Analysis and modeling of multilevel parallel and crossing interconnection lines

Analytical and numerical techniques to study the pulse propagation characteristics such as delay, distortion, and crosstalk in multilevel interconnections associated with high-speed digital IC's including VLSI chips are presented. The parallel and crossing interconnections at various levels are modeled as lossy coupled lumped distributed parameter systems, which are analyzed for their time domain characteristics. The characterizing electrical parameters of the structures are computed by utilizing the network analog method that has been formulated to solve for the lossy line constants and parasitic coupling associated with a three-dimensional multiconductor system in a layered lossy medium. It is shown that the time domain response of the multiport structures can be computed by using standard CAD programs such as SPICE by utilizing compatible circuit models developed from the solution of such systems. Examples of the step and pulse response of typical systems are included to demonstrate the versatility, usefulness, and accuracy of the techniques presented in the paper.