Novel DUV photoresist modeling by optical thin-film decomposition from spectral ellipsometry/reflectometry data

New metrology for characterizing the chemically amplified resist is required to meet the stringent demands of DW lithography. In this paper, we present a systematic methodology to characterize DW photoresist by decomposing the resist thin-film into different empirical components according to their optical properties. The innovation of this metrology includes three parts: ellipsometry and reflectometry measurement data de-noising; sophisticated dispersion models derived from the Kramers-Kronig relations for optical thin-film component description; and an intelligent simulated annealing algorithm for the optimization computational engine.