Pad conditioner control using feedback from a measured polishing pad roughness level

• US 20040259477A1
• Filed: 06/18/2003
• Published: 12/23/2004
• Est. Priority Date: 06/18/2003
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Lam Research Corporation
• Inventors: Anderson, Thomas W.
• Granted Patent: US 7,018,269 B2
• Time in Patent Office: Days
• US Class Current: 451/21
• CPC Class Codes: B24B 21/04 for grinding plane surfaces
• CPC Class Codes: B24B 49/18 taking regard of the presence of dressing tools
• CPC Class Codes: B24B 53/017 Devices or means for dressing, cleaning or otherwise conditioning lapping tools
• CPC Class Codes: H01L 21/30625 With simultaneous mechanical treatment, e.g. mechanico-chemical polishing

Abstract

The present invention is a system for controlling a pad conditioner in a CMP device. The system includes a roughness-sensing device mounted in proximity to a polishing pad. The roughness-sensing device generates an output responsive to a roughness of the polishing pad. A signal-processing unit then generates a roughness value of the polishing pad in response to the output from the roughness-sensing device, and generates a control signal in response to the generated roughness value. Finally, a control device controls motion of the pad conditioner in response to the control signal.

Claims

1. A system for controlling a pad conditioner in a CMP device, comprising:

a polishing pad;

a spindle downforce assembly mounted in proximity to the polishing pad, the spindle downforce assembly configured to hold a semiconductor wafer for planarization by the polishing pad;

a roughness-sensing device located in proximity to the polishing pad, the roughness-sensing device configured to generate an output responsive to a roughness of the polishing pad;

a signal-processing unit configured to generate a roughness value of the polishing pad in response to the output from the roughness-sensing device, the signal-processing unit further configured to generate a control signal in response to the generated roughness value; and

a control device configured to control motion of the pad conditioner in response to the control signal.

2. The system of claim 1 wherein the roughness-sensing device is a stylus profilometer.

3. The system of claim 1 wherein the roughness-sensing device is an optical profilometer.

4. The system of claim 1 wherein the roughness-sensing device is a scatterometer.

5. The system of claim 1 further comprising a display coupled to the signal-processing unit.

6. A system for controlling a pad conditioner in a CMP device, comprising:

a roughness-sensing device configured to be mounted in proximity to a polishing pad, the roughness-sensing device further configured to generate an output responsive to a roughness of the polishing pad;

a signal-processing unit configured to generate a roughness value of the polishing pad in response to the output from the roughness-sensing device, the signal-processing unit further configured to generate a control signal in response to the generated roughness value; and

a control device configured to control motion of the pad conditioner in response to the control signal.

7. The system of claim 6 wherein the roughness-sensing device is a stylus profilometer.

8. The system of claim 6 wherein the roughness-sensing device is an optical profilometer.

9. The system of claim 6 wherein the roughness-sensing device is a scatterometer.

10. The system of claim 6 wherein the control device is pneumatically controlled.

11. The system of claim 6 wherein the roughness value is an average roughness.

12. The system of claim 6 wherein the roughness value is an rms roughness.

13. The system of claim 6 wherein the roughness value is a power spectral density function.

14. The system of claim 6 wherein the roughness value is an autocorrelation function.

15. The system of claim 6 further comprising a display coupled to the signal-processing unit.

16. A method for controlling a pad conditioner in a CMP device, comprising:

sensing a roughness of a CMP polishing pad using a roughness-sensing device;

determining a roughness value of the CMP polishing pad based on the sensed roughness;

generating a control signal in response to the roughness value; and

applying the control signal to a pad conditioner motion control device.

17. The method of claim 16 further comprising repeating the steps of sensing a roughness, determining a roughness value, generating a control signal, and applying the control signal until the roughness value is within a prescribed range of roughness.

18. The method of claim 16 wherein the step of applying the control signal creates a non-linear roughness on the polishing pad by applying one or more conditioning variables, wherein the conditioning variables are selected from a group consisting of pad conditioner rotational rate, pad conditioner pressure, and pad conditioner time in contact with the polishing pad.

19. The method of claim 16 wherein the roughness value is displayed as an average roughness value.

20. The method of claim 16 wherein the roughness value is displayed as an rms roughness value.

21. The method of claim 16 wherein the roughness value is displayed as a result from a power spectral density function.

22. The method of claim 16 wherein the roughness value is displayed as a result from an autocorrelation function.

23. A system for controlling a pad conditioner in a CMP device, comprising:

a means for sensing roughness configured to be mounted in proximity to a CMP polishing pad;

a means for generating a roughness value of the polishing pad based on a sensed roughness; and

a means for controlling a motion of the pad conditioner based on the roughness value.