Abstract: Methods and systems for generating bright-field ellipsometric images indicative of structural defects sized below the optical resolution limit are presented herein. In some examples, bright-field ellipsometric images offer a higher signal to noise ratio of small defect signals to nuisance pattern noise signals compared to dark-field imaging at the null condition. Various ellipsometric imaging techniques are employed to generate images of a wafer or reticle under inspection. The images provide intensity contrast that is indicative of phase differences induced by the scattering response of different structures in the imaging field of the ellipsometric imaging system. In one aspect, an ellipsometric imaging system employs a polarizer in the illumination path and an analyzer and at least one waveplate in the imaging path. The ellipsometric imaging system generates images having intensity differences that differentiate defects of interest from nuisance pattern noise with relatively high signal to noise ratio.

Abstract: The present invention provides an optical device comprising: (a) a substrate; and (b) a plurality of units on the substrate. Each of the units comprises a plurality of tapered waveguides wherein: (i) each of the waveguides has a light input surface adjacent the substrate (a) and a light output surface distal from the light input surface and the light input surface area is greater than the light output surface area; (ii) each of the waveguides tapers from its light input surface to its light output surface at an angle; and (iii) at least one of the light input surface area or the light output surface area of at least one of the tapered waveguides is different than the corresponding surface area of the remaining tapered waveguides in the unit. Preferably, the optical device is a viewing film. The present viewing film has reduced or substantially eliminated intensity hot spots and interference patterns.