7 December 2016 Phase-structured illumination as a tool to detect nanometer asymmetries
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J. of Micro/Nanolithography, MEMS, and MOEMS, 15(4), 044005 (2016). doi:10.1117/1.JMM.15.4.044005
Phase-structured illumination is investigated as a possible extension of scatterometric measurement methods for silicon line gratings. This is done by means of rigorous simulations. Special emphasis is put on the capability of this approach to detect nanoscale fabrication asymmetries such as sidewall angles, bottom rounding, and floor tilt. The studied setup features a focused spot (numerical aperture=0.7), i.e., scanned over the sample, while analyzing the phase distribution in the image plane. This phase distribution can be accessed via holographic imaging. The results are compared to conventional nonstructured illumination. It is shown that by employing phase structuring, the resulting phase changes are larger, even if only symmetric deviations are considered. For asymmetric deviations, phase-structured illumination provides much higher sensitivity and better capability to detect the sign of the asymmetry.
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
Sandy Peterhänsel, Maria Laura Gödecke, Karsten Frenner, Wolfgang Osten, "Phase-structured illumination as a tool to detect nanometer asymmetries," Journal of Micro/Nanolithography, MEMS, and MOEMS 15(4), 044005 (7 December 2016). https://doi.org/10.1117/1.JMM.15.4.044005

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