Multiple response optimization in a fully automated FAB: an integrated tool and vehicle dispatching strategy∗

The infrastructure of the timed EOPNs-based multiple-objective real-time scheduling system for 300 mm wafer fab

“…In this hierarchical structure, AMHSs vehicles are assumed to travel along the single-level, one-directional loops as they move between stockers, and each of the AMHS vehicles is restricted to its designated loop. Each AMHS track loop has a series of stop points at which vehicles can stop to unload/pick up lots or as a bypass station in which to park (Tyan and Du 2004). These stop points represent the interaction I/O point between the track and the stocker, and each stop point EOPNs-based multiple-objective real-time scheduling system 5025 comprises a bypass track, an in-port and an out-port.…”

“…the vehicle-initiated dispatching (VID) and lot-initiated dispatching (LID) (Tyan and Du 2004). The nearest vehicle (NV) rule is selected as the LID rule.…”

“…With rapid advancements in manufacturing technologies, the modern semiconductor wafer fabrication system (SWFS) is moving from 200 mm to 300 mm wafer processing, and the dual promises of more chips produced per wafer and economy of scale have attracted leading semiconductor manufacturers to develop and implement 300 mm fabs (Tyan and Du 2004). However, in today's global semiconductor market, competitive advantage is achieved by offering a wide variety of IC products, high-quality standards, short lead times, and timely delivery, which cannot be addressed only through automation and promotion of the hardware facilities.…”

“…SDS uses a hierarchical tree covering all possible states and corresponding rules required to make dispatching decisions. An integrated processing tools and vehicle dispatching (ITV) mechanism was also developed based on the SDS for the automated 300 mm wafer fab (Tyan and Du 2004). However, owing to certain difficulties in the modelling process and the complexity of constructing a decision tree, the current SDS approach can only handle three state variables, i.e.…”

On-line reconfiguration to enhance the routing flexibility of complex automated material handling operations

“…For example, in the area of hardware design and control, Mori [1] proposed a dynamic control technique for inter-line material movements in a foundry, Dong [2] presented a new lot transportation approach that uses the ''Pull'' concept to improve the efficiency of the AMHS, Bodner et al [3,4] described a generic control architecture for coordinating automated processing and material handling activities based on discrete event systems representation. In the areas of optimisation and simulation, Bahri [5] described a simulation model that uses a logistical algorithm to improve the traffic conditions of network-like AMHS by up to 30% in delivery times, Grunow [6] presented a novel heuristic dispatching algorithm of multi-load automated guided vehicle (AGV) used for seaport container handling, and Tyan [7] described an integrated tool and vehicle (ITV) dispatching strategy that uses state-dependent methodology and multiple response optimisation in a fully automated fab environment. However, very little research could be found on both on-line and dynamic reconfiguration for AMHS.…”