SiP模块键合线疲劳寿命预测及可靠性分析

Fatigue Life Prediction and Reliability Analysis of SiP Module Bonding Wire

针对SiP中键合线易疲劳失效问题,为提高键合线模块可靠性,展开疲劳寿命预测研究。梳理了键合线的常见失效机理和温循实验中瞬态热力耦合原理;对整体模块进行对称简化建立有限元模型,并对单根键合线进行参数化建模,在相同的温度循环载荷下,对比研究了键合线的直径、拱高、一二焊点的水平和垂直间距四种结构参数的等效应力、塑性应变幅值;建立了键合线模块的疲劳寿命模型,揭示了键合线结构参数对可靠性的影响。结果表明,键合线易失效点集中在焊点颈部和足底部分;在一定范围内,减小键合线的直径、减小一二焊点间水平和垂直间距、增加键合线的拱高,可提高键合线结构的可靠性,延长疲劳寿命。

Aiming at the problem of easy fatigue failure of bonding wire in SiP,the study on fatigue life prediction is carried out to improve module reliability.The common failure mechanism of bonding wire and the transient thermodynamic coupling principle in temperature cycle experiment are discussed.The whole module symmetrical simplified finite element model and the bonding wire param-eterized model were established.Under the same temperature cyclic load,the equivalent stress and plastic strain amplitude of four kinds of structure parameters,such as the bonding wire diameter,high arch,the horizontal and vertical spacing of solder joints were comparatively carried out.The model of bonding wire module was established,and the influence of bonding wire structural parameters on reliability was revealed.The results show that the failure points of bonding wire are concentrated in the neck and soles of solder joint.In a certain range,decreasing the diameter of the bonding wire,decreasing the horizontal and vertical distance between two solder joints and increasing the arch height of the bonding wire can improve the reliability of the bonding wire structure and prolong the fatigue life.