Wetting process of electrolyte in high density Cu/Sn micro-bumps electrodepositing

▶ High density Cu/Sn micro-bumps electrodepositing. ▶ Electrolyte is hard to reach up to the bottom of micro-hole. ▶ Under mechanical action, void free micro-bumps was achieved with depth of 60 μm and radius of 30 μm. ▶ A model shows wetting process of electrolyte.