Influences of structure parameters of PCBA and random vibration spectra on the fatigue life of BGA solder joint

In order to investigate the effect of structure parameters of PCBA and random vibration power spectrum density(PSD) on ball grid array(BGA) package solder joint vibration fatigue life, a 3D finite element model(FEM)consisting of printed circuit board, BGA package and solder joints was constructed using HYPERMESH software, and the random vibration responses of PCBA was analyzed with ANYSYS software. The results show that with the PCB thickness increase, the fatigue life of BGA solder joint presents increasing trend. When the thickness of the PCB increases from 1.2mm to 2.2 mm, vibration fatigue life N of BGA solder joint significantly increases from 45 363 to 557 386. The appropriate mounting space of package can significantly improve the fatigue life of solder joint vibration, especially when the chips are mounted close to the fixed constraints and located in the middle of two fixed constraints. When the first order natural frequency of PCBA is located in the frequency range corresponding to the maximum amplitude of random vibration spectrum, the fatigue life of BGA solder joint significantly decreases.