Impact of supercritical C O 2 drying on roughness of hydrogen silsesquioxane e-beam resist

Surface roughness (SR) and, especially, the closely related line-edge roughness (LER) of nanostructures are important issues in advanced lithography. In this study, the origin of surface roughness in the negative tone electron resist hydrogen silsesquioxane is shown to be associated with polymer aggregate extraction not only during resist development but also during resist drying. In addition, the impact of exposure dose and resist development time on SR is clarified. Possibilities to reduce SR and LER of nanostructures by optimizing resist rinsing and drying are evaluated. A process of supercritical C O 2 resist drying that delivers remarkable reduction of roughness is presented.