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Water Vapor Uptake in Photolithographic Polymers Observed by Infrared Near-Field Scanning Optical Microscopy in a Controlled Environment

Published

Author(s)

L A. McDonough, B Dragnea, J Preusser, S R. Leone, W D. Hinsberg

Abstract

An infrared Near-field Scanning Optical Microscope (NSOM) is used in vacuum to detect water vapor uptake in thin polymer films for the first time. A chemically amplified photoresist sample composed of alternating 2 m lines of the original 1000 nm thick poly-(t-butylmethacrylate) (PTBMA) and the photochemically modified 500 nm thick poly (methacrylate acid) (PMAA) is studied both in vacuum and in a water vapor environment. the degree of water vapor absorption by the sample is measured using the infrared transmission of 2.85 m light on a small spatial scale (>500 nm). The accompanying topographic swelling of the samples is measured using a shear-force feedback loop. Distortion of the topographic structure and variation in transmission contrast indicate that the PMAA zones absorb more water than the PTBMA regions in the water vapor environment. The PMAA swells 280 nm more than PTBMA when exposed to a partial pressure of water vapor of 2.1 kPa (16 Torr), while the infrared optical contrast is increased to a 6 1% difference in the PMAA regions compared to the PTBMA.
Citation
Journal of Physical Chemistry Part B Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
Volume
107
Issue
No. 21

Keywords

near-field scanning optical microscope (, water vapor uptake in polymers

Citation

McDonough, L. , Dragnea, B. , Preusser, J. , Leone, S. and Hinsberg, W. (2003), Water Vapor Uptake in Photolithographic Polymers Observed by Infrared Near-Field Scanning Optical Microscopy in a Controlled Environment, Journal of Physical Chemistry Part B Condensed Matter, Materials, Surfaces, Interfaces & Biophysical (Accessed March 4, 2024)
Created April 30, 2003, Updated October 12, 2021