Method of forming a metal silicide layer on non-planar-topography polysilicon
AssigneeMacronix International Co., Ltd.
InventorChi-Tung Huang
Life of this patent
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Abstract
A process is described for creating a uniformly thick layer of titanium, cobalt, or nickel silicide over a layer of polysilicon that has features or a non-planar topography. A dual layer of metal is deposited onto patterned polysilicon such that the first layer covers the bottoms and tops of the non-planar topography and the second layer covers the sidewalls and tops of the non-planar topography. By heating the metal, etching away any un-reacted metal, and heating the result a second time, a metal silicide layer of uniform thickness, reduced stress and reduced resistivity is formed.
Claims20
A method for forming a semiconductor device, comprising:
- forming on a substrate a polysilicon layer having a non-planar topography;
- directing particles at a first angle of incidence and forming a first metal layer on the non-planar topography polysilicon layer;
- directing particles at another angle of incidence different from the first angle and forming a second metal layer on the non-planar topography polysilicon layer, the second metal layer having one of (a) a sidewall coverage that is greater than a sidewall coverage of the first metal layer and (b) a bottom coverage that is greater than a bottom coverage of the first metal layer;
- and
- performing thermal processing to generate a metal silicide layer.
A method for forming a semiconductor device, comprising:
- forming a featured polysilicon layer on a substrate;
- forming a first metal layer on the featured polysilicon layer, the first metal layer covering lateral surfaces of the featured polysilicon layer to a greater extent than vertical surfaces;
- forming a second metal layer over the featured polysilicon layer, the second metal layer covering vertical surfaces of the featured polysilicon layer to a greater extent than a coverage of vertical surfaces by the first metal layer, an angle of incidence at which metal particles are directed toward the featured polysilicon layer being different for the forming of the second metal layer than for the forming of the first metal layer;
- and
- performing thermal processing to generate a metal silicide layer.
A method for forming a semiconductor device, comprising:
- forming a featured polysilicon layer on a substrate;
- forming a first metal layer on the featured polysilicon layer;
- performing thermal processing to generate a first metal silicide layer within the first metal layer, the first metal silicide layer having a greater bottom coverage than a sidewall coverage;
- forming a second metal layer over the featured polysilicon layer, whereby during formation of the second metal layer metal particles are directed at a different angle of incidence than during formation of the first metal layer;
- and
- performing thermal processing to generate a second metal silicide layer, which has a greater sidewall coverage than a sidewall coverage of the first metal silicide layer.
A method for forming a semiconductor device, comprising:
- forming on a substrate a polysilicon layer having a non-planar topography;
- forming a first metal layer on the non-planar topography polysilicon, the forming of the first metal layer including directing metal particles toward the non-planar topography polysilicon layer at a first angle of incidence;
- forming a second metal layer over the non-planar topography polysilicon layer, the forming of the second metal layer including directing metal particles toward the non-planar topography polysilicon at a second angle of incidence, which is not equal to the first angle of incidence;
- and
- performing thermal processing to generate a metal silicide layer.
Dependencies are inferred from the claim text.