Finite-difference time-domain analysis of complex interconnect structures

Abstract

This thesis considers the application of the finite-difference time-domain (FD-TD) method to the electromagnetic characterization of multichip-module (MCM) interconnects with perforated (mesh) reference planes. The limitations of the method in finding the propagation characteristics, characteristic impedance, Z0, and phase constant, beta, are investigated. A different method for the characterization of MCM interconnects is suggested which exploits the capabilities of the FDTD method. This alternative approach uses the results from the FDTD method to extract a per unit length delay and an approximate impulse response of the system. These results can be used to identify the effects of the perforated reference plane on signal propagation. In particular the validity of the TEM approximation for signal propagation in realistic MCM structures is examined. For those cases where the TEM approximation is valid, a quasi-TEM approach is developed to find equivalent transmission line characteristics of MCM interconnects. This quasi-TEM method can be used to obtain effective transmission line parameters for both single and coupled interconnects, which in turn can be used directly in SPICE-like waveform simulation tools for an overall electrical analysis of complex MCM interconnect nets.