电子封装热应力数值分析

针对目前电子封装的封装密度越来越高、封装厚度越来越薄、封装体在基板上所占面积越来越大,发热引起的失效越来越严重等问题,以晶体管瞬态热应力分析为例,建立热力耦合力学模型.利用ansys研究电子封装热失效问题,得到温度场、应力场和变彤场的分布规律.温度和应力的主要规律包括两点,一是温度和应力都在角点处变化明显,应力比较集中.温度从上到下逐层变化,逐渐减小,并且层与层之间温度变化不大,模型中间部分温度层厚度几乎相同,下半部分同一温度层有规律的变化.二是当温度较高时,在受约束面上和角点处应力值较大,并且在模型的角点和中部出现应力集中现象.

Numerical Analysis on Thermal Stress of Electronic Packaging

Aiming at the present problems that electronic packaging package density more and more high,with encapsulation thiekness thin- ner, encapsulation system in the substrate occupied area more and more big, failure caused by the fever more and more severe, an based on the transistor transient thermal stress analysis as an example, coupled thermo-meehanical mechanical model is established, using ansys research e- lectronic packaging thermal failure problems, obtaining the temperature field and stress field and deformation field distributions. The main laws of temperature and stress have two points. Firstly, the change of temperature and stress is obvious at the comer point. The temperature become more and more low from top to bottom layers. Temperature difference is not obvious in the different layer. The thickness of temperature layers is almost the same in the middle of the model. The change of temperature is regular in the lower part of the model. Secondly, when the temperature is high, the stress is larger at the comer point and the constrained surface. At the same time, the phenomenon of stress concentra- tion is oceurrsed in the middle of and at the comer point of the model.