Characterizing acid diffusion lengths in chemically amplified resists from measurements of deprotection kinetics

Journal Article · Wed Oct 01 00:00:00 EDT 2014 · Journal of Micro/Nanolithography, MEMS, and MOEMS

DOI:https://doi.org/10.1117/1.JMM.13.4.043017· OSTI ID:1352826

Patil, Abhijit A. ^[1]; Pandey, Yogendra Narayan ^[1]; Doxastakis, Manolis ^[2]; Stein, Gila E. ^[1]

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1. University of Houston, Department of Chemical and Biomolecular Engineering, 4800 Calhoun Road, Houston, Texas 77204, United States
2. Institute for Molecular Engineering, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States

The acid-catalyzed deprotection of glassy poly(4-hydroxystyrene-co-tertbutyl acrylate) films was studied with infrared absorbance spectroscopy and stochastic simulations. Experimental data were interpreted with a simple description of subdiffusive acid transport coupled to second-order acid loss. This model predicts key attributes of observed deprotection rates, such as fast reaction at short times, slow reaction at long times, and a nonlinear dependence on acid loading. Fickian diffusion is approached by increasing the post-exposure bake temperature or adding plasticizing agents to the polymer resin. These findings demonstrate that acid mobility and overall deprotection kinetics are coupled to glassy matrix dynamics. To complement the analysis of bulk kinetics, acid diffusion lengths were calculated from the anomalous transport model and compared with nanopattern line widths. The consistent scaling between experiments and simulations suggests that the anomalous diffusion model could be further developed into a predictive lithography tool.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; National Science Foundation (NSF); Semiconductor Research Corporation (SRC)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1352826
• Journal Information: Journal of Micro/Nanolithography, MEMS, and MOEMS, Vol. 13, Issue 4; ISSN 1932-5150
• Country of Publication: United States
• Language: English