Cu Displacement Plating on Electroless Plated CoWB Layer on SiO2 and Its Adhesion Property

For realizing high aspect ratio TSV with a low cost, the all-wet process utilizing electroless barrier and Cu-seed layers prior to Cu electroplated fill is one of the most promising methods. However, improvement of adhesion property of electroless plated barrier and seed layers on SiO 2 has been intensively required. In this study, we studied displacement plating of Cu on electroless CoWB layer formed on SiO 2 in an acidic bath. It turned out that displacement-plated Cu film grew with sacrifice of the partial CoWB layer, and showed a high adhesion strength that was enough to pass CMP process.