The User Interface and Implementation of an IC Layout Editor

This paper describes several novel aspects of Caesar, a layout editor for Manhattan-style integrated circuits. The program's user interface is similar to painting. By hiding many irrelevant details, the painting mechanism provides a powerful yet simple user interface. Its implementation using horizontal strips is efficient in both time and space. To handle large circuits efficiently, Caesar represents them hierarchically and capitalizes on their hierarchical structure to avoid excess computation and I/O. Mask information is rendered on color displays with a novel combination of transparent and opaque layers that clarifies layer interactions even in the presence of a large number of mask layers.