Reservation-based dispatching rule for make-to-order wafer FAB with high-priority lots

Abstract

Make-to-order wafer Fabrications (FABs) have to deal with two different types of lots: high priority and normal. Highpriority lots have shorter cycle times, tighter target due dates, and higher margins than normal lots. This article presents a dispatching rule for on-time delivery of high-priority lots with low tardiness for normal lots. The proposed dispatching rule uses the concept of reservation, which refers to the provisional allocation of capacity for high-priority lots. The reservation policy has been applied to ensure capacity for high-priority lots in real FABs. The reservations of highpriority lots may cause considerable tardiness of normal lots. To cope with the problem, the proposed dispatching rule considers tool utilization as well as the on-time delivery of high-priority lots. Also, we introduce the concept of reservation depth to control the influence level of the reservation. The proposed dispatching rule has been implemented and outperforms conventional dispatching rules and conventional reservation policy.

Configuration space–based discrete event system specification formalism for a smart factory with real-time flexibility

“…Traditionally, simulation technology has been applied to evaluate the performance of design alternatives. Simulation is an essential tool for the evaluation and analysis of complex systems that cannot be easily described by analytical or mathematical models, and it is useful for calculating utilization statistics, finding bottlenecks, identifying scheduling errors, and even creating manufacturing schedules (Anglani et al, 2002; Chung et al, 2017; Klingstam and Gullander, 1999; Park et al, 2010). To reap the benefits of simulation technology, it is necessary to construct a reliable simulation model with high fidelity.…”