Microstructural Evolution and IMC Control in RHA-Reinforced SSC507 Solder Joints

With the rising demand for robust and high-performance solder interconnects for electronic packaging, the modification of solder materials through composite technology has become an essential area of research. The impact of rice husk ash (RHA) reinforcement on the microstructure and interfacial intermetallic compound (IMC) development in SSC507 solder composites is examined in this study. Powder metallurgy was used to develop solder systems with different RHA concentrations (0–1.0 wt%), which were then reflow-soldered onto Cu substrates. In comparison to the reinforced composites, the plain solder showed a greater density of dispersed IMCs inside the solder matrix, according to microstructural examination. Scallop-type Cu₆Sn₅ was found to be the predominant IMC phase at the solder/Cu interface, while a thin, continuous Cu₃Sn layer was consistently detected in all samples. IMC development at the interface and within the solder bulk was greatly inhibited by the addition of RHA. Notably, under as-soldered conditions, the SSC507–0.75 wt% RHA composite showed the lowest IMC thickness, attaining a decrease of 42.4% in comparison to the plain solder. These findings demonstrate that by inhibiting IMC growth and diffusion, the optimum addition of RHA enhances microstructural and interfacial stability. In advanced, electronic packaging applications, it is anticipated that such regulated IMC formation will lessen interfacial brittleness and enhance the mechanical integrity and lasting reliability of SSC507 solder connections.