Method of improving adhesion of capping layers to cooper interconnects

Abstract

The adhesion of a barrier or capping layer to a Cu or Cu alloy interconnect member is significantly enhanced by treating the exposed surface of the Cu or Cu alloy interconnect member, after CMP, in a reaction chamber with a plasma containing ammonia and nitrogen for a brief period of time to reduce the surface oxide and then introducing silane into the reaction chamber to deposit the barrier layer, e.g., silicon nitride, under high density plasma conditions in the presence of nitrogen. The presence of nitrogen during plasma oxide layer reduction and plasma barrier layer deposition significantly improves adhesion of the barrier layer to the Cu or Cu alloy surface.