In: Proc. IEEE Int. Conf. on Systems, Man, and Cybernetics (SMC'99), 12-15 October 1999, Tokyo, Japan, Vol. 1, pages 835-840. 1999.
Abstract: This paper presents a real-time scheduling policy for the fabrication of multiple wafer types. The real-time scheduling policy provides a method of controlling the mean and the standard deviation of the flow time of the cassettes. Generalized stochastic Petri nets (GSPNs) are used to model the wafer and to evaluate the performance of the workstations in the wafer fabrication. From the performance analysis of the workstations, the utilization index representing the status of the workstations, which is used as the control method, is computed. The control method consists of the sequence control and the input release control, where the former selects the cassette to be processed in an available machine, and the latter is used for determining the type of a cassette and the time to be released into the fabrication. OPNDD (operation due date) rule and `regulation of buffer length' are developed for the sequence control, and pre-simulation and `feedback control' are developed for the input release control.
Keywords: stochastic Petri nets, wafer fabrication.