Cu–SiO2Hybrid Bonding

Three-dimensional technology will enable a future generation of microelectronic devices with vertical interconnection being one of the challenging issues. One of the possible techniques to address this issue appears to be the formation of interconnections via bonding of Cu pads. In this chapter, direct bonding of patterned Cu–SiO2 surfaces at room temperature with atmospheric pressure and ambient air is described. High bonding quality with precise alignment between the Cu interconnects is achieved for both wafer-to-wafer (W2W) and die-to-wafer (D2W) bonding approaches. Electrical characterizations and reliability of Cu–Cu contacts are presented for multiple contact areas and postbonding annealing temperatures, showing the high quality of the technique.