Crystal growth on novel Cu electroplating using suspension of supercritical CO2 in electrolyte with Cu particles

► Cu electroplating with supercritical CO2 (sc-CO2) suspension is proposed by addition of Cu particles to sc-CO2 emulsion. ► Dissolution of Cu seed layer originally observed in sc-CO2 emulsion is inhibited in sc-CO2 suspension. ► The proposed method is applied in filling of holes having 60 and 70 nm in diameter, and complete Cu filling was obtained. ► Cu filled in the holes was found to be either single crystal or twin crystals with [111] orientation. ► The filling mechanism should be bottom-up growth.