Lot Dispatching and Scheduling Integrating OHT Traffic Information in a 300mm Wafer Fab
Date Issued
2007
Date
2007
Author(s)
Huang, How-Wei
DOI
en-US
Abstract
In this thesis, we focus on the lot dispatching and vehicle dispatching problems in a 300mm wafer fab. We propose a two phase lot dispatching and vehicle dispatching integrated algorithm. The first phase is the offline optimization phase and the second phase is the online dispatching phase. In the offline optimization phase, we focus on the lot dispatching problem. We propose a scheduler which can search for appropriate weights of several equipment-based selection rules and combines them into one mixed rule. Genetic algorithm is used to find the optimal combination of these heuristic rules. And the mixed rule is used in online dispatching phase as equipment based selection rule. In the online dispatching phase, we focus on the vehicle dispatching problem. We take the real time traffic information into consideration and we apply Markov decision model to model the estimate of the cost of traversing a congested edge. Compared with the traditional shortest path method that searches for the shortest distance path, in our traffic model we search for the path with least expected travel time.
Subjects
半導體
遺傳演算法
懸吊式搬運車交通控制
semiconductor manufacturing
genetic algorithm
OHT traffic control
Type
thesis
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