An equivalent circuit model for a Faraday cage substrate crosstalk isolation structure

Abstract

-We have developed a physics-based equivalent circuit model for a novel Faraday cage substrate crosstalk isolation structure. This compact isolation approach relies on high-aspect ratio, solid copper substrate vias that are shorted to ground. A cage constructed with these vias can be used to enclose sensitive or noisy portions of a chip and has been proven effective up to 50 GHz. The Faraday cage equivalentcircuit model is based on a well-established substrate crosstalk model with the substrate node shunted to ground through a series inductor-resistor branch that represents the substrate vias. This straightforward approach provides good agreement with the measured data into the millimeter-wave regime for different layouts of the Faraday cage.

A Through-Wafer Interconnect in Silicon for RFICs

“…This result, together with the via spacing results suggest that a simple cage of sparse substrate vias can significantly reduce crosstalk through the substrate. Further insight into the noise suppression of the Faraday cage can be obtained by deriving a lumped-element equivalent circuit model, which has been presented in [26].…”