In-Situ Detection of Plasma Processing Equipment Using a V-Mask Control Chart
To improve equipment throughput and device yield, plasma processing equipment should be tightly monitored. A cumulative-sum (CUSUM) control chart is used to monitor off-line process qualities. In this study, a V-mask control chart (VCC) is presented for detecting in-situ process variability.
This consisted of a modified cumulative-sum and a V-mask-parameterized belief function. The presented control chart was applied to monitor a radio frequency matching of plasma impedance. Experimental data were measured by using a real-time impedance monitoring system. Detection performance
was studied either for the fixed or time-varying VCC parameters. Analysis was more detailed by defining several diagnostic parameters. The detection performance of VCC monitor system was very sensitive to the variations in the design parameters. Optimizing the impact of design parameters considerably
improved the detection performance of VCC system. In particular, VCC employing time-varying parameters demonstrated improved detection accuracy. The presented technique can be utilized to monitor other in-situ equipment data.
Keywords: CUSUM; Control; Control chart; Detection; Diagnosis; Equipment; Impedance matching; In-situ; Monitor; Plasma; Process; Semiconductor; Sensor; V-mask; Vacuum
Document Type: Research Article
Affiliations: 1: School of Computer Engineering, Sejong University, Seoul, South Korea 2: Department of Electronic Engineering, Sejong University, Seoul, South Korea
Publication date: 01 December 2009
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