The Effect of Misaligned Passive Component on Fatigue Life of Solder Joints and Solder Shape

In the surface mount technology (SMT), the pick and place process of the passive components such as capacitors and resistors may induce systematic misplacement because of the various environmental factors in the manufacturing. Particularly, in the reflowing process, it encompasses skewing, overhanging, or tilting by the driven force from the self-alignment of the molten solder. The solder joint shape variations with the passive component misplacement could severely affect to determine the fatigue life of the solder joint. In this research, surface evolver software was used to create a 3D model based on energy minimization and we used it to determine the solder shape. A finite element method was used to predict the fatigue life of solder joints using an energy-based method under thermal cycling in ANSYS while the passive component is misaligned. Through varying passive component offset and solder paste volume, the fatigue life could be predicted. The solder joint fatigue life result of misaligned passive components could provide the guideline for choosing solder paste volume and placement offset of passive component as well as determining reflow solder joint defects.