Integrated process for sputter deposition of a conductive barrier layer, especially an alloy of ruthenium and tantalum, underlying copper or copper alloy seed layer

摘要

A fabrication method and a product for the deposition of a conductive barrier or other liner layer in a vertical electrical interconnect structure. One embodiment includes within a a hole through a dielectric layer a barrier layer of RuTaN, an adhesion layer of RuTa, and a copper seed layer forming a liner for electroplating of copper. The ruthenium content is preferably greater than 50 at % and more preferably at least 80 at % but less than 95 at %. The barrier and adhesion layers may both be sputter deposited. Other platinum-group elements substitute for the ruthenium and other refractory metals substitute for the tantalum. Aluminum alloying into RuTa when annealed presents a moisture barrier. Copper contacts include different alloying fractions of RuTa to shift the work function to the doping type.