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THOMAS ARZT, Clean Room Consulting GmbH, Freiburg, Germany
FREDDY BULCKE, eFBe International Marketing and Engineering Consultancy bvba, Belgium

ABSTRACT

There has been quite some speculation in the semiconductor industry recently with regard to the transition to 300 mm wafer fabs. In the meantime, it seems obvious that the ambitious time schedule will experience some changes and a severe delay. This delay in the launching of 300 mm wafer fabs forces the semiconductor industry to consider further improvements of 200 mm automation scenarios both in CIM/MES and AMHS. In this paper a new low cost approach for an automated material handling system (AMHS) was investigated using a conveyor system for interbay transport and intrabay WIP buffering located on the subfloor of a wafer fab. For the first time a model wafer fab was simulated with a conveyor system responsible for the complete material handling. In comparison to the typical scenario where operators are responsible for lot transportation, the simulation results indicate that a conveyor system does not have a negative impact on the key performance parameters of the wafer fab such as cycle time, WIP, and throughput, which probably can not be said for other types of AMHS systems. The AMHS system was built according to the results of the simulation conducted with the discrete event simulator AutoMod/AutoSched to provide improved production flexibility and to minimize the system and operational costs. Initial industry comments favour this concept. One advantage of this new approach is that it certainly helps to build experience before launching 300 mm AMHS automation.