We report on a novel procedure to measure the linewidth of steep microstructures, based on the polarization anisotropy caused by the structure edges. A liquid-crystal phase shifter and a polarizer are introduced into the imaging optics of a reflection-mode microscope. We apply the principle of phase-shifting interferometry to measure the phase and contrast of a TM-polarized image with the TE-polarized image as reference. The method provides selective edge detection because the polarization difference is localized at the structure edges.
© 1999 Optical Society of America
(120.2130) Instrumentation, measurement, and metrology : Ellipsometry and polarimetry
(120.3940) Instrumentation, measurement, and metrology : Metrology
(120.4630) Instrumentation, measurement, and metrology : Optical inspection
(180.0180) Microscopy : Microscopy
(230.3720) Optical devices : Liquid-crystal devices
M. Totzeck and H. J. Tiziani, "Phase-shifting polarization interferometry for microstructure linewidth measurement," Opt. Lett. 24, 294-296 (1999)