The application of the optimal design for twin die stacked package

The fatigue life and reliability of 3D stacked die package becomes very important due to the coupling effect among all materials, especially in twin die stacked package. The article presents the quickly and more accurate optimal design for such case. Firstly, the Darveaux model is applied to predict the solder ball reliability of the stacked die package under a cyclic thermal loading condition. Then, the concept of the average value of the strain energy density induced by thermal loading in solder balls is introduced to act as the optimization indicator of the reliability. Such viewpoint as this can ignore the critical solder ball´s position which used before and get the analysis result more efficient. Finally, the Box-Behnken regression model is adopted to construct all the experiments. Each experiment analyzes the reliability from various parameters of the package. Subsequently, the pattern search algorithm is applied to search for optimal parameters.