Fabrication and Characteristics of SnAgCu Alloy Nanowires for Electrical Connection Application

As electronic products become more functional, the devices are required to provide better performances and meet ever smaller form factor requirements. To achieve a higher I/O density within the smallest form factor package, applying nanotechniques to electronic packaging can be regarded as a possible approach in microelectronic technology. Sn-3.0 wt% Ag-0.5 wt% Cu (SAC305) is a common solder material of electrical connections in microelectronic devices. In this study, SAC305 alloy nanowire was fabricated in a porous alumina membrane with a pore diameter of 50 nm by the pressure casting method. The crystal structure and composition analyses of SAC305 nanowires show that the main structure of the nanowire is β-Sn, and the intermetallic compound, Ag₃Sn, locates randomly but always appears on the top of the nanowire. Furthermore, differential scanning calorimetry (DSC) results indicate the melting point of SAC305 alloy nanowire is around 227.7 °C. The melting point of SAC305 alloy nanowire is significantly higher than that of SAC305 bulk alloy (219.4 °C). It is supposed that the non-uniform phase distribution and composite difference between the nanowires causes the change of melting temperature.