Copper electrodeposition in a through-silicon via evaluated by rotating disc electrode techniques

Via filling is a critical process for metallization of a through-silicon via (TSV) in a 3D MEMS device. This study uses a rotating disc electrode (RDE) at 1000 rpm, 100 rpm and 10 rpm to simulate the mass-transfer environment of metallization on the wafer surface, at the bottom of shallow vias and the deep vias, respectively. RDE techniques display the difference of suppression action among three rotation speeds clearly. The calculated filling power is higher over a wide surface current density using the plating bath of 50 g L?1 Cu2+ than that of 25 or 75 g L?1 Cu2+. TSV filling in a wafer-segment scale, with 15 ?m via diameter and 150 ?m via depth, verifies the performance predicted by the RDE techniques.