Copper Direct Bonding Characterization and its Interests for 3D Integration Circuits

3D technology will be the next step for the development of microelectronic devices. Vertical interconnection is one of the challenging issue. Metal bonding might be one of the possible technique to address it. In this work, direct Cu/Cu bonding at room temperature, atmospheric pressure and ambient air is investigated. At room temperature, a 2.8 J/m2 bonding toughness is achieved. EELS spectrum pointed out the absence of copper oxide at the interface. Morphological evolutions versus post bonding annealing are presented with TEM and XRD analyses. The ohmic behavior of the bonding is highlighted.