差画像検出方式異物検査装置の開発

概要

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An automatic particle detection system for patterned wafers has been developed. The system consists of optical image processing and electrical signal processing that enable detection of much smaller particles. A specific area of the wafer is illuminated with 4-lasers at ±45° diagonal in reference to an orientation-flat shaped on the wafer. The scattered light is detected by an objective lens. The images of the adjacent two-chips are detected with an image sensor. The subtracted signal of the two detected images is transformed into a binary signal with a threshold. This system is performed so as to detect 0.6 μm standard particles on a first photo-process wafer, and 1.0-1.5 μm standard particles on a latter photo-process wafer in 1.5 minutes on 5-inch-diameter wafers.
社団法人精密工学会の論文
1991-11-05