Stress analysis and structure optimization of copper cylinders in 3D packaging

This paper analysed the whole stress of the 3D packaging structure and the local copper cylinders stress in the process of chip heating. And the three-dimensional structure was optimized by using finite element simulation software ANSYS. The result showed that the maximum stress was distributed at the location between the outer corner and the bottom of the copper cylinder. The structural parameter was optimized taking the maximum stress of the copper cylinders as a response. The orthogonal optimization method including three factors and three levels was adopted, varied factors being copper cylinder diameter, the copper cylinder height and the copper cylinder pitch. The result showed that the copper cylinder diameter had the maximum effect on the stress, the copper cylinder height had the weakest influence, the effect of copper cylinder pitch was moderate. What's more, with the increase of the three factors mentioned above, the maximum equivalent stress between the outer corner and the bottom of the copper column decreased gradually.