Model research and features simplification for scheduling of wafer fabrication system

Scheduling of wafer fabrication system with machine failures and repair time is studied by Neuro-dynmamic programming in this paper. States set and scheduling set are constructed, state transition probability is deduced and dynamic programming model with closed-release policy is analyzed. Key features are derived by simplification of non-bottleneck stations, and then scheduling policy can be obtained by approximation of optimization cost function with simulation. TRC model of HP is scheduled to illustrate the validity of the method.