A monochromatic waveguide model that can predict the optical microscope images of line objects with arbitrary edge geometry is presented. The lines may be patterned in thick layers, including multilayer structures with sloping, curved, and undercut edges; granular structures such as lines patterned in polysilicon; and asymmetric objects. The model is used to illustrate the effects of line edge structure on the optical image. Qualitative agreement with experimentally obtained optical image profiles is demonstrated. Application of the model to studying the effects of variations in layer thickness and edge geometry on linewidth measurements made at different stages of manufacturing integrated-circuit devices is discussed.
© 1988 Optical Society of America
Diana Nyyssonen and Chris P. Kirk†, "Optical microscope imaging of lines patterned in thick layers with variable edge geometry: theory," J. Opt. Soc. Am. A 5, 1270-1280 (1988)