PBGA solder joint fatigue under temperature cycling, random vibration and combined vibration and thermal cycling loading conditions

In this paper, temperature cycling, random vibration and combined loading tests were conducted on plastic ball grid array assemblies. The fatigue lives, the failure modes of the solder joints and the location of the failed solder joints for single loading and combined loading conditions were compared and analyzed. The results show much earlier solder joint failure for combined loading than that for either temperature cycling or pure vibration loading at room temperature. During temperature cycling and random vibration loading tests, the components at the central region have more failed solder joints than other components. The effect of the component location on the stresses and strains at the solder joints is not significant for combined loading. The primary failure mode is cracking within the bulk solder under temperature cycling, whereas the crack propagation path is along the intermetallic compound (IMC) layer for vibration loading. The solder joints subjected to combined loading exhibit both failure modes that occur for the temperature cycling and the vibration loading conditions.