Polishing pad for in-situ endpoint detection

• US 6,860,791 B2
• Filed: 11/25/2003
• Issued: 03/01/2005
• Est. Priority Date: 03/28/1995
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Birang, Manoocher, Gleason, Allan
• Primary Examiner(s): Hall, III, Joseph J.
• Assistant Examiner(s): McDonald, Shantese L.
• Application Number:
  US10/722,305
• Publication Number:
  US 20040106357A1
• Time in Patent Office: 462 Days
• Field of Search: 451/6, 451/8, 451/10, 451/41, 451/526, 451/527, 451/533
• 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 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 article for use in a chemical mechanical polishing system, said polishing article comprising:

a polishing pad having a polishing surface and a bottom surface; and

a window from said polishing surface to said bottom surface, said window including a solid light transmissive element abutting and secured to the polishing pad, the solid light transmissive element being more transmissive to light than the polishing surface.

2. The polishing pad of claim 1, wherein a top surface of said light transmissive element is flush with the polishing surface.

3. The polishing article of claim 1, wherein side surfaces of said light transmissive element abut side surfaces of said polishing pad.

4. The polishing article of claim 1, wherein said light transmissive element is integrally molded into the polishing pad.

5. The polishing article of claim 1, wherein said polishing pad includes a covering layer having the polishing surface and a backing layer.

6. The polishing article of claim 5, wherein said light transmissive element is positioned in said covering layer.

7. The polishing article of claim 6, wherein a bottom surface of said light transmissive element is flush with a bottom surface of said covering layer.

8. The polishing article of claim 6, wherein a top surface of said light transmissive element is flush with the polishing surface.

9. The polishing article of claim 6, wherein said light transmissive element and said covering layer have the same thickness.

10. The polishing article of claim 6, wherein said light transmissive element is made of a polymer material.

11. The polishing article of claim 6, wherein said backing layer is removed in an area overlaid by said light transmissive element.

12. The polishing article of claim 1, wherein said light transmissive element is made of a polymer material.

13. A polishing article for use in a chemical mechanical polishing system, said polishing article comprising:

a polishing pad having a polishing surface and a bottom surface; and

a window from said polishing surface to said bottom surface, the window including a solid light transmissive element integrally molded to the polishing pad, the light transmissive element being more transmissive to light than the polishing surface.

14. The polishing article of claim 13, wherein said polishing pad and said light transmissive element include polyurethane.

15. The polishing article of claim 13, wherein a top surface of said light transmissive element is flush with the polishing surface.

16. The polishing article of claim 13, wherein side surfaces of said light transmissive element abut side surfaces of said polishing pad.

17. The polishing article of claim 13, wherein said polishing pad includes a covering layer having the polishing surface and a backing layer.

18. The polishing article of claim 17, wherein said light transmissive element is positioned in said covering layer.

19. The polishing article of claim 18, wherein said light transmissive element and said covering layer have the same thickness.

20. The polishing article of claim 19, wherein said backing layer is removed in an area overlaid by said light transmissive element.

21. A polishing article for use in a chemical mechanical polishing system, said polishing article comprising:

a light transmissive first layer spanning the polishing article; and

a second layer that is less transmissive to light than the first layer, the second layer having an aperture threrethrough.

22. The polishing article of claim 21, wherein the first layer includes a polishing surface.

23. The polishing article of claim 22, wherein the second layer is a backing layer adjacent the first layer.

24. The polishing article of claim 21, wherein said first layer includes polyurethane.

25. The polishing article of claim 21, wherein said second layer includes polyurethane.

26. The polishing article of claim 21, wherein the aperture comprises a hole through the second layer.