三维封装芯片键合IMC焊点应力分析及结构优化

利用ANSYS有限元软件对三维封装芯片键合过程中金属间化合物焊点及芯片的应力分布情况进行模拟，并对三维封装的结构进行了优化设计．结果表明，铜柱及焊点的第一主应力最大点出现在底层外部边缘拐角处，芯片应力最大点出现在通孔内表面；以焊点的最大应力作为响应设计正交试验，来模拟封装结构参数对焊点残余应力的影响，采用3因素3水平的正交试验，选择填充树脂的厚度、芯片厚度和填充树脂的硬度3个影响封装体内部残余应力的主要因素作为封装结构参数．填充树脂的厚度对焊点应力的影响最大，影响适中的是芯片厚度，最弱的是填充树脂的硬度．

Stress analysis and structure optimization of IMC joints in 3D package

The stress distribution in intermetallic compound(IMC) joints and chips during 3D packaging was simulated with ANSYS finite element software, and the structure of 3D package was optimally designed.The results showed that the maximum value of the first main stress in the copper columns and joints appeared in the edge corner of the lowest layer, and the maximum stress in the chips appeared in the inner surface of the TSV.In order to simulate the influence of structure parameters on the residual stress, the orthogonal test with three factors and three levels was designed using the maximum stress of the joints as the response.The three main factors influencing the residual stress in the package, the resin thickness, the chip thickness and the resin hardness, were chosen to be the parameters of the package structure.The results showed that the resin thickness played the most important role but the resin hardness played the least important role in affecting the stress in the joint.