Petri net modeling combined with heuristic search provides a new scheduling method for Integrated Circuits (IC) manufacturing systems.The method includes two steps.First

it formulates the scheduling problem with extended timed-place Petri net model.Second

with the help of heuristic function to limit the search space

it applies a search algorithm to reachability graph of the Petri net model to find an optimal or near optimal feasible schedule in terms of the firing sequence of the transitions.Introducing the test arc to traditional timed-place Petri net

this paper proposed a new Petri net

the extended timed-place Petri net.It can concisely represent not only features of IC manufacturing system

such as routing flexibility

shared resources

varied lot sizes

etc.

but also the device maintenance

device priority and operation priority.Therefore

the schedule obtained is more practical.Experimental results are presented to show the effectiveness of the method.