Chip to wafer copper direct bonding electrical characterization and thermal cycling

Copper direct bonding technology is considered to be one of the most promising approach for matching the miniaturization needs of future 3D integrated high performance circuits (3D-IC). In this study, we discuss the recent achievements in copper direct bonding technology with oxide/copper mixed surface and present the latest electrical and physical characterizations of chip to wafer bonding structures after annealing at 400°C and thermal cycling tests. In addition, electrical performance of chip to wafer bonding on 300mm wafers is also presented. Finally, thermo-mechanical finite element simulations showing the impact of the annealing conditions on the closure of the interface are shown.