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Reduction of polysilicon residue in a trench for polysilicon trench filling processes

  • US 9,230,851 B2
  • Filed: 02/07/2014
  • Issued: 01/05/2016
  • Est. Priority Date: 02/07/2013
  • Status: Active Grant
First Claim
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1. A method of fabricating a semiconductor device, comprising:

  • forming at least one trench from a top side of a semiconductor surface, wherein said trench is lined with a trench dielectric liner and filled by a first polysilicon layer;

    etching a surface of said trench dielectric liner, wherein dips are formed relative to a top surface of said first polysilicon layer which form a polysilicon protrusion comprising said first polysilicon layer;

    etching said first polysilicon layer to remove at least a portion of said polysilicon protrusion;

    forming a second dielectric layer over at least said trench after etching said first polysilicon layer;

    depositing a second polysilicon layer, andetching said second polysilicon layer to remove said second polysilicon layer over said trench and provide a patterned second polysilicon layer without substantially recessing from said top side of said semiconductor surface.

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