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Automated material handling systems (AMHS) play a central role in modern wafer fabrication facilities (fabs). Typically, AMHS used in wafer fabs are based on discrete vehicle-based overhead systems such as overhead hoisted vehicles. Conveyor-based continuous flow transport (CFT) implementations are starting to gain support with the expectations that CFT(More)
This paper proposes an analytical model useful in the design of conveyor-based Automated Material Handling Systems (AMHS) to support semiconductor manufacturing. The objective is to correctly estimate the work-in-process on the conveyor and assess the system stability. The analysis approach is based on a queuing model, but takes into account details of the(More)
Finding the optimal layout of Automated Material Handling Systems (AMHS) is critical for the design of next generation semiconductor wafer fabs. This paper proposes a greedy heuristic to determine the configuration of a conveyor-based AMHS featuring turntables and crossovers. Using a conveyor-based analytical model, the heuristic identifies the crossover(More)
This research explores analytical models useful in the design of vehicle-based Automated Material Handling Systems (AMHS) to support semiconductor manufacturing. The objective is to correctly estimate the throughput and move request delay. This analysis proposes a computationally effective analytical approach to multi-vehicle AMHS performance modeling for a(More)
The purpose of this research was to identify the factors in a wafer fabrication facility that significantly affect the cycle times of two main technologies that are currently in process and in demand for the next few years. Moreover, the goal was to construct the characteristics curves that would provide information about the different capabilities of a(More)
This paper describes a methodology to tackle the problem of designing Automated Material Handling Systems (AMHS) for 300mm wafer fabrication facilities. The proposed framework divides the design process into two levels: architectural and elaborative. Prior to the design, fab data are preprocessed using simulation of manufacturing operations. The output data(More)
This research explores analytical models useful in the design of vehicle-based Automated Material Handling Systems (AMHS) to support semiconductor manufacturing. The objective is to correctly estimate the throughput and move request delay. The analysis approach is based on queuing network models, but taking into account details of the operation of the AMHS.(More)
Genetic algorithms (GAs) are one of the many optimisation methodologies that have been used in conjunction with simulation modelling. The most critical step with a GA is the assignment of the selective probabilities to the alternatives. Selective probabilities are assigned based on the alternatives' estimated performances which are obtained using(More)
In this paper, a scheduling heuristic was developed to aid the operators in semiconductor fabs in choosing what type of lots to process next on bottleneck facilities and whether to change machine setup in order to reduce cycle time. The scheduling heuristic aims at balancing workload levels for implanters processing lots at different stages of the wafer(More)