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.