中文摘要：

对芯片尺寸封装（CSP）中Sn-3．5Ag无铅焊点在热循环加速载荷下的热疲劳寿命进行了预测．首先利用ANSYS软件建立CSP封装的三维有限元对称模型，运用Anand本构模型描述Sn-3．5Ag无铅焊点的粘塑性材料特性；通过有限元模拟的方法分析了封装结构在热循环载荷下的变形及焊点的应力应变行为，并结合Darveaux疲劳寿命模型预测了无铅焊点的热疲劳寿命．

英文摘要：

The thermal fatigue life time of Sn-3.5Ag lead-free solder joint of a chip scale package subjected to a thermal cycling load is predicted. Using the finite element analysis software ANSYS, a three dimensional symmetric model of the chip scale package is established, which uses the Anand constitutive model to describe the viscoplastic material property of Sn-3. SAg lead-free solder joints. The deformation of the CSP package and the stress-strain variation of the solder joint under a thermal cycling load are investigated through thermal stress analysis. The Darveaux fatigue life prediction method is used to calculate the fatigue life time of the lead-free solder joint based on the finite element simulation results.