Multi-step, in-situ pad conditioning system and method for chemical mechanical planarization

• US 20050186891A1
• Filed: 01/25/2005
• Published: 08/25/2005
• Est. Priority Date: 01/26/2004
• Status: Active Grant

• Current Assignee: TBW Industries Incorporated
• Original Assignee: TBW Industries Incorporated
• Inventors: Benner, Stephen J.
• Granted Patent: US 7,040,967 B2
• Time in Patent Office: Days
• US Class Current: 451/56
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: B24B 57/02 for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]

Abstract

An arrangement for performing a multi-step polishing process on a single stage chemical mechanical planarization (CMP) apparatus utilizes an in-situ conditioning operation to continuously clean and evacuate debris and spent polishing slurry from the surface of the polishing pad. By presenting a clean, virtually “new” polishing pad surface at the beginning of each planarization cycle, polishing agents of different chemistries, morphologies, temperatures, etc. may be used without the need to remove the wafer to change the polishing source or transfer the wafer to another CMP polishing station. A multi-positional valve may be used to control the introduction of various process fluids, including a variety of different polishing slurries and conditioning/flushing agents. The use of different conditioning materials allows for the surface of the polishing pad to be altered for different process conditions (e.g., neutralizing prior polishing chemicals, modifying the surface temperature of the pad to control polishing rate, use of surfactants to dislodge particles that become attracted to the pad surface, etc.).

Claims

1. A method of providing an in-situ process for conditioning the surface of a polishing pad used in a chemical mechanical planarization (CMP) process, the in-situ conditioning process comprising the steps of:

a) processing the surface of a polishing pad to dislodge contaminants associated with the CMP process;

b) evacuating the dislodged contaminants away from the polishing pad to prepare a cleaned polishing pad surface; and

c) presenting the cleaned polishing pad surface for use in a subsequent planarization operation.

2. The method as defined in claim 1 wherein steps a) and b) are performed subsequent to each planarization operation so as to remove contaminants and prevent cross-contamination between planarization operations.

3. The method as defined in claim 1 wherein in performing step a), the surface of the polishing pad is abraded to dislodge the contaminants.

4. The method as defined in claim 1 wherein step b) further includes introducing a conditioning agent onto the polishing pad surface to assist the conditioning process.

5. The method as defined in claim 4 wherein ultra-pure water (UPW) is applied as the conditioning agent.

6. The method as defined in claim 4 wherein the temperature of the introduced conditioning agent is controlled to affect the temperature of the polishing pad surface.

7. The method as defined in claim 4 wherein the chemistry of the introduced conditioning agent is selected to neutralize the reaction of any previously-applied CMP process materials with the wafer surface.

8. The method as defined in claim 7 wherein the previously-applied CMP process materials include a polishing slurry.

9. The method as defined in claim 1 wherein in performing step b), a vacuum force is applied to evacuate the dislodged contaminants.

10. The method as defined in claim 1 wherein subsequent to presenting the cleaned polishing pad, a polishing slurry is introduced onto the cleaned polishing pad without resulting in cross-contamination effects with the chemistry of prior-applied CMP materials.

11. The method as defined in claim 10 wherein the prior-applied CMP materials include a prior-applied polishing slurry.

12. The method as defined in claim 11 wherein the subsequent polishing slurry exhibits different chemical characteristics than the prior-applied polishing slurry.

13. The method as defined in claim 11 wherein the subsequent polishing slurry exhibits a different abrasive particulate concentration than the prior-applied slurry.

14. The method as defined in claim 11 wherein the subsequent polishing slurry exhibits a different abrasive particulate size than the prior-applied polishing slurry.

15. The method as defined in claim 10 wherein the prior-applied CMP materials include a prior-applied conditioning agent.

16. The method as defined in claim 1 wherein in performing step a), a diamond-surfaced conditioning disk is rotated on the polishing pad surface to dislodge the contaminants from the polishing pad surface.

17. A chemical mechanical planarization (CMP) system for performing multi-step polishing at a single polishing station, the system comprising

a polishing pad for interacting with a semiconductor wafer surface to remove unwanted material from the surface thereof;

a conditioning apparatus disposed over at least a portion of the polishing pad, the conditioning apparatus including an abrasive, apertured conditioning disk for abrading the polishing pad to dislodge debris, and a vacuum-assisted component to remove the dislodged debris as it is created; and

a dispenser for introducing a plurality of polishing slurries onto the cleaned polishing pad in a controlled manner, wherein the conditioning performed by the conditioning apparatus functions to remove contaminants from the polishing pad between each polishing operation, thus presenting a clean polishing pad surface for each planarization operation and preventing cross-contamination between polishing slurries.

18. The CMP system of claim 17 wherein the dispenser is further capable of introducing various conditioning agents to the conditioning apparatus so as to assist in the cleaning operation at the polishing pad surface.

19. The CMP system of claim 17 wherein the dispenser includes at least a neutralizing conditioning agent to prevent cross-contamination between polishing slurries of different chemistries.

20. The CMP system of claim 17 wherein the dispenser includes a conditioning agent exhibiting a predetermined temperature associated with maintaining a desired operating temperature at the polishing pad surface.

21. The CMP system of claim 17 wherein the dispenser includes a conditioning agent including a surfactant element to reduce the electrical attraction between debris particles and the polishing pad surface.

22. The CMP system of claim 17 wherein the dispenser introduces polishing slurries from multiple sources.

23. A chemical mechanical planarization (CMP) system for performing multi-step polishing at a single polishing station, the system comprising

a polishing pad for interacting with a semiconductor wafer surface to remove unwanted material from the surface thereof;

and

a conditioning apparatus disposed over at least a portion of the polishing pad, the conditioning apparatus including

a dispenser for introducing polishing or conditioning materials onto the polishing pad surface in a controlled manner;

an abrasive, apertured conditioning disk for abrading the polishing pad to dislodge debris and clean the polishing pad surface; and

a vacuum-assisted component to remove the dislodged debris through the apertured conditioning disk as debris is created, wherein the conditioning apparatus removes contaminants between each polishing operation.

24. A chemical mechanical planarization (CMP) system as defined in claim 23 wherein the conditioning apparatus functions to present a clean polishing pad surface for each sequential step in the multi-step polishing process, thereby preventing cross-contamination between the polishing or conditioning materials dispensed onto the polishing pad surface.