PCB各向异性行为对焊点疲劳寿命的影响研究

Research on the effect of anisotropic behavior of PCB on the fatigue of solder joints

当前微系统不断向着小型化、高密度和高可靠性方向发展,印制电路板(PCB)为微系统器件提供电气连接和机械支撑,对系统的服役可靠性起着至关重要的作用。根据PCB在不同方向上热膨胀系数(CTE)的差异,通过数值模拟研究了3种PCB模型在温度循环载荷下焊点的寿命和应力应变响应情况,并对比了3种模型得到的计算结果,发现3种模型得到的结果存在较大差别。通过试验结果验证了仿真的准确性,表明在进行板级有限元分析时,关注焊球寿命时应充分考虑PCB复合材料的各向异性行为。同时,定量分析了由不同类别PCB模型获得的焊点寿命,为建立板级高保真数值模型和调控焊点寿命提供依据。

Microsystems are constantly developing towards miniaturization,high density,and high reliability.Printed circuit boards(PCBs)provide electrical connections and mechanical support for the components of microsystems,playing a crucial role in the reliability of the system in service.Based on the differences in coefficient of thermal expansion(CTE)of PCB boards in different directions,this article studies the solder joint life and stress-strain response of three PCB board models under temperature cycling load through numerical simulation,and compares the calculation results obtained by the three models.It is found that there are significant differences in the results obtained by the three models.The accuracy of the simulation is verified by the experimental results,indicating that when conducting board level finite element analysis,the anisotropic behavior of PCB board composite materials should be fully considered when paying attention to the solder ball life.At the same time,quantitative analysis is conducted on the similarities and differences in solder joint lifespan obtained from different types of PCB models,providing guidance for establishing high-fidelity numerical models at the board level and regulating solder joint lifespan.