Publications

    February 2017
    Real Time Learning Temperature Control for Increased Throughput in LED Manufacturing

    J. L. Ebert, J. K. Lee, L. L. Porter, D. de Roover, and N. Acharya

    Presentation at 2017 SSL R&D Workshop, Long Beach, CA, Jan. 31 – Feb. 2, 2017

    The research results presented here have demonstrated the feasibility of an innovative temperature control technology for the Metal-Organic Chemical Vapor Deposition (MOCVD) process used in the fabrication of Multi-Quantum Well (MQW) LEDs. The control technology has the strong potential to improve both throughput and performance quality of the manufactured LED. The color of the light […]

    October 2016
    Model-Based Temperature/CD Tuning of Multi-Zone Heated Plates

    D. de Roover, J. L. Ebert, G.W. van der Linden, L. L. Porter, R. L. Kosut and A. Emami-Naeini

    Presentation at APC Conference XXVIII 2016, Mesa, AZ, Oct. 17-20, 2016

    Driven by ever-increasing requirements on improved wafer temperature uniformity for smaller features on the wafer, equipment manufacturers are developing heated plates (or chucks) with more and more actuator zones to achieve finer resolution of the actuated heat. From a control standpoint, two principally different plate designs can be distinguished: one that has a temperature sensor […]

    July 2016
    Feedback Control of Dynamic Systems – Seventh Edition

    Gene F. Franklin, J. David Powell, Abbas Emami-Naeini

    Feedback Control of Dynamic Systems, 7th edition, Pearson, 2015, ISBN-10: 0133496597 • ISBN-13: 9780133496598

    Feedback Control of Dynamic Systems, 7/e covers the material that every engineer, and most scientists and prospective managers, needs to know about feedback control, including concepts like stability, tracking, and robustness. Each chapter presents the fundamentals along with comprehensive, worked-out examples, all within a real-world context and with historical background information. The authors also provide […]

    October 2015
    PID Tuning for Temperature Control of Heated Plates Using the Waterbed Effect

    D. de Roover, A. Emami-Naeini and J. L. Ebert

    Presentation at APC Conference XXVII 2015, Austin, TX, Oct. 12-14, 2015

    Driven by ever-increasing requirements on improved wafer temperature uniformity for smaller features on the wafer, equipment manufacturers are developing heated plates (or chucks) with more and more actuator zones to achieve finer resolution of the actuated heat. From a control standpoint, two principally different plate designs can be distinguished: one that has a temperature sensor […]

    October 2014
    Rapid In-Line Detection of Macro Defects in Semiconductor Manufacturing

    D. de Roover, G.W. van der Linden, S. Ghosal, R. L. Kosut, J. L. Ebert and A. Emami-Naeini

    Presentation at APC Conference XXVI 2014, Ann Arbor, MI, Oct. 1-2, 2014

    The manufacturing of Integrated Circuits (ICs) on semiconductor wafers involves hundreds of complex and expensive process steps. Defects can occur during any of several steps such as etch, resist removal, particle contamination, incomplete process, process variations, dislocations, scratches, cracks, etc. Defects range in size from submicron to visually-detectable “macro” defects that may be as large […]

    March 2014
    Real-Time Estimation of the Structural Response Using Limited Measured Data

    Hassan Sedarat, Iman Talebinejad, Abbas Emami-Naeini, David Falck, Gwendolyn van der Linden, Farid Nobari, Alex Krimotat, Jerome Lynch

    Proc. SPIE 9063, Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2014, 906311 (9 March 2014) • © 2014 SPI; doi: 10.1117/12.2044617

    This study introduces an efficient procedure to estimate the structural response of a suspension bridge in real time based on a limited set of measured data. Unlike conventional techniques, the proposed procedure does not employ mode shapes and frequencies. In this study, the proposed technique is used to estimate the response of a suspension bridge […]

    March 2014
    Implementation of Damage Detection Algorithms for the Alfred Zampa Memorial Suspension Bridge

    I. Talebinejad, H. Sedarat, A. Emami-Naeini, A. Krimotat, Jerome Lynch

    Proc. SPIE Vol. 9063, 906312 (9 March 2014) Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2014 • © 2014 SPIE; doi: 10.1117/12.2044539

    This study investigated a number of different damage detection algorithms for structural health monitoring of a typical suspension bridge. The Alfred Zampa Memorial Bridge, a part of the Interstate 80 in California, was selected for this study. The focus was to implement and validate simple damage detection algorithms for structural health monitoring of complex bridges. […]

    October 2013
    Using Model-Based Fingerprinting to Characterize Process Variations in an RF Etch System

    J. L. Ebert, G. Crispieri, A. Emami-Naeini, D. de Roover, and L. Porter

    Presentation at APC Conference XXV 2013, Ann Arbor, MI, Oct. 14-17, 2013

    Detecting the health and proper operation of equipment during manufacturing is an important part of maintaining high yields. This paper describes a model-based approach to detecting changes in equipment during manufacturing. Physics-based mathematical models of the electrostatic chuck (ESC) temperature, RF plasma impedance, and chamber pressure were built for a commercial etch system. Each model […]

    March 2013
    Calibrating a High-Fidelity Finite Element Model of a Highway Bridge Using a Multi-Variable Sensitivity-Based Optimisation Approach

    Amir A. Mosavi, Hassan Sedarat, Sean M. O'Connor, Abbas Emami-Naeini, & Jerome Lynch

    Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance, DOI:10.1080/15732479.2012.757793

    This article presents the implementation of a calibration procedure for a finite element (FE) model of a state highway bridge using sensory data measured on the bridge. The objective is to modify the high-fidelity FE model of the bridge so that its dynamic behaviour matches, as closely as possible, that of the bridge under analysis. […]

    December 2012
    The Generalized Nyquist Criterion and Robustness Margins with Applications

    Abbas Emami-Naeini and Robert L. Kosut

    51st IEEE Conference on Decision and Contro,l December 10-13, 2012.

    Multivariable Nyquist eigenloci provide a much richer family of curves as compared to the SISO case. The eigenloci may be computed symbolically in many simple cases. Inspection of the generalized Nyquist eigenloci plot allows the determination of the exact values of the multivariable gain margin (GM), phase margin (PM), and the complex margin (CM). Hence […]

    October 2012
    Experimental Validation of Model of Electro-Chemical-Mechanical Planarization (ECMP) of Copper

    J. L. Ebert, S. Ghosal, D. de Roover, and A. Emami-Naeini

    Proceedings of the 2012 COMSOL Conference, Boston, October 3-5, 2012.

    This paper describes the development of a COMSOL model of Electro-Chemical-Mechanical Planarization (ECMP) that was validated with experimental data. ECMP is used for processing of semiconductor wafers. We developed a 2D model of flow of phosphoric acid solution (the electrolyte) between two parallel plates that focuses on the physics and electrochemistry in ECMP. The model […]

    September 2012
    Use of Monte Carlo Techniques in Robustness Evaluation of Different Temperature Control Methods of Heated Plates

    D. de Roover, A. Emami-Naeini, J. L. Ebert, G.W. van der Linden, L. L. Porter and R. L. Kosut

    Presentation at APC Conference XXIV 2012, Ann Arbor, MI, Sept. 10-12, 2012

    Many modern thermal processing systems involve temperature control of heated plates. In many systems such as Metal-Organic Chemical Vapor Deposition (MOCVD) and epitaxial deposition (Epi) systems, the plates are often thick carriers or susceptors on which one or more wafers are placed. Typically these plates are heated by radiation from hot filaments and the temperature […]

    April 2012
    Finite Element Model Updating of a Skewed Highway Bridge Using a Multi-Variable Sensitivity-Based Optimization Approach

    Amir A. Mosavi, Hassan Sedarat, Sean M. O’Connor, Abbas Emami-Naeini, Vince Jacob, Alex Krimotat, Jerome Lynch

    Proc. SPIE 8347, Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2012, 834727 (April 26, 2012); doi:10.1117/12.916163

    A Finite Element (FE) model which can precisely predict the actual dynamic responses of a bridge is necessary for accurate condition assessment and health monitoring purposes. However, most of the bridge FE models initially developed for design purposes may not be able to accurately simulate the current response of the bridges due to various reasons. […]

    September 2011
    Control Methods for Temperature Control of Heated Plates

    D. de Roover, A. Emami-Naeini, J. L. Ebert, G.W. van der Linden, L. L. Porter and R. L. Kosut

    Presentation at APC Conference XXIII 2011, Ann Arbor, MI, Sept. 12-15, 2011

    Many modern thermal processing systems involve temperature control of heated plates. In most Rapid Thermal Processing (RTP) systems, the ‘plate’ is a single wafer that is heated from one or both sides by an array of tungsten halogen lamps. In many other systems such as Metal-Organic Chemical Vapor Deposition (MOCVD) and epitaxial deposition (epi) systems, […]

    June 2011
    Optimal Sensor Placement for Health Monitoring of Civil Structures

    G. W. van der Linden, A. Emami-Naeini, R .L. Kosut, H. Sedarat, and J. P. Lynch

    2011 American Control Conference, San Francisco, CA, USA, June 29 - July 01, 2011, pp. 3116 -3121, 2011.

    In this paper we focus on comparing three candidate approaches to the optimal placement of sensors for state estimation-based continuous health monitoring of structures. The first aims to minimize the static estimation error of the structure deflections, using the linear stiffness matrix derived from a finite element model. The second approach aims to maximize the […]

    March 2011
    A Two-Tiered Self-Powered Wireless Monitoring System Architecture for Bridge Health Management

    M. Kurata, J. P. Lynch, T. Galchev, M. Flynn, P. Hipley, V. Jacob, G. W. van der Linden, A. Mortazawi, K. Najafi, R. L. Peterson, L.-H. Sheng, D. Sylvester, E. Thometz

    Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2010, Ed. Peter J. Shull, Aaron A. Diaz, H. Felix Wu, doi: 10.1117/12.848212, Proc. of SPIE Vol. 7649, San Diego, CA, USA, March 7-11, 2010.

    Bridges are an important societal resource used to carry vehicular traffic within a transportation network.  As such, the economic impact of the failure of a bridge is high; the recent failure of the I-35W Bridge in Minnesota (2007) serves as a poignant example.  Structural health monitoring (SHM) systems can be adopted to detect and quantify […]

    June 2010
    An Integrated Tool for Estimation of Material Model Parameters

    S. Ghosal, N. Acharya, T. E. Abrahamson, L. Porter II, H. W. Schreier

    Proceedings of the SEM Annual Conference, Indianapolis, IN, June 7-10, 2010.

    March 2010
    Near-Optimal Sensor Placement for Health Monitoring of Civil Structures

    G. W. van der Linden, A. Emami-Naeini, R. L. Kosut, H. Sedarat, J. P. Lynch

    Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2010, Ed. Peter J. Shull, Aaron A. Diaz, H. Felix Wu, doi: 10.1117/12.847704, Proc. of SPIE Vol. 7649, San Diego, CA, USA, March 7-11, 2010.

    In this paper we focus on the optimal placement of sensors for state estimation-based continuous health monitoring of structures using three approaches.  The first aims to minimize the static estimation error of the structure deflections, using the linear stiffness matrix derived from a finite element model.  The second approach aims to maximize the observability of […]

    January 2010
    Feedback Control of Dynamic Systems – Sixth Edition

    Gene F. Franklin, J. David Powell, Abbas Emami-Naeini

    Feedback Control of Dynamic Systems, 6th edition, Prentice-Hall, 2010, ISBN-10: 0136019692, ISBN-13: 9780136019695.

    Feedback Control of Dynamic Systems, 6/e covers the material that every engineer, and most scientists and prospective managers, needs to know about feedback control, including concepts like stability, tracking, and robustness. Each chapter presents the fundamentals along with comprehensive, worked-out examples, all within a real-world context and with historical background information. The authors also provide […]

    December 2008
    Quantum Process Tomography via L1-norm Minimization

    Robert L. Kosut

    arXiv:0812.4323v1 [quant-ph], 12/23/2008

    For an initially well designed but imperfect quantum information system, the process matrix is almost sparse in an appropriate basis. Existing theory and associated computational methods (L1-norm minimization) for reconstructing sparse signals establish conditions under which the sparse signal can be perfectly reconstructed from a very limited number of measurements (resources). Although a direct extension […]

    December 2008
    Control in Semiconductor Wafer Manufacturing

    Abbas Emami-Naeini, Dick de Roover

    Proceedings of the Symposium to honor W.~Wolovich, the 47th IEEE Conference on Decision and Control, Cancun, Mexico, December 9-11, 2008.

    A semiconductor wafer undergoes a wide range of processes before it is transformed from a bare silicon wafer to one populated with millions of transistor circuits. Such processes include Physical or Chemical Vapor Deposition, (PVD, CVD), Chemical-Mechanical Planarization (CMP), Plasma Etch, Rapid Thermal Processing (RTP), and photolithography.  As feature sizes keep shrinking, process control  plays […]

    October 2008
    Channel-Optimized Quantum Error Correction

    Soraya Taghavi, Robert L. Kosut, Daniel A. Lidar

    arXiv:0810.2524v1 [quant-ph], 10/14/2008.

    We develop a theory for finding quantum error correction (QEC) procedures which are optimized for given noise channels. Our theory accounts for uncertainties in the noise channel, against which our QEC procedures are robust. We demonstrate via numerical examples that our optimized QEC procedures always achieve a higher channel fidelity than the standard error correction […]

    September 2008
    Model-Based Control and Virtual Sensing with Application to a Vertical Furnace

    J. L. Ebert, N. Acharya, D. de Roover, A. Emami-Naeini, R. L. Kosut, J. Zhang

    AEC/APC Symposium, Salt Lake City, Utah, 2008.

    March 2008
    Quantum Metrology Subject to Instrumentation Constraints

    Robert L. Kosut

    arXiv:0803.4284v1 [quant-ph], 3/29/2008

    Maximizing the precision in estimating parameters in a quantum system subject to instrumentation constraints is cast as a convex optimization problem. We account for prior knowledge about the parameter range by developing a worst-case and average case objective for optimizing the precision. Focusing on the single parameter case, we show that the optimization problems are […]

    September 2007
    Robust Quantum Error Correction via Convex Optimization

    R.L. Kosut, A. Shabani, D.A. Lidar

    arXiv:quant-ph/0703274v2, Phys. Rev. Lett. 100, 020502 (2008)

    We present a semidefinite program optimization approach to quantum error correction that yields codes and recovery procedures that are robust against significant variations in the noise channel. Our approach allows us to optimize the encoding, recovery, or both, and is amenable to approximations that significantly improve computational cost while retaining fidelity. We illustrate our theory […]

    May 2007
    An All-Digital Cantilever Controller for MRFM and Scanned Probe Microscopy Using a Combined DSP/FPGA Design

    D. de Roover, L. Porter II, A. Emami-Naeini, J. Marohn, S. Kuehn, S. Garner, and D. Smith

    NanoTech 2007: NSTI Nanotechnology Conference and Trade Show, Santa Clara, May 20-24, 2007.

    An all-digital cantilever controller for magnetic resonance force microscopy (MRFM) was developed through a close collaboration between SC Solutions, Cornell University, and the U.S. Army Research Laboratory. The advantage of an all-digital controller is its absence of thermal drift, as well as its great tuning flexibility. This versatile controller is comprised of a Field Programmable […]

    April 2007
    Optimal Control of Quantum Gates and Suppression of Decoherence in a System of Interacting Two-Level Particles

    Matthew Grace, Constantin Brif, Herschel Rabitz, Ian A. Walmsley, Robert L. Kosut, Daniel A. Lidar

    arXiv:quant-ph/0702147v2, J. Phys. B: At. Mol. Opt. Phys. 40, S103-S125 (2007)

    Methods of optimal control are applied to a model system of interacting two-level particles (e.g., spin-half atomic nuclei or electrons or two-level atoms) to produce high-fidelity quantum gates while simultaneously negating the detrimental effect of decoherence. One set of particles functions as the quantum information processor, whose evolution is controlled by a time-dependent external field. […]

    February 2007
    Optimal Control of High-Fidelity Quantum Gates in the Presence of Decoherence

    Matthew Grace, Constantin Brif, Herschel Rabitz, Ian Walmsley, Robert Kosut, Daniel A. Lidar

    arXiv:quant-ph/0611189v2, 2/2/2007

    This work studies the feasibility of optimal control of high-fidelity quantum gates in a model of interacting two-level particles. One set of particles serves as the quantum information processor, whose evolution is controlled by a time-dependent external field. The other particles are not directly controlled and serve as an effective environment, coupling to which is […]

    January 2007
    Fidelity of Optimally Controlled Quantum Gates with Randomly Coupled Multiparticle Environments

    Matthew D. Grace, Constantin Brif, Herschel Rabitz, Daniel A. Lidar, Ian A. Walmsley, Robert L. Kosut

    arXiv:0712.2935v1 [quant-ph], Special issue of the Journal of Modern Optics: 37th Winter Colloquium on the Physics of Quantum Electronics, 2-6 January 2007.

    This work studies the feasibility of optimal control of high-fidelity quantum gates in a model of interacting two-level particles. One particle (the qubit) serves as the quantum information processor, whose evolution is controlled by a time-dependent external field. The other particles are not directly controlled and serve as an effective environment, coupling to which is […]

    June 2006
    Quantum Error Correction via Convex Optimization

    Robert L. Kosut, Daniel A. Lidar

    arXiv:quant-ph/0606078v1, 6/9/2006.

    We show that the problem of designing a quantum information error correcting procedure can be cast as a bi-convex optimization problem, iterating between encoding and recovery, each being a semidefinite program. For a given encoding operator the problem is convex in the recovery operator. For a given method of recovery, the problem is convex in […]

    June 2006
    On the Distance Between Unitary Propagators of Quantum Systems of Differing Dimensions

    Robert L. Kosut, Matthew Grace, Constantin Brif, Herschel Rabitz

    arXiv:quant-ph/0606064v1, 6/7/2006.

    A distance measure is presented between two unitary propagators of quantum systems of differing dimensions along with a corresponding method of computation. A typical application is to compare the propagator of the actual (real) process with the propagator of the desired (ideal) process; the former being of a higher dimension then the latter. The proposed […]

    May 2006
    Encoding a Qubit into Multilevel Subspaces

    Matthew Grace, Constantin Brif, Herschel Rabitz, Ian Walmsley, Robert Kosut, Daniel Lidar

    arXiv:quant-ph/0412059v3, New J. Phys. 8, 35 (2006).

    We present a formalism for encoding the logical basis of a qubit into subspaces of multiple physical levels. The need for this multilevel encoding arises naturally in situations where the speed of quantum operations exceeds the limits imposed by the addressability of individual energy levels of the qubit physical system. A basic feature of the […]

    April 2006
    Feedback Control of Dynamic Systems – Fifth Edition

    Gene Franklin, J. David Powell, Abbas Emami-Naeini

    Feedback Control of Dynamic Systems, 5th edition, Prentice-Hall, 2006, ISBN: 0-13-149930-0, 912p.

    Featuring a brand new chapter on nonlinear systems, this revision of the best-selling textbook on feedback control has been recognized for even greater instructor flexibility and student readability. Design is emphasized throughout as well as analysis techniques to provide motivation for the study of control. The authors include many carefully worked-out examples to illustrate the […]

    December 2005
    Active Control of Flow Over a Backward-Facing Step

    A. Emami-Naeini, S.A. McCabe, D. de Roover, J.L. Ebert; R.L. Kosut

    44th IEEE Conference on Decision and Control 2005 and 2005 European Control Conference CDC-ECC '05., page(s): 7366 - 7371, 12-15 Dec. 2005.

    We describe a control-oriented model reduction process from partial differential equation (PDE) descriptions of aerodynamic flow systems, and the design of low-order feedback controllers using these procedures. An effective approach for flow model reduction for active control using balanced truncation approaches was developed. The techniques were applied to a flow control problem representative of aerospace […]

    November 2004
    Optimal Experiment Design for Quantum State and Process Tomography and Hamiltonian Parameter Estimation

    Robert Kosut, Ian A. Walmsley, Herschel Rabitz

    arXiv:quant-ph/0411093v1, 11/12/2004.

    A number of problems in quantum state and system identification are addressed. Specifically, it is shown that the maximum likelihood estimation (MLE) approach, already known to apply to quantum state tomography, is also applicable to quantum process tomography (estimating the Kraus operator sum representation (OSR)), Hamiltonian parameter estimation, and the related problems of state and […]

    June 2004
    Model-Based Control for Chemical-Mechanical Planarization (CMP)

    de Roover, D.; Emami-Naeini, A.; Ebert, J.L.

    Proceedings of the 2004 American Control Conference, Volume 5, 30 June-2 July 2004, pp. 3922-3929, 2004.

    The research described in this tutorial paper involves an effort for physical modeling and model-based sensing and control of CMP systems.  A dynamic model of a rotational CMP process is developed, as well as simulation software. This dynamic model is used for feedback control design based on  in-situ thickness measurements, as well as run-to-run control […]

    June 2004
    Model-Based Control for Semiconductor and Advanced Materials Processing: An Overview

    A. Emami-Naeini, J.L. Ebert, R.L. Kosut, D. de Roover, S. Ghosal

    Proceedings of the 2004 American Control Conference, 30 June -2 July 2004, page(s): 3902 - 3909 vol.5, 2004.

    A semiconductor wafer undergoes a wide range of processes before it is transformed from a bare silicon wafer to one populated with millions of transistor circuits. Such processes include physical or chemical vapor deposition, (PVD, CVD), chemical-mechanical planarization (CMP), plasma etch, rapid thermal processing (RTP), and photolithography. As feature sizes keep shrinking, process control plays […]

    June 2004
    Multiscale Modeling and Control of RF Diode Sputter Deposition for GMR Thin Films

    S. Ghosal, R. L. Kosut, J. L. Ebert, and L. L. Porter II

    Proceedings of the 2004 American Control Conference, 30 June-2 July 2004, Volume: 5, pp. 3930-3941, 2004.

    Radio frequency (RF) diode sputtering is widely used for depositing Giant Magneto-Resistive (GMR) thin films for multilayers, spin valves,  and spin-dependent tunneling (SDT) devices used in data storage, computer memory, etc.  However, the thin films thus produced often show unacceptably high variation in GMR properties from wafer to wafer.  This paper describes a modeling and […]

    June 2004
    Model-Based Control of Rapid Thermal Processing for Semiconductor Wafers

    Ebert, J.L.; de Roover, D.; Porter, L.L., II; Lisiewicz, V.A.; Ghosal, S.; Kosut, R.L.; Emami-Naeini, A.

    Proceedings of the 2004 American Control Conference, page(s): 3910 - 3921 vol.5, 2004.

    This work describes the application of model-based control system design techniques to rapid thermal processing (RTP). The work considers all aspects of the distributed temperature control problem from physics-based modeling to implementation of the real-time embedded controller. With its exceptionally stringent performance requirements (low non-uniformity of wafer temperature, high temperature ramp rates), RTP temperature control […]

    March 2004
    Quantum State Detector Design: Optimal Worst-Case a posteriori Performance

    Robert L. Kosut, Ian Walmsley, Yonina Eldar, Herschel Rabitz

    arXiv:quant-ph/0403150v1, 3/21/2004.

    The problem addressed is to design a detector which is maximally sensitive to specific quantum states. Here we concentrate on quantum state detection using the worst-case a posteriori probability of detection as the design criterion. This objective is equivalent to asking the question: if the detector declares that a specific state is present, what is […]

    September 2003
    Modeling and Control of Distributed Thermal Systems

    A. Emami-Naeini, J. L. Ebert, D. de Roover, R. L. Kosut, M. Dettori, L. M. Porter, S. Ghosal

    IEEE Transactions on Control Systems Technology, Volume 11, Issue 5, Page(s):668 - 683, Sept. 2003.

    This paper investigates the application of model-based control design techniques to distributed temperature control systems. Multivariable controllers are an essential part of modern-day rapid thermal processing (RTP) systems. We consider all aspects of the control problem beginning with a physics-based model and concluding with implementation of a real-time embedded controller. The thermal system used as […]

    January 2001
    Iterative Adaptive Control: Windsurfing with Confidence

    R. L. Kosut

    Chapter in "Model Identification and Adaptive Control: From Windsurfing to Telecommunications ", G. Goodwin (ed.), Springer-Verlag, 2001.

    Part of a collection of contributions written in honor of Professor Brian Anderson's 60th birthday.

    December 2000
    On Achieving Reduced Error Propagation Sensitivity in DFE Design via Convex Optimization

    R. L. Kosut, W. Chung, C. R. Johnson, Jr., and S. P. Boyd

    Proceedings of the 39th IEEE Conference on Decision and Control, Sydney, Australia, December, 2000.

    November 2000
    Multi-Scale Model of the RF Diode Sputter Deposition of GMR Thin Films

    S. Ghosal, R. L. Kosut, J. L. Ebert, A. Kozak, T. E. Abrahamson, W. Zou, X. W. Zhou, J. F. Groves, Y. G. Yang, H. N. G. Wadley, D. Brownell, and D. Wang

    Application notes, 2000.

    A reactor-scale model incorporating the principal physical processes involved in RF diode sputtering has been developed and then integrated into a detailed steady-state input-output model of the growth of copper films. The model links critical aspects of the process (plasma power and pressure), the geometry of the chamber, and the materials (working gas, target materials) […]

    November 2000
    Command Shaping for MIMO Nonlinear Systems Using Iterative Learning Control with Application to an RTP System

    D. de Roover, A. Emami-Naeini, J. L. Ebert, R. L. Kosut

    Proceedings of the ASME Dynamic Systems and Control Divison-2000, pp. 153-161, November 2000.

    October 2000
    Control of Sputter Process for Improved Run-to-Run Repeatability

    S. Ghosal, R. L. Kosut, J. L. Ebert, L. Porter, D. Brownell, and D. Wang

    S. C. Application Notes, 2000.

    Radio frequency (RF) diode sputtering deposition is a widely used process for depositing GMR thin films for multilayers, spin valves, spin-dependent tunneling (SDT) devices, etc. However, the thin films thus produced often show significant variation in GMR properties from wafer to wafer. A multiscale model based on the primary physical phenomena – gas flow, plasma discharge, […]

    December 1999
    Feedback Control of Morphology During III-V Semiconductor Growth by Molecular Beam Epitaxy

    R. L. Kosut, R. Caflisch, M. Gyure, D. G. Meyer, A. Engelmann

    Proceedings of the 38th Conference on Decision & Control, Phoenix, AZ, December 1999, pp. 4204-4208.

    September 1999
    Reactor-Scale Modeling and Control for MOCVD of YBCO High Temperature Superconductors

    SC Solutions, Inc.

    Application Notes, SC Solutions, Inc., 1999.

    This whitepaper details a systematic methodology for concurrent development of reactor-scale physical model and model-based process control development for metal-organic chemical vapor deposition (MOCVD). The example used for illustrating the approach is the deposition of yttrium-barium-copper oxide (YBa2Cu3O7-x or YBCO) thin films with high temperature superconducting (HTS) properties. Information about the gas-phase chemical mechanisms, obtained from experimental […]

    September 1999
    Reactor-Scale Models for RF Diode Sputtering of Metal Thin-Films

    S. Desa, S. Ghosal, R. Kosut, J. L. Ebert, T. E. Abrahamson, A. Kozak, W. Zou, X. W. Zhou, J. F. Groves, and H. N. G. Wadley

    Journal of Vacuum Science & Technology A, Vol. 17, No. 4, pp. 1926-1933, 1999.

    September 1999
    Silicon Epitaxy White Paper

    SC Solutions, Inc.

    Application Notes, 1999.

    In this white paper, we describe the numerical simulation of CVD process for epitaxial growth of silicon using trichlorosilane (SiHCl3). This study uses the one-step, finite-rate chemistry for the 2-D reactor geometry from the literature, and successfully reproduces the published results. A commercial software package, CFD-ACEe, popular in the semiconductor industry, was used for our […]

    September 1999
    Tradeoffs in Temperature Control of Fast-Ramp RTO and RTA Systems

    D. de Roover, A. Emami-Naeini, J. L. Ebert, R. L. Kosut

    Proceedings of the Seventh International Conference on Advanced Thermal Processing of Semiconductors, RTP '99, Colorado Springs, September 1999.

    June 1999
    Active Control in Structures

    H. Sedarat, R. Kosut

    13th ASCE Engineering Mechanics Division Conference held in Baltimore, June 13-16, 1999.

    In this paper the application of control theory to structural engineering has been presented from a structural engineering perspective. The objective of this paper is to summarize key steps that are required to design an active control system for a structure. Total acceleration feedback with H2/LQG controller is used in this paper. The structural control […]

    May 1999
    Model-Based Control of MOCVD Rate, Uniformity and Stoichiometry

    S. Ghosal, J. L. Ebert, D. de Roover, and A. Emami-Naeini

    Presented at the Third Symposium of Process Control, Diagnostics, and Modeling in Semiconductor Manufacturing, 195th Meeting of the Electrochemical Society, Seattle, May 2-6, 1999.

    A 2D model of MOCVD reactor has been developed for deposition of YBCO thin films. System characterization showed the need for control of growth rate, deposition uniformity, and oxide stoichiometry at the surface. A run-to-run control architecture was developed, and is being implemented.

    May 1999
    A Physical Model for Drying of Gelcast Ceramics

    S. Ghosal, A. Emami-Naeini, Y. P. Harn, B. Draskovich, and J. P. Pollinger

    Journal of the American Ceramic Society, Vol. 82, No. 3, pp. 513-520, 1999.

    Gelcasting is a promising new technology for manufacturing advanced structural ceramic components. The process involves drying of the ‘green’ gelcast part before densiï¬cation. The physical mechanisms controlling this relatively long drying process are not well understood. In this study, several controlled experiments were performed to elucidate the key mechanisms. A one-dimensional drying model was formulated […]

    December 1998
    Linear Multivariable Servomechanisms Revisited: System Type and Accuracy Trade-Offs

    B. A. L. de la Barra, A. Emami-Naeini, and E. R. Chinchon

    Automatica, Vol. 34, No. 11, pp. 1449-1452, 1998.

    December 1998
    Run-to-Run Control of Static Systems

    D. de Roover, R. L. Kosut, A. Emami-Naeini, and J. L. Ebert

    Proceedings of the 37th IEEE Conference on Decision and Control, pp. 695-700, Tampa, Florida, December, 1998.

    Run-to-run control using static linear models is examined. Conditions are presented for stability, (statistical) performance, and robustness using standard control theory. A simulation example shows the usefulness of the method applied to a rapid thermal oxidation (RTO) process.

    September 1998
    Model-Based Control of Fast-Ramp RTP Systems

    D. de Roover, A. Emami-Naeini, J. L. Ebert, S. Ghosal, and G. W. van der Linden

    Proceedings of the Sixth International Conference on Advanced Thermal Processing of Semiconductors, RTP '98, Kyoto, Japan, September 9-11, 1998.

    December 1997
    Efficient CFD Modeling of Single Wafer Semiconductor Systems for Closed-Loop Evaluation

    J. L. Ebert, G. W. van der Linden, R. L. Kosut, and A. Emami-Naeini

    Proceedings of the 36th IEEE Conference on Decision and Control, pp. 830-831, December, 1997.

    October 1997
    Real-Time Model-Based Control Systems Design for Gelcast Drying Process

    Y. P. Harn, S. Ghosal, G. Aral, A. Emami-Naeini, B. Draskovich, and L. C. Maxey

    Proceedings of the 1997 IEEE International Conference on Control Applications, Hartford, CT. October 5-7, 1997.

    Gelcasting is a new method for manufacturing advanced structural ceramics for use, for example, in the aerospace industry. The process involves a drying stage, where moisture, which constitutes approximately a quarter of the mass of the part, is removed in a commercial dryer. The control system design for the gelcast ceramic drying process is complicated […]

    September 1997
    Efficient CFD Modeling of Single Wafer System for Closed-Loop Evaluation

    J. L. Ebert, G. W. van der Linden, R. L. Kosut, and A. Emami-Naeini

    Proceedings of the Fifth International Conference on Advanced Thermal Processing of Semiconductors, RTP '97, New Orleans, LA, September 3-5, 1997.

    June 1991
    Robust Control Law Development for a Hypersonic Cruise Aircraft

    Mark R. Anderson, Abbas Emami-Naeini, and James H. Vincent

    American Control Conference, June 26-28, 1991

    Systems Control Technology, Inc. is participating in the Air Force program entitled “Robust Control Law Development for Modern Aerospace Vehicles” (MAVRIC) as a subcontractor to Northrop Aircraft Division. The goal of this program is to apply state-of-the-art robust control law design methodologies to high-performance aircraft with significant modelling errors (uncertainties). The uncertainties which are being […]

    December 1985
    Integrated Control: A Decentralized Approach

    A. Emami-Naeini, R. P. Anex, and S. M. Rock

    24th IEEE Conference on Decision and Control, December 1985

    A decentralized, robust, multivariable controls method is described for the functional integration of subsystems in large-scale systems characterized by dynamic coupling among subsystem elements. In an integrated environment, a decentralized control structure reduces the complexity of the control by distributing the control authority to local controllers. The method relies upon generation of a set of […]

    March 1983
    Robust Control of Flexible Spacecraft

    Robert L. Kosut, Horst Salzwedel, and Abbas Emami-Naeini

    Journal of Guidance, Control, and Dynamics, Vol. 6, No. 2 (1983), pp. 104-111.

    A well-designed feedback control system exhibits the properties of external disturbance attenuation and performance robustness with respect to plant uncertainty. The plant uncertainties of flexible spacecraft include unmodeled dynamics and parameter uncertainties. Singular value robustness measures are used to compare performance and stability robustness properties of different control design techniques in the presence of residual […]