Abstract: The application of automated cluster tools in monolithic wafer processing has effectively improved wafer production efficiency. In order to further improve the utilization of cluster tools, this paper investigates feasible scheduling for dual-arm cluster tools considering concurrent wafer processing and mask change in chambers, while satisfying wafer residency constraints. First, a novel terminal transient scheduling strategy based on a virtual wafer method is proposed. A Petri net model with the new strategy is established and transition triggering conditions are defined to avoid deadlocks for control system operation. Then, according to the process requirements and temporal characteristics, different scheduling conditions are considered, while the waiting time during transient states is redistributed. An algorithm is developed to generate the mask changing time in transient states and the activity sequences of the transfer robot. Finally, the feasibility of the strategy is verified by two examples. Experimental results show that, compared with the traditional approach of mask changing after processing, the proposed scheduling strategy can effectively reduce the batch switching time of single-product wafers without affecting the completion time of terminal transient states, thereby minimizing the total mask changing time.