Gary W. Rubloff - US grants

9402384 MARCUS This award supports the Engineering Research Center at the University of Maryland and the Harvard University to focus on the integration and control of complex engineering system for the next five years. The Center will use and expand its well-established industrial collaboration programs to facilitate the rapid transfer of developed system methodologies. This will be achieved through three cross-disciplinary thrust areas: 1) intelligent control systems which involves the design of robust control systems with many sensors and many feedback loops using algorithm and tools for optimization-based design, 2) intelligent signal processing and communication system which involves the modelling, design, and control of wireless and high- speed communication networks, 3) system integration methodology which involves model complexity, architectures for control, and communication systems. In addition, there are three demonstration projects: (1) electromechanical motion control prototyping project which will develop basic research and engineering innovation needed to build high-performance, low-cost, motion control system, (2) wire- less multimedia shop communication project which will develop the research and technology for designing multimedia communication subsystems for manufacturing, (3) virtual factories for electro- mechanical devices manufacturing project which will develop an integrated tool kit for design, planning, and manufacturing of electromechanical devices. This award provides support for the ERC for three years. ***

Abstract
EEC-9978123
Gary Rubloff, PI

This award provides funding from the Engineering Research Centers (ERC) Program to the self-sustaining NSF ERC called the Institute for Systems Research (ISR) at the University of Maryland, College Park, and the NSF/SRC ERC for Environmentally- Benign Semiconductor Manufacturing (CEBSM) at the University of Arizona, Tucson, to jointly develop a portfolio of interactive, computer-based simulator learning modules to support education in the design for environment (DFE). These modules will be developed by application domain experts at CEBSM and software and cognitive science developers of simulator-based learning systems at ISR. The modules will incorporate existing simulator codes developed by CEBSM as a part of their research program in areas such as water purification, water usage in wafer rinsing, and the water recycle process. Students will be able simulate an entire system as well as explore the design of subsystems. The modules will incorporate components that are appropriate for learning at the high school, undergraduate and graduate levels and by practicing engineers and scientists. The modules will be evaluated at various educational levels, including testing by industry experts, and disseminated among the CEBSM institutions.

Abstract - Adomaitis - 0085633

An exploratory research program is planned to design a chemical vapor deposition (CVD) reactor that will enable across-wafer spatial control of deposition characteristics. An existing CVD reactor will be modified and used to generate data for developing a detailed simulator for reactor design and operation. The goals are to evaluate the actuation capabilities of this programmable reactor and establish its process simulation, optimization, sensing, and control requirements. The research is expected to demonstrate proof of concept for an entirely new mode of CVD processing.

Specific tasks will include:
(1) Proving a new concept for CVD reactor design that will demonstrate spatially controllable reactant delivery to the wafer: This will enable across-wafer uniformity to be achieved at virtually any process design point desired for material performance or manufacturing throughput. It will also allow intentional, programmed non-uniformity to reduce cost and time in process development.
(2) Developing object-oriented simulation-based design, analysis, optimization, and process control tools for the programmable CVD reactor system.
(3) Establishing a prototype for the next generation of CVD reactors for use in a materials development environment for conducting combinatorial CVD studies to rapidly evaluate new processes and materials.
(4) Demonstrating a concept in semiconductor processing equipment design that can be extended to other important manufacturing processes, including plasma-enhanced CVD, reactive ion etching, and possibly liquid-phase processes such as wafer cleaning and plating.

NSF support of $5000 is requested for student participation at the 2000 International Conference Characterization and Metrology for ULSI Technology. This Conference will be held at NIST, Gaithersburg, MD, June 26-29, 2000. It continues a sequence of two highly successful conferences held in 1995 and 1998, each of which led to a formidable Proceedings book published by the AIP Press. The funds will support student travel and registration for about 20 students who will be making presentations and submitting papers for the Conference Proceeings. The Semiconductor Research Corporation (SRC) and the American Vacuum Society (AVS) are also contributing funds toward student support ($5K from SRC, $2K from AVS).

Research:

The purpose of this small Information Technology Research (ITR) project is to develop a new paradigm for semiconductor manufacturing equipment - flexible equipment design enabled by information technology. The current paradigm of fixed equipment design limits performance of equipment in a rapidly changing technology environment, where tradeoffs must be made between product performance and manufacturing efficiency. The concept is based on procedures where process conditions can be spatially programmed to (1) decouple manufacturing constraints (e.g., uniformity across large wafers) from product performance (e.g., material quality); (2) reduce experimentation time by enabling parallel, combinatorial experiments on each wafer; and (3) provide the basis for a flexible, extendible equipment technology. Work has already begun on an experimental test bed (chemical vapor deposition in a manufacturing cluster tool) using a physically based simulation of the prototype system. This project is for developing the IT infrastructure required to link object-oriented simulation and model reduction methodologies to web-accessible experimental data archives and physical property databases to techniques for real-time control of parallel and multiplexed sensor/actuator arrays.


Impact:

The project has the potential to fundamentally change the design paradigm of a major industry - semiconductor-manufacturing equipment - to one that directly exploits a broad spectrum of information technology. Integration of research and education are planned on a number of fronts: (1) the project provides an opportunity for interdisciplinary teaming (e.g., between engineers and computer scientists and between materials engineers and systems engineers) in the classroom, (2) using spatially programmable equipment design as the project focus in a materials/systems project course at the graduate level, and (3) developing simulation-based learning software for technicians and engineers in industry.

0243803 Gupta

This award funds a five-year Research Experience for Undergraduates (REU) Site at the University of Maryland for fifteen students each summer for twelve weeks for research opportunities at the university's Institute for Systems Research. Students at colleges, universities, and community colleges will be recruited nationwide through a process involving efforts to reach students who would otherwise not have access to a research experience. The program incorporates activities that will involve participants in the following research directions of the institute: global communications systems, sensor-actuator networks, next-generation product realization systems, societal infrastructure systems, and cross-disciplinary systems education. Through the program students will be able to (1) establish a basis for systems thinking by conducting research and thus understand systems engineering as a discipline; (2) acquire broader and deeper understanding of both the research process and the practice of engineering and how new knowledge is created and communicated; (3) develop multicultural understanding and team competence and become aware of the societal implications of research; and (5) successfully seek admission in a four-year program and/or graduate school.

ABSTRACT

PI: Raymond A. Adomaitis and Gary W. Rubloff
Institution: University of Maryland
Proposal Number: 0554045
Title: The Nearest Uniformity Producing Profile (NUPP): A Generalized Optimization
Criterion for Thin-Film Processing Applications

The development of a new criterion for spatial uniformity control in thin film deposition processes (e.g., chemical vapor deposition for semiconductor manufacturing) is planned, applicable to any film quality (thickness, composition, microstructure, and electrical properties, among others) for all deposition systems where the substrate is rotated to improve uniformity. The approach is based on identifying the subspace of all deposition profiles on the stationary substrate (e.g., stalled wafer) that produce uniform films under rotation and then projecting a deposition profile to be controlled onto a sequence of uniformity-producing basis functions spanning that subspace to determine the Nearest Uniformity Producing Profile (NUPP). This mathematical criterion depends only on the geometrical characteristics of the deposition system, and control and optimization methods can be developed to reduce the deviation from the NUPP giving a universally applicable film control methodology. An important contribution of the NUPP concept and underlying theory is that the latter reveals new structure in the uniformity and
nonuniformity producing subspaces, providing insight into thin-film process design and control principles and an opportunity to unify these principles across a range of reactor designs.

Intellectual Merit

The research would develop a completely new approach to the control of thin film processing and demonstrate its effectiveness in an industrial setting. Preliminary research on the development of this new analysis and control technique has revealed open issues in terms of the mathematical and computational aspects of the framework, and the long standing relationship of the PI with the industrial partner creates an ideal situation for testing this control approach.

Broader Impact

A unique aspect of the uniformity control technique is that it is based on a minimal number of physical assumptions, resulting in a technique applicable to any uniformity criterion in a wide range of thin film processing control, optimization, and design applications, including all CVD, etch, PVD (physical vapor deposition), atomic layer deposition (ALD), and any other thin film process with a rotating substrate, giving the technique very broad industrial impact. Thin film processing in semiconductor, optoelectronic, optical coatings, and other industries will benefit from this approach. The majority of funding will be dedicated to providing undergraduate and graduate research opportunities in a state-of-the-art industrial research and production facility; the computational tools to be developed will be ideally suited for packaging and broad distribution in the format of a MATLAB toolbox and an associated short course.

NONTECHNICAL DESCRIPTION
The corrosion of silver artifacts, especially polished silver surfaces, is a monumental problem for art collections throughout the world. As objects in major museums are typically one of a kind, conservation methods and techniques require overwhelming evidence of treatment effectiveness, improvement over existing methods, and reversibility. This research will develop a novel multilayer, multifunctional transparent barrier coating for silver using a very powerful technique known as "atomic layer deposition" (ALD), which allows for the creation of nanometer thick layers of metal oxides with an exquisite level of control, literally at the atomic level. The resulting multilayer films will be optimized to reduce the rate of silver corrosion, while complying with the rigorous standards of art conservation practice. This museum and university partnership will result in an effective, low-cost strategy to reduce silver artifact corrosion, which also preserves artifact appearance and composition without precluding future conservation-treatment strategies. These benefits will be shared with the global museum conservation community through publications and presentations.

TECHNICAL DETAILS
In this work multilayer-structured, multifunctional atomic layer deposition (ALD) films for conservation of silver art objects are fabricated, characterized and optimized. Tarnishing of silver is a critical problem, presently producing irreparable damage to priceless art objects in museum collections throughout the world. The approach is based upon ALD: an innovative, thermally activated gas phase process for synthesizing nanometer-thick solid films by sequential exposure to 2 or more gas reactants to induce self-limited chemisorbed surface reactions, which reduces the rate of oxidant arrival at the underlying surface by orders of magnitude. Multiple compositions and layer structures are explored to optimize barrier performance and optical clarity. Tarnishing is evaluated via reflectance spectroscopy, and using x-ray photoelectrons spectroscopy (XPS) to measure the amount of sulfur on the surface subsequent to stripping the oxide after a series of exposures. Accelerated transport of oxidants through the film and reaction at the silver surface, using both exposure to atmospheres with controlled, elevated concentrations of H2S, and increasing the temperature of ALD coated samples are employed to establish the characteristic time scales, likely decades or longer. The reversibility of ALD metal oxide coatings is evaluated to determine if either the deposition or the removal of thin layers of metal oxides on silver changes the physical characteristics or chemical composition of the silver surface. The direct impingement of oxidant molecules through pinholes in barrier coatings is prevented by depositing multiple layers of alternating oxides of aluminum and titanium. Novel oxidant gettering functionality is introduced via deposition of buried layers of platinum into the films. Patterning of silver substrates is used to quantify the effect coatings have on the optical properties of micro and macro features and evaluation of the role of the starting topography on the topographical and compositional stability of the surfaces of art objects during ALD oxide deposition, removal, and on the local rate of tarnishing. Students at both the graduate and undergraduate level are trained in cutting-edge ALD film fabrication and characterization techniques, and in museum conservation practices in this collaboration between the Walters Art Museum and the University of Maryland.

1264509
Sintim, Herman O.

This award is supporting the research of Professors Herman O. Sintim, William Bentley and Gary Rubloff of the University of Maryland at College Park. The team will develop multimodal and multifunctional microfluidic systems for studying cell signaling by integrating stimuli-responsive biofabrication with device-imposed, complex gradient generation of bacterial signaling molecules. This device will then be used to systematically investigate the response of bacterial cells to quorum sensing molecules and environmental cues. Additionally, the device will be used to identify new molecules that inhibit bacterial chemotaxis.

Due to the central role that bacterial cell signaling plays in bacterial physiology, there is a high interest in understanding or unraveling the various factors that control bacterial response to signaling molecules. Transformative technologies that can aid the screening of molecules that inhibit bacterial communication would have potential applications in medicine, agriculture and industry. The broader impact of this project includes development of a new technological platform to study how bacteria interact with each other and the environment. This project is highly multidisciplinary, involving chemical biologists, bioengineers and biosystems engineers. Therefore, the students who will be involved with the project will be trained to solve scientific problems using diverse approaches.

This award by the Biotechnology, Biochemical, and Biomass Engineering Program of the CBET Division is co-funded by the Systems and Synthetic Biology Program of the Division of Molecular and Cellular Biology.

This grant supports the development of a new approach to nanotechnology-based transparent conducting electrodes. Exploiting the exceptional electrical conductivity and transparency of single or few-layer graphene, the research focuses on a key nanomanufacturing challenge, which is how to electrically connect small graphene flakes to form a large area continuous conductor. Atomic layer deposition (ALD) will be employed to provide ultrathin conducting layers that stitch or glue the graphene flakes together, with emphasis on selective deposition nucleated at edges of the flakes and on defect sites within the graphene flakes. Work will include continuous, roll-to-roll printing of electronics with graphene ink, and model defects on graphene surfaces to identify selective deposition processes. Tradeoffs between material distribution on the nano- and micro-scales, electrical conductivity, and optical transparency will serve as guidelines for prototype scale-up, and to assess manufacturing viability.

This research will provide prototype demonstration of a novel manufacturing technology for transparent electrodes based on low-cost graphene materials and scalable fabrication processes. The project will create new knowledge in surface chemistry, nanofabrication, nano-scale material transport and optoelectronics. It will underscore the critical role of defect management in moving nanoscience to the marketplace. It will have broad technological impact in areas of nanotechnology, such as displays, solar cells, and flexible electronics. Research activities and other nanomanufacturing ?stories? will be used as the basis for development of a new senior/graduate level course.