Development of micro-spot spectroscopic ellipsometer using reflective objectives

We developed a micro-spot spectroscopic ellipsometer using reflective objective, which has twomirrored Schwarzschild configuration. Using only small portion of numerical aperture and selecting off-axis illumination, we achieved spotsize of 60 micrometer in diameter. As the object is composed of mirrors, chromatic abberation was not a concern but reflection from mirrors caused polarization errors. We show details of the system including the effects of polarization errors.