Research:
Nanomanufacturing

Sensing and Advanced Process Control for Widegap Semiconductor Growth

We are applying mass spectrometry as a real-time, in-situ sensor in GaN-based MOCVD processes, a joint project with Northrop Grumman.  Integrated reaction product signals provide a thickness metrology, which is used to terminate the 20 nm AlGaN cap layer whose thickness determines device speed. We have found these sensor signatures to be useful as well in predicting GaN material quality and for detection of equipment and process faults, in the context of advanced process control.  This work is closely allied with modeling and simulation work by Prof. Adomaitis' group.

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Real-time Chemical Process Sensing for Metrology and Advanced Process Control

Our group has been a leader in applying real-time, in-situ chemical sensors to CVD processes.  We have used mass spectrometry to observe the fundamental chemistry of these processes, to develop a thickness metrology using product generation and reactant depletion signals, and to detect equipment and process faults, leading to an effective approach for advanced process control.  We have also demonstrated the use of acoustic and Fourier transform infrared spectroscopy sensors for thickness metrology.

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Simulation and Optimization in Dynamic Process Systems

Our group regularly develops dynamic simulations for processes and equipment related to our research.  Platforms for such simulations are powerful means for designing equipment, understanding its behavior, and developing simulation models to assess optimization and tradeoff issues.  Such simulations have benefited a range of projects, from design of mass spectrometric sampling systems and developing new modes of atomic layer deposition process cycling, to co-optimization of environmental and manufacturing metrics as well as integration of these continuous parameter dynamic simulations with discrete event simulations of cluster tool and factory workflow.

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Selected Accomplishments

Real-time end point control for 20 nm AlGaN cap layer in GaN HEMT devices
Material quality prediction in real-time during GaN MOCVD growth
Sensor-based control of MOCVD source materials
Real-time sensors for film thickness metrology in chemical vapor deposition process
Run-to-run and real-time thickness control for advanced process control
Process optimization for manufacturing and environmental metrics

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Students

Laurent Henn-Lecordier (MSE grad, staff)
Erin Robertson (MSE grad)
Parag Banerjee (MSE grad)
Nicholas Mostovych (MSE undergrad)

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Collaborators

Ray Adomaitis (ChE/ISR, UMCP)
Tomomi Ino (Toshiba)
Deborah Partlow (Northrop Grumman)
Michael Aumer (Northrop Grumman)
Darren Thomson (Northrop Grumman)
Jim Oliver (Northrop Grumman)

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Support

Northrop Grumman Electronic Systems
NSF/SRC Center for Environmentally Benign Semiconductor Manufacturing
Autonomous Province of Trentino/ITC-irst, Trento, Italy
MKS Instruments
Inficon
Toshiba Corporate Manufacturing Center

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Selected Publications

" In-situ chemical sensing in AlGaN/GaN high electron mobility transistor metalorganic chemical vapor deposition process for real-time prediction of product crystal quality and advanced process control ", Soon Cho, Gary W. Rubloff, Michael E. Aumer, Darren B. Thomson, Deborah P. Partlow, Rinku Parikh, and Raymond A. Adomaitis, J. Vac. Sci. Technol. B 23 (4), 1386-1397 (Jul/Aug 2005).

" In-situ chemical sensing in AlGaN/GaN metal organic chemical vapor deposition process for precision film thickness metrology and real-time advanced process control ", S. Cho, D. S. Janiak, G. W. Rubloff, M. E. Aumer, D. B. Thomson, and D. P. Partlow, J. Vac. Sci. Technol. B 23 (5), 2007-2013 (Sep/Oct 2005).

" Real-time material quality prediction, fault detection and contamination control in AlGaN/GaN high electron mobility transistor metalorganic chemical vapor deposition process using in-situ chemical sensing ", Soon Cho, Gary W. Rubloff, Michael E. Aumer, Darren B. Thomson, and Deborah P. Partlow, J. Vac. Sci. Technol. B 23 (5), 1849-1855 (Sept/Oct 2005).

" Real-time acoustic sensing and control of metalorganic chemical vapor deposition precursor concentrations delivered from solid phase sources ", L. Henn-Lecordier, J.N. Kidder, Jr., and G.W. Rubloff, J. Vac. Sci. Technol. A 22(5) 1984-1991 (Sept/Oct 2004).

" Real-time acoustic sensing and control of metalorganic chemical vapor deposition precursor concentrations delivered from solid phase sources ", L. Henn-Lecordier, J.N. Kidder, Jr., and G.W. Rubloff, J. Vac. Sci. Technol. A 22(5) 1984-1991 (Sept/Oct 2004).

" In-situ mass spectrometry in a 10 torr W chemical vapor deposition process for film thickness metrology and real-time advanced process control ", Soon Cho , Laurent Henn-Lecordier , Yijun Liu, and Gary W. Rubloff, J. Vac. Sci. Technol. B 22(3) 880-887 (MayJun 2004).

" Dynamic Simulation and Optimization of Cu CVD Unit Process for Environmentally Benign Manufacturing ", Soon Cho , Wei Lei , Adam Melvin, and Gary W. Rubloff , IEEE Trans. Semi. Manuf. 17 (3), 455-469 (Aug 2004).

" In-Situ Metrology: the Path to Real-Time Advanced Process Control ", Gary W. Rubloff, Invited Paper, Proc. 2003 International Conference on Characterization and Metrology for ULSI Technology, Austin, TX, March 24-28, 2003, ed. by D. G. Seiler et. al., AIP Conf. Proc. Vol. 683, ISBN 0-7354-0152-7 (AIP, Melville NY , 2003), 583-591.

" Real-time, in-situ film thickness metrology in a 10 Torr W chemical vapor deposition process using an acoustic sensor ", L. Henn-Lecordier, J. N. Kidder, Jr., and G. W. Rubloff, J. Vac. Sci. Technol. B 21 (3), 1055-1063 (May/Jun 2003).

" Thickness Metrology and End Point Control in W-CVD Process from SiH 4 /WF 6 Using in-situ Mass Spectrometry ", Y. Xu, T. Gougousi, L. Henn-Lecordier, Y. Liu, S. Cho, and G. W. Rubloff, J. Vac. Sci. Technol. B 20 (6), 2351-2360 (Nov/Dec 2002).

" Influence of Gas Composition on Wafer Temperature Control in a Tungsten Chemical Vapor Deposition Reactor ", H.-Y. Chang, R. A. Adomaitis, J. N. Kidder, Jr., and G. W. Rubloff, J. Vac. Sci. Technol. B 19 (1), 230-38 (Jan/Feb 2001).

" Understanding the Impact of Equipment and Process Changes with a Heterogeneous Semiconductor Manufacturing Simulation Environment ", J.W. Herrmann, B.F. Conaghan, L. Henn-Lecordier, P. Mellacheruvu, M-Q Nguyen, G.W. Rubloff, and R.Z. Shi, Proc. 2000 Winter Simulation Conference, December 10-13, 2000, Orlando, FL.,. ed. by J. A. Joines, R. R. Barton, K. Kang, and P. A. Fishwick, vol. 2, pp. 1491-1498 (2000).

"Evaluating the Impact of Process Changes on Cluster Tool Performance", J. W. Herrmann, N. Chandrasekharan, B. F. Conaghan, M-Q Nguyen, G. W. Rubloff, and R. Z. Shi, IEEE Trans. Semicond. Manuf. 13 (2), 181-192 (May 2000).

" Integrated Dynamic Simulation of Rapid Thermal Chemical Vapor Deposition of Polysilicon ", G. Lu, M. Bora, L. L. Tedder, and G. W. Rubloff, IEEE Trans. Semicond. Manuf. 11 (1), pp. 63-74 (Feb., 1998).

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