The motivation of this study is that the effect of solder joint shape and volume on the fatigue life is directly related to the quality of the soldering process. The solder profiles were calculated at given stand-off heights and solder volume. The calculated solder profile with Surface Evolver was compared with experimental results. Using ABAQUS, deformation and plastic strain distributions of four different cases were calculated.
The specimen used in the experiments is BGA-type solder-printed circuit board(PCB). The solder joints specimen were made by conventional surface mount technology(SMT). BGA-type solder/PCB joints have been tested isothermally, in shear under total displacement-controlled tests, at 25℃. Isothermal low cycle fatigue of 63Sn/37Pb solder is studied. The joints were subjected to fully reversed ramp cycling with fixed displacement limits. The fatigue life was defined by a 10 and 25-percent load drop under a given displacement cycle. The plastic strain range was favored to be the governing parameter in fatigue life of near-eutectic BGA solder joint. Through experiments and finite element analysis results the optimal solder joint shape can be determined for the reliability of Surface Mount Components.
