IGBT Module Failure Modeling And Simulation Based On Multi-physical Field Coupling

Insulated Gate Bipolar Transistor(IGBT)has become an important unit of new energy power generation,electric vehicles and smart grid due to its advantages such as low saturation voltage and small on-state current.Therefore,its safety and reliability have attracted more and more attention.At present,there are two main packaging forms of IGBT modules: welding type and compression type,among them,welding type is more mature and widely used.In this paper,the three-dimensional model of IGBT module is established based on the multi-phys ical field coupling,and several fa ilure states of welded IGBT module are simulated,so as to propose the possibility of optimizing the module.The main research results are as follows:1.Based on the finite element simulation software of mult iple physical fields,an IGBT module was selected and its three-dimens ional model was established.The bonding wire and solder layer were taken as the main research objects.According to different research emphases,the models were optimized to meet differ ent research needs.When the bonding wire is taken as the research object,the working state of the bonding wire shedding is simulated by deleting the lead wire.When solder layer is the object of study,the existence of bonding line is ignored and the model is simplified.2.Firstly,the steady state and transient state of the bonding line are simulated respective ly,and the temperature changes on the upper and lower surface of the bond Angle and the maximum temperature of the whole module are observed,so as to obtain the main factors affecting the temperature distribution of IGBT module.The working state after the failure of the bonding line is simulated,and the influence of the partial shedding of the bonding line on the reliability of IGBT module is obtained.Then,the simulation of normal working conditions of the solder layer is made for comparison,and the influence of different positions and sizes of solder layer voids on the maximum temperature of IGBT module chip is studied to obtain the key factors affecting the reliability of the solder layer.3.This paper proposes a new materia l C7025 as bonding wire material compared with the traditiona l aluminum wire as bonding wire material may have the advantages,and through the comparison with aluminum w ire to verify the feasibility,in order to achieve the purpose of extending the service life of IGBT module bonding wire as far as possible.The advantages of Sn-Ag-Cu-0.5Sb as solder over Sn-Ag-Cu as traditional solder layer are studied.The performance comparison of the two solders under various working conditions is simulated to prove the advantages of the new solder,so as to extend the service life of IGBT module solder layer as far as possible.Through the above research on IGBT module reliability mod eling and simulation,the possible module optimization method proposed can provide some guidance for extending the service life of IGBT module.