Method and system for polishing a semiconductor wafer

• US 6,609,946 B1
• Filed: 07/14/2000
• Issued: 08/26/2003
• Est. Priority Date: 07/14/2000
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Tran, Minh Quoc
• Primary Examiner(s): RACHUBA, MAURINA T
• Application Number:
  US09/616,473
• Time in Patent Office: 1,138 Days
• Field of Search: 451/5, 451/8, 451/6, 451/10, 451/41, 451/285, 451/287, 451/288
• US Class Current: 451/5
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 49/04 involving measurement of the workpiece at the place of grinding during grinding operation

Abstract

The present invention provides a method and system for polishing a wafer surface. The method and system comprises determining whether a thickness of the wafer surface is uniform while the wafer surface is being polished, and adjusting the polishing process while the wafer surface is being polished based on the determination of whether the thickness of the wafer surface is uniform. Through the use of the method and system in accordance with the present invention, in-situ adjustments can be made to the CMP polishing process while the wafer is actually being polished. This results in a substantial improvement in polishing uniformity.

Claims

1. A method for polishing a wafer comprising the steps of:

a) determining whether a thickness of the wafer surface is uniform while the wafer surface is being polished, wherein step a) further comprises;

a1) fast sampling the thickness of the wafer surface while the wafer surface is being polished; and

a2) determining a characterization of the polishing process; and

b) adjusting the polishing process while the wafer surface is being polished based on step (a).

2. The method of claim 1 wherein the thickness of the wafer surface is sampled at a rate of every microsecond.

3. The method of claim 1 the characterization is non-uniform.

4. The method of claim 3 wherein the non-uniform characterization is edge fast.

5. The method of claim 3 wherein the non-uniform characterization is edge slow.

6. The method of claim 1 wherein step b) further comprises:

b1) adjusting at least one of a plurality of polishing parameters based on the characterization of the polishing process.

14. The method as recited in claim 6, wherein said at least one of said plurality of polishing parameters comprises at least one of the following:

head speed, platen speed, slurry flow, and downward pressure.

7. A system of polishing a wafer surface comprising:

means for determining whether the thickness of the wafer surface is uniform while the wafer surface is being polished; and

means for adjusting the polishing process while the wafer surface is being polished based on whether the thickness of the wafer surface is uniform, wherein the means for determining whether the thickness of the wafer surface is uniform further comprises;

means for fast sampling the thickness of the wafer surface while the wafer surface is being polished; and

means for determining a characterization of the polishing process.

8. The system of claim 7 wherein the thickness of the wafer surface is sampled at a rate of every microsecond.

9. The system of claim 7 wherein the characterization is non-uniform.

10. The system of claim 8 wherein the non-uniform characterization is edge fast.

11. The system of claim 8 wherein the characterization is edge slow.

12. The system of claim 8 wherein the means for adjusting the polishing process further comprises:

means for adjusting at least one of a plurality of polishing parameters based on the characterization of the polishing process.

13. The system of claim 8 wherein the means for determining a characterization of the polishing process comprises computer implemented software modeling.

15. The system as recited in claim 12, wherein said at least one of said plurality of polishing parameters comprises at least one of the following:

head speed, platen speed, slurry flow, and downward pressure.