基于瞬态热阻的IGBT焊料层失效分析
Evaluation of Solder Failure of an IGBT Module Based on Transient Thermal Impedance
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摘要: 焊料层失效是绝缘栅双极晶体管(insulated gate bipolar transistor,IGBT)器件最主要的失效方式之一,有效的焊料层失效评估方法对提高系统可靠性尤其重要。该文提出了基于瞬态热阻的IGBT焊料层健康状态评估及失效部位判定方法,量化分析芯片焊料层失效、DBC焊料层失效对器件整体失效的贡献。首先,利用三维有限元仿真证明该方法评估功率器件焊料层疲劳老化的可行性;然后,提取IGBT模块的结构函数曲线建立三阶Cauer模型,实现对不同焊料层失效程度的量化评估以及失效点判定;最后,搭建试验平台,分析不同工况和失效状态下瞬态热阻曲线的变化规律,验证所提出的瞬态热阻法评估IGBT焊料层失效的有效性。Abstract: According to statistics, solder failure is responsible for a significant proportion of overall faults of insulated gate bipolar transistor（IGBT） module. Therefore, an effective method to evaluate solder fatigue degree of IGBT module is essential to system reliability. A method based on transient thermal impedance to evaluate solder fatigue degree and identify failure point was proposed in this paper, which is also helpful to quantitative analysis of chip solder and DBC solder fatigue degrees, respectively. Firstly, a 3 D finite element method（FEM） of IGBT module was built to demonstrate that transient thermal impedance can be chosen as a character of solder failure. Then, three order Cauer thermal model of IGBT module was extracted from structure function, which is calculated by transient thermal impedance, to analyze chip solder and DBC solder failure stages and identify failure point. Lastly, an experimental platform was designed and established to validate the proposed method.
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