Effect of Harmonic Excitation on PCB and Component Assembly

The plastic ball grid array (PBGA) package has become a major packaging type in recent years, due to its high capacity for the input/output counts. However, vibration loading is encountered during the service life of PBGA. This study investigates the effect of vibration loading on the solder ball response. A two-dimensional finite element model of the printed circuit board (PCB) and PBGA component assembly is released using COMSOL Multiphysics software. The natural frequencies and modes were calculated. Forced vibration analysis was performed around the first natural frequency to determine the solder joints having highest stress and strain concentration under harmonic excitation. It showed that the interface between solder ball and the PCB is the most vulnerable part. Displacement and Von Mises stress variation were calculated in the most critical point. It was found that the height amplitude of displacement and Von Mises stress may conduct to decrease the solder interconnects lifetime. Moreover, resonance may conduct to the failure of the solder joints.