Stress analysis and structure optimization of copper cylinders based on 3D packaging

In this paper, the thermal cyclic loading was adopted to analyze TSV copper cylinders stress distribution by using simulation software ANSYS, a cycle is 29min, the temperature range from-55 to 125°C. In order to study the stress of copper cylinders in TSV, at the first a set of suitable parameters were used to simulate the stress, then the structure parameters were optimized in this paper, and take copper cylinders maximum von-mises stress as response, by using MINITAB software and Taguchi orthogonal test method to analyse the influence of the copper cylinders diameter, copper cylinders height, copper cylinders pitch on the stress of copper cylinders in TSV. The simulation based on a set of suitable parameters, the results shown that the maximum von-mises stress was located at the outer corner of the copper cylinders in contact with the bottom position. Orthogonal test method was used, which found that the copper cylinders diameter had a big influence on maximum von-mises stress of copper cylinders, copper cylinders height followed, copper cylinders pitch minimal impact. By average of main effects plot found that within the parameters selected range, maximum von-mises follows a non-monotonic trend for TSV diameter and TSV height and also found that with the increase of the TSV pitch the stress between the outer corner and the bottom of the copper cylinders decrease gradually.