基于子模型的电子封装焊点寿命预测方法研究

Life Prediction Research for Solder Joints in Electronic Package Based on the Submodel Method

在向无铅化过渡的过程中,封装材料与工艺改变所带来的最突出的问题之一就是无铅焊点的可靠性问题。由于焊点区非协调变形导致的热疲劳失效是电子封装焊点的主要失效形式。到目前为止,仍无公认的焊点寿命和可靠性的评价方法。本文采用统一型粘塑性本构模型描述SnAgCu焊点的变形行为,在对焊点可靠性分析的基础上采用基于能量的寿命模型进行焊点寿命预测;在有限元方面采用子模型的处理技术,并采用节点平均化以及体积平均化方法计算寿命模型相关参数。力图从理论方面和有限元处理技术方面改进以达到提高焊点寿命预测效率及预测精度的目的。

In the transition to lead-free process, one of the most prominent problems as the changes of packaging materials and process has brought about is the lead-free solder oint reliability. Thermomechanical fatigue failure caused by nonconforming deformation of the soldering area is the main failure mode for solder joints in electronic package. Up to now, there is no life prediction and reliability evaluation method for solder joint which is generally accepted. In this paper, a unified viscoplastic constitutive model was used to describe the deformation behavior of SnAgCu solder joint, and the solder joint life was predicted based on solder joint reliability analysis. For finite element analysis, submodel method was adopted, and the life model parameters were obtained by data average processing, such as node average and element average. Based on the theory optimization and effective data processing for finite element analysis, the efficiency as well as the precision of life prediction for solder joint may be improved.