In. Thestructure are shown in Fig. 1. For comparison purpose, SAC/ Cu and SnBi/Cu solder joints were soldered at 260 °C and 160 °C for 80 s respectively. Here the ball height of all the three kinds of solder joints is 470 μm. Cross-sections of the solder joints were prepared following the grinding and polishing processes. Optical microscope, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscope (EDS) were used for the materials characterization. The shear test was conducted by RESCH PTR-1000 tester according to JESD22-B117B-2014 standard. The shear height was set as 45 μm and the shear speed was 0.1 mm/s. The shear fractures were observed with SEM and KEYENCE super resolution digital microscope results of this study have provided a novel idea to improve the