微电子塑料封装中常用的聚合物材料因易于吸收周围环境中的湿气而对器件本身的可靠性带来很大影响,本文回顾了封装材料中湿气扩散、湿应力及蒸汽压力的产生这3个互相联系过程的研究情况,从理论分析、特征参数描述及其实验测定、有限元模拟分析的角度来分别予以介绍.从已有的理论分析与实验结果中可以看出,塑封材料吸收湿气会给器件的可靠性带来诸多影响,湿气的吸收、扩散、蒸发等过程,实验测量,以及由湿气带来的其它相关问题正成为微电子封装可靠性研究领域中的新热点,受到越来越多的关注与重视.
The polymers commonly used in plastic electronic packaging are apt to absorb moisture in the environment, which greatly affects the reliability of packages. In this article the studies on moisture diffusion process, hygroscopic stresses and moisture-induced vapor pressure are reviewed, with the emphasis on the theoretical analysis, parameter characterization and its experimental measurement and validation, as well as the finite element simulation. Based on the moisture absorption of polymer materials in mechanism analysis and experimental results, it can be seen that plastic packages can degrade its reliability significantly. More and more researches are focused on the study of moisture absorption, diffusion and evaporation processes, and on the experimental methods to measure and characterize the above processes.