A real-time scheduling method for the cluster tool with wafer transfer delay

Abstract

In this study, we propose an effective real-time scheduling method based on the timetabling technique for the cluster tool. Instead of considering the no-wait assumption generally adopted in almost all of the previous literature, we take wafer transfer delay into consideration, which implies that a wafer can stay at the current chamber for a certain, limited time before proceeding to the next chamber. In order to improve the total cycle time, an additional pulling procedure to the timetabling is introduced and applied. Numerical examples show that the proposed method gives effective schedules in real time even for practical-sized problems.