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METHOD OF ANISOTROPIC EXTRACTION OF SILICON NITRIDE MANDREL FOR FABRICATION OF SELF-ALIGNED BLOCK STRUCTURES

  • US 20180277386A1
  • Filed: 02/23/2018
  • Published: 09/27/2018
  • Est. Priority Date: 02/23/2017
  • Status: Active Grant
First Claim
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1. A method of preparing a self-aligned block (SAB) structure, comprising:

  • providing a substrate having raised features defined by a first material containing silicon nitride and a second material containing silicon oxide formed on side walls of the first material, and a third material containing an organic material covering some of the raised features and exposing some raised features according to a block pattern formed in the third material;

    forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas;

    exposing the first, second, and third materials on the substrate to the first chemical mixture;

    thereafter, forming a second chemical mixture by plasma-excitation of a second process gas containing S, F, and optionally a noble element; and

    exposing the first, second, and third materials on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second and third materials.

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