Mechanical and microstructural properties of SiC-mixed Sn-Bi composite solder bumps by electroplating

SiC-nanoparticle-mixed Sn58Bi solders were successfully produced by electroplating and the mechanical and microstructural properties of Sn58Bi+SiC solders were observed and analyzed in this study. Dispersed SiC nanoparticles by ultrasonic horn were added into Sn-Bi plating solution. With the SiC added Sn-Bi plating solution, solder bumps were electroplated. After electroplating, the solder bump specimens were aged up to 400 hrs at 100degC. The melting temperature of SiC-mixed Sn-58Bi solder was same as non-mixed Sn-58Bi. The shear strength of Sn58Bi+SiC solder bumps increased by 6% as compared with Sn58Bi solder bumps. The thicknesses of intermetallic compound were almost same for both Sn58Bi and Sn58Bi+SiC samples. The Sn58Bi+SiC solder bumps had finer eutectic structures and grain sizes than Sn-Bi without SiC nanoparticles. From the fracture surface analysis, fracture occurred at solder side not at the joint interface. Therefore, the shear strength values represent the solder materials itself and the finder microstructure of Sn58Bi+SiC improved the shear strength.