27 December 2002 Calibration and long-term stability evaluation of photo mask CD-SEM utilizing JQA standard
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Rapid changes in the feature size of photo masks have made it clear that there is an obvious limitation to the use of optical measurement tools, and mask makers now have the necessity to use CD-SEMs as a measurement tool for forefront patterns. The level of measurement precision and accuracy required for mask CD metrology has reached a point at which magnification calibration using the standard scale becomes indispensable. Since CD-SEM measurements are heavily influenced by local pattern irregularities compared to optical measurements, however, proper statistical treatment of data is necessary to estimate accurate values. In this paper, the tool repeatability, sample dispersion, line edge roughness amount and tool's long-term precision will be determined by the treatment of numerous measurement data. The general calibration of the tool is done by line pitch measurement of JQA standard, in that case the disagreement between line width measured values and user's desired values could be appeared. In this case we propose the method to change threshold value of measurement, and in this paper the evaluation of this method will be shown.
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Izumi Santo, Izumi Santo, Masashi Ataka, Masashi Ataka, Katsuyuki Takahashi, Katsuyuki Takahashi, Norimiti Anazawa, Norimiti Anazawa, "Calibration and long-term stability evaluation of photo mask CD-SEM utilizing JQA standard", Proc. SPIE 4889, 22nd Annual BACUS Symposium on Photomask Technology, (27 December 2002); doi: 10.1117/12.468088; https://doi.org/10.1117/12.468088

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