双面散热功率模块的热阻建模与测试表征研究

Modeling and Characterizing for Thermal Resistance of Double-sided Cooling Power Module

相对于单面散热(single-sided cooling,SSC)封装,双面散热(double-sided cooling,DSC)封装能有效降低功率模块的结–壳热阻,大幅提升变流器的功率密度,是功率集成的发展趋势。DSC功率模块具有双通道传热的特征,然而现有研究仍然沿用SSC功率模块单通道传热的热阻模型和评测方法。因此,DSC功率模块的热阻研究存在物理意义不明、热路模型缺乏、评测方法空白等基础问题,严重制约DSC功率模块的装备研发、可靠运行和规模应用,亟待技术突破。文中基于等温剖面和温度梯度的概念,揭示功率模块热阻的传热学机理,阐释DSC功率模块热阻的物理意义,建立DSC功率模块的热路模型,分析双通道传热和单通道传热的热阻规律,仿真分析和实验测试的结果,验证模型和方法的可行性和有效性。结果表明:相对于SSC功率模块,DSC功率模块的双通道热阻,从物理上、数学上和表征上,都不是两个单通道热阻的直接并联。此外,DSC功率模块在降低73%尺寸的同时,可以降低65%的结–壳热阻。这些研究发现将为DSC功率模块的研发与应用及制定多通道传热半导体器件的热阻标准,提供有益的参考。

Due to considerably reduced junction-case thermal resistance,the double-sided cooling(DSC)packaging can dramatically promote the power density of converters compared with the single-sided cooling(SSC)counterpart,which is the cutting-edge of the power integration.However,the thermal-dependent modeling and characterizing of the DSC power module still follow the methodologies of the SSC power module,and the specific double channel thermal paths of the DSC power module are overlooked.Therefore,the physical insight,thermal model,and assessment approach are lacked to understand the thermal resistance of the DSC power module,thereby locking the research development,reliability facilitation,and massive production of the DSC power module.In this paper,with the aids of the concepts of isothermal surface and temperature gradient,the thermal mechanisms of the SSC and DSC power modules were revealed,respectively.Based on the proposed physical essence of the DSC power module,the thermal network model of the DSC power module was created.Moreover,concerning the DSC power module,the principles of the thermal resistances with single path and double thermal paths were clarified.Comprehensive simulation results and experimental measurements ensured the feasibility and validity of the developed model models and methods.It was found that the junction-case thermal resistance of the DSC power module was not the simple parallel connection of the two thermal resistances of the partial SSC power modules physically,mathematically,or experimentally.Furthermore,compared with the SSC power module,the DSC power module could save 73%footprint while reducing 65%junction-case thermal resistance.These findings are extremely significant for the development,implementation,and standardization for the thermal resistance of the next-generation semiconductor devices.