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IMA Workshops 6 & 7
Sponsored by ARPA and NSF

The improved design of materials processing equipment and systems must rely on an integrated "cycle" that begins, and ends, with materials. The first, or "analytical," part of the cycle begins with the identification of key material needs, followed by process definition, the development of physical models, and, finally, (large-scale) simulation; the second, or "synthetic" part of the cycle, proceeds *from* simulation to simplified process models to model--based optimization and control to selection of sensors and actuators and, finally, to process innovation and improved product. In actual practice,the cycle will not be sequential; for example, control strategies must be considered during initial process characterization and system design.

In these two workshops we will investigate this materials processing design cycle, with the first and second workshops focused primarily, though not exclusively, on the first and second parts of the cycle, respectively. The materials systems of foremost interest are thin films, however the application of mathematical techniques from other areas--including domains well outside materals
processing--is an important theme of both workshops, particularly the second. Speakers and participants will be drawn from industry, government laboratories, and academia, and will represent a broad range of physical and mathematical interests.

Key issues to be addressed in the first workshop include the collaborative *experimental*/mathematical development of appropriate physical models for thin films and related
systems; the reconciliation of disparate atomistic and continuum time and length scales; the
evaluation of current atomistic and continuum simulation capabilities and limitations; and the identification of materials processes well--suited to both stimulate *and* demonstrate the benefits of integrated modeling, simulation, optimization, control, and sensing. Key issues to be addressed in thesecond workshop include the role of large-scale simulation, both direct and indirect, in system
design, optimization, and control; the identification of the range of variables and associated models relevant to optimization and feedforward and feedback control in materals processing systems; and the need for new control, optimization, and sensing advances for materials processing applications

Workshops 6
Modeling of Film Growth and Deposition Processes-Evolution of Film Microstructure and Morphology
January 24-26,1995

Organizers: Malcolm R. Beasley, Louis Auslander, Geoffrey McFadden, David Srolovitz.

The first workshop will focus on three main issues. The first is the development of physical models of film growth processes. This includes the identification of the microscopic physics that determines microstructure, morphology and property evolution in thin films and the relationship of these to deposition conditions. The second issue is the extraction of continuum (PDE) level representations of these physical phenomena. The third theme is the development of simulation procedures for the film and/or deposition chamber scale modeling of the growth process.

The workshop sessions will begin with a discussion of the overall need for modeling of film growth
processes and review recent experience in implementation of physically based modeling of materials processing/film growth in industry. The next session will focus on the experimental state-of-the-art and the problems and opportunities in several different film growth technologies. The following sessions will address the physical modeling of film growth on increasing time and length scales. This will include atomic scale, microstructural scale, continuum level descriptions of thin film structure/property development and deposition chamber level modeling of the growth processes. A central issue to be addressed here is the spanning of these disparate length/time scales and the identification of the important features that must be extracted at each scale. Next, the workshop will focus on the mathematical issues central to the practical computational implementation of the film growth modeling on appropriate length and time scales and approaches for combining modeling at
different scales where appropriate.

The workshop will consist of invited presentations, extended discussion periods and cross-disciplinary break-out groups, culminating in a final synthesis session.

Workshops 7
Optimization and Control for Materials Processing Applications: Simulations, Models, and Strategies
February 1-3, 1996
Organizers: Stephen Boyd, and Tony Patera.

The second workshop will focus on three issues. The first issue is the need for new methods for the
incorporation of large--scale simulation into the system design process, from direct insertion of
large--scale simulation in optimization procedures, to the development of static and dynamic
reduced--order models for subsequent optimization and real--time control. The second issue is the
need for a hierarchy of variables and associated models in the design process, from large--scale
system models for nonlinear optimization, through intermediate models for feedforward control
(recipe generation), to fast, local models for real--time sensing and control. The third theme is the
need for new control and optimization advances, including methods that blend real--time feedback
control with run-to-run feedback control and step-to-step feedforward compensation; control
system design tools for materials processing applications that permit, for example, rapid
identification of promising sensor/actuator configurations; and improved computational algorithms
for open--loop process optimization.

The workshop sessions will include case studies of current industrial practice in equipment and
process design; case studies of current commercial and research simulation successes in materials
processing and related applications; techniques for optimization and control based on
partial--differential--equation state desciptions; methods for the development of static and dynamic
reduced--order models from large--scale simulation; case studies of applications of control theory
to real materials processing systems; techniques for model--based control and optimization; system
identification and statistical approaches in materials processing applications; and innovative sensing
strategies and technologies.

The workshop sessions will consist of invited presentations, discussions, topical and
cross-disciplinary break--out groups, and closing summary and synthesis sessions. Presentations
will address the workshop themes through cases studies, descriptions of relevant current research,
or reviews.

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