Design and Implementation for a Procedural VLSI Layout

This paper describes the main features of a Integrated Circuit Layout system called ALI2. The system is based on a procedural layout language which allows the designer to specify layouts at a conceputal level. The system attempts to make layout design similar to software design. The language has a cell mechanism that is hierarchical and parametric, and allows the user to design truly generic cells whose instances are dependent on the environments in which the cell is invoked. Several layouts have been successfully designed and fabricated using the system. Initial versions of the system were designed and implemented when the authors were at Princeton University, and later versions were developed when the first author was still at Princeton and the second author was at Georgia Institute of Technology.