Research On Key Technologies Of High Voltage Power Semiconductor Device Packaging

Under the background of the new energy revolution,the voltage level of power semiconductor devices is continuously increasing.Due to the lack of systematic theoretical guidance in packaging design at the present stage,the electrical insulation design of highvoltage power semiconductors packaging has been beset with difficulties with the higher withstand voltage level of power semiconductors.The rapid development of wide bandgap devices such as silicon carbide has brought challenges to the multi-physics coupling design of power device packaging.This thesis focuses on the design and manufacturing of highvoltage power semiconductor device packaging.Firstly,based on the overview of high-voltage power semiconductor device packaging,the challenges faced in electrical insulation design are summarized,and the current research status of the design methods for electric field optimization and multi-physics field coupling optimization inside the packaging are concluded.The key positions of the high-voltage device packaging in the insulation design are pointed out and the root causes of its discharge are analysed,including the electric field concentration around the chip,electric field concentration of the triple point inside the packaging,and the mechanism of gas ionization discharge on the surface of the housing.A stacked press-pack packaging structure is proposed for high-voltage silicon carbide DSRD devices in the field of pulse power.The superiority of the packaging in the field of pulse power applications is verified,which is reflected in the extremely low parasitic inductance,reasonable thermal resistance and heat capacity,and lower thermal stress than soldered packaging by electro-thermal-force finite element simulation.The electric field distribution at the edge of the chip is optimized by changing the extension length of the metal layer inside the packaging.Taking 4500 V high-voltage IGBT chip as the research object,the design of half-bridge power module is developed and the design idea of high-voltage and high-power device packaging is proposed.Firstly,an electric field evaluation method that the maximum electric field strength under 3D electric field simulation is decoupled from the mesh grid and correlated with the experimental data of partial discharge is proposed.Then the influence of different structures and material parameters in the packaging on the electric field strength in the triple point area is analysed and compared.The thermal resistance,parasitic parameters of the packaging and the electric field strength in the triple point area are mathematically modeled.The nonlinear multi-variable optimization algorithm for multiphysics coupling design for DBC is used instead of traditional manual iterative packaging design method,to realize the optimized packaging structure with the best thermal resistance satisfying the insulation and electromagnetic performance,which is verified by finite element simulation that the thermal resistance of the optimized module junction case is reduced by 13%,and the reduction of thermal resistance does not lead to the deterioration of the electric field distribution of the triple point.Finally,the housing of the 4500 V power module was designed under the requirements of minimum electrical clearance and minimum creepage distance of 22 mm and 45 mm,respectively,according to specific standards.Based on the designed structure and housing,the fabrication of 4500 V high-voltage IGBT half-bridge power module is completed.Combined with industry standards,the module has been tested for high potential test,thermal impedance and double pulse tests to verify the good insulation,heat dissipation performance and dynamic characteristics of the fabricated modules,which lays the foundation for the application of high-voltage power modules in industrial sites.