A highly programmable environment designed to support the most complex of TCAD tasks has been presented. The concept of evaluable entities provides a sound basis for the definition and execution of nested and aggregate analysis problems. Heterogeneous simulators and framework services are effectively encapsulated and form the basic building blocks for higher-level applications in process design, process analysis, and process optimization. Available data wrappers equally support the operation with both PIF-based and foreign simulation tools. The user can specify standard analysis tasks in terms of high-level operations like response-surface generation or optimization loops; existing analyses can be combined to form more complex tasks. The complete task description can be submitted to the TCAD environment as a batch job for automatic simulation. Offering a task-level programming model together with a powerful task-level interpreter sets VISTA/SFC apart from other available TCAD frameworks and makes it a versatile, extensible TCAD system. Prototype versions of the simulation environment have been successfully used by Austria Mikro Systeme AG as well as by other international semiconductor manufactures. License agreements and test versions are available from our WWW page.