三维封装铜柱应力及结构优化分析

文中利用有限元模拟软件ANSYS对三维立体封装芯片发热过程中整体应力及局部铜柱的应力情况进行了分析，并对三维封装的结构进行了优化设计.结果表明，最大应力分布在铜柱层，铜柱的应力最大点出现在铜柱外侧拐角与底部接触位置.以铜柱处最大应力作为响应，进行了结构参数优化，采用三因素三水平正交试验方法，分别使用铜柱直径、铜柱高度、铜柱间距三个影响因素作为变化的结构参数.结果表明，铜柱直径的变化对等效应力影响最大，铜柱间距次之，铜柱高度影响最小.且发现随着铜柱高度、铜柱间距、铜柱直径的不断增大其铜柱外侧拐角与底部接触位置的最大等效应力不断减小.

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.