Routing method in computer aided customization of a two level automated

Abstract

A routing method implemented in the stored programs of a digital computer ich is programmably operated to generate the wire interconnect masks for a two level metallization automated universal array having undefined roadbeds between rows of cells comprised of identical semiconductor device basic units which are further interconnected to provide a particular integrated circuit structure. Conductor routing is provided by a computer aided design system that, among other things, carries out a route analysis process which determines in which roadbed each wire should be tentatively routed in conjunction with generating a routing density profile for minimizing congestion for a particular circuit design and when the roadbed density is exceeded, certain wires are removed under a set of criteria for routing by a pathfinder routing process. Following route analysis, detailed routing and rerouting is performed sequentially by a direct routing process, a greedy channel routing process, and a pathfinder routing process with rerouting being performed after each channel router and pathfinding process. Furthermore, the greedy channel routing process makes a single pass from left to right in all wires which cross successive points simultaneously and, if necessary, deleting a wire or wires which are then rerouted by the pathfinding process.