Scheduling Single-Arm Cluster Tools with Emergency Order Insertion

With the change of wafer fabrication mode to multi-species and small lot, urgent order insertion occurs frequently in the actual production process, and the wafer flow patterns of the different wafer types may be different such that cluster tools are deadlock-prone. To improve the production flexibility of cluster tools, this paper investigates the scheduling problem of single-arm cluster tools facing urgent order insertion under the consideration of wafer residency time. Firstly, the processing process of emergency insertion order is analyzed, and the scheduling rules of the robot for single-arm cluster tools are proposed to realize the schedulability of the processing process. Secondly, the linear programming model for solving the robot waiting time is given. Finally, the optimal scheduling algorithm is proposed for the cluster tools when facing emergency order insertion, and the effectiveness of the scheduling method is verified by means of example verification and comparative analysis.