Optical Scatterometry for Fast Evaluation of R2R Processed Structures

Optical Scatterometry measurements were performed on a mold and imprint produced by roll-to-roll UV-assisted nanoimprinting lithography (R2R UV-NIL) in the visible spectral range, and their diffraction efficiencies were calculated. The specimens were imaged by AFM to obtain the topographic parameters of period and height of the periodic structures. Using the AFM-measured and nominal parameters, the diffraction efficiencies of the specimens were modeled employing the RCWA method. Comparing the measured and modeled diffraction efficiencies of the mold and imprint revealed that optical scatterometry was capable of characterizing the topographical structure of the periodic structures, with a high level of confidence.