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 hole (88) through a dielectric layer (86) a barrier layer (132) of RuTaN, an adhesion layer (112) of RuTa, and a copper seed layer (114) 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 (192, 194) when annealed presents a moisture barrier. Copper contacts (232, 238) include different alloying fractions of RuTa to shift the work function to the doping type of the silicon (216, 218).