Optimal Scheduling Models of Semiconductor Manufacturing

We present a scheduling model with objective of optimizing the average WIP (Work In Process) of semiconductor manufacturing systems based on the fluid network model. It is usually very difficult to solve these models, but they are decomposable. This means the complex scheduling problems on the whole scheduling horizon can be decomposed into a series subproblems on individual subareas of time. The subproblems can be further simplified in the context of semiconductor manufacturing. Above results can be applied as a scheduling rule to simulation-based scheduling, which is used to improve the approximation of the fluid network model. Because this new scheduling method uses the global state information in decision, the optimization ability and performance of simulation-based scheduling are improved.