A Symbolic-Interconnect Router for Custom IC Design

The router described in this paper is part of a complete CAD system which aims at hierarchical designs of customized VLSI MOS circuits. It routes global signals as symbolic interconnect and is guaranteed to complete all routing in one pass. The router is fully automatic as well as highly interactive. It employs the novel idea of bouyancy and produces wires with a natural bus structure. The router is fully operational, and has been used in routing a number of real-world integrated circuits.