Cu-Cu Bonding with Cu Nanowire Arrays for Electronics Integration

Due to the demand of miniaturization and high reliability, heterogeneous integration of wide band gap semiconductors requires advanced interconnect materials that enable optimum designs of component and hierarchical architectural dispositions. Although traditional Cu-Cu thermocompression bonding is considered as a front-runner compared to solder-based bonding approaches, the high soldering temperature (300~400°C) and pressure may cause degradation of the performance of bonded devices. In this study, robust Cu-Cu interconnections have been achieved through the interdigitation and interfacial diffusion of spaced, vertically grown free-standing Cu nanowire arrays (Cu-NWAs). These Cu-NWAs were prepared through template assisted electrodeposition on Cu substrates, consisting of densely distributed nanowires with 150 nm diameter and 8 μm length. With application of pressure, compact joints with Cu-NWAs can be produced even under ambient condition.