Structures with copper doped hybrid metallization for line and via

A structure for interconnecting semiconductor circuits on a substrate, comprising:

• a dual damascene structure with at least one opening with a sidewall from an upper surface to an underlying metallic layer of copper, wherein the dual damascene structure has a lower portion that is a via and an upper portion that is a trench;
• a barrier layer of tantalum nitride only on the sidewall of the at least one opening;
• a liner layer of cobalt or ruthenium on the barrier layer and on the underlying metallic layer;
• a first copper layer with a dopant with a first dopant content on the liner layer that completely fills the via of the lower portion of the dual damascene structure, wherein the first dopant content is approximately 0.5 percent to approximately 10 percent and wherein the dopant has a higher concentration within the first copper layer at interfaces of the first copper layer nearest the barrier layer;
• and
• a second copper layer with the dopant with a second dopant content on the first copper layer and filling the at least one opening, wherein the second dopant content is zero percent to approximately 0.5 percent of the dopant and is less than the first dopant content and wherein the second copper layer is separated from the liner layer by the first copper layer.