Semiconductor device having copper lines with reduced electromigration using an electroplated interim copper-zinc alloy film on a copper surface

摘要

The present invention relates to the semiconductor device fabrication industry. More particularly a semiconductor device, having an interim reduced-oxygen Cu-Zn alloy thin film ( 30 ) electroplated on a blanket Cu surface ( 20 ) disposed in a via ( 6 ) by electroplating, using an electroplating apparatus, the Cu surface ( 20 ) 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 film ( 30 ); filling the via ( 6 ) with further Cu ( 26 ); annealing and planarizing the interconnect structure ( 35 ). The reduction of electromigration in copper interconnect lines ( 35 ) is achieved by decreasing the drift velocity in the copper line ( 35 )/via ( 6 ), thereby decreasing the copper migration rate as well as the void formation rate, by using an interim conformal Cu-rich Cu-Zn alloy thin film ( 30 ) electroplated on a Cu surface ( 20 ) from a stable chemical solution, and by controlling the Zn-doping thereof, which improves also interconnect reliability and corrosion resistance.