illumination path and the second illumination path merge into a common illumination path leading to the surface of the sample.

38. The system of claim 36, wherein the first illumination path is an imaging path and the second illumination path is an image based autofocus path.