Prediction and Analysis of Radiated EMI From a Wafer-Level Package Based on IC Source Modeling

Abstract

This article proposes a comprehensive analysis and prediction method for wafer-level radiated electromagnetic interference (EMI) based on integrated circuit (IC) source modeling. An IC and a simplified wafer-level package (WLP) with a redistribution layer (RDL) were designed and fabricated for the research. The IC that draws currents through the RDL is efficiently modeled as a Thevenin equivalent circuit in the frequency domain. The equivalent EMI source model can simply replace complex time-domain operations of the IC that cannot be easily implemented in a full-wave field solver. To simulate the radiated EMI from the wafer-level RDL, the EMI source model is incorporated into the full-wave solver. The proposed approach is validated by comparing the simulated fields using the EMI source model and the measured fields on the WLP. The tendency of the radiated fields shows a high correlation with the common-mode current flowing through the RDL. The IC source modeling approach enables the decomposition of EMI factors into an IC operation and WLP structure.