| Summary: | 博士 === 國立交通大學 === 工業工程與管理系所 === 92 === Highly automated material handling is one of the most concerns to foundry practitioners because efficient manual operations and coordination have been the core competence in 300mm manufacturing. Especially, one of the critical problems is how to provide an almost no-wait transport for hot lots in an automatic material handling environment.
However, there is no effective method for hot lots handling in 300mm Overhead Hoist Transport (OHT) intrabay operation and no effective method to estimate delivery time in 300mm automatic material handling systems (AMHS) operation.
There are two objectives of this paper. The first is to develop an effective OHT dispatching method, Preemptive Priority Policy (PPP), to provide the transport services for hot lots against the normal lots transport requirements under 300mm frequently blocking transportation situation. The second objective is to propose an analytic methodology, Modularized Simulation Method (MSM), to estimate the loop-to-loop delivery time for differentiated lots.
Simulation experiments based on realistic data from a 300mm wafer foundry are conducted. The results demonstrate that the PPP method can effective expedite the movement of the hot lots for 21% shorter original delivery time. The MSM is also credible in estimating lot delivery times. The time differences between MSM and simulation for both priority lots and regular lots are 0.2 second and 0.1 second, respectively. The results of PPP and MSM have been verified by some 300mm fab managers and are both affirmative.
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