Quantitative Tool Characterization of a 193 nm Scatterfield Microscope

摘要

An investigation of an optical microscope tool characterization was presented for the quantitative measurements of deep sub-wavelength features using Fourier plane normalization method. The NIST 193 nm scatterfield microscope operating with an ArF Excimer laser, which has a capability of articulating the angular incident beam at the sample plane using an aperture scanning at the conjugate back focal plane (CBFP), was characterized through the illumination and collection optical paths. Each incident cone beam at the sample plane can be approximated as a plane wave as in Kflhler configuration, simplifying the analysis of the scattered light induced by the discrete illumination beam at the sample plane. Under this approximation, the illumination and entire tool function sets were measured at the sample and imaging CCD planes, respectively, producing the collection tool function set numerically. The two sets of optical tool functions will be used to normalize scattering simulations in the Fourier space domain of the CCD image in the collection path. We investigated some aspects of the beam distributions of the illumination beam at the sample plane with respect to the change of the optical components and report the illumination and collection tool function distributions that were obtained by angular scanning of an aperture at conjugate back focal plane.