A practical ball‐grid‐array transition modelling methodology for accurate and fast multi‐interposer package simulation

Abstract

An equivalent circuit modelling methodology for the ball‐grid‐array (BGA) transition is proposed and validated with full‐wave electromagnetic simulation and measurement results. The BGA transitions modelled with the proposed methodology are validated to have a good accuracy up to 40 GHz. Unlike the existing BGA modelling methodologies which cannot model the BGA transition with short transmission lines within the anti‐pad region, the proposed methodology is developed from the practical BGA modelling scenario and models the irregular‐shape solder pads with transmission lines within the anti‐pad region. The BGA transitions modelled with the proposed methodology can be used for accurate and fast signal integrity simulations, analyses, and optimizations on 2.5D and 3D packaging. Additionally, factors impacting the accuracy of the equivalent circuit model are revealed by the proposed methodology.