Leo Liberti, James Ostrowski
Journal of Global Optimization
The use of chemically amplified photoresists for the fabrication of sub-100 nm features will require spatial control with nanometer level resolution. To reach this goal, a detailed understanding of the complex reaction-diffusion mechanisms at these length scales is needed and will require high spatial resolution measurements. In particular, few experimental methods can directly measure the spatial evolution of the deprotection reaction front and correlate it with the developed structure. In this work, we demonstrate the complementary use of neutron (NR) and x-ray (XR) reflectometry to measure the reaction front profile with nanometer resolution. Using a bilayer geometry with a lower deuterium-substituted poly(tert-butoxycarboxystyrene) (d-PBOCSt) layer and an upper poly(hydroxystyrene) (PHOSt) layer loaded with a photoacid generator (PAG), we directly measure the spatial evolution of the reaction front. We show that the reaction front profile is broader than the initial interface after a post-exposure bake and the compositional profile changes upon development in an aqueous base solution. We also directly correlate the final developed structure with the reaction front profile. The spatial detail enabled by this general methodology can be used to differentiate between and evaluate quantitatively reaction-diffusion models. © 2002 SPIE · 0277-786X/02/$15.00.
Leo Liberti, James Ostrowski
Journal of Global Optimization
Elizabeth A. Sholler, Frederick M. Meyer, et al.
SPIE AeroSense 1997
R.B. Morris, Y. Tsuji, et al.
International Journal for Numerical Methods in Engineering
John R. Kender, Rick Kjeldsen
IEEE Transactions on Pattern Analysis and Machine Intelligence