焊点疲劳寿命的量化评价方法及其影响因素

Quantitative method evaluating the fatigue life of solder joint and some factors influencing the evaluation

焊点蠕变疲劳是电子产品破坏中一种最主要的形式,对焊点疲劳寿命的量化评价是电子产品可靠性分析中的关键环节。总结了IPC标准中的焊点蠕变疲劳模型,然后利用实例说明了如何在实际使用中对焊点寿命进行分析和预计,最后重点讨论了模型中的6个相关参数对焊点疲劳寿命及参数设计优化所带来的影响。分析表明,当有、无引脚器件的焊点间距分别大于1.143 0与0.063 5 cm时,器件的疲劳寿命均随引脚间距变大而急剧减小;此外,热失配仍然是影响焊点疲劳寿命的主要因素。

Creep fatigue of solder joint is one of the most important reasons for the failure of electronics products,and evaluating the fatigue life of solder joint quantitatively is necessary for the reliability analysis of electronics products.First the creep-fatigue models for solder joint described in the IPC standards was summarized,then how to use these models to analyze and predict the life of solder joint in real cases using an example was showed,and finally the effects of 6 key parameters on the fatigue life of solder joint and the optimization of parameter design was discussed.When the maximum distance between two solder joints,measured from the center of two joints,are larger than 1.143 0 and 0.063 5 cm respectively for components with and without pin,the fatigue life of component decreases sharply with increasing distance.In addition,thermal mismatch is still a main factor influencing the fatigue life of solder joint.