IGBT模块封装回流焊的应力翘曲分析

Stress warpage analysis of IGBT modulepackage reflow soldering

为探究回流焊接工艺对功率器件封装的影响,应用DesignModeler建立了基于绝缘栅双极晶体管(insulated gate bipolar transistor,IGBT)模块的3D封装模型;运用ANSYS软件对IGBT模块进行热-结构耦合分析;结合单元生死法与焊料Anand模型得到IGBT模块温度分布、应力分布以及翘曲分布;最后利用正交分析法对不同组件厚度的翘曲及应力分布进行对比。结果表明:IGBT模块翘曲随基板厚度的增大而减小,随键合铜(direct bonded copper,DBC)铜层厚度的增大而增大,随纳米银焊料层厚度的增大先增大后减小。焊料层厚度对模块翘曲影响最大,纳米银焊料层厚度对模块翘曲影响最小,各组件参数对焊料层残余应力无较大影响。综合考虑得出最优的材料参数,翘曲结果较最初的参数降低了77.24%,为IGBT模块的封装设计提供参考。

In order to explore the impact of reflow soldering process on power device packaging,a 3D package model based on insulated gate bipolar transistor(IGBT)module was established using DesignModeler,and then ANSYS software was used to perform thermal-structural coupling analysis on the IGBT module,stress distribution and warpage distribution of the IGBT module were obtained by combining the unit life and death method with the solder Anand model,and finally the warpage and stress distribution of different component thicknesses were compared using the orthogonal analysis method.The results show that the warpage of the IGBT module decreases with the increase of the thickness of the substrate,increases with the increase of the thickness of the DBC copper layer,and first increases and then decreases with the increase of the thickness of the Nano silver solder layer.The thickness of the solder layer has the greatest influence on the warpage of the module,and the thickness of the Nano silver solder layer has the least influence on the warpage of the module.The parameters of each component has no major influence on the residual stress of the solder layer.After comprehensive consideration,the optimal material parameters were obtained,and the warpage results are reduced about by 77.24%,compared with the initial parameters,which provides a reference for the package design of the IGBT module.