Patent ID: 8288276

Claim:
A method of forming an interconnect structure comprising: providing a structure including a first dielectric material having a first conductive material embedded therein and a second dielectric material located above said first dielectric material, said second dielectric material having a combined via and line opening which exposes a surface of said first conductive material and a bare horizontal surface of said second dielectric material in a line opening portion of said combined via and line opening, wherein said second dielectric material includes a patterned hard mask located on an upper surface thereof; forming a metallic interfacial layer only on said exposed surface of said first conductive material, and along a horizontal wall portion of said line opening portion and in direct contact with said bare horizontal surface of said second dielectric material in said line opening portion, wherein said patterned hard mask protects the upper surface of the second dielectric so that said metallic interfacial layer does not form thereon and wherein said forming said metallic interfacial layer consists essentially of selecting a metal from the group consisting of V, Nb, Ta, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt and In and depositing said metal; forming a diffusion barrier liner within said combined via and line opening and atop the patterned hard mask, wherein a portion of said diffusion barrier liner is located atop said metallic interfacial layer containing said metal; forming a second conductive material on said diffusion barrier liner; and performing a planarization step, wherein said planarization step removes portions of the second conductive material, said diffusion barrier liner and said patterned hard mask forming a structure in which said second conductive material has an upper surface that is coplanar with the upper surface of said second dielectric.