Petri Net Modeling and Scheduling of a Close-Down Process for Time-Constrained Single-Arm Cluster Tools

• Published in: IEEE transactions on systems, man, and cybernetics. Systems Vol. 48; no. 3; pp. 389 - 400
• Main Authors: Zhu, QingHua, Zhou, MengChu, Qiao, Yan, Wu, NaiQi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Batch processing; Cluster tool; Clusters; discrete event systems; Optimal scheduling; Optimization; Petri net (PN); Preventive maintenance; robotic systems; Robots; Schedules; scheduling; Semiconductor device modeling; Steady-state; Time factors; Transient analysis; wafer fabrication
• ISSN: 2168-2216; 2168-2232
• DOI: 10.1109/TSMC.2016.2598303

In wafer fabrication, a robotic cluster tool is required to be closed down in order for engineers to perform its on-demand and preventive maintenance and switch between different wafer lots. They often deal with a close-down process subject to wafer residency time constraints, i.e., a wafer must exit from a processing chamber before its quality degradation within a certain time limit. To obtain higher yield, it is very important to optimize a close-down process for a cluster tool. Yet the existing literature pays no or little attention to this issue. By focusing on a time-constrained single-arm cluster tool, this paper intends: 1) to build its Petri net model to analyze its schedulability and 2) to develop computationally efficient algorithms to find an optimal and feasible schedule for its closing-down process under different workloads at its steps. Industrial examples are used to illustrate the application of the proposed method.