Optimal Design And Life Model Of Double-sided Cooling SiC Power Module

Silicon Carbide(SiC)is a wide band gap semiconductor material.With notable advantages over band gap,electron mobility,breakdown field strength and operating temperature,it can help power electronic systems achieve the goal,namely,high efficiency,miniaturization,lightweight.Double-sided cooling(DSC)SiC packaging can make good use of the properties of SiC chips,which means that low-inductance,high temperature,and high-power density packaging no longer too far to reach.As an important branch,the development of double-sided cooling sic power module will not be ignored.However,there are numerous technical obstacles(i.e.,insufficient optimization,and lack of reliability research for DSC SiC power module,etc)should be addressed for the emerging DSC SiC power module.From the perspective of under-optimization,although the conventional packaging design method can improve the performance of the double-sided heat dissipation SiC power module,it relies too much on experience and trial and error method,resulting in a long cycle,high cost,and low competitiveness.From the perspective of reliability research,due to high price and low productivity of the DSC SiC power module,to acquire life data of it is challenged,which is a key factor in establishing the life model for the DSC SiC power module.To fulfill these research gaps,this paper follows the ideas from single chip to multi-chip,theory to verification,and establishes a thermal-mechanical collaborative optimization design method for double-sided heat dissipation modules,and a multi-chip optimized layout method based on DSC packaging.Additionally,whit the life model and the failure mechanism of the DSC SiC power module researched,it was tested by the power cycle ecperiment,after the package integration.(1)The thermal-mechanical multi-objective optimization design model of the DSC power module were proposed.Aiming at the under-optimization problem of the DSC module,this paper characterizes the thermal resistance and stress of the DSC module,which are verified by the FEA software at the same time.Finally,the multi-objective optimization design model is extracted and solved by the non-dominated sorting genetic algorithm-II(NSGA-II).Based on the advantages of the DSC module in the layout,this paper also proposes an optimized layout method for the multi-chip layout,and carries out a low-inductance and current-sharing design.(2)Established the life prediction model of the DSC SiC power module.Often it requires a large quantity of life testing data to create an accurate model of life,which is costly and time-consuming process to obtain by traditional accelerated aging experiments.Moreover,because of the high price and low productivity of DSC SiC power modules,it is almost impossible to obtain life data through power cycle tests.Therefore,this paper established a FEA model of the power module,and verified its accuracy with the life data of a large number of existing Si single-sided cooling(SSC)modules.Then,this model was transferred to the DSC SiC power module,and the stress behavior and failure mode of the SSC power module were compared and analyzed,and the service life was evaluated.Using the established FEA model,the influence of material optimization on the DSC SiC power module is analyzed,and it is found that the spacer material has the greatest impact on the module.The life of the copper spacer DSC SiC module is only 1/4 of the molybdenum spacer power module.(3)The influence of the optimized design on the DSC SiC power module was explored,and the package integration of the DSC SiC power module was realized,and experimental verification and comparative analysis were carried out.Firstly,the principle of the power cycle experiment and the experimental platform are introduced.Then the DSC SiC power module is packaged and integrated,and the packaging steps are described in detail.A power cycle test platform was built,and DSC SiC power modules of different designs were tested to verify the impact of packaging optimization on the reliability of power modules.Finally,this paper also tested and analyzed SSC SiC devices under the same conditions to verify the advantages of DSC SiC power modules in terms of reliability.