Low Melting Point Nano-Solder Particles: Synthesis and Their Feasibility as Nano-Soldering Materials for Electronics Assembly

We report a simple method to synthesize single crystalline tin nanorods with [200] plane in presence of an anionic surfactant - sodium dodecyl sulfate (SDS). The formation mechanism for forming different shapes of tin nanostructures is proposed based on observations from field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Melting behavior of the tin solder nanorods, which is critical for nanosoldering applications, is studied. Interconnect formation, dielectrophoretic (DEP) assembly, and I-V property of these nano-solder particles are also investigated and the results show the lead-free solder nanoparticles are promising candidate as nanoscale soldering materials. In addition, solder nanoparticles based on tin/indium (Sn/In) alloy are also synthesized from the facile one-step surfactant based reduction method.