Analytical modeling and 3D finite element simulation of line edge roughness in scatterometry

摘要

The influence of edge roughness in angle resolved scatterometry atperiodically structured surfaces is investigated. A good description of theradiation interaction with structured surfaces is crucial for the understandingof optical imaging processes like, e.g. in photolithography. We compared ananalytical 2D model and a numerical 3D simulation with respect to thecharacterization of 2D diffraction of a line grating involving structureroughness. The results show a remarkably high agreement. The diffractionintensities of a rough structure can therefore be estimated using the numericalsimulation result of an undisturbed structure and an analytically derivedcorrection function. This work allows to improve scatterometric results for thecase of practically relevant 2D structures.