An Extended Object-oriented Petri Nets Modeling Based Simulation Platform for Real-time Scheduling of Semiconductor Wafer Fabrication System

Real-time scheduling of semiconductor wafer fabrication system (SWFS) is complicated due to the following factors: re-entrant product flow, high uncertainties in operations and rapidly changing products and technologies. This paper presents a simulation platform for real-time scheduling of SWFS, which is designed and developed based on extended object-oriented petri net (EOPN) to describe the complicated wafer fabrication process and serve as the foundation of realtime scheduling. In addition, a dynamic bottleneck dispacthing (DBD) algorithm is designed to detect bottlenecks in a timely way and make adaptive dispatching decisions according to the real-time conditions. The results of the simulation experiments and analysis show that the DBD algorithm is superior to CR+FIFO and EDD methods.