Reconstruction of Latent Images from Dose-Pitch Matrices of Line Width and Edge Roughness of Chemically Amplified Resist for Extreme Ultraviolet Lithography

Abstract

The line width and line edge roughness (LER) of resist patterns are related to the concentration and its gradient of chemical compounds that determine the solubility of the resist, respectively. Therefore, latent images can be obtained from the line width and LER of resist patterns. In this study, two-dimensional (exposure dose and half-pitch) matrices of resist line width and LER were analyzed on the basis of the sensitization mechanisms of chemically amplified resists used for extreme ultraviolet (EUV) lithography. In the reconstruction of latent images, the effective reaction radius for catalytic chain reaction is an important parameter. The probable range of effective reaction radius was from 0.05 to 0.2 nm. In this range, latent images were successfully reconstructed. The finding that the effective reaction radius is smaller than the typical size of a counteranion suggests that the resist performance can be improved by increasing the effective reaction radius.