Chemical Vapor Deposition (CVD) processes constitute an important unit operation for micro electronic device fabrication in the semiconductor industry. Simulators of the deposition process are powerful tools for understanding the transport and reaction conditions inside the deposition chamber and can be used to optimize and control the deposition process. This thesis discusses the development of a set of object-oriented modular simulation tools for solving lumped and spatially distributed models generated from chemical process design and simulation problems. The application of object-oriented design and modular approach greatly reduces the software development cycle time associated with designing process systems and improves the overall efficiency of the simulation process. The framework facilitates an evolutionary approach to simulator development, starting with a simple process description and building model complexity and testing modeling hypothesis in a step-by-step manner. Modularized components can be easily assembled to form a modeling system for a desired process. The framework also brings a fresh approach to many traditional scientific computing procedures to make a greater range of computational tools available for solving engineering problems. Two examples of tungsten chemical vapor deposition simulation are presented to illustrate the capability of the tools developed to facilitate an evolutionary simulation approach. The first example demonstrates how the framework is applied for solving systems assembled from separate modules by simulating a tungsten CVD deposition process occurring in a single wafer LPCVD system both at steady-state and dynamically over a true processing cycle. The second example considers the development of a multi-segment simulator describing the gas concentration profiles in the newly designed Programmable CVD reactor system. The simulation model is validated by deposition experiments conducted in the three-segment prototype. To facilitate the CVD system design, experimental data archiving, and distributed simulation, a three-tier Java and XML-based integrated information technology system has also been developed.