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

• US 7,018,269 B2
• Filed: 06/18/2003
• Issued: 03/28/2006
• Est. Priority Date: 06/18/2003
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Lam Research Corporation
• Inventors: Anderson, Thomas W.
• Primary Examiner(s): RACHUBA, MAURINA T
• Application Number:
  US10/465,731
• Publication Number:
  US 20040259477A1
• Time in Patent Office: 1,014 Days
• Field of Search: 451/5, 451/6, 451/8, 451/11, 451/41, 451/56, 451/21, 451/443, 451/444, 451285-289
• US Class Current: 451/5
• 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 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 control device to non-uniformly condition the polishing pad to a roughness profile with a continuously varying shape.

2. The method of claim 1 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.

3. The method of claim 1 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.

4. The method of claim 1 wherein the roughness value is displayed as an average roughness value.

5. The method of claim 1 wherein the roughness value is displayed as an rms roughness value.

6. The method of claim 1 wherein the roughness value is displayed as a result from a power spectral density function.

7. The method of claim 1 wherein the roughness value is displayed as a result from an autocorrelation function.