Reliability Optimization of Stacked System-in-Package Using FEA

In this work, thermo-mechanical reliability of solder joints of stacked thinned bare dice system-in-package is studied with the finite element method using three-dimensional models. The studied package consists of one to five layers. In every layer two 5 mm times 5 mm silicon chips have been joined with flip chip method onto an 8 mm times 14 mm aramid-epoxy or FR-4 interposer. The package has been simulated varying the number of layers, the thicknesses of interposers and silicon chips, interposer material. Moreover, the package with three layers is studied for component placement optimization. Different sized components are used to find optimal layer structure depending on their size. The results show that every studied aspect has effect on the reliability of stacked system-in-package and with good design it is possible to increase the life time of the package