功率封装钝化层开裂原理分析  

Analysis on Crack Mechanism of Passivation Layer in Power Packaging

作　　者：陈志文 胡兴旺 刘勇 刘俐 刘胜 CHEN Zhiwen;HU Xingwang;LIU Yong;LIU Li;LIU Sheng(Institute of Industrial Sciences,Wuhan University,Wuhan,Hubei 430061,China;ON Semiconductor,Arizona 85008,USA;School of Materials Science and Engineering,Wuhan University of Technology,Wuhan,Hubei 430061,China)

机构地区：[1]武汉大学工业科学研究院,湖北武汉430061 [2]安森美半导体,美国亚利桑那州85008 [3]武汉理工大学材料科学与工程学院,湖北武汉430061

出　　处：《机车电传动》2021年第5期156-160,共5页Electric Drive for Locomotives

基　　金：国家自然科学基金项目(61904127,62004144);广东省基础与应用基础研究基金项目(2021A1515010651);中央高校基本科研业务费专项资金资助项目(202401002,203134004,20212VA100,2021VB006);湖北省自然科学基金项目(2020CFA032);国家重点研发计划项目(2019YFB1704600)。

摘　　要：功率芯片表面的钝化层裂纹严重影响功率器件的可靠性。文章通过典型的D-PAK模块温度循环试验,对钝化膜失效原理进行了深入研究。温度循环试验结果表明,裂纹在靠近边界覆盖有铝膜的钝化层中生长,但是很少出现在铝条中。如果钝化膜中的裂纹始终和制造过程中最先产生的裂纹保持一致,那么器件的寿命将会很长。这要求应力强度因子总是小于钝化膜的韧性,否则裂纹就会在后续的服役周期中生长并扩展;应用Griffith准则可以知道裂纹是否会产生。最后,给出了裂纹萌生周期临界值的估算方法,并绘制了裂纹萌生图作为钝化层的失效准则。文章提出的系统性检测钝化层产生棘轮变形和开裂的方法,可以提高器件的可靠性。Passivation crack on the surface of power chip seriously affects the reliability of power devices. In this paper, the mechanism of passivation layer failure was explored by temperature cycling test on D-PAK module. Temperature cycling tests showed that the cracks developed in the passivation film over the aluminum film close to the boundary, but were rarely observed in stripe. If the cracks in passivation film remains the same as the first cracks in manufacturing processes, there would be a long service life for the device. This requires that the stress intensity factor is always less than the toughness of passivation film. Otherwise, the crack will grow and propagate in the subsequent cycles. Griffith criterion can be used to know whether cracks will occur or not. Finally, the estimation method of the critical value of crack initiation cycle was provided, and the crack initiation diagram was illustrated as the failure criterion of passivation layer. A method was proposed to predict whether the passivation has ratcheting deformation or crack to improve the reliability of devices.

关 键 词：钝化层开裂 棘轮效应 功率封装 可靠性 

分 类 号：TN305.94[电子电信—物理电子学]