The objective of this research is to significantly advance the-state-of-the-art in operation of semiconductor manufacturing. Specifically, it will address real-time control of wafer production (i.e., the fabrication of integrated circuits onto silicon wafers). If successful, this research will lead to substantial improvements in factory operations, and ultimately, increased competitiveness of United States microelectronics manufacturers. This research addresses development of an advanced real-time system control framework that will direct the efficient operation of large wafer fabrication facilities. Specifically, the research will develop control policies within a new framework (Generalized Semi- Markov Decision Processes) that controls to target sets rather than to moments. With this research, the investigator will seek to develop the fundamental science base required to significantly advance real-time product flow control of wafer fabrication processes.