Buffer Space Configuration and Scheduling Analysis of Single-Arm Multi-cluster Tools

This work studies the buffer space configuration problem to obtain an optimal one-wafer cyclic schedule for single-arm multi-cluster tools with a linear topology. To do so, a Petri net model is developed to describe the dynamic behavior of the system by extending the resource-oriented Petri nets such that a schedule can be parameterized with robots' waiting time. Based on this model, conditions for the existence of a one-wafer cyclic schedule with the lower bound of cycle time are presented, and algorithm is developed to find such an optimal schedule. The algorithm requires only simple calculation to set the robots' waiting time and configure the buffer spaces between two individual tools. An example is presented to show the application and power of the proposed method.