Browsing by Author "Chiou, CW"

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Scrap rules for small lots in wafer fabrication
(2002)
Wu, MC
;
Chiou, CW
;
Hsu, HM
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
This paper presents a genetic algorithm for determining the-rules for scrapping small lots in a semiconductor fab. Small lots are lots which carry less than 25 wafers due to yield problem. Simulation results show that the proposed approach can increase contribution margin up to 24% in the case of low yield and high average, selling price.
Scrapping small lots in a low-yield and high-price scenario
(2004-02-01)
Wu, MC
;
Chiou, CW
;
Hsu, HM
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Some wafers in a lot may become spoiled after they are processed at a workstation; such a lot is called a small lot. In a low yield and high price scenario, scrapping small lots may increase revenue and profit; yet, this notion has seldom been examined. This study presents a model for formulating the decision-making problem of scrapping small lots. A genetic algorithm is used to solve the problem when the solution space is large. An exhaustive search method is used when the solution space is small. Some numerical examples are used to evaluate the outcome of scrapping small lots. The profit obtained by the proposed scrapping method may be up to 23% higher than that obtained without scrapping.