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영어

In this paper, a practical estimation method is developed for the lot travel distance in order to evaluate semiconductor unified fabrication layouts using the absorbing Markov chain. The lot travel distance is defined as the total distance that a lot travels from the first process to the last process; it can be used to investigate whether a fabrication layout design is reasonable. Furthermore, unified fabrication has not yet been introduced in the literature; it is a fabrication method that uses only one type of automated material handling system (AMHS). When designing semiconductor fabrication layouts, every aspect of all alternatives should be investigated meticulously. The widely known and accepted methods, such as sophisticated simulations and mathematical modeling with high accuracy, require an extensive time period to build the model. However, in the early stages of the layout design, simple and insightful methods are required in order to investigate the numerous alternatives during a short time period. This paper presents a simple estimation method for the travel distance of a lot during its lifetime in a fabrication.