Tin/silver alloy nanoparticles for low temperature lead-free interconnect applications

A chemical reduction method was used to synthesize tin/silver alloy nanoparticles with various sizes and their thermal properties were studied by differential scanning calorimetry. Both the particle size dependent melting temperature and latent heat of fusion have been observed. The melting point can be achieved as low as 194 °C when the diameter of the nanoparticles is around 10 nm. The 64 nm (average diameter) SnAg alloy nanoparticle pastes showed good wetting properties on the cleaned copper foil surface and the intermetallic compounds formed. These low melting point SnAg alloy nanoparticles could be used for low temperature lead-free interconnect applications.