Method of reducing electromigration by forming an electroplated copper-zinc interconnect and a semiconductor device thereby formed

Abstract

A method of reducing electromigration in a dual-inlaid copper interconnect line ( ) by filling a via ( ) with a Cu-rich Cu—Zn alloy ( ) electroplated on a Cu surface ( from a stable chemical solution, and by controlling the Zn-doping thereof, which also improves interconnect reliability and corrosion resistance, and a semiconductor device thereby formed. The method involves using a reduced-oxygen Cu—Zn alloy as fill ( ) for the via ( ) in forming the dual-inlaid interconnect structure ( ). The alloy fill ( ) is formed by electroplating the Cu surface ( ) in a unique chemical solution containing salts of Zn and Cu, their complexing agents, a pH adjuster, and surfactants, thereby electroplating the fill ( ) on the Cu surface ( ); and annealing the electroplated Cu—Zn alloy fill ( ); and planarizing the Cu—Zn alloy fill ( ), thereby forming the dual-inlaid copper interconnect line ( ).