球栅阵列封装板级跌落试验与有限元分析

通过板级跌落试验研究球栅阵列(BGA)封装在冲击脉冲下的动态响应和失效模式,并运用有限元软件ABAQUS对跌落过程进行模拟。模拟计算结果与实验结果一致,应力最大值出现在最外围拐角焊点与印刷电路板PCB侧焊盘的连接处,剥离应力是导致焊点裂纹萌生、扩展最终完全断裂的主要原因。此外,研究了外围尺寸相同的3种不同焊点分布对PCB挠度和最外围拐角焊点剥离应力的影响,结果表明:焊点分布对PCB挠度影响较小;外围焊点分布密度显著影响最外围拐角焊点的剥离应力。

Experiment and finite element analysis of ball grid array packages under board-level drop impact

Dynamic response and failure mode of ball grid array （BGA） packages under impact impulse were studied through board-level drop test. The drop process was simulated by finite element software ABAQUS, and the simulation results were in accordance with the experiment. The maximum stress appeared at the outermost corner solder joint close to printed circuit board （PCB） side. Peeling stress was the primary cause of crack germination, crack extension and crack fracture. The effect of three different solder joint distributions on the deflection of PCB and the peeling stress in the dangerous solder joint were explored. E- ven though the distributions are different, the outermost corner solder joints are in the same location on PCBs. Distribution of solder joint has little effect on PCB deflection, while density of outer solder joints has a great effect on the peeling stress of the dangerous solder joint.