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SEMICONDUCTOR DEVICE HAVING TRENCH TOP ISOLATION LAYER AND METHOD FOR FORMING THE SAME

  • US 20040209422A1
  • Filed: 07/16/2003
  • Published: 10/21/2004
  • Est. Priority Date: 04/15/2003
  • Status: Active Grant
First Claim
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1. A method for forming a semiconductor device having a trench top isolation layer, comprising the steps of:

  • providing a substrate having at least one trench therein;

    forming a collar insulating layer over the sidewall of a lower portion of the trench;

    forming a first conductive layer protruding to the collar insulating layer in the lower portion of the trench;

    forming a second conductive layer overlying the first conductive layer and covering the collar insulating layer;

    forming an insulating spacer over an upper portion of the sidewall of the trench and separated from the second conductive layer by a gap;

    thermally oxidizing a portion of the second conductive layer to form an oxide layer thereon whereby the gap is filled;

    removing the oxide layer to expose the second conductive layer;

    forming a reverse T-shaped insulating layer by chemical vapor deposition to serve as the trench top isolation layer; and

    removing the insulating spacer.

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