US Patent 7745282 Interconnect structure with bi-layer metal cap

A structure and method of fabricating an interconnect structures with bi-layer metal cap is provided. In one embodiment, the method includes forming an interconnect feature in a dielectric material layer; and forming a bi-layer metallic cap on a top surface of the interconnect feature. The method further includes depositing a blanket layer of a dielectric capping layer, wherein the depositing covers an exposed surface of the dielectric material layer and a surface of the bi-layer metallic cap. The bi-layer metallic cap includes a metal capping layer formed on a conductive surface of the interconnect feature; and a metal nitride formed on a top portion of the metal capping layer. An interconnect structure is also described having an interconnect feature formed in a dielectric layer; a bi-layer metallic cap formed on a top portion of the interconnect feature; and a dielectric capping layer formed over the bi-layer metallic cap.