New simulation procedure for accurate package modeling considering chip-package interaction

This paper presents a novel simulation procedure for full-wave electromagnetic simulations for generating package models taking into account chip-package interaction. If a simulated structure is split into two sub simulations, the accuracy of the overall simulation decreases. This is mainly the case if no clean separation of a composition into sub simulations is possible due to interactions between the sub domains. We show by means of a simple example of an embedded Wafer Level Ball grid array (eWLB) package that the simulation results of a cascade of an eWLB package and a chip are different to the simulation of the complete composition. The proposed simulation procedure delivers a package model with the package-chip interactions included and therefore cascading with integrated circuit model is possible with a higher accuracy. We show that the simulation results of a cascade of a package model obtained with the new procedure and a chip are virtually equal to a simulation of the whole composition. Furthermore we show that the created model of the package obtained from the proposed procedure is independent of the electrical circuit on the chip. This proves that the separation of the package from the chip with the proposed procedure is valid.