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Dry etching method

  • US 5,733,820 A
  • Filed: 04/24/1996
  • Issued: 03/31/1998
  • Est. Priority Date: 04/27/1995
  • Status: Expired due to Fees
First Claim
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1. A dry etching method for etching silicon material layers by using plasma of a gas mixture including oxygen and at least one halogen/halide, the method including the steps of:

  • measuring intensities of a first emission from the plasma at a first wavelength and a second emission from the plasma at a second wavelength;

    obtaining a ratio of the intensity of the first emission to that of the second emission;

    measuring selectivity of silicon material layers to an oxide layer formed over a substrate for a condition of the plasma for which the emission intensity ratio is obtained;

    obtaining a correlation between the emission intensity ratio and the selectivity; and

    setting a plasma condition for a desired selectivity based on a measured emission intensity ratio by using the correlation.

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