一种采用柔性缓冲垫块的双面散热SiC MOSFET双向开关模块研究

Double-sided SiC MOSFET Bi-directional Module with Flexible Buffering Spacers

随着功率模块朝着高温、高功率、高密度方向发展,这对模块的封装结构提出了新的要求。较传统的引线键合结构,双面散热结构由于具有高散热能力和低寄生电感等特点受到广泛关注。但是双面散热结构材料间热膨胀系数的差异使之承受较大的热-机械应力,降低了功率模块的可靠性。因此,为设计具有低热-机械应力双面散热双向开关,本研究首先使用仿真分析了芯片布局对模块散热性能以及寄生电感的影响,在此基础上提出了一种具有低杨氏模量的柔性缓冲垫块,综合仿真及试验初步证明其降低热-机械应力、提高模块可靠性的可行性。

The development of power modules towards high temperature,high power and high density raises higher requirements for the packaging structures of modules.Compared with the traditional wire-bond structure,the double-sided structure has attracted more and more attention owing to its characteristics such as high heat dissipation capacity and low parasitic inductance.However,the mismatch of thermal expansion coefficient between materials used in the doublesided structure makes the structure suffer tremendous thermo-mechanical stress,thus reducing the reliability of power module.Therefore,to develop double-sided bi-directional modules with low thermo-mechanical stress,the effects of chip layouts on the heat dissipation performance of modules and the parasitic inductance were analyzed by simulations at first.Then,a flexible buffering spacer with low Young’s modulus is proposed accordingly.The feasibility of reducing the thermo-mechanical stress and improving the reliability of the module was preliminarily proved by simulation and experimental results.