Method and apparatus for using across wafer back pressure differentials to influence the performance of chemical mechanical polishing

• US 6,179,956 B1
• Filed: 11/16/1999
• Issued: 01/30/2001
• Est. Priority Date: 01/09/1998
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Nagahara, Ronald J., Lee, Dawn M.
• Primary Examiner(s): Utech, Benjamin L.
• Assistant Examiner(s): DEO, DUY VU NGUYEN
• Application Number:
  US09/442,078
• Time in Patent Office: 441 Days
• Field of Search: 451/5, 451/41, 451/189, 451/199, 451/285, 451/186, 451/289, 451/388, 451/398, 451/397, 451/287, 451/288, 438/692, 438/691, 438/693
• US Class Current: 156/345.14
• CPC Class Codes: B24B 37/30 for single side lapping of plane surfaces

Abstract

Methods and apparatus for planarizing the surface of a semiconductor wafer by applying non-uniform pressure distributions across the back side of the wafer are disclosed. According to one aspect of the present invention, a chemical mechanical polishing apparatus for polishing a first surface of a semiconductor wafer includes a polishing pad which polishes the first surface of the semiconductor wafer. The apparatus also includes a first mechanism which is used to hold, or otherwise support, the wafer during polishing, and a second mechanism that is used to apply a non-uniform pressure distribution through the first mechanism, directly onto a second surface of the wafer. The second mechanism is further used to facilitate polishing the first surface of the semiconductor wafer such that the first surface of the semiconductor wafer is evenly polished. In one embodiment, the second mechanism is arranged to apply both positive pressure and negative pressure substantially simultaneously across the second surface of the semiconductor wafer.

Claims

1. A chemical mechanical polishing apparatus for polishing a first surface of a semiconductor wafer, the apparatus comprising:

a platen arranged to hold polishing pad to contact the first surface of the semiconductor wafer to polish the first surface of the semiconductor wafer; and

a mechanism for applying a non-uniform pressure distribution directly on portions of a second surface of the semiconductor wafer, the mechanism further being arranged to support the semiconductor wafer, wherein the non-uniform pressure distribution facilitates polishing the first surface of the semiconductor wafer such that the first surface of the semiconductor wafer is evenly polished;

wherein the mechanism for applying the non-uniform pressure distribution includes;

a retaining ring,

a carrier, and

a carrier film, wherein the retaining ring, the carrier, and the carrier film cooperate to support the semiconductor wafer;

wherein the carrier and the carrier film are arranged to facilitate the application of the non-uniform pressure distribution along the second surface of the semiconductor wafer;

wherein a plurality of openings is defined through both the carrier and the carrier film, the plurality of openings being in communication with an air supply to provide the non-uniform pressure distribution along the second surface of the semiconductor wafer;

wherein the plurality of openings is arranged as a plurality of circles, the circles being concentric with respect to an axial center of the semiconductor wafer; and

wherein a first opening selected from the plurality of openings has a first diameter and a second opening selected from the plurality of openings has a second diameter.

2. A chemical mechanical polishing apparatus as recited in claim 1 wherein the mechanism for applying the non-uniform pressure distribution further includes an air supply arranged to provide the non-uniform pressure distribution along the second surface of the semiconductor wafer.

3. A chemical mechanical polishing apparatus as recited in claim 2 wherein the air supply is arranged to provide negative pressures.

4. A chemical mechanical polishing apparatus as recited in claim 2 wherein the air supply is arranged to provide positive pressures.