Spectrophotometric Method for Measuring the Groove Depth of Calibration Reflection Gratings
V. P. Korol'kov, S. A. Konchenko
Institute of Automation and Electrometry, Siberian Branch of Russian Academy of Sciences Novosibirsk State University
victork@iae.nsk.su
Keywords: measuring the depth of microrelief, calibration structures, spectrophototometric method, reflection measurements
Pages: 119-127
Abstract
A method for measuring the groove depth of calibration gratings is proposed which is based on measuring the spectral dependence of the the zero-order reflection diffraction efficiency. The errors of the method are determined by three main factors: the shift of the maxima of the spectrum due to the wall slope of the grating grooves, the error in setting the wavelength of the spectrophotometer, and the divergence of the light beam in the setup. It is shown theoretically that the measurement error is in the range of 0.25-1 %, depending on the fabrication technology of the grating and measuring equipment. The method was tested experimentally using commercial calibration gratings. The range of applicability of the method is discussed in terms of the geometrical parameters of the microstructure of reflection gratings and the characteristics of the spectrophotometer used.
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