22 May 1995 Extendibility of laser scanning tools for advanced wafer inspection
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This paper describes a broad range of design issues that influence the performance of optical equipment for in-line inspection of random (logic) and repetitive (memory) patterns. In particular, we describe the angular distribution of signals from defects on a patterned wafer illuminated by a focused optical beam. We analyze the configuration of both illumination and collection optics to maximize the signal to background ratio for the detection of submicron defects on pattern. In addition, we analyze the distribution of the scattered light as a function of pattern periodicity and orientation with respect to the illuminating beam. The advantages of polarization selection and spatial filtering techniques are explored to enhance the detection sensitivity on repetitive and random pattern wafers. From these results we have developed a new patterned wafer inspection system that offers increased sensitivity and improved defect capture.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Brian M. Trafas, Mehrdad Nikoonahad, Keith B. Wells, R. Johnson, Stanley E. Stokowski, "Extendibility of laser scanning tools for advanced wafer inspection", Proc. SPIE 2439, Integrated Circuit Metrology, Inspection, and Process Control IX, (22 May 1995); doi: 10.1117/12.209199; https://doi.org/10.1117/12.209199

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