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Etching of high aspect ratio structures

  • US 6,921,725 B2
  • Filed: 06/28/2001
  • Issued: 07/26/2005
  • Est. Priority Date: 06/28/2001
  • Status: Expired due to Fees
First Claim
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1. A method of forming an aperture in a silicon oxide layer, the method comprising:

  • generating a plasma containing fluorine and at least one element selected from the group consisting of bromine and iodine;

    accelerating ions from the plasma toward a surface of the silicon oxide layer;

    etching an exposed portion of the silicon oxide layer, thereby advancing an etch front into the silicon oxide layer and forming the aperture having sidewalls;

    absorbing components containing the at least one element on the sidewalls of the aperture; and

    continuing to advance the etch front and absorb components containing the at least one element on the sidewalls of the aperture until a desired aspect ratio is attained;

    wherein the desired aspect ratio is greater than about 5;

    1; and

    wherein a content of the at least one element is sufficient to produce a taper angle of the sidewalls of greater than about 87°

    at the desired aspect ratio.

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