Fabrication of high aspect ratio through-wafer copper interconnects by reverse pulse electroplating

This study aims to fabricate high aspect ratio through-wafer copper interconnects by a simple reverse pulse electroplating technique. High aspect-ratio (∼18) through-wafer holes obtained by a two-step deep reactive ion etching (DRIE) process exhibit a taper profile, which might automatically optimize the local current density distribution during the electroplating process, thereby achieving void-free high aspect-ratio copper vias