Study of the fundamental contributions to line edge roughness in a 193 nm,top surface imaging system

Top surface imaging systems based on vapor phase silylation have been inves tigated for use at a variety of wavelengths. This approach to generating hi gh aspect ratio, high resolution images held great promise particularly for 193 nm and EUV lithography applications. Several 193 nm top surface imagin g (TSI) systems have been described that produce very high resolution (low k factor) images with wide process latitude. However, because of the line e dge roughness associated with the final images, TSI systems have fallen fro m favor. In fact, TSI does not appear in the strategy or plan for any imagi ng technology at this time. Most of the 193 nm TSI systems that have been s tudied are based on poly(p-hydroxystyrene) resins. These polymers have an u nfortunate combination of properties that limit their utility in this appli cation. These limiting properties include (1) high optical density, (2) poo r silylation contrast, and (3) low glass transition temperature of the sily lated material. These shortcomings are related to inherent polymer characte ristics and are responsible for the pronounced line edge roughness in the p oly(p-hydroxystyrene) systems. We have synthesized certain alicyclic polyme rs that have higher transparency and higher glass transition temperatures. Using these polymers, we have demonstrated the ability to print high resolu tion features with very smooth sidewalls. This article describes the synthe sis and characterization of the polymers, their application to top surface imaging at 193 nm, and the analysis that was used to tailor the processing and the polymer's physical properties to achieve optimum imaging. (C) 2000 American Vacuum Society. [S0734-211X(00)01905-3].