(739e) Investigation of Lead-Free Solders, Solderable Nanowires, and Their Reflow and Assembly Properties

Lead-free nano-solders have shown promise in the assembly and integration of nanowires for nanoelectronics and nanosystem applications. In this research, multi-segmented nanowires with solder materials were fabricated with different functional segments which were then assembled into ordered structures. The potential application of these nanosolder materials in the assembly of micro- and nanoelectronics was investigated. Nanowires were assembled into 2D structures and were then formed nano-solder connections following a solder reflow process. The 3D assembly of the nanowires was also exploited. In the thermal property study, the effect of rosin based fluxes was investigated during the nanosolder reflow process in the inert environment with or without reducing agent in different temperature range. An Ostwald ripening phenomenon was observed. The inter-metallic diffusion between the nano-solders and contact pads were studied as well. These assembly techniques combined with nano-soldering method have potential applications in not only nanoscale assembly and nanoscale ball grid array (BGA) formation, but also the integration of sensors by using tin-based nanosolders.