Spectroscopic ellipsometry on lamellar gratings R. Antos a, * , I. Ohlidal a,1 , J. Mistrik a , K. Murakami a , T. Yamaguchi a , J. Pistora b , M. Horie c , S. Visnovsky d a Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8011, Japan b Technical University Ostrava, 17. listopadu 15, 70833 Ostrava-Poruba, Czech Republic c Dainippon Screen Mfg. Co., Ltd., Kyoto 602-8585, Japan d Institute of Physics, Charles University, Ke Karlovu 5, 12116 Praha 2, Czech Republic Received 31 May 2004; accepted 22 September 2004 Available online 7 January 2005 Abstract Deep lamellar diffraction gratings fabricated by etching a transparent quartz plate are studied using spectroscopic ellipsometry. The rigorous coupled-wave analysis is used to calculate the optical response of the gratings. Three parameters of the rectangular profile are determined by utilizing the least-square method. Detailed investigation of the spectral dependences demonstrates the uniqueness of the solution. Observing the spectral dependences of Wood anomalies suggests that even complicated profiles can be fitted with high authenticity. # 2004 Elsevier B.V. All rights reserved. PACS: 06.20.Dk; 42.25.Fx; 42.70.Ce; 42.79.Dj; 42.82.Bq Keywords: Optical metrology; Scatterometry; Spectroscopic ellipsometry; Diffraction grating; Wood anomaly; RCWA 1. Introduction Periodically patterned gratings are important standard samples used in diagnostics for the integrated circuit production. Increasing precision of the litho- graphic process as well as decreasing critical dimensions has made the classical metrological techniques insufficient. Cross-sectional scanning electron microscopy and atomic force microscopy can deliver the geometrical information about the structures directly, but they are expensive, destructive, incapable to monitor the features below the surface, and inapplicable for in situ. The measurement and simulation of the optical response of gratings therefore become very important for the metrological and topographical analyses. Spectroscopic ellipsometry (SE) is now the most frequently used method in scatterometry because of its high precision and sensitivity on all the features of the illuminated structures. www.elsevier.com/locate/apsusc Applied Surface Science 244 (2005) 225–229 * Corresponding author. Tel.: +81 53 478 1344; fax: +81 53 478 1344. E-mail address: antos@karlov.mff.cuni.cz (R. Antos). 1 Present address: Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic. 0169-4332/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2004.09.160