Research On Damage Condition Monitoring Of IGBT Module Packaging

The electric-thermal-force load of the IGBT module is complex and variable,which causes the package structure of module to withstand thermal cycling and damage.The shedding of the bond lines is reduced,so that the bonding resistance is increased,and the crack and voids of the solder layer cause degradation of the resistance-capacitance characteristics of the module,resulting in an increase in the junction temperature of the IGBT under the same power stress.Therefore,the condition monitoring technology of IGBT module package damage is an important part of IGBT module reliability research.To study the damage condition monitoring methods of IGBT module packaging and the effect of packaging damage on junction temperature,for bonding points,wires and chip solder layer,DBC solder layer deployment theory,simulation and experimental research,the main work includes:(1)Aiming at the bonding lines of IGBT module,comprehensively considering the electromotive force of the bonding lines and the shear stress of the bonding points,the electro-thermal-force multi-field coupling of the bonding lines and the points is simulated,and the influence mode of bonding damage caused by electromotive force of the bonding lines and the shear stress of the bonding points is found The perfect feedback evolution framework of bonding damage,electro-thermal-force and bonding resistance is proposed.To quantitatively study bonding damage under bonding lines drop mode.The interaction law of its origin is analyzed and tested.(2)The bonding resistance monitoring method based on the linear relationship between the height of the miller platform and the collector current in the turn-off process of the IGBT module is proposed.Based on this,the method is proposed to be monitored online under wind and electricity conditions.In the implementation scheme,a five-level bonding damage state characterization method based on the number of bonding lines dropouts and equivalent number of bond wire detachments is proposed.(3)Aiming at the solder layer of IGBT module,the damage evolution mechanism of solder layer is analyzed,and the positive feedback process of solder layer damage evolution is combed;the thermal-stress field and damage evolution law of solder layer are simulated,and the influence of solder layer damage mode on IGBT junction temperature and shear stress is quantitatively studied;A monitoring method of solder layer damage based on transient thermal impedance and Cauer model is proposed,and the correctness of the proposed method is verified by experiments.(4)To study the effect of IGBT module packaging damage on junction temperature,an electro-thermal coupling model considering packaging damage was established.The switching energy consumption,on-state power consumption and transient thermal impedance of IGBT module under different damage levels were tested.The empirical degradation model of IGBT module was established.Then the electro-thermal coupling model considering packaging damage was constructed to study the effect of packaging damage on IGBT junction temperature.