Scheduling of dual-arm multi-cluster tools considering wafer residency time constraints

Multi-cluster tool represents the current trends of wafer fabrication equipment, resulting that its scheduling and control can directly affect the overall economic efficiency of semiconductor chip manufacturers. Considering the wafer residency time constraint in semiconductor chip fabrication, a feature-transformation-based scheduling approach is presented to improve the productivity of dual-arm multi-cluster tools. Firstly, a conceptual wafer fabrication system called the characteristic dual-arm cluster tool is proposed, and its steady-state scheduling method is investigated as well. Secondly, by using a feature transformation approach, a multi-cluster tool with arbitrary topology can be effortlessly reduced into a characteristic dual-arm cluster tool. Thirdly, according to the transformed characteristic dual-arm cluster tool, the individual robot activity sequence is reassigned, and then a feasible steady-state schedule for the multi-cluster tool can be obtained. Finally, illustrative examples are offered to validate the effectiveness of the presented approach.