Technology computer-aided design (TCAD) is essential to the design of modem integrated circuit fabrication processes. TCAD tools must not only model real processes accurately, to allow predictive simulation during technology research and development, but they must work together as an integrated system to allow efficient exploration of technology options. Sensitivity and statistical analyses using an integrated TCAD system provide rapid technology characterization, including the examination of process extremes, before fabrication. This predictive capability reduces the technology design interval, and enables the design of optimized, manufacturable designs. This paper describes the integrated TCAD system in use at AT & T.