9403571 Kumar Semiconductor manufacturing is a complex process, involving hundreds of steps of processing. Wafer return several times to many tools, leading to a highly re-entrant process flow. This proposal addresses the problems of efficient operation, analysis and design of plants. The goal is to advance the state-of-the art on two important fronts: (1) Optimization of Cycle-Time Performance, and (2) Performance Evaluation of Semiconductor Manufacturing Plants. This proposal pursues an approach of studying the constraints on the mean value of certain random variables. It develops a programmatic procedure for obtaining performance bounds, and illustrates its application to various fab models and scheduling policies. This approach can be used to establish the stability, i.e. performance recurrence, and even the boundedness of moments, of the Markov chain underlying the system. The research proposed in this proposal is application driven, and uses a variety of tools ranging from simulations, heuristics, and software development, to theory. The goal is to advance the state of the art in scheduling semiconductor fabs, as well as the theoretical foundation of the proposed approach. ***
