考虑参数随机性的焊点热疲劳失效分析

目的研究电子产品焊点几何参数的随机性对焊点热疲劳寿命的影响。方法基于Coffin-Masson的修正式Engelmaier模型,建立考虑多参数随机性的引线型封装的焊点热疲劳寿命评估模型,并利用蒙特卡罗法对该模型的精确度进行验证。以SMT鸥翼型(gull-wing)TSOP062封装为例,将焊点几何参数的随机性对热疲劳寿命的影响进行量化分析。结果影响焊点寿命的几何参数离散系数越大,焊点疲劳寿命越小,随机变量越多,焊点热疲劳寿命下降的越明显,焊点高度是影响元器件热疲劳寿命的敏感参数。结论该方法在已知小批次产品的参数波动信息的情况下,能预测整批次产品的热疲劳寿命,极大地减少试验时间和成本,提高电子产品及装备的可靠性。

Thermal Fatigue Failure of Solder Joints Considering Randomness of Parameters

Objective To research influences of geometric parameters on the thermal fatigue life of solder joints.Methods Based on the Engelmaier model, the variant form of Coffin-Masson's and lead package of multiparameter randomness, a solder fatigue life probability evaluation model was established. Monte Carlo method was adopted to verify the accuracy of the model. SMT (Surface Mount Technology) gull-wing TSOP062 package was taken as an example. Quantitative analysis on influences of geometrical parameters of solder joints on thermal fatigue life was carried out.Results The fatigue life of solder joint decreased with the increase of geometric parameters discrete coefficient. The more random variable of geometric parameters, the lower re-liability of solder joints. The height of welder joint was a sensitive parameter which affects the thermal fatigue life of elements. Conclusion This method can predict the whole batch thermal fatigue life of products, reduce the test time and cost greatly, and improve reliability of product and equipment on the premise that information on parameter fluctuation of small batch product is obtained..