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System for real-time control of semiconductor wafer polishing including optical monitoring

  • US 5,658,183 A
  • Filed: 10/24/1995
  • Issued: 08/19/1997
  • Est. Priority Date: 08/25/1993
  • Status: Expired due to Term
First Claim
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1. A system for polishing a semiconductor wafer, the system comprising:

  • a wafer polishing assembly for polishing a face of a semiconductor wafer at a polishing rate and a polishing uniformity, the wafer polishing assembly including a platen subassembly defining a polishing area, a slurry supply system delivering a slurry to the polishing area, and a polishing head selectively supporting a semiconductor wafer and holding a face of the semiconductor wafer in contact with the platen subassembly;

    an endpoint detector operating on the wafer to determine whether polishing of the wafer is complete, the endpoint detector having an optical measurement system including an optical window spaced apart from the platen subassembly, including a liquid filled, wafer receiving area, on one side of the optical window, which selectively receives the wafer, and including optics on the other side of the window, and movable relative to the wafer receiving area, which scan the wafer face while the wafer face remains stationary, the optical measurement system measuring film thickness at multiple different locations on the wafer face while the wafer face is in contact with a liquid, wherein drying of the wafer is impeded while the film thickness measurements are taken; and

    a robot selectively moving the wafer between the platen subassembly and the wafer receiving area.

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