ONE-WAFER CYCLIC SCHEDULING FOR TIME CONSTRAINED PROCESS-DOMINANT MULTI-CLUSTER TOOLS

摘要

A method for scheduling a multi-cluster tool in the presence of wafer residency time constraints is provided. The method is applicable for a single-arm or a dual-arm multi cluster tool as well as a hybrid multi-cluster tool comprising both single- and dual-arm cluster tools. The method is developed by first developing a Petri net model to describe the dynamic behavior of the multi-cluster tool. By this model, a schedule is parameterized by robots' waiting time. Based on this model, the necessary and sufficient conditions under which a feasible one-wafer cyclic schedule exists are established. Efficient algorithms are then given to find such a schedule. These algorithms require simply determining the robots' waiting time and thus are efficient. Thus, it is applicable to real-time scheduling and control in operating a multi-cluster tool. Abstract figure: FIG. 1 Docket No.: UM1138AUOO 31 coo cico