| Prelegent: | prof. MengChu Zhou, New Jersey Institute of Technology Newark, NJ 07102, USA, e-mail: zhou@njit.edu |
| Title: | Roles of Petri Nets in Optimal Scheduling of Cluster Tools in Wafer Fabrication |
| Abstract: | This talk intends to clarify the roles that Petri nets can play in the optimal scheduling and real-time control of single and multi-cluster tools that are widely used in semiconductor manufacturing industry. We illustrate how to use Petri nets to model various wafer production features involved in these highly expensive robotic manufacturing systems. Then we show how to use the resultant Petri net models to establish various schedulability conditions and derive extremely efficient algorithms that can compute optimal schedules for single and multi-cluster tools. When the bounded variation of activity time is caused in a fabrication process, we finally demonstrate how to adjust the scheduled robot wait time to offset such variation in order to achieve desired real-time optimal execution results. Our work focuses on those process-bounded cluster tools in which robots are fast enough such that they have some idle time in realizing an optimal schedule. |
