Metrological evaluation of signal formation in CD‐SEM—a quantitative computer simulation

Recent progress in the study of secondary electron (SE) emission has enabled the secondary yields to be evaluated quantitatively for major part of material of practical interest, inorganic, and metrological substances.1 We have been involved in the development of quantitative computer-simulation program to provide precise knowledge of SE-signal formation in CD-SEM (critical dimension scanning electron microscopy) by using the database on (k, α), describing the SE yield by where (dE/dz)Ep is the energy dissipation in-depth to be derived from Monte Carlo simulation for an incident electron of primary energy Ep. This approach allows for the precise assessment of the edge positions of a mask pattern from the experimental δ profile. Applying different thicknesses of Cr to the mask pattern, Cr/SiO2, we obtained a calibration curve between the real position of Cr-pattern edge and peak position of a theoretical δ-profile to be measured with CD-SEM. Copyright © 2008 John Wiley & Sons, Ltd.