Modeling and scheduling for semiconductor wafer fabrication systems

Two methods were presented to model the semiconductor wafer fabrication system and an AI based search was introduced for the scheduling. First, resource based Petri net was defined to model the structure of the system so that the net will not expanded rapidly with the process going on. Then, a modeling method which integrated IDEF0 with Petri net was given to character the function of system, which can describe the function of the system and sub-system and the relationships among them at length. Based on the model, ant colony optimization algorithm (ACO) was introduced to find the optimization schedule. A semiconductor manufacturing model with six-machine five-step from Intel was used here as an example, which shows exciting results in reduced the manufacturing cycle time and so on.