Nondestructive analysis of coated periodic nanostructures from optical data.

Optical data are essential for the accurate nondestructive determination of profiles of periodic structures in integrated-circuit technology. In rigorous coupled-wave analysis, the sample is generally modeled as layers consisting of a single material and the ambient. We extend present capabilities to the analysis of structures with overlayers and demonstrate our approach by determining quantitatively the thicknesses of top, sidewall, and bottom oxides of deliberately and naturally oxidized structures.