Thermal-mechanical analysis and fatigue life prediction of nano-silver sintering layer for SiC chip packaging
The coefficient of thermal expansion of nano-silver differs significantly from that of other components in the module,leading to thermal fatigue failure in harsh environments.Therefore,it is a critical to predict the thermal fatigue life of nano-silver sintering layer.For SiC power module,finite element analysis and the modified Coffin-Manson life prediction model were used to analyze the maximum equivalent stress and fatigue life of nano-silver sintering layer under thermal cycling loading.Through response surface method analysis,the optimal combination between SiC chip and nano-silver sintering layer was determined with fatigue life as the optimization objective,and the effect of nickel plating on fatigue life of copper substrate was explored as well.The research results indicate that under accumulated thermal cycles the maximum equivalent stress occurs at the corner of the nano-silver sintering layer,making it more susceptible to thermal fatigue failure.The optimized thickness of SiC chip and nanosilver sintering layer are 0.15 mm and 0.1 mm,respectively,which reduce the maximum equivalent stress by 1.36％and increase the fatigue life by 1.57 times.Additionally,the nickel layer on the substrate is compatible with the nano-silver sintering layer,which can reduce the equivalent stress of the nano-silver sintering layer and increase its fatigue life.
finite element analysisnano-silverstressfatigue lifenickel plating
万方数据
维普
