Cyclic Scheduling of Single-arm Cluster Tools with Equipment Front-End Module and One-in-one-out Loadlocks

Scheduling cluster tools with EFEM involves collaborative scheduling among several modules, i.e., a vacuum module (VM), a loadlock module (LLM), and an equipment front-end module (EFEM). Typically, one-in-one-out loadlocks are widely employed in wafer fabrication. Additionally, for module cooperation, LLM functioning as a shared module is essential in collaboration. However, LLM has pressure management capabilities, introducing additional challenges for collaborative scheduling. To address such collaborative scheduling, we analyze interaction behaviors among VM, EFEM, and LLM, focusing on the robot cooperative relationship. Then, we introduce a timeliness analysis of robot activities, providing insights into the scheduling problem. Based on these, a closed-form algorithm is derived, offering a methodology to ascertain a schedule that minimizes tool cycle time. Moreover, the algorithm facilitates the identification of system bottlenecks, providing guidance for systematic improvements to enhance system performance. Furthermore, the developed algorithm can be embedded into the cluster tool controller, enabling the implementation of the obtained schedules.