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New Insights into Sequential Infiltration Synthesis



James Alexander Liddle, Jeffrey Elam, Mahua Biswas, Seth B. Darling, Angel Yanguas-Gil, Jonathan Emery, Alex Martinson, Paul Nealey, Tamar Segal-Peretz, Qing Peng, Jonathan P. Winterstein, Y. C. Tseng


Sequential infiltration synthesis (SIS) is a process derived from ALD in which a polymer is infused with inorganic material using sequential, self-limiting exposures to gaseous precursors. SIS can be used in lithography to harden polymer resists rendering them more robust towards subsequent etching, and this permits deeper and higher-resolution patterning of substrates such as silicon. Herein we describe recent investigations of a model system: Al2O3 SIS using trimethyl aluminum (TMA) and H2O within the diblock copolymer, poly(styrene-block-methyl methacrylate) (PS-b-PMMA). Combining in-situ Fourier transform infrared absorption spectroscopy, quartz-crystal microbalance, and synchrotron grazing incidence small angle X-ray scattering with high resolution scanning transmission electron microscope tomography, we elucidate important details of the SIS process: 1) TMA adsorption in PMMA occurs through a weakly-bound intermediate; 2) the SIS kinetics are diffusion-limited, with desorption 10x slower than adsorption; 3) dynamic structural changes occur during the individual precursor exposures. These findings have important implications for applications such as SIS lithography.
ECS Transactions


nanofabrication, self-assembly, block copolymer


Liddle, J. , Elam, J. , Biswas, M. , Darling, S. , Yanguas-Gil, A. , Emery, J. , Martinson, A. , Nealey, P. , Segal-Peretz, T. , Peng, Q. , Winterstein, J. and Tseng, Y. (2015), New Insights into Sequential Infiltration Synthesis, ECS Transactions, [online],, (Accessed July 22, 2024)


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Created October 1, 2015, Updated November 29, 2022