微电子封装中焊锡接点的界面应力奇异性

摘要

The Cu/solder interfacial stress singularity in solder joints for different shapes and solder materials are evaluated based on the theory of interfacial mechanics.The interfacial stresses are computed by the finite element method to investigate the influence of solder joint shapes,solder materials and material models on the interfacial stress distribution.Results show that a fatter solder shape increases the interfacial singularity,and the singularity of Sn37Pb/Cu interface is greater than those of Sn3.5Ag/Cu and Sn3.0Ag0.5Cu/Cu interfaces.Elastic-plastic deformation and strain effects of the solder under drop/impact loadings reduce the interfacial stresses.%采用界面力学理论计算了不同形状的含铅/无铅焊锡接点界面应力奇异性指数,建立了焊锡接点的有限元模型,计算了线弹性、弹塑性和Johnson-cook材料模型的界面应力分布.结果表明：随着焊锡接点接触角的增加,界面应力奇异性增强;Sn37Pb/Cu界面比Sn3.5Ag/Cu和Sn3.0Ag0.5Cu/Cu界面的应力奇异性明显;弹塑性变形和应变率效应降低界面应力.