A novel failure response policy for single-arm cluster tools with residency time constraints

It is very challenging to schedule a residency time-constrained single-arm cluster tool with failure-prone process modules. In some cases, when a failure occurs, the degraded tool is not schedulable. However, it is highly desired to respond to a process module failure properly such that the tool can continue working and the wafers in the tool can be completed in a feasible way. Thus, in this paper, Petri net models are developed to describe the discrete-event behavior of a single-arm cluster tool. With the models, failure response policies are given to control the cluster tool such that it can keep working without violating any residency time constraints. They are implemented via efficient real-time control laws. Illustrative examples are presented to show their usage.