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SELECTIVE SUPPRESSION OF DRY-ETCH RATE OF MATERIALS CONTAINING BOTH SILICON AND OXYGEN

  • US 20130052827A1
  • Filed: 04/18/2012
  • Published: 02/28/2013
  • Est. Priority Date: 08/26/2011
  • Status: Active Grant
First Claim
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1. A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed silicon-and-oxygen-containing region and an exposed region of a second material having a different chemical stoichiometry from the exposed silicon-and-oxygen-containing region, the method of etching the patterned substrate comprising sequential steps of:

  • (1) a first dry etch stage comprising;

    flowing each of a first fluorine-containing precursor and a hydrogen-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a first plasma in the remote plasma region to produce first plasma effluents, andforming protective solid by-product on the exposed silicon-and-oxygen-containing region to form a protected silicon-and-oxygen-containing region, wherein forming the protective solid by-product comprises flowing the first plasma effluents into the substrate processing region in a showerhead;

    (2) a second dry etch stage comprisingflowing a second fluorine-containing precursor into the remote plasma region while forming a second plasma in the remote plasma region to produce second plasma effluents, andetching the exposed region of the second material faster than the protected silicon-and-oxygen-containing region by flowing the second plasma effluents into the substrate processing region through through-holes in the showerhead; and

    (3) sublimating the protective solid by-product from the protected silicon-and-oxygen-containing region by raising a temperature of the patterned substrate.

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