Direct Measurement of the Reaction Front in Chemically Amplified Photoresists
Eric K. Lin,1*
Christopher L. Soles,1
Dario L. Goldfarb,3
Brian C. Trinque,4
Sean D. Burns,4
Ronald L. Jones,1
Joseph L. Lenhart,1
Marie Angelopoulos,3
C. Grant Willson,4
Sushil K. Satija,2
Wen-li Wu1
The continuing drive by the semiconductor industry
to fabricate smaller structures using photolithography will soon
require dimensional control at length scales comparable to the size of the polymeric molecules in the materials used to pattern them. The current technology, chemically amplified photoresists, uses a
complex reaction-diffusion process to delineate patterned areas with
high spatial resolution. However, nanometer-level control of this
critical process is limited by the lack of direct measurements of the
reaction front. We demonstrate the use of x-ray and neutron reflectometry as a general method to measure the spatial evolution of
the reaction-diffusion process with nanometer resolution. Measuring compositional profiles, provided by deuterium-labeled reactant groups
for neutron scattering contrast, we show that the reaction front within
the material is broad rather than sharply defined and the compositional
profile is altered during development. Measuring the density profile,
we directly correlate the developed film structure with that of the
reaction front.
1 Polymers Division and
2 Center for Neutron Research, National Institute of
Standards and Technology, Gaithersburg, MD 20899-8541, USA.
3 IBM T. J. Watson Research Center, Yorktown
Heights, NY 10598, USA.
4 Departments of Chemistry
and Chemical Engineering, University of Texas at Austin, Austin, TX
78712, USA.
*
To whom correspondence should be addressed. E-mail:
eric.lin{at}nist.gov
