15 April 2008 A comparison of the reaction-diffusion kinetics between model-EUV polymer and molecular-glass photoresists
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It has been recently postulated that sub-22 nm photolithography with polymeric photoresists has reached a materials design barrier due to its large molecular mass and distribution. In this argument, the "pixel" size, which is related to the smallest molecular unit, determines the feature fidelity and resolution of the lithographic process. This hypothesis remains unproven, but molecular glass photoresists can provide a test because they can share similar chemical functionality to polymer resists, but with low molecular mass and a monodisperse molecular mass distribution. The low molecular mass leads to the smaller pixel size compared to the radius of gyration of the polymer photoresist. In this work, we compare the deprotection reaction-diffusion kinetics of a common photoacid generator in a polymer and molecular glass resist with similar resist chemistry to elucidate effects of molecular architecture on photoresist performance. We determine the mechanism of reaction, photoacid trapping behavior, and diffusivity by measuring and comparing the reaction kinetics parameters as a function of temperature and exposure dose. These results permit an analysis of the latent image formation which is a crucial factor in resolution and line-edge roughness. Further, knowledge of the reaction-diffusion parameters of each type of resist provides a quantitative approach to predict line-space features, crucial for design for resolution-enhancement features.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Shuhui Kang, Shuhui Kang, Kristopher Lavery, Kristopher Lavery, Kwang-Woo Choi, Kwang-Woo Choi, Vivek M. Prabhu, Vivek M. Prabhu, Wen-Li Wu, Wen-Li Wu, Eric K. Lin, Eric K. Lin, Anuja De Silva, Anuja De Silva, Nelson Felix, Nelson Felix, Christopher Ober, Christopher Ober, "A comparison of the reaction-diffusion kinetics between model-EUV polymer and molecular-glass photoresists", Proc. SPIE 6923, Advances in Resist Materials and Processing Technology XXV, 692317 (15 April 2008); doi: 10.1117/12.773018; https://doi.org/10.1117/12.773018

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