Structures with copper doped hybrid metallization for line and via

Abstract

Interconnect structures on a substrate have low resistivity and high dopant interfaces. In some embodiments, the structures may have an opening with a sidewall from an upper surface to an underlying metallic layer of copper, a barrier layer of tantalum nitride formed on the sidewall of the opening, a liner layer of cobalt or ruthenium formed on the barrier layer and on the underlying metallic layer, a first copper layer with a dopant with a first dopant content formed on the liner layer and filling a lower portion of the opening to form a via—the first dopant content is approximately 0.5 percent to approximately 10 percent, and a second copper layer with the dopant with a second dopant content formed on the first copper layer and filling the at least one opening—the second dopant content is more than zero to approximately 0.5 percent of the dopant and is less than the first dopant content.