振动载荷加载下功率模块的响应与疲劳寿命预测

Response and fatigue life prediction of power module under vibration load

针对功率模块焊料层在振动载荷加载下的可靠性问题,建立了三组分别采用SAC305、Sn63Pb37、Ag3.5Sn96.5材料芯片焊料层的功率模块模型,使用振动分析仪、加速度传感器等验证模型的合理性。并利用有限元仿真软件对不同模型进行模态分析、谐响应分析以及随机振动分析。选择基于高斯分布的Steinberg模型和Manson经验高周疲劳关系式,结合线性疲劳损伤累积准则,对三组不同材料芯片焊料层功率模块进行振动疲劳寿命预测。结果表明,在一阶固有频率和五阶固有频率处,不同材料功率模块均易出现共振现象。焊料层的材料对固有频率无影响,施加激励的方向对焊料层承受应力的大小有重要影响。三种材料SAC305、Sn63Pb37、Ag3.5Sn96.5焊料层的振动疲劳寿命分别为8.97×105 h,6.39×105 h,1.98×104 h。

In view of the reliability problem of the power module solder layer under vibration load,three sets of power module models were established with the chip solder layers as SAC305,Sn63Pb37,and Ag3.5Sn96.5 materials,respectively.The models were verified using the vibration analyzers,acceleration sensors,etc.The modal analysis,harmonic response analysis and random vibration analysis of different models were also carried out using finite element simulation software.The Steinberg model based on Gaussian distribution and Mansons empirical high-fatigue relationship equation,combining with the linear fatigue damage accumulation criterion,were chosen to predict the vibration fatigue life of the power modules with different material chip solder layers.The results show that the power modules of different materials are susceptible to the resonance phenomena at the first order intrinsic frequency and the fifth order intrinsic frequency.The material of the solder layer has no effect on the intrinsic frequency,and the direction of the applied excitation has an important influence on the magnitude of the stresses on the solder layer.The vibration fatigue life of the solder layer under SAC305,Sn63Pb37,and Ag3.5Sn96.5 are 8.97×105 h,6.39×105 h,and 1.98×104 h,respectively.