title: Fitting-determined formulation of effective medium approximation for 3D trench structures in model-based infrared reflectrometry.
abstract: The success of the model-based infrared reflectrometry (MBIR) technique relies heavily on accurate modeling and fast calculation of the infrared metrology process, which continues to be a challenge, especially for three-dimensional (3D) trench structures. In this paper, we present a simplified formulation for effective medium approximation (EMA), determined by a fitting-based method for the modeling of 3D trench structures. Intensive investigations have been performed with an emphasis on the generality of the fitting-determined (FD)-EMA formulation in terms of trench depth, trench pitch, and incidence angle so that its application is not limited to a particular configuration. Simulations conducted on a taper trench structure have further verified the proposed FD-EMA and demonstrated that the MBIR metrology with the FD-EMA-based model achieves an accuracy one order higher than that of the conventional zeroth-order EMA-based model.
authors.affiliation: Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China.
authors.forename: Chuanwei
authors.initials: C
authors.lastname: Zhang
authors.forename: Shiyuan
authors.initials: S
authors.lastname: Liu
authors.forename: Tielin
authors.initials: T
authors.lastname: Shi
authors.forename: Zirong
authors.initials: Z
authors.lastname: Tang