Physics-based via model development and verification

Vias are widely modeled and investigated as they are one of the most concerns for the critical signal nets in high-speed digital systems. 3-D full-wave modelling can predict the electrical performance of a via accurately with correct model settings, which are related to the understood of the physics behind the signal transition and the wave propagation associated with the via. This paper will detail physics-based via model development by tracking the current path and mapping the via structures to circuit components/blocks where the peeling and partitioning method is used to decompose the entire via structure into via blocks. A simple via structure with the signal transitions from a microstrip to a microstrip is studied as an example. Good agreement has been achieved between the physics-based via simulation and the full-wave modeling in the frequency-domain with S-parameters and in the time-domain with eye-height and eye-width at different data rates.