https://doi.org/10.1051/epjconf/202430902011
Influence of line edge roughness in optical critical dimension metrology
Friedrich Schiller University Jena Institute of applied physics, Albert-Einstein-Straße 15, 07745 Jena
Published online: 31 October 2024
We present the impact of line edge roughness (LER) on the optical critical dimension (OCD) metrology of nanostructures. The consideration of LER in OCD requires numerically expensive forward models and is therefore usually neglected. We present an analytical approach that allows estimation of the impact on the uncertainty. Systematic differences between CD measured by SEM and OCD were observed in different experiments. While SEM is basically sensitive to the local volume density, optical methods are sensitive to the permittivity of the material. We discuss an analytical upper bound on the contribution of the LER. For high index gratings, the contribution is as high as 3.7 nm for TM-polarized light and 1.2 nm for TE-polarized light, making this crucial for sub-nanometer metrology.
© The Authors, published by EDP Sciences, 2024
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
