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Method for modulating work function of semiconductor device having metal gate structure by gas treatment

  • US 9,728,467 B2
  • Filed: 10/12/2015
  • Issued: 08/08/2017
  • Est. Priority Date: 09/15/2015
  • Status: Active Grant
First Claim
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1. A method for modulating a work function of a semiconductor device having a metal gate structure, comprising:

  • providing a first stacked gate structure and a second stacked gate structure having an identical structure on a substrate, wherein the first stacked gate structure and the second stacked gate structure respectively comprise a first work function metal layer of a first type;

    forming a patterned hard mask layer, wherein the patterned hard mask layer exposes the first work function metal layer of the first stacked gate structure and covers the first work function metal layer of the second stacked gate structure;

    performing a first gas treatment to the first work function metal layer of the first stacked gate structure exposed by the patterned hard mask layer, wherein a gas used in the first gas treatment comprises nitrogen-containing gas or oxygen-containing gas;

    providing a third stacked gate structure on the substrate, wherein the third stacked gate structure comprises a second work function metal layer of the first type, and the second work function metal layer and the first work function metal layer have different thicknesses; and

    providing a fourth stacked gate structure on the substrate, wherein the fourth stacked gate structure and the third stacked gate structure have an identical structure, and the patterned hard mask layer exposes the second work function metal layer of the third stacked gate structure and covers the second work function metal layer of the fourth stacked gate structure.

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