【作者】 夏溢；

【导师】 李英梅；

【作者基本信息】 东北大学 ， 固体力学， 2008， 硕士

【摘要】 电子封装就是一种将集成电路用绝缘的塑料或陶瓷材料打包的技术。电子封装是连接半导体芯片和电子系统的一道桥梁,随着半导体产业的飞速发展及其向各行业的迅速渗透,电子封装因此在近三十年内获得长足的进步。今日的电子封装不但要提供芯片保护,同时还要在一定的成本下满足不断增加的性能、可靠性、散热、功率分配等功能。其可靠性问题,即在功率循环和热循环中由于电子元件与基板材料之间存在热膨胀失配,使焊点内部产生应力而失效,最终导致焊点失效的问题越来越受到人们的关注。本文的主要内容是采用双尺度的理论分析和有限元非线性求解两种方法,对带有底充胶的CBGA电子封装元件在热循环载荷下的力学行为进行了研究。首先,将均匀化理论和高阶逐层离散层板理论相结合,采用热弹塑性增量理论,考虑焊料的粘塑性行为,建立了CBGA电子封装元件热粘弹塑性非线性力学分析模型及其双尺度增量控制方程；其次,采用瑞利—里兹法,求解了在热循环载荷作用下CBGA宏观、细观的双尺度问题的解析解,与数值分析结果的对照,验证了理论分析的正确性,并就加载速率、材料参数和结构几何参数对焊球应力、应变行为的影响的进行了分析,为CBGA电子封装元件结构的设计提供了理论参考；在数值分析中,利用有限元数值分析软件ANSYS软件,采用3D模型,对CBGA在热循环载荷下的力学行为进行非线性有限元模拟,分析了结构在升温段、保温段、降温段焊球应力应变的变化情况,最后,通过各焊球的应力应变迟滞回线,得出最容易发生失效的焊球,为进一步的CBGA元件可靠性分析提供数值依据。更多还原

【Abstract】 Electronic packaging is a technology which packages intergrated circuit using insulating plastics and ceramics and a connection between semiconductor die and electronic system. With the development of semiconductor and penetrating other industries, electronic packaging has made a significant progress in three decades. Today, electronic packaging not only provide chip protection, but also be satisfied with increasing performance, reliability, heat dissipation and power distribution in some cost. Reliability performance is the key people consider. Stress in solder joints leads to invalidation which is due to coefficient of thermal expansion mismatches in different materials.The effect of underfill in ceramic ball grid array(CBGA) package under thermal cycling load is studied in this paper by using double-scale homogenization theory and finite element nonlinear ananlysis.Firstly, combining double-scale homogenization theory and high order discrete plate using thermal elastic-plastic increment theory, taking account of viscoplastic behaviour of solder joints, it builds nonlinear thermal elastic-plastic model and double-scale homogenization constitutive equation of CBGA.Secondly, using Rayleigh-Ritz method, it gets macro and micro ananlysis solutions of CBGA. Comparing with numerical result, it approves right. It also takes accout of loading velocity, material properties and model structure parameters and provide theoretics for design of CBGA.It simulates nonlinear finite element mechanics behaviour of CBGA under thermal cycling load with ANSYS by using 3-D model. It analyses the change of stress and strain of solder joints when model is in heat increasing, heat preservating and heat decreasing. Finally, it gets solder jiont where most easily happens invalidation by stress strain hysteresis loop and provides proof for further studying reliability of CBGA.更多还原