AN EFFICIENT TRANSIENT MODELING FOR 3-D MULTILEVEL INTERCONNECTIONS IN A STRATIFIED DIELECTRIC MEDIUM

An efficient method is presented to model the transient characteristic s of distributed resistor-capacitor of ULSI multilevel interconnection s on complex topography, in which the reformulation of the boundary-el ement method (BEM) associated with the Padi-via-Lanczos (PVL) algorith m can avoid the redundant works on both volume mesh and transient anal ysis associated with the finite-difference method. An adaptive multila yer closed-form spatial Green's function for BEM is developed to exami ne the voltage and current responses of the multilevel conductor syste m by using the boundary-element method of integral formulation, in whi ch arbitrary triangular elements on the surface of conductors are used to efficiently calculate the free-charge distributions of complex str ucture based on actual topography/processes. Applying the Galerkin pri nciple over boundary elements, all of the surface integrals of charge distribution have been discretized and evaluated analytically for cons tant element. To improve the timing-analysis efficiency of the finite- difference method, the dominant poles are obtained by introducing the Pade-via-Lanczos (PVL) algorithm for model-order reduction. Hence, it is easy to calculate the transient characteristics of both parallel co nductors and complicated configurations such as crossing lines, corner s, contacts, multilayers and their combinations. Therefore, a simple a nd more general method is proposed for solving the combinations of com plex structures based on actual topography/processes and arbitrary geo metric configurations of multilevel interconnection lines in order to link with the present CAD tools. (C) 1998 Published by Elsevier Scienc e Ltd. All rights reserved.