<title>Photoresist metrology based on light scattering</title>

Abstract

Angle resolved light scatterometry along with advanced data analysis is a promising new metrology technique to meet the challenges of today's and tomorrow's submicron technology. The measurement accuracy strongly depends on the performance capabilities of the algorithms utilized for data exploration and analysis. Presently, multivariate regression methods such as inverse least squares and principal component approaches are preferred. Substantial accuracy gains may be achieved by applying quasi-nonlinear methods, i.e. nonlinear data pretreatment followed by the usual linear regression. In this way, not only were the linewidth prediction errors in measuring developed resist lines pushed to below 20 nm, but likewise more complicated tasks such as silylation profile evaluation and latent image measurement could be addressed satisfactorily.