Modeling of 3-D trench structures with corrected effective medium approximation for model-based infrared reflectrometry

Model-based infrared reflectrometry (MBIR) has been introduced recently for measuring deep trench structures in microelectronics. The success of this technique relies heavily on accurate modeling and fast calculation of the infrared metrology process, which still remains as one challenge. In this paper, we propose a modeling method named corrected effective medium approximation (CEMA) for accurate and fast reflectivity calculation of three-dimensional (3-D) trench structures. The independence of the CEMA on trench depth, azimuth of incidence and the polarization state has been investigated to demonstrate the validity of the CEMA.