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FORMING A FIN USING DOUBLE TRENCH EPITAXY

  • US 20160315174A1
  • Filed: 04/22/2015
  • Published: 10/27/2016
  • Est. Priority Date: 04/22/2015
  • Status: Active Grant
First Claim
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1. A method comprising:

  • forming a first dielectric layer on a substrate;

    partially removing the first dielectric layer exposing an upper surface of the substrate, and forming a lower trench extending across a length of the substrate;

    filling the lower trench and forming a second dielectric layer on the first dielectric layer;

    forming a third dielectric layer on the second dielectric layer;

    removing one or more portions of the third dielectric layer down to the second dielectric layer to form one or more upper trenches, leaving a remaining portion of the third dielectric layer above the lower trench and having a width greater than a width of the lower trench;

    completely removing the second dielectric layer exposing the first dielectric layer and exposing the upper surface of the substrate;

    forming an epitaxial layer on the upper surface of the substrate and on the first dielectric layer, the epitaxial layer filling the lower trench and the one or more upper trenches up to a height above an upper surface of the third dielectric layer; and

    removing the epitaxial layer above the upper surface of the third dielectric layer, making an upper surface of the epitaxial layer substantially flush with the upper surface of the third dielectric layer.

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