Synthesis and thermal and wetting properties of Tin/Silver alloy nanoparticles for low melting point lead-free solders

Tin/silver alloy nanoparticles with various sizes were synthesized via a low-temperature chemical reduction method, and their thermal properties were studied by differential scanning calorimetry. The particle size dependency of the melting temperature and the latent heat of fusion was observed. The melting point was achieved as low as 194 degrees C when the average diameter of the alloy nanoparticles was around 10 nm. The wetting test for as-prepared 64 nm (average diameter) SnAg alloy nanoparticle pastes on a Cu surface showed the typical Cu6Sn5 intermetallic compound (IMC) formation. These low melting point SnAg alloy nanoparticles could be used for low-temperature lead-free interconnect applications.