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Method and apparatus for detecting an ion-implanted polishing endpoint layer within a semiconductor wafer

  • US 6,268,224 B1
  • Filed: 06/30/1998
  • Issued: 07/31/2001
  • Est. Priority Date: 06/30/1998
  • Status: Expired due to Term
First Claim
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1. A method of fabricating a semiconductor wafer, comprising the steps of:

  • implanting ions into said wafer so as to form a polishing endpoint layer in said wafer, said ion-implanted polishing endpoint layer having a first outer level and a second outer level;

    polishing said wafer in order to remove material from said wafer;

    detecting a first change in friction when material of said ion-implanted polishing endpoint layer begins to be removed during said polishing step so as to determine that said wafer has been polished to said first outer level of said ion-implanted polishing endpoint layer;

    detecting a second change in friction when material of said ion-implanted polishing endpoint layer ceases to be removed during said polishing step so as to determine that said wafer has been polished to said second outer level of said ion-implanted polishing endpoint layer; and

    terminating said polishing step in response to detection of said second change in friction.

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