SGRED - A Symbolic Graphics Editor For VLSI Layout

This paper gives an overview of SGRED, a third generation connectivity based symbolic layout editor for integrated circuits. The major problems with existing layout editors and their adverse impact on custom cell designers are presented. The unique editing features which solve many of these problems are then described. Some of these features include: electrical connectivity checks, hierarchical net tracing, ability to place and automatically connect cell instances, automatic contact generation, automatic rerouting after area moves, and hierarchy management. The paper concludes by summarizing the fast turnaround times achieved by chip designers using this editor at AT&T Bell Laboratories.