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24 May 2004 Innovative rapid photogoniometry method for CD metrology
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We present an innovating method to measure simultaneously the specular and non specular diffraction pattern of sub-micronic periodic structures. The sample is illuminated at fixed wavelength in the visible range (green laser) versus a large angular aperture both in incidence (0 to 80°) and azimuth (0 to 180°). A special optical setup including Fourier optics and a CCD camera allows to measure the entire diffraction pattern. The measurement spot size can be reduced to less than 50μm and its position can be visualized directly with the same optical setup. Polarimetric measurements can be made in less than two seconds. This new system is presented in details and the accuracy of the measurement is tested on homogeneous reference SiO2/Si samples. Then the system is applied to submicron gratings. We show that fixed incidence angle measurements are useful to visualize the specular and non specular order. So, the periodicity of the can be extracted directly. In addition the specular and non specular intensity can be used to extract more accurately the topology of the samples. We show that specular reflection versus azimuth angle can provide similar results than conventional techniques. First experimental results on bi-periodic structures are also shown.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Pierre Boher, Mathieu Luet, Thierry Leroux, Jerome Petit, Pierre Barritault, Jerome Hazart, and Patrick Chaton "Innovative rapid photogoniometry method for CD metrology", Proc. SPIE 5375, Metrology, Inspection, and Process Control for Microlithography XVIII, (24 May 2004);

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