Method and apparatus for conditioning a polishing pad with sonic energy

• US 6,875,091 B2
• Filed: 02/28/2001
• Issued: 04/05/2005
• Est. Priority Date: 01/04/2001
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Lam Research Corporation
• Inventors: Lacy, Michael S., Boehm, Robert G., Dunton, Eric A., Radman, Allan M., Jensen, Alan J., Treichel, Helmuth
• Primary Examiner(s): Hail, III, Joseph J.
• Assistant Examiner(s): Ojini, Anthony
• Application Number:
  US09/796,955
• Publication Number:
  US 20020086622A1
• Time in Patent Office: 1,497 Days
• Field of Search: 451/56, 451/72, 451/443, 451/910, 451285-290, 511/21, 511/22, 512/30, 513/17, 438/633, 438/692, 438/959
• US Class Current: 451/56
• CPC Class Codes: B24B 1/04 subjecting the grinding or polishing tools, the abrading or polishing medium or work to vibration, e.g. grinding with ultrasonic frequency polishing or abrading surfaces on work by means of tumbling apparatus B24B31/00, involving oscillating or vibrating containers B24B31/06; superfinishing surfaces on work, e.g. by means of abrading blocks reciprocating with high frequency, B24B35/00
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: B24B 53/10 of travelling flexible backings coated with abrasives; Cleaning of abrasive belts

Abstract

A method and apparatus for conditioning a polishing pad is described, wherein the polishing pad has a polishing surface for polishing the semiconductor wafer. The method includes positioning a sonic energy generator above the polishing surface of the polishing pad, and applying sonic energy to the polishing surface of the polishing pad. The apparatus a sonic energy generator adapted to be positioned above the polishing surface, the sonic energy generator including a transducer, and a liquid carrier in flow communication with the transducer, wherein the transducer transmits sonic energy into the liquid carrier and the liquid carrier is applied to the polishing surface of the polishing belt.

Claims

1. A method for conditioning a polishing pad used in chemical mechanical planarization of a semiconductor wafer, the polishing pad having a polishing surface for polishing the semiconductor wafer, the method comprising:

positioning a sonic energy generator above the polishing surface of the polishing pad;

applying sonic energy to at least one discrete stream of an abrasive-free liquid carrier being transported to the polishing surface of said polishing pad; and

dislodging particles from said polishing surface of the polishing pad with sonic energy generated from said sonic energy generator.

2. The method of claim 1, wherein the sonic energy is between 100 and 1000 watts of power.

3. The method of claim 1, wherein the sonic energy is at a frequency of between about 500 and 1200 kHz.

4. The method of claim 1, wherein the polishing pad is a linear belt.

5. The method of claim 4 further comprising running the liquid carrier onto at least a portion of the sonic energy generator and the polishing surface.

6. The method of claim 1, wherein the polishing pad is a radial disc.

7. The method of claim 1, wherein the sonic energy comprises one of ultrasonic energy and megasonic energy.

8. The method of claim 1, wherein the sonic energy generator is positioned within 25 millimeters of the polishing surface.

9. The method of claim 1 wherein said at least one discrete stream is continuous.

10. The method of claim 1 wherein said at least one discrete stream is a pressurized stream.

11. The method of claim 10 wherein said pressurized stream is simultaneously applied to more than one half of one of a width and a radius of said polishing surface of the polishing pad.

12. The method of claim 11 wherein said polishing pad comprises a radial disc.

13. The method of claim 11 wherein said polishing pad comprises a linear belt.

14. The method of claim 10 wherein said at least one discrete stream of the liquid carrier is dispensed through at least one nozzle.

15. The method of claim 10 wherein said at least one discrete stream of the liquid carrier is dispensed through at least one small slit.

16. A method for conditioning a polishing pad used in chemical mechanical planarization of a semiconductor wafer, the polishing pad having a polishing surface for polishing the semiconductor wafer, the method comprising:

applying sonic energy to an abrasive-free liquid carrier; and

simultaneously transporting the liquid carrier onto the polishing surface of the polishing pad to dislodge particles from said polishing surface with sonic energy.

17. The method of claim 16, wherein the sonic energy is between 100 and 1000 watts of power.

18. The method of claim 16, wherein the sonic energy is at a frequency of between about 500 and 1200 kHz.

19. The method of claim 16, wherein the liquid carrier is at a pressure of between about 100 kPa and about 300 kPa.

20. The method of claim 16, wherein the sonic energy generator is mounted onto a mechanical arm.

21. A wafer polisher for chemical mechanical planarization of a semiconductor wafer, the wafer polisher comprising:

a polishing pad having a polishing surface for polishing a semiconductor wafer; and

a pad conditioner for conditioning the polishing pad, wherein the pad conditioner comprises a sonic energy generator configured to transmit sonic energy to at least one discrete stream of an abrasive-free liquid carrier being transported to the polishing surface of the polishing pad sufficient to dislodge particles from the polishing surface of said polishing pad.

22. The wafer polisher of claim 21, wherein the sonic energy generator comes into direct contact with the polishing surface of the polishing pad.

23. The wafer polisher of claim 21, wherein the polishing pad is a continuous, linear belt.

24. The wafer polisher of claim 21, wherein the sonic energy is applied to the liquid carrier and the liquid carrier is applied to the polishing surface.

25. The wafer polisher of claim 21, wherein the pad conditioner includes a liquid distribution unit for applying the liquid carrier onto the polishing surface.

26. A pad conditioner for conditioning a polishing pad having a polishing surface for polishing a semiconductor wafer, the pad conditioner comprising:

a sonic energy generator positioned above the polishing surface, the sonic energy generator comprising a transducer;

a continuous, abrasive-free liquid carrier in flow communication with the transducer, wherein the transducer transmits sonic energy into the liquid carrier and the liquid carrier is applied to the polishing surface of the polishing pad, dislodging particles from said polishing surface of the polishing pad, wherein the polishing surface is conditioned such that particles are removed.

27. The pad conditioner of claim 26 further comprising a liquid distribution unit for applying the liquid carrier onto the polishing surface.

28. The pad conditioner of claim 26, wherein the sonic energy is between 100 and 1000 watts of power.

29. The pad conditioner of claim 26, wherein the sonic energy is at a frequency of between about 500 and 1200 kHz.

30. The pad conditioner of claim 26, wherein at least a portion of the pad conditioner is positioned within 25 millimeters of the polishing surface.

31. The apparatus of claim 26 wherein the liquid carrier is selected from the group consisting of:

a) Water;

b) potassium hydroxide;

c) ammonium hydroxide;

d) a combination of hydrogen peroxide with water, potassium hydroxide, or ammonium hydroxide;

e) a combination of hydrogen peroxide and a chelating agent with water potassium hydroxide, or ammonium hydroxide; and

f) a combination of ammonia, water, and hydrogen peroxide.