At the early stages of development, the primary goal of the Simulation Flow Control module (SFC) [PS93b] was to use a set of single-process simulation tools like PROMIS and SAMPLE [Ele91] to automatically simulate complete VLSI fabrication processes, the main concern being the integration of process simulation tools by providing uniform interfaces for the exchange of simulation data and for controlling the execution of the tools. Chapter 4 presents in detail the strategies adopted in VISTA/SFC for coupling heterogeneous process and device simulation tools.