Thermal Properties of Tin/Silver Alloy Nanoparticles for Low Temperature Lead-free Interconnect Technology

Tin/silver alloy nanoparticles with various sizes were synthesized by the chemical reduction method 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 194degC 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.