Modelling and performance evaluation of an overhead hoist transport system in a 300 mm fabrication plant
Journal
International Journal of Advanced Manufacturing Technology
Journal Volume
20
Journal Issue
2
Pages
153-161
Date Issued
2002
Author(s)
Kuo C.-H.
Abstract
In a 300 mm wafer fabrication plant, the automated wafer transport system is more important than in a 200 mm one. The weight of 25 pieces of 300 mm wafer in a front opening unified pod (FOUP) makes the frequent manual carrying and lifting impractical. An overhead hoist transport (OHT) provides the pod transport between process tools and stockers in an intrabay with high efficiency and safety. A modular-based coloured timed Petri net (CTPN) is used to model the dynamic behaviour of the OHT. The OHT system performance is evaluated using an object-based simulation technique. Performance measures are used to determine the number of OHT vehicles in the planning stage and also to control the dispatching of the OHT system in the operation stage. The CTPN token competition and conflict resolution rules are used to develop the intelligent controller. Finally, a simplified intrabay with four stations is constructed and evaluated.
Subjects
Computer simulation
Graphical user interfaces
Integrated circuit manufacture
Intelligent control
Materials handling
Materials handling equipment
Performance
Petri nets
Robotics
Scheduling
Coloured timed petri net
Object-based simulation technique
Overhead hoist transport system
Computer aided manufacturing
Type
journal article