Method and apparatus of eddy current monitoring for chemical mechanical polishing

• US 20030148706A1
• Filed: 04/16/2002
• Published: 08/07/2003
• Est. Priority Date: 02/06/2002
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Birang, Manoocher, Swedek, Boguslaw A., Kim, Hyeong Cheol
• Granted Patent: US 7,001,242 B2
• Time in Patent Office: Days
• US Class Current: 451/6
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/205 provided with a window for inspecting the surface of the work being lapped
• CPC Class Codes: B24B 49/10 involving electrical means B24B49/02, B24B49/08 take precedence
• CPC Class Codes: B24B 49/105 using eddy currents
• CPC Class Codes: B24B 49/12 involving optical means

Abstract

A polishing system can have a rotatable platen, a polishing pad secured to the platen, a carrier head to hold a substrate against the polishing pad, and an eddy current monitoring system including a coil or ferromagnetic body that extends at least partially through the polishing pad. A polishing pad can have a polishing layer and a coil or ferromagnetic body secured to the polishing layer. Recesses can be formed in a transparent window in the polishing pad.

Claims

1. A polishing system, comprising:

a polishing pad having a polishing surface;

a carrier to hold a substrate against the polishing surface of the polishing pad; and

an eddy current monitoring system including an induction coil positioned on a side of the polishing surface opposite the substrate, the induction coil extending at least partially through the polishing pad.

2. The polishing system of claim 1, wherein the polishing pad includes a recess formed in a bottom surface thereof, and the coil is at least partially positioned into the recess.

3. The polishing system of claim 1, wherein the coil is secured to the polishing pad.

4. The polishing system of claim 3, wherein the coil is embedded in the polishing pad.

5. The polishing system of claim 1, wherein the eddy current monitoring system includes a core, and the coil is wound about the core.

6. The polishing system of claim 1, further comprising an optical monitoring system including a transparent window, and wherein the coil extends at least partially through the transparent window.

7. The polishing system of claim 1, wherein the polishing pad is mounted on a top surface of a platen and the coil is supported by the platen.

8. A polishing system, comprising:

a polishing pad having a polishing surface;

a carrier to hold a substrate against the polishing surface of the polishing pad; and

an eddy current monitoring system including a ferromagnetic body positioned on a side of the polishing surface opposite the substrate, the ferromagnetic body extending at least partially through the polishing pad.

9. The polishing system of claim 8, wherein the polishing pad includes a recess formed in a bottom surface thereof, and the ferromagnetic body is positioned into the recess.

10. The polishing system of claim 9, wherein the polishing pad is attached to a platen, and the ferromagnetic body is supported by the platen.

11. The polishing system of claim 10, wherein a gap separates the ferromagnetic body from the polishing pad.

12. The polishing system of claim 8, wherein the polishing pad includes an aperture formed therethrough, and the ferromagnetic body is positioned in the aperture.

13. The polishing system of claim 8, wherein the eddy current monitoring system includes a core, and core is aligned with the ferromagnetic body when the polishing pad is secured to the platen.

14. The polishing system of claim 8, further comprising an optical monitoring system including a transparent window, and wherein the ferromagnetic body extends at least partially through the transparent window.

15. The polishing system of claim 8, wherein the ferromagnetic body is secured to the polishing pad.

16. The polishing system of claim 15, wherein the ferromagnetic body is secured in the polishing pad with a polyurethane epoxy.

17. The polishing system of claim 15, wherein the ferromagnetic body is embedded in the polishing pad.

18. The polishing system of claim 8, further comprising a coil wound around the ferromagnetic body.

19. The polishing system of claim 18, wherein the coil extends at least partially through the polishing pad.

20. The polishing system of claim 8, further comprising means for biasing the ferromagnetic body against the polishing pad.

21. A polishing system, comprising:

a polishing pad having a polishing surface and a backing surface with a recess formed therein; and

an eddy current monitoring system including an induction coil positioned at least partially in the recess.

22. A polishing system, comprising:

a polishing pad having a polishing surface and a backing surface with a recess formed therein; and

an eddy current monitoring system including a ferromagnetic body positioned at least partially in the recess.

23. A carrier head for a polishing system, comprising:

a substrate receiving surface; and

a ferromagnetic body in the carrier head on a side opposite the substrate receiving surface.

24. A polishing pad, comprising:

a polishing layer; and

an induction coil secured to the polishing layer.

25. The polishing pad of claim 24, wherein the induction coil is embedded in the polishing pad.

26. The polishing pad of claim 24, wherein the polishing layer includes a recess formed in a bottom surface thereof, and the coil is positioned into the recess.

27. The polishing pad of claim 24, wherein the coil is positioned with a primary axis perpendicular to a surface of the polishing layer.

28. The polishing pad of claim 24, wherein the coil is positioned with a primary axis at an angle greater than 0 and less than 90 degrees to a surface of the polishing layer.

29. A polishing pad, comprising:

a polishing layer; and

a ferromagnetic body secured to the polishing layer.

30. The polishing pad of claim 29, wherein the polishing layer includes a recess formed in a bottom surface thereof, and the ferromagnetic body is positioned into the recess.

31. The polishing pad of claim 30, wherein the polishing layer includes a plurality of recesses formed in a bottom surface thereof, and a plurality of ferromagnetic bodies are positioned into the recesses.

32. The polishing pad of claim 29, wherein the polishing layer includes an aperture formed therethrough, and the ferromagnetic body is positioned in the aperture.

33. The polishing pad of claim 32, further comprising a plug holding the ferromagnetic body in the aperture.

34. The polishing pad of claim 33, wherein the plug has a top surface substantially flush with a surface of the polishing layer.

35. The polishing pad of claim 32, wherein the polishing pad further comprises a backing layer.

36. The polishing pad of claim 32, wherein a top surface of the ferromagnetic body is exposed to the polishing environment.

37. The polishing pad of claim 29, wherein a position of the ferromagnetic body relative to a surface of the polishing layer is adjustable.

38. The polishing pad of claim 29, wherein the ferromagnetic body is positioned with a longitudinal axis perpendicular to a surface of the polishing layer.

39. The polishing pad of claim 29, wherein the ferromagnetic body is positioned with a longitudinal axis at an angle greater than 0 and less than 90 degrees to a surface of the polishing layer.

40. The polishing pad of claim 29, wherein the ferromagnetic body is secured to the polishing layer with an epoxy.

41. The polishing pad of claim 29, further comprising a transparent window through the polishing layer, and wherein the ferromagnetic body is secured to the transparent window.

42. The polishing pad of claim 41, wherein the transparent window includes a recess formed in a bottom surface thereof, and the ferromagnetic body are positioned into the recess.

43. The polishing pad of claim 42, wherein the transparent window includes an aperture formed therethrough, and the ferromagnetic body is positioned in the aperture.

44. The polishing pad of claim 29, further comprising a coil wound around the ferromagnetic body.

45. A method of polishing, comprising:

bringing a substrate into contact with a polishing surface of a polishing pad;

positioning an induction coil on a side of the polishing surface opposite the substrate so that the induction coil extends at least partially through the polishing pad;

causing relative motion between the substrate and the polishing pad; and

monitoring a magnetic field using the induction coil.

46. A method of polishing, comprising:

bringing a substrate into contact with a polishing surface of a polishing pad;

positioning a ferromagnetic body on a side of the polishing surface opposite the substrate so that the ferromagnetic body extends at least partially through the polishing pad;

eausing relative motion between the substrate and the polishing pad; and

monitoring a magnetic field using an induction coil that is magnetically coupled to the ferromagnetic body.