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Multi-channel plasma discharge endpoint detection method

  • US 5,160,402 A
  • Filed: 05/24/1990
  • Issued: 11/03/1992
  • Est. Priority Date: 05/24/1990
  • Status: Expired due to Term
First Claim
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1. A method of monitoring a plasma process which comprises(a) optically monitoring a plurality of preselected emission spectra developed by a plasma in a plasma chamber,(b) amplifying and digitizing a plurality of spectra signals of said spectra,(c) weighting and summing said signals to form a composite function, and(d) comparing the slope of the composite function to a predetermined value to determine preselected conditions within said plasma.

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