Cu/BCB hybrid bonding with TSV for 3D integration by using fly cutting technology

In this research, the wafer level Cu/BCB hybrid bonding with TSV for 3D integration by using fly cutting technology is proposed. As we know Cu bump surface is rough by electroplating, and BCB is spin-coated on Cu bump wafer induced high topography. Cu bump surface roughness and Cu/BCB co-planarization are improved by fly cutting to achieve good Cu to Cu and BCB to BCB bonding interface without any large bonding voids at 250°C for 30min, and the result of the bonding strength is evaluated by shear test. TSV fabrication, micro-bumping, hybrid bonding, wafer thinning and backside RDL formation are well developed and integrated to perform the 3D integration platform. Cu/BCB hybrid bonding with TSV for 3D integration is successfully developed and demonstrated in this paper.