Due-date based algorithm for order-lot pegging in a semiconductor wafer fabrication Facility

Abstract

This thesis focuses on a pegging problem or an order-lot assignment problem in a semiconductor wafer fabrication facility. Pegging is a process of assigning each lot to an order. In general, there are two types of pegging policies used in semiconductor manufacturing systems: hard pegging policy and soft pegging policy. Under the hard pegging policy, lots are assigned to an order and the lot-order assignment is maintained until the order and lots are completed. On the other hand, under the soft pegging policy, the lot-order assignment can be modified while they are being processed. We develop new pegging algorithms for the soft pegging policy for the objective of minimizing the number of tardy orders. To evaluate these proposed algorithms, we perform simulation experiments using randomly generated data. Results of the simulation tests show that the new algorithms for the soft pegging policy work better than an existing algorithm as well as the hard pegging policy.