Abstract: To deal with scheduling problems of multi-cluster tools (MCTs) with different wafer types effectively， a scheduling algorithm considering diverse wafer flow patterns was put forward. Considered the wafer flow patterns， resource and residency constraints， mathematical programming models were set up with an objective of minimizing the Makespan. The scheduling problem of the single-armed MCTs was divided into two stages: determine the processing sequence of wafer lots and schedule the operating sequence of the robot arms. Applying ant colony search and bidirectional search strategies， ant system algorithm was introduced into the process of dynamic and adaptive time constraint set iterations. A new scheduling algroithm was built based on the ant systems and time (AS & TC). Simulation experiments results indicated that the algorithm is feasible.

Key words: multi-cluster tools(MCTs), diverse wafer flow patterns, residency constraints, time constraint set, heuristic algorithm