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Endpoint detector for a chemical mechanical polishing system

  • US 5,846,882 A
  • Filed: 10/03/1996
  • Issued: 12/08/1998
  • Est. Priority Date: 10/03/1996
  • Status: Expired due to Term
First Claim
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1. An endpoint detector for a chemical mechanical polishing apparatus having a polishing surface, a positioning member for positioning a substrate in contact with the polishing surface, and a motor for creating relative movement between the polishing surface and the substrate, comprising:

  • a monitor to measure the power input to the motor and generate an output signal representing the power input;

    an accumulator to sum the output signal over time; and

    a comparator to compare the sum to a reference value to indicate when an endpoint condition has been reached.

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