Method of electroless ag layer formation for cu interconnects

摘要

A dielectric layer has an opening which communicates with a metal line therebeneath. A layer of silver is deposited over the structure and into the opening, and copper is deposited by electroplating in the opening. An additional silver layer is the deposited, and an anneal step is undertaken so that the copper is surrounded or encapsulated by alloy containing copper and silver. After removal of appropriate portions of the silver layers, the copper remains encapsulated or encased by copper-silver alloy.