Cluster tools are highly integrated machines that can perform a sequence of semiconductor manufacturing processes. The sequence of wafer handler moves affects the total time needed to process a set of wafers.

Reducing this time can reduce cycle time, reduce tool utilization, and increase tool capacity. This paper introduces the cluster tool scheduling problem for hybrid cluster tools, which are multiple-stage tools that have at least one stage with two or more parallel chambers.

This paper presents algorithms that can find superior sequences of wafer handler moves. Experimental results show that the tool performance can be improved significantly if the wafer handler follows a cyclic sequence instead of using a dispatching rule.