The effect of Ag3Sn and Cu3Sn nanoparticles on the IMC morphology of Sn-3.0Ag-0.5Cu solder

In electronic packaging, the interface reaction between solder and substrate directly determines the reliability of the solder joint. An interfacial reaction occurs at the interface between solder and substrate to form an interfacial intermetallic compound (IMC). The growth of the interface IMC has a positive effect on improving the strength of the solder joints, preventing solder diffusion and oxidation, However, if the interface IMC is overmuch, the non-uniform distribution of IMC will adversely affect the performance of the solder joint. Researches have shown that adding nanoparticles to the Sn-Ag-Cu alloy can improve the structure and slow the growth of interfacial IMC, which benefits the performance of the solder. In our work, Sn-3.0Ag-0.5Cu solder was selected as the matrix, and nano-Ag3Sn and Cu3Sn particles were used as additive components. The composite solder paste with different content of nanoparticles was prepared and reflowed. The growth of IMC was observed by Hitachi TM-3000 benchtop scanning electron microscope and FEI Sirion 200 scanning electron microscope (SEM). The morphology of IMC was observed to study the effect of additive nanoparticles on IMC growth. The results show that the addition of 0.3% nano-Ag3Sn and Cu3Sn particles to Sn-3.0Ag-0.5Cu alloy solder can improve the growth of IMC at the solder joint interface, making the IMC morphology of the scallop body shape gentler and more uniform, while adding an excessive amount of Ag3Sn nanoparticles makes the IMC morphology non-uniform.