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Method of etching silicon nitride spacers with high selectivity relative to oxide in a high density plasma chamber

  • US 20030207585A1
  • Filed: 05/02/2002
  • Published: 11/06/2003
  • Est. Priority Date: 05/02/2002
  • Status: Active Grant
First Claim
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1. A method of selectively etching silicon nitride spacers for sub 0.25 μ

  • m devices, where the selectivity of silicon nitride relative to silicon oxide is in the range of about 15;

    1 to about 24;

    1, the method comprising;

    a) providing a substrate which includes a silicon oxide layer adjacent a silicon nitride layer, wherein the thickness of the silicon oxide layer is less than about 20 Å

    ;

    b) etching said silicon nitride layer to form at least one silicon nitride spacer, wherein the upper shoulder of the spacer is rounded, and said etching is carried out using a plasma source gas including SF6, HBr, and N2, wherein a pressure in an etch chamber in which said etching is carried out is at least 35 mTorr, and wherein a temperature of said substrate during said etching is less than about 75°

    C.

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