Abstract: To effectively solve scheduling problems of multicluster tools of wafer fabrication system with reentrant constraints in running process， a scheduling algorithm was proposed. Firstly， the characteristics of reentrant constraints of doublecluster tools were analyzed. The problem domain of doublecluster tool scheduling was established and mathematical programming models were set up to minimize the system cycle time. The scheduling problems of the doublecluster tools were decomposed into scheduling problems of singlecluster tool using the decomposition policy. A novel enlighten algorithm of robotic sequence searching was presented. Finally， simulation experiments were carried out to evaluate the proposed algorithm. The results indicate that the proposed algorithm is valid.

Key words: multicluster tools, scheduling, reentrant constraints, algorithm, simulation experiments