| Summary: | 碩士 === 國立交通大學 === 工業工程與管理系 === 91 === Integrated circuits manufacturing companies usually use the c-chart to control the wafer defects. The clustering of defects on a wafer becomes evident when the wafer size increases. The clustering phenomenon causes the Possion based c-chart invalid. Many modified c-charts have been developed to reduce the false alarms caused by defect clustering. However, there are still some drawbacks in employing the modified c-charts. This study proposed a statistical process control procedure for monitoring wafer defects and defect clustering simultaneously. The method employs hierarchical clustering analysis to remove the interaction of defect clustering and defect counts and obtain the modified defect counts to construct the c-chart. In addition to the c-chart for the modified defect counts, this study uses a cluster index, which does not require any assumption on the distribution of defects, to establish a procedure for monitoring defect clustering. Finally, a real-world case and a simulated case are presented to verify the effectiveness of the proposed procedure.
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