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DUAL SHALLOW TRENCH ISOLATION STRUCTURE

  • US 20090072355A1
  • Filed: 09/17/2007
  • Published: 03/19/2009
  • Est. Priority Date: 09/17/2007
  • Status: Abandoned Application
First Claim
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1. A method of manufacturing a semiconductor structure, comprising:

  • forming a trench having a first depth and containing a pair of substantially planar trench sidewalls in a semiconductor substrate;

    forming an oxidation barrier layer on a lower portion of said pair of substantially planar trench sidewalls;

    forming a thermal oxide collar on an upper portion of said pair of substantially planar trench sidewalls above a second depth, wherein said pair of substantially planar trench sidewalls becomes separated by an upper portion width within said upper portion; and

    etching said lower portion of said pair of substantially planar trench sidewalls below said second depth to form another pair of substantially planar trench sidewalls separated by a lower portion width, wherein said lower portion width is greater than said upper portion width.

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