The VISTA/SFC TCAD environment has been designed to support the development of semiconductor processes and devices at different stages of the design process. It has evolved from early attempts based on the VISTA TCAD framework [SFF91] [Fas94] [Hal94] to create a tool for controlling and automating the sequential execution of semiconductor process simulation tools [PS93a] [PS93b]. At the present stage of development, it comprises simulation tool integration, process flow representation, process flow simulation, and task-level automation for optimization, calibration, and response-surface modeling tasks. The remainder of this chapter gives an account of the objectives and the overall architecture of the simulation environment.