Method for determining crystalline orientation using raman spectroscopy

Abstract

A method of determining the crystalline orientation of a crystal surface of a workpiece using Raman spectroscopy. A beam of substantially monochromatic light is directed to be incident on the crystal surface at a predetermined angle of incidence. The beam of light is substantially polarized. The workpiece is rotated relative to the beam of light about a rotation axis substantially normal to the crystal surface. A Raman shift of scattered light is measured at each of a number of rotational positions during the rotation of the workpiece. The crystalline orientation of the crystal surface is determined based on the measured Raman shifts. Data indicating the determined crystalline orientation of the crystal surface is stored.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed description when read in connection with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures:

FIG. 1 is a side plan drawing illustrating an exemplary Raman spectrometry system that may be used with exemplary methods according to the present invention.

FIG. 2 is a flowchart illustrating an exemplary Raman spectrometry method for determining crystalline orientation according to the present invention.

FIG. 3 is a flowchart illustrating an alternative exemplary Raman spectrometry method for determining crystalline orientation according to the present invention.

FIG. 4 is a flowchart illustrating another alternative exemplary Raman spectrometry method for determining crystalline orientation according to the present invention.

FIG. 5 is a flowchart illustrating a further alternative exemplary Raman spectrometry method for determining crystalline orientation according to the present invention.

FIG. 6 is a side plan drawing illustrating a prior art Raman spectrometry system.

FIG. 7 is a top plan drawing illustrating exemplary coordinate axes that may be used to identify the orientation of a workpiece.

FIGS. 8A and 8B are schematic drawings illustrating exemplary propagation directions of light incident on a crystal layer in the exemplary method of FIG. 9.

FIG. 9 is a flowchart illustrating an additional exemplary Raman spectrometry method for determining crystalline orientation according to the present invention.

Claims

1. A method of determining a crystalline orientation of a crystal surface of a workpiece using Raman spectroscopy, the method comprising the steps of: a) directing a beam of substantially monochromatic light to be incident on the crystal surface at a predetermined angle of incidence, the beam of light being substantially polarized;b) rotating the workpiece relative to the beam of light about a rotation axis substantially normal to the crystal surface;c) measuring a Raman shift of scattered light at each of a plurality of rotational positions during the rotation of the workpiece;d) determining the crystalline orientation of the crystal surface based on the plurality of Raman shifts measured in step (c); ande) storing data indicating the determined crystalline orientation of the crystal surface.

2. A method according to claim 1, wherein the beam of light is one of substantially linearly polarized or substantially circularly polarized.

3. A method according to claim 1, wherein: the beam of light is substantially linearly polarized; andthe predetermined angle of incidence is about 0°.

4. A method according to claim 1, wherein step (c) includes the steps of: c1) filtering the scattered light such that the filtered light has a narrow bandwidth corresponding to a predetermined Raman peak of the crystal surface; andc2) measuring a power of the filtered light at each of the plurality of rotational positions to determine the Raman shift of the scattered light at that rotational position.

5. A method according to claim 1, further comprising the step of: f) marking the workpiece consistent with the stored crystalline orientation data.

6. A method according to claim 1, further comprising the step of: f) using the stored crystalline orientation data of the crystal surface to determine a location of at least one cleavage plane through the workpiece; andg) cleaving the workpiece along the at least one cleavage plane.

7. A method according to claim 1, further comprising the step of: f) using the stored crystalline orientation data of the crystal surface to determine a location of at least one dicing street on the crystal surface; andg) dicing the workpiece along the at least one dicing street.

8. A method according to claim 1, further comprising the step of: f) using the stored crystalline orientation data of the crystal surface to align at least one of: a photolithographic mask to the crystal surface;a scan line of a laser writer on the crystal surface;a scan line of an e-beam writer on the crystal surface; ora tool path of a single-point micro-machining system on the crystal surface.

9. A method of determining a crystalline orientation of a crystal surface of a workpiece using Raman spectroscopy, the method comprising the steps of: a) directing a beam of substantially monochromatic light to be incident on the crystal surface at an angle of incidence, the beam of light being substantially polarized;b) varying the angle of incidence between the beam of light and the crystal surface;c) measuring the Raman shift of scattered light at each of a plurality of angles of incidence;d) determining the crystalline orientation of the crystal surface based on the plurality of Raman shifts measured in step (c); ande) storing data indicating the determined crystalline orientation of the crystal surface.

10. A method according to claim 9, wherein the beam of light is one of substantially linearly polarized or substantially circularly polarized.

11. A method according to claim 9, wherein step (c) includes the steps of: c1) filtering the scattered light such that the filtered light has a narrow bandwidth corresponding to a predetermined Raman peak of the crystal surface; andc2) measuring a power of the filtered light at each of the plurality of angles of incidence to determine the corresponding Raman shift of the scattered light.

12. A method according to claim 9, further comprising the step of: f) marking the workpiece consistent with the stored crystalline orientation data.

13. A method according to claim 9, further comprising the step of: f) using the stored crystalline orientation data of the crystal surface to determine a location of at least one cleavage plane through the workpiece; andg) cleaving the workpiece along the at least one cleavage plane.

14. A method according to claim 9, further comprising the step of: f) using the stored crystalline orientation data of the crystal surface to determine a location of at least one dicing street on the crystal surface; andg) dicing the workpiece along the at least one dicing street.

15. A method according to claim 9, further comprising the step of: f) using the stored crystalline orientation data of the crystal surface to align at least one of: a photolithographic mask to the crystal surface;a scan line of a laser writer on the crystal surface;a scan line of an e-beam writer on the crystal surface; ora tool path of a single-point micro-machining system on the crystal surface.

16. A method of determining a crystalline orientation of a crystal surface of a workpiece using Raman spectroscopy, the method comprising the steps of: a) directing a beam of substantially monochromatic light to be incident on the crystal surface at a predetermined angle of incidence, the beam of light being substantially linearly polarized;b) varying a polarization angle of the substantially linearly polarized beam of substantially monochromatic light;c) filtering light scattered from the crystal surface such that the filtered light has a narrow bandwidth corresponding to a predetermined Raman peak of the crystal surface;d) measuring a power of the filtered light at each of a plurality of polarization angles;e) determining the crystalline orientation of the crystal surface based on the plurality of power levels measured in step (d); andf) storing data indicating the determined crystalline orientation of the crystal surface.

17. A method according to claim 16, wherein the predetermined angle of incidence is about 0°.

18. A method according to claim 16, further comprising the step of: g) marking the workpiece consistent with the stored crystalline orientation data.

19. A method according to claim 16, further comprising the step of: g) using the stored crystalline orientation data of the crystal surface to determine a location of at least one cleavage plane through the workpiece; andh) cleaving the workpiece along the at least one cleavage plane.

20. A method according to claim 16, further comprising the step of: g) using the stored crystalline orientation data of the crystal surface to determine a location of at least one dicing street on the crystal surface; andh) dicing the workpiece along the at least one dicing street.

21. A method according to claim 16, further comprising the step of: g) using the stored crystalline orientation data of the crystal surface to align at least one of: a photolithographic mask to the crystal surface;a scan line of a laser writer on the crystal surface;a scan line of an e-beam writer on the crystal surface; ora tool path of a single-point micro-machining system on the crystal surface.

22. A method of determining a crystalline orientation of a crystal surface of a workpiece using Raman spectroscopy, the method comprising the steps of: a) directing a beam of substantially monochromatic light to be incident on the crystal surface at a predetermined angle of incidence, the beam of light being substantially linearly polarized;b) varying a polarization angle of the substantially linearly polarized beam of substantially monochromatic light;c) detecting scattered light at each of a plurality of polarization angles of the incident beam of light such that all polarizations of the scattered light are detected;d) measuring a Raman shift of the detected light at each of the plurality of polarization angles;e) determining the crystalline orientation of the crystal surface based on the plurality of Raman shifts measured in step (d); andf) storing data indicating the determined crystalline orientation of the crystal surface.

23. A method according to claim 22, wherein the predetermined angle of incidence is about 0°.

24. A method according to claim 22, wherein step (d) includes the steps of: d1) filtering the scattered light such that the filtered light has a narrow bandwidth corresponding to a predetermined Raman peak of the crystal surface; andd2) measuring the power of the filtered light at each of the plurality of polarization angles to determine the Raman shift of the scattered light at that polarization angle.

25. A method according to claim 22, further comprising the step of: g) marking the workpiece consistent with the stored crystalline orientation data.

26. A method according to claim 22, further comprising the step of: g) using the stored crystalline orientation data of the crystal surface to determine a location of at least one cleavage plane through the workpiece; andh) cleaving the workpiece along the at least one cleavage plane.

27. A method according to claim 22, further comprising the step of: g) using the stored crystalline orientation data of the crystal surface to determine a location of at least one dicing street on the crystal surface; andh) dicing the workpiece along the at least one dicing street.

28. A method according to claim 22, further comprising the step of: g) using the stored crystalline orientation data of the crystal surface to align at least one of: a photolithographic mask to the crystal surface;a scan line of a laser writer on the crystal surface;a scan line of an e-beam writer on the crystal surface; ora tool path of a single-point micro-machining system on the crystal surface.

29. A method of determining a crystalline orientation of a top crystal surface of a workpiece that includes a crystal layer using Raman spectroscopy, the top crystal surface defining an X-Y plane, a Z axis being outwardly normal to the top crystal surface, the method comprising the steps of: a) directing a beam of substantially monochromatic and substantially polarized light to be incident on a side surface of the crystal layer of the workpiece, the beam of light propagating substantially parallel to the X-Y plane at incidence;b) rotating the workpiece about a rotation axis substantially parallel to the Z axis;c) measuring a Raman shift of scattered light at each of a plurality of rotational positions during the rotation of the workpiece;d) determining the crystalline orientation of the top crystal surface based on the plurality of Raman shifts measured in step (c); ande) storing data indicating the determined crystalline orientation of the top crystal surface.

30. A method according to claim 29, wherein the beam of light is one of substantially linearly polarized or substantially circularly polarized.

31. A method according to claim 29, wherein step (c) includes the steps of: c1) filtering the scattered light such that the filtered light has a narrow bandwidth corresponding to a predetermined Raman peak of the top crystal surface; andc2) measuring a power of the filtered light at each of the plurality of angles of incidence to determine the corresponding Raman shift of the scattered light.

32. A method according to claim 29, further comprising the step of: f) marking the workpiece consistent with the stored crystalline orientation data.

33. A method according to claim 29, further comprising the step of: f) using the stored crystalline orientation data of the top crystal surface to determine a location of at least one cleavage plane through the workpiece; andg) cleaving the workpiece along the at least one cleavage plane.

34. A method according to claim 29, further comprising the step of: f) using the stored crystalline orientation data of the top crystal surface to determine a location of at least one dicing street on the top crystal surface; andg) dicing the workpiece along the at least one dicing street.

35. A method according to claim 29, further comprising the step of: f) using the stored crystalline orientation data of the top crystal surface to align at least one of: a photolithographic mask to the top crystal surface;a scan line of a laser writer on the top crystal surface;a scan line of an e-beam writer on the top crystal surface; ora tool path of a single-point micro-machining system on the top crystal surface.