High-speed through-silicon via filling method using Cu-cored solder balls

A novel low-cost and high-speed via filling method using Cu-cored solder balls was investigated for through-silicon via manufacture. Cu-cored solder balls with a total diameter of 100 mu m were used to fill 150 mu m deep, 110 mu m wide vias in silicon. The wafer-level filling process can be completed in a few seconds, which is much faster than using the traditional electroplating process. Thermo-mechanical analysis of via filling using solder, Cu and Cu-cored solder was carried out to assess the thermo-mechanical properties of the different filling materials. It was found that the vias filled with Cu-cored solder exhibit less thermal-mechanical stresses than solder-filled vias, but more than Cu-filled vias.