Polarized angle-resolved spectral reflectometry for real-time ultra-thin film measurement

Jian Wang, Lihua Peng, Fuqi Zhai, Dawei Tang, Feng Gao, Xiangchao Zhang, Rong Chen, Liping Zhou, Jane Jiang

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

We propose a polarized, angle-resolved spectral (PARS) reflectometry for simultaneous thickness and refractive-index measurement of ultra-thin films in real time. This technology acquires a two-dimensional, angle-resolved spectrum through a dual-angle analyzer in a single shot by radially filtering the back-focal-plane image of a high-NA objective for dispersion analysis. Thus, film parameters, including thickness and refractive indices, are precisely fitted from the hyper-spectrum in angular and wavelength domains. Through a high-accuracy spectral calibration, a primary PARS system was built. Its accuracy was carefully verified by testing a set of SiO2 thin films of thicknesses within two µm grown on monocrystalline-Si substrates against a commercial spectroscopic ellipsometer. Results show that the single-shot PARS reflectometry results in a root-mean-square absolute accuracy error of ∼1 nm in film thickness measurement without knowing its refractive indices.
Original languageEnglish
Article number6552
Pages (from-to)6552-6565
Number of pages14
JournalOptics Express
Volume31
Issue number4
Early online date8 Feb 2023
DOIs
Publication statusPublished - 13 Feb 2023

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