Faculty
Research Profile |
 Richard
D. Braatz
Professor
Department of
Chemical and Biomolecular Engineering
University of Illinois at Urbana-Champaign
93 RAL
600 S. Mathews
Ave. ,
Urbana, IL 61801
217-333-5073
braatz@uiuc.edu
http://www.scs.uiuc.edu/chem_eng/Faculty/braatz.html
Research
Summary
New applications in materials,
medicine, and computers are being discovered where the control of
events at the molecular and nanoscopic scales is critical to product
quality, although the primary manipulation of these events during
processing occurs at macroscopic length scales. This drives our research
program in the creation of tools for the design and control of multiscale
systems that have length scales ranging from the atomistic to the
macroscopic.
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Research
Projects
- Multiscale
Systems and Control
The challenges to building such tools include uncertainties in
the physicochemical mechanisms as well as the values of thermodynamic
and kinetic parameters, complexities in the simulation of model
equations that can span the subatomic to the macroscopic scales,
lack of direct real-time manipulations and measurements of most
properties at the nanoscale during processing, and the inapplicability
of most existing mathematical systems tools to address systems
described by noncontinuum and dynamically coupled continuum-noncontinuum
models.
These challenges
are being addressed by a systematic approach to multiscale systems
engineering that includes stochastic parameter sensitivity analysis,
Bayesian parameter estimation applied to ab initio
calculations and experimental data, hypothesis mechanism selection,
and multiscale optimization. This enables multiscale systems
to be designed based on the simulation codes that are most appropriate
for simulating the various time and length scales of the process.
New developments
in multiscale systems theory are driven by applications to a
variety of complex chemical systems including the crystallization
of pharmaceuticals and proteins, the extrusion of thin polymer
films, the formation of transistor junctions in advanced CMOS
devices (in collaboration with Prof. E. Seebauer), and the manufacture
of copper interconnects in electronic devices (in collaboration
with Prof. R. Alkire). For pharmaceutical crystallization, an
integrated system incorporating ATR-FTIR spectroscopy, process
video microscopy, and laser backscattering has been created
to reduce time to production. For polymer film extrusion, first-principles
models are being created for incorporation into novel algorithms
to control the film uniformity. For ultrashallow junctions,
the results provide specific recommendations for microelectronics
tool manufacturers on how to optimize processes to produce shallower
junctions. For copper interconnects, systems principles are
used to suppress numerical instabilities in multiscale simulation
codes, gain fundamental insights into surface reaction mechanisms,
and design nonlinear feedback controllers.
Most of our research
is in collaboration with industry, where algorithms have been
implemented and are currently in use.
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