A method of fabricating 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); and a
semiconductor device thereby formed. 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.