US Patent 7215024 Barrier-less integration with copper alloy

A new method is provided for the creation of a barrier-free copper interconnect. A dual damascene structure is created in a layer of dielectric, a thin metal barrier layer is deposited. The metal barrier layer is oxidized, two layers are then deposited with the first layer comprising doped copper and the second layer comprising pure copper. The dual damascene structure is filled with copper, a thermal anneal is applied, stabilizing the deposited copper filling the dual damascene structure and forming metal oxide of the doped minority element. Excess copper is then removed from the dielectric.