Long Term Reliability of Power Modules with Low Amplitude Thermomechanical Stresses and Initial Defects
Long Term Reliability of Power Modules with Low Amplitude Thermomechanical Stresses and Initial Defects
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DOI：
10.1109/ecce.2018.8558137
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
Borong Hu;Sylvia Konaklieva;L. Ran;N. Kourra;M. Williams;Wei Lai;P. Mawby
中科院分区：
文献类型：
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作者：
Borong Hu;Sylvia Konaklieva;L. Ran;N. Kourra;M. Williams;Wei Lai;P. Mawby
焊料连接的IGBT功率模块广泛用于可再生能源和智能电网应用中，其中热机械应力循环的幅度相对较低，但器件的服务职责预计将持续数十年。虽然焊料层中的初始缺陷空洞和裂纹被广泛认为是初始老化的触发器，但仍有必要准确描述和模拟其局部区域在低幅应力循环下的物理疲劳行为。为了研究损伤的增长，本文开发了一个二维对称有限元分析（FEA）模型来评估初始缺陷的焊料层的热机械行为，这是通过功率循环试验和微分辨率计算机断层扫描（CT）扫描相结合来验证的。模型及其实验验证提供了一种理解，即分布在焊料层中的空隙可能会转移到初始裂纹中，然后逐渐快速生长;邻近芯片-焊料界面的空隙将特别减少寿命。这为进一步研究焊点界面损伤过程奠定了理论基础。
Solder-attached IGBT power modules are widely use in renewable energy and smart grid applications where the thermomechanical stress cycles are relatively low in amplitude but the service duties of the devices are expected to last for decades. Although the initial defect voids and cracks in the solder layer are widely recognized as the triggers of initial aging, it is still necessary to describe and simulate the physical fatigue behavior in their local regions accurately under low amplitude stress cycling. In order to investigate the growth of the damage, in this paper a 2D symmetrical finite element analysis (FEA) model is developed to evaluate the thermo mechanical behavior of the solder layer with initial defects, and this is verified by a combination of power cycling test and micro-resolution computed tomography (CT) scanning. The modeling and its experimental validation provides an understanding that the voids distributed in the solder layer may transfer into initial cracks which then grow progressively rapidly; the voids adjacent to the chip-solder interface will particularly reduce the lifetime. This establishes the basis of a modeling theory for further investigation of the damage progress on solder interface.