Abstract
The strength of micro solder joints was experimentally investigated under combined tensile and torsional loads. A new testing equipment for the combined loads was constructed to investigate to strength of micro solder joints. The testing specimen was prepared using a single solder ball according to the BGA model. The strength of the micro solder joint specimen was measured under various combined loading conditions. The load is applied to the joint specimen at higher strain rate than the steady state creep rate to reduce the effect of creep deformation on plastic deformation. The solder joint strength under combined loads at room tempereture was higher than that expected by the von Mises Criterion. But, at 100°C, the joint strength coincided with the Mises criterion.
