Modeling, extraction and simulation of CMOS I/O circuits under ESD stress

A CAD tool set for VLSI CMOS I/O circuit design is developed. It includes a circuit simulator, a layout extractor and a substrate resistance solver. This paper presents a new layout extractor for CMOS I/O circuits and a new method for modeling the substrate resistance. With these tools, for the first time, full I/O circuits can be simulated accurately at the circuit-level with the substrate-coupling effects taken into consideration. The CAD tools are demonstratively applied to an industrial circuit.