钼缓冲层对SiC功率器件封装可靠性的影响  

Effect of molybdenum buffer on the reliability of SiC power device packaging

作　　者：刘洋志 卢盛辉 吴丽娟[1] 宋宣廷 李良良 LIU Yangzhi;LU Shenghui;WU Lijuan;SONG Xuanting;LI Liangliang(Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering,Changsha University of Science and Technology,Changsha 410114,China;School of Artificial Intelligence,Nanning College for Vocational Technology,Nanning 530008,China)

机构地区：[1]长沙理工大学湖南省柔性电子材料基因组工程重点实验室,湖南长沙410114 [2]南宁职业技术学院人工智能学院,广西南宁530008

出　　处：《电子元件与材料》2022年第11期1236-1244,共9页Electronic Components And Materials

基　　金：湖南省自然科学基金(2021JJ30738);南宁职业技术学院2021年高层次人才科技项目(2021GCC13)。

摘　　要：采用有限元分析方法,对有无钼缓冲层的两种封装结构进行了热循环和稳态热机械可靠性对比研究。结果表明,在封装中加入钼缓冲层后对芯片的金属化层的影响较小,但使碳化硅芯片的等效应力降低了60.2%,芯片焊料层的等效应力降低了46.28%,同时芯片焊料层的疲劳寿命增加了约1380倍。进一步用响应面法(RSM)分析了钼缓冲层的尺寸对封装中各组件的应力和应变的影响,结果表明,钼缓冲层的直径接近芯片的对角线长度时,寿命最佳;增加缓冲层厚度可提升缓冲效果,但会降低底座焊料层寿命;钼缓冲层最优厚度为0.5~0.7 mm,对应的芯片焊料层寿命为2058771~1867470次循环,底座焊料层寿命为1026~1049次循环,分别为无钼缓冲层结构的2983~2706倍和1.49~1.52倍。在相同热功耗下,芯片焊料层应力和底座焊料层应力仍分别降低83.6%~85.1%和17.2%~15.1%。The thermal cycle and steady-state thermo-mechanical reliability of two packaging structures with or without molybdenum buffer layer were investigated by using finite element analysis method.The results show that the additional molybdenum buffer layer in the package has little effect on the metallization layers of the silicon carbide die,while the equivalent stresses of the die and its solder are reduced by 60.2%and 46.28%,respectively.Besides,the fatigue life of die solder is increased by about 1380 times.The response surface method(RSM)was used to further analyze the impact of the size of molybdenum buffer layer on the stress and strain of each component in the package.The results show that the best fatigue life is achieved when the diameter of the molybdenum buffer layer is close to the diagonal length of the die.The thickness increment of the buffer layer improves the buffer effect,but reduces the fatigue life of the base solder layer.The optimal thickness of the buffer layer is 0.5-0.7 mm,corresponding to 2058771-1867470 cycles for the fatigue life of die solder and 1026-1049 cycles for the fatigue life of base solder,which are 2983-2706 times and 1.49-1.52 times of the structure without molybdenum buffer,respectively.The chip solder layer stress and base solder layer stress are reduced by 83.6%-85.1%and 17.2%-15.1%,respectively,at the same power loss.

关 键 词：封装可靠性 钼缓冲层 温度循环 疲劳寿命 有限元分析 热应力 

分 类 号：TN306[电子电信—物理电子学]