Apparatus and method for in-situ endpoint detection for chemical mechanical polishing operations

• US 6,676,717 B1
• Filed: 09/28/2000
• Issued: 01/13/2004
• Est. Priority Date: 03/28/1995
• Status: Expired due to Fees

• Current Assignee: Allan Gleason, Manoocher Birang
• Original Assignee: Allan Gleason, Manoocher Birang
• Inventors: Birang, Manoocher, Gleason, Allan
• Primary Examiner(s): SINGH-PANDEY, ARTI R
• Application Number:
  US09/672,532
• Time in Patent Office: 1,202 Days
• Field of Search: 428/131, 428/133, 428/409, 428/43, 428/46, 428/47, 428/53, 428/66.6, 428/72, 428/132, 428/137, 428/142, 428/156, 428/315.5, 512/96, 512/98, 451/41, 451/527, 451/530, 451/537, 438/8, 442/148, 442/221, 442/286, 442/370, 442/394, 437/225, 437/228
• US Class Current: 51/296
• 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 47/12 by mechanical gearing or electric power B24B47/16 takes precedence
• CPC Class Codes: B24B 49/04 involving measurement of the workpiece at the place of grinding during grinding operation
• CPC Class Codes: B24B 49/12 involving optical means
• CPC Class Codes: B24B 51/00 Arrangements for automatic control of a series of individual steps in grinding a workpiece if applicable to other machine tools, G05B takes precedence
• CPC Class Codes: G01B 11/0683 measurement during deposition or removal of the layer
• CPC Class Codes: Y10T 428/15 Sheet, web, or layer weakened to permit separation through thickness
• CPC Class Codes: Y10T 428/162 Transparent or translucent layer or section
• CPC Class Codes: Y10T 428/163 Next to unitary web or sheet of equal or greater extent
• CPC Class Codes: Y10T 428/17 Three or more coplanar interfitted sections with securing means
• CPC Class Codes: Y10T 428/218 Aperture containing
• CPC Class Codes: Y10T 428/234 including elements cooperating to form cells
• CPC Class Codes: Y10T 428/24273 including aperture
• CPC Class Codes: Y10T 428/24281 Struck out portion type
• CPC Class Codes: Y10T 428/24289 Embedded or interlocked
• CPC Class Codes: Y10T 428/24322 Composite web or sheet
• CPC Class Codes: Y10T 428/24364 with transparent or protective coating
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/249978 Voids specified as micro
• CPC Class Codes: Y10T 428/31 : Surface property or characteristic of web, sheet or block

Abstract

An apparatus and method of chemical mechanical polishing (CMP) of a wafer employing a device for determining, in-situ, during the CMP process, an endpoint where the process is to be terminated. This device includes a laser interferometer capable of generating a laser beam directed towards the wafer and detecting light reflected from the wafer, and a window disposed adjacent to a hole formed through a platen. The window provides a pathway for the laser beam during at least part of the time the wafer overlies the window.

Claims

1. A polishing pad for use in a chemical mechanical polishing system, said polishing pad comprising:

a polishing surface;

a bottom surface, wherein said bottom surface and said polishing surface of said polishing pad include a hole formed therein; and

a window within said hole, said window being transmissive to light;

wherein said window comprises a light transmissive film between the polishing surface and the bottom surface.

2. The polishing pad of claim 1 wherein said window is made of a polyurethane material.

3. A polishing pad for use in a chemical mechanical polishing system, said polishing pad comprising:

a polishing surface;

a bottom surface, wherein said bottom surface and said polishing surface of said polishing pad include a hole formed therein; and

a window within said hole, said window being transmissive to light, wherein said window comprises a light transmissive plug between the polishing surface and the bottom surface.

4. The pad of claim 3 wherein said plug is made of a polymer material.

5. A polishing pad for use in a chemical mechanical polishing system, said polishing pad comprising:

a polishing surface;

a bottom surface; and

a window from said bottom surface to said polishing surface, said window being more transmissive to light than the polishing surface, wherein the window comprises a light-transmissive plug positioned in the polishing pad.

6. The polishing pad of claim 5, wherein the plug is integrally molded into the polishing pad.

7. The polishing pad of claim 6, wherein a top surface of said plug is flush with the polishing surface.

8. The polishing pad of claim 6, wherein the polishing pad comprises a covering layer having the polishing surface and a backing layer.

9. The polishing pad of claim 8, wherein said plug is positioned in said covering layer.

10. The polishing pad of claim 9, wherein said plug and said covering layer have the same thickness.

11. The polishing pad of claim 10, wherein said plug is made of a polymer material.

12. The polishing pad of claim 9, wherein the backing layer is removed in an area overlaid by the plug.

13. The polishing pad of claim 5, wherein a top surface of said plug is flush with the polishing surface.

14. The polishing pad of claim 13, wherein said plug is positioned in said covering layer.

15. The polishing pad of claim 14, wherein said plug and said covering layer have the same thickness.

16. The polishing pad of claim 5, wherein the polishing pad comprises a covering layer having the polishing surface and a backing layer.

17. The polishing pad of claim 5, wherein said plug is made of a polymer material.

18. A polishing pad for use in a chemical mechanical polishing system, said polishing pad comprising:

a polishing surface;

a bottom surface; and

a window from said bottom surface to said polishing surface, said window comprising a solid light-transmissive material positioned entirely between said polishing surface and said bottom surface, said light-transmissive material being more transmissive to light than the polishing surface.

19. The polishing pad of claim 18, wherein a top surface of said solid light-transmissive material is flush with the polishing surface.

20. The polishing pad of claim 18, wherein the polishing surface has grooving and the solid light-transmissive material lacks the grooving.

21. The polishing pad of claim 20, wherein the light-transmissive material includes polyurethane.

22. The polishing pad of claim 18, wherein the light-transmissive material is integrally molded into the pad.

23. A polishing pad for use in a chemical mechanical polishing system, said polishing pad comprising:

a layer of polishing material having a polishing surface with grooving;

a window in said layer of polishing material, said window comprising a solid light-transmissive material having an upper surface flush with said polishing surface, said light-transmissive material being more transmissive to light than the polishing material and lacking the grooving of the polishing material.

24. The polishing pad of claim 23, further comprising a backing layer secured to a bottom surface of the layer of polishing material.

25. The polishing pad of claim 24, wherein the backing layer includes an aperture aligned with the window in the layer of polishing material.

26. The polishing pad of claim 24, wherein the light-transmissive material is positioned entirely between said polishing surface and a bottom surface of the backing layer.

27. The polishing pad of claim 24, wherein the light-transmissive material is positioned entirely between said polishing surface and a bottom surface of the polishing layer.