Semiconductor device with copper-filled via includes a copper-zinc/alloy film for reduced electromigration of copper

摘要

A method of reducing electromigration in copper interconnect lines by restricting Cu-diffusion pathways along a Cu surface via doping the Cu surface with Zn from an interim copper-zinc alloy (Cu—Zn) thin film electroplated on the copper (Cu) surface from a stable chemical solution, and controlling the Zn-doping thereof, which also improves interconnect reliability and corrosion resistance, and a semiconductor device thereby formed. The method involves using interim reduced-oxygen Cu—Zn alloy thin films for forming an encapsulated dual-inlaid interconnect structure. The films are formed by electroplating a Cu surface via by electroplating, the Cu surface in a unique chemical solution containing salts of Zn and Cu, their complexing agents, a pH adjuster, and surfactants; and annealing the interim electroplated Cu—Zn alloy thin films and a Cu-fill; and planarizing the interconnect structure.