Method for in-situ endpoint detection for chemical mechanical polishing operations

• US 6,537,133 B1
• Filed: 09/28/2000
• Issued: 03/25/2003
• Est. Priority Date: 03/28/1995
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Birang, Manoocher, Gleason, Allan, Johansson, Nils
• Primary Examiner(s): Eley, Timothy V.
• Application Number:
  US09/672,549
• Time in Patent Office: 908 Days
• Field of Search: 451/5, 451/6, 451/41, 451/7, 451/285, 451/287, 451/288, 451/63
• US Class Current: 451/6
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/205 provided with a window for inspecting the surface of the work being lapped
• CPC Class Codes: B24B 47/12 by mechanical gearing or electric power B24B47/16 takes precedence
• CPC Class Codes: B24B 49/04 involving measurement of the workpiece at the place of grinding during grinding operation
• CPC Class Codes: B24B 49/12 involving optical means
• CPC Class Codes: B24B 51/00 Arrangements for automatic control of a series of individual steps in grinding a workpiece if applicable to other machine tools, G05B takes precedence
• CPC Class Codes: G01B 11/0683 measurement during deposition or removal of the layer

Abstract

An apparatus and method of chemical mechanical polishing (CMP) of a wafer employing a device for determining, in-situ, during the CMP process, an endpoint where the process is to be terminated. This device includes a laser interferometer capable of generating a laser beam directed towards the wafer and detecting light reflected from the wafer, and a window disposed adjacent to a hole formed through a platen. The window provides a pathway for the laser beam during at least part of the time the wafer overlies the window.

Claims

1. A method of endpoint detection during polishing of semiconductor wafers using a polishing pad, said method comprising,

polishing a said wafer with said polishing pad having a transparent portion of transparent solid material having an upper surface and a lower surface,

transmitting detection light through said transparent portion of said polishing pad to a wafer surface of said wafer being polished, and

receiving a reflection of said light reflecting off of said wafer surface and passing through said transparent portion of said polishing pad.

2. The method of claim 1 wherein said polishing includes polishing with said polishing pad having said transparent portion made of a polyurethane film.

3. The method of claim 1 wherein said polishing includes polishing with a pad having a nontransparent portion made of a different material than said transparent portion.

4. The method of claim 3 wherein said polishing includes polishing with said polishing pad having said nontransparent portion comprising microporous polyurethane.

5. The method of claim 3 wherein said transparent portion has a first upper surface and said nontransparent portion has a second upper surface and said first and second upper surfaces are coplanar.