Optimal Design for Vibration Reliability of Package-on-Package Assembly Using FEA and Taguchi Method

In this paper, the Taguchi method and finite-element analysis (FEA) were used to improve the vibration reliability of the package-on-package (PoP) assembly and to achieve an optimal design of the PoP under random vibration loading. A finite-element model of the PoP assembly was developed, and experimental modal tests were performed to verify the finite-element model. Four geometry parameters of the PoP were chosen as the variable factors, including body size of PoP, bottom solder joint standoffs, thickness of bottom substrate, and top solder joint standoffs. The volume averaged von Mises stress of the critical solder joint obtained by FEA was chosen as the quality factor, and an
$L_{9}$
(
$3^{4})$
orthogonal array was applied for Taguchi experiment to estimate the effects of the four factors and find the optimal design of the PoP on the vibration reliability. It is found that bottom solder joint standoffs have an important effect on the reliability, and more than 36% of the volume averaged Von Mises stress could be reduced by the optimal design.