Interconnect with composite barrier layers and method for fabricating the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChen-Hua Yu, Horng-Huei Tseng, Syun-Ming Jang, Chenming Hu
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Abstract
Composite ALD-formed diffusion barrier layers. In a preferred embodiment, a composite conductive layer is composed of a diffusion barrier layer and/or a low-resistivity metal layer formed by atomic layer deposition (ALD) lining a damascene opening in dielectrics, serving as diffusion blocking and/or adhesion improvement. The preferred composite diffusion barrier layers are dual titanium nitride layers or dual tantalum nitride layers, triply laminar of tantalum, tantalum nitride and tantalum-rich nitride, or tantalum, tantalum nitride and tantalum, formed sequentially on the opening by way of ALD.
Claims37
A method for fabricating an interconnect structure, comprising:
- providing a semiconductor substrate with a first conductor thereon;
- forming a dielectric layer overlying the semiconductor substrate;
- forming an opening in the dielectric layer exposing the first conductor;
- forming a composite diffusion barrier layer by atomic layer deposition, lining the opening;
- and
- filling the opening with a conductive material as a second conductor, electrically connecting the first conductor,
- wherein the composite diffusion barrier layer is formed by:
- forming a first layer of titanium nitride or tantalum nitride;
- plasma-treating the first layer of titanium nitride or tantalum nitride in hydrogen ambient;
- forming a second layer of titanium nitride or tantalum nitride on the treated first layer.
A method for fabricating an interconnect structure, comprising:
- providing a semiconductor substrate;
- forming a first low-k dielectric layer overlying the semiconductor substrate with a first copper or copper alloy conductor embedded therein;
- forming a second low-k dielectric layer overlying the first low-k dielectric layer;
- forming an opening in the second low-k dielectric layer exposing the first copper or copper alloy conductor;
- forming a composite diffusion barrier layer by atomic layer deposition, lining the opening;
- and
- forming a second conductor embedded in the opening and electrically connecting the first copper or copper alloy conductor, and the surface of the second low-k dielectric layer is lower than the surface of the second conductor;
- wherein the second conductor is composed of copper or copper alloy.
Dependencies are inferred from the claim text.