Challenges and limits to patterning using extreme ultraviolet lithography

With high-numerical aperture extreme ultraviolet (EUV) exposure tools soon to be available for utilization by chip makers, the factors that could limit the useable resolution of these systems are considered, to address these potential limitations and thereby enable patterning close to the theoretical optical resolution limit. Extended volumes of solubility-switched resist around the absorption sites of individual photons will limit resolution and lead to large line-edge roughness. If the volumes of chemically converted resist are small, there need to be many such volumes to provide continuous paths for development. Hence, the matters of exposure dose and molecular considerations are not fully separable. New resist architectures will be needed to avoid extremely high exposure doses to pattern features below 10-nm half-pitch. More energy-efficient EUV light sources will be needed. Computational lithography must account for a multiplicity of issues, necessitating increased automation of mask pattern optimization.