Characterization and modeling of a chemically amplified resist for ArF lithography

摘要

Abstract: There is increasing interest in chemically amplified (CA) single-layer photoresist for 193 nm excimer laser lithography as a route to sub-quarter micron imaging. A quantitative understanding of the factors that limit the ultimate resolution of CA resists requires a detailed knowledge of both the kinetics of the acid-catalyzed chemical reaction and the diffusion properties of the photogenerated acid. Information of this type is key to the accurate modeling of all CA resists regardless of exposure wavelength. We have investigated the exposure, thermal processing and dissolution behavior of a methacrylate terpolymer-based 193 nm resist. The chemical reactions occurring during post-exposure bake were monitored by FTIR microscopy over a range of PEB temperatures and exposure doses. Using the FTIR data and dissolution contrast curves, parameters for a model of the exposure, the post-exposure bake and the development were extracted. The model was implemented in the SAMPLE lithography simulation tool to predict resist profiles and process latitudes of methacrylate resists on a 193 nm step and scan tool. Excellent agreement between the simulated photoresist profiles and SEM cross-sections was obtained. !11