Dr. Joseph Fu Profile

Dr. Joseph Fu

Technician at National Institute of Standards and Technology

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Author

Publications (21)

SPIE Journal Paper | 26 August 2016 Open Access

Evaluation of carbon nanotube probes in critical dimension atomic force microscopes

Jinho Choi, Byong Chon Park, Sang Jung Ahn, Dal-Hyun Kim, Joon Lyou, Ronald Dixson, Ndubuisi Orji, Joseph Fu, Theodore Vorburger

JM3, Vol. 15, Issue 03, 034005, (August 2016) https://doi.org/10.1117/12.10.1117/1.JMM.15.3.034005

KEYWORDS: Scanning electron microscopy, Line edge roughness, Carbon nanotubes, Atomic force microscope, Metrology, Atomic force microscopy, Standards development, Silicon, Manufacturing, Ion beams

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SPIE Journal Paper | 4 June 2013

Distributed force probe bending model of critical dimension atomic force microscopy bias

Vladimir Ukraintsev, Ndubuisi Orji, Theodore Vorburger, Ronald Dixson, Joseph Fu, Richard Silver

JM3, Vol. 12, Issue 02, 023009, (June 2013) https://doi.org/10.1117/12.10.1117/1.JMM.12.2.023009

KEYWORDS: Atomic force microscopy, Data modeling, 3D modeling, Numerical analysis, Error analysis, Metrology, Statistical modeling, Carbon nanotubes, Solids, Standards development

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Proceedings Article | 3 April 2012 Paper

On CD-AFM bias related to probe bending

V. Ukraintsev, N. Orji, T. Vorburger, R. Dixson, J. Fu, R. Silver

Proceedings Volume 8324, 83240V (2012) https://doi.org/10.1117/12.916737

KEYWORDS: Data modeling, 3D modeling, Numerical analysis, Metrology, Atomic force microscopy, Statistical analysis, Standards development, Semiconductors, 3D metrology, Statistical modeling

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SPIE Journal Paper | 1 January 2011

Multilaboratory comparison of traceable atomic force microscope measurements of a 70-nm grating pitch standard

Ronald Dixson, Donald Chernoff, Shihua Wang, Theodore Vorburger, Siew-Leng Tan, Ndubuisi Orji, Joseph Fu

JM3, Vol. 10, Issue 1, 013015, (January 2011) https://doi.org/10.1117/12.10.1117/1.3549914

KEYWORDS: Calibration, Metrology, Atomic force microscope, Atomic force microscopy, Standards development, Error analysis, Interferometry, Scanners, Interferometers, Helium neon lasers

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Proceedings Article | 10 June 2010 Paper

Interlaboratory comparison of traceable atomic force microscope pitch measurements

Ronald Dixson, Donald Chernoff, Shihua Wang, Theodore Vorburger, Siew Leng Tan, Ndubuisi Orji, Joseph Fu

Proceedings Volume 7729, 77290M (2010) https://doi.org/10.1117/12.858353

KEYWORDS: Calibration, Metrology, Atomic force microscopy, Atomic force microscope, Error analysis, Standards development, Interferometers, Scanners, Helium neon lasers, Head

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Proceedings Article | 23 March 2009 Paper

Reference metrology in a research fab: the NIST clean calibrations thrust

Ronald Dixson, Joe Fu, Ndubuisi Orji, Thomas Renegar, Alan Zheng, Theodore Vorburger, Al Hilton, Marc Cangemi, Lei Chen, Mike Hernandez, Russell Hajdaj, Michael Bishop, Aaron Cordes

Proceedings Volume 7272, 727209 (2009) https://doi.org/10.1117/12.815499

KEYWORDS: Calibration, Metrology, Scanning electron microscopy, Standards development, Atomic force microscopy, Scanners, Nanotechnology, Profiling, Dimensional metrology, Semiconductors

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Proceedings Article | 30 October 2007 Paper

Photomask applications of traceable atomic force microscope dimensional metrology at NIST

Ronald Dixson, Ndubuisi Orji, James Potzick, Joseph Fu, Richard Allen, Michael Cresswell, Stewart Smith, Anthony Walton, Andreas Tsiamis

Proceedings Volume 6730, 67303D (2007) https://doi.org/10.1117/12.746755

KEYWORDS: Metrology, Calibration, Atomic force microscopy, Photomasks, Standards development, Phase shifts, Dimensional metrology, Atomic force microscope, Resistance, Microelectronics

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The National Institute of Standards and Technology (NIST) has a multifaceted program in atomic force microscope (AFM) dimensional metrology. Three major instruments are being used for traceable measurements. The first is a custom in-house metrology AFM, called the calibrated AFM (C-AFM), the second is the first generation of commercially available critical dimension AFM (CD-AFM), and the third is a current generation CD-AFM at SEMATECH - for which NIST has established the calibration and uncertainties. All of these instruments have useful applications in photomask metrology. Linewidth reference metrology is an important application of CD-AFM. We have performed a preliminary comparison of linewidths measured by CD-AFM and by electrical resistance metrology on a binary mask. For the ten selected test structures with on-mask linewidths between 350 nm and 600 nm, most of the observed differences were less than 5 nm, and all of them were less than 10 nm. The offsets were often within the estimated uncertainties of the AFM measurements, without accounting for the effect of linewidth roughness or the uncertainties of electrical measurements. The most recent release of the NIST photomask standard - which is Standard Reference Material (SRM) 2059 - was also supported by CD-AFM reference measurements. We review the recent advances in AFM linewidth metrology that will reduce the uncertainty of AFM measurements on this and future generations of the NIST photomask standard. The NIST C-AFM has displacement metrology for all three axes traceable to the 633 nm wavelength of the iodine-stabilized He-Ne laser. One of the important applications of the C-AFM is step height metrology, which has some relevance to phase shift calibration. In the current generation of the system, the approximate level of relative standard uncertainty for step height measurements at the 100 nm scale is 0.1 %. We discuss the monitor history of a 290 nm step height, originally measured on the C-AFM with a 1.9 nm (k = 2) expanded uncertainty, and describe advances that bring the step height uncertainty of recent measurements to an estimated 0.6 nm (k = 2). Based on this work, we expect to be able to reduce the topographic component of phase uncertainty in alternating aperture phase shift masks (AAPSM) by a factor of three compared to current calibrations based on earlier generation step height references.

Proceedings Article | 5 April 2007 Paper

Application of carbon nanotube probes in a critical dimension atomic force microscope

B. Park, J. Choi, S. Ahn, D-H Kim, J. Lyou, R. Dixson, N. Orji, J. Fu, T. Vorburger

Proceedings Volume 6518, 651819 (2007) https://doi.org/10.1117/12.712326

KEYWORDS: Silicon, Carbon nanotubes, Metrology, Atomic force microscopy, Standards development, Scanning electron microscopy, Line edge roughness, Ion beams, Atomic force microscope, Platinum

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Proceedings Article | 24 March 2006 Paper

Traceable atomic force microscope dimensional metrology at NIST

Ronald Dixson, Ndubuisi Orji, Joseph Fu, Michael Cresswell, Rich Allen, Will Guthrie

Proceedings Volume 6152, 61520P (2006) https://doi.org/10.1117/12.656803

KEYWORDS: Calibration, Metrology, Standards development, Atomic force microscopy, Dimensional metrology, Atomic force microscope, Prototyping, Error analysis, Crystals, Photomasks

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Proceedings Article | 20 August 2004 Paper

Study of an image stitching method for linewidth measurement

Wei Chu, Xuezeng Zhao, Joseph Fu, Theodore Vorburger

Proceedings Volume 5446, (2004) https://doi.org/10.1117/12.557767

KEYWORDS: Image registration, Atomic force microscopy, Carbon nanotubes, Distortion, Image fusion, 3D image processing, Standards development, Error analysis, Metrology, Electrical engineering

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Proceedings Article | 24 May 2004 Paper

An image stitching method to eliminate the distortion of the sidewall in linewidth measurement

Xuezeng Zhao, Joseph Fu, Wei Chu, Cattien Nguyen, Theodore Vorburger

Proceedings Volume 5375, (2004) https://doi.org/10.1117/12.536692

KEYWORDS: Atomic force microscopy, Image registration, Distortion, Carbon nanotubes, Scanning electron microscopy, Standards development, Semiconductor manufacturing, Data storage, Crystals, Oxides

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Proceedings Article | 24 July 2002 Paper

New design and uncertainty budget for a metrology UHV-STM used in direct measurements of atom spacings

Satoshi Gonda, Hui Zhou, Joseph Fu, Richard Silver

Proceedings Volume 4608, (2002) https://doi.org/10.1117/12.465125

KEYWORDS: Semiconductor lasers, Scanning tunneling microscopy, Interferometers, Metrology, Chemical species, Diodes, Calibration, Crystals, Polarization, Tunable lasers

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Proceedings Article | 24 July 2002 Paper

Effects of etching time and wafer miscut on the morphology of etched Si(111) surfaces

Hui Zhou, Joseph Fu, Sotoshi Gonda, Richard Silver

Proceedings Volume 4608, (2002) https://doi.org/10.1117/12.465124

KEYWORDS: Etching, Semiconducting wafers, Silicon, Hydrogen, Metrology, Standards development, Chemical species, Ultrasonics, Semiconductor manufacturing, Manufacturing

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Proceedings Article | 22 August 2001 Paper

Silicon single atom steps as AFM height standards

Ronald Dixson, Ndubuisi Orji, Joseph Fu, Vincent Tsai, Ellen Williams, Raghu Kacker, Theodore Vorburger, Hal Edwards, Debra Cook, Paul West, Ralph Nyffenegger

Proceedings Volume 4344, (2001) https://doi.org/10.1117/12.436739

KEYWORDS: Silicon, Calibration, Atomic force microscopy, Oxides, Metrology, Statistical analysis, Chemical species, Standards development, Error analysis, Atomic force microscope

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Proceedings Article | 2 June 2000 Paper

Accurate dimensional metrology with atomic force microscopy

Ronald Dixson, Rainer Koening, Joseph Fu, Theodore Vorburger, Brian Renegar

Proceedings Volume 3998, (2000) https://doi.org/10.1117/12.386492

KEYWORDS: Atomic force microscopy, Calibration, Standards development, Metrology, Interferometers, Sensors, Dimensional metrology, Capacitance, Holography, Prototyping

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Proceedings Article | 30 November 1999 Paper

Step-height metrology for data storage applications

Rainer Koening, Ronald Dixson, Joseph Fu, Brian Renegar, Theodore Vorburger, Vincent Tsai, Michael Postek

Proceedings Volume 3806, (1999) https://doi.org/10.1117/12.371161

KEYWORDS: Calibration, Interferometers, Metrology, Data storage, Compact discs, Atomic force microscopy, Capacitance, Head, Metals, Atomic force microscope

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Proceedings Article | 14 June 1999 Paper

Dimensional metrology with the NIST calibrated atomic force microscope

Ronald Dixson, Rainer Koening, Vincent Tsai, Joseph Fu, Theodore Vorburger

Proceedings Volume 3677, (1999) https://doi.org/10.1117/12.350822

KEYWORDS: Calibration, Atomic force microscopy, Capacitance, Sensors, Edge detection, Metrology, Interferometers, Silicon, Motion measurement, Dimensional metrology

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Proceedings Article | 8 June 1998 Paper

Measurement of pitch and width samples with the NIST calibrated atomic force microscope

Ronald Dixson, Rainer Koening, Theodore Vorburger, Joseph Fu, Vincent Tsai

Proceedings Volume 3332, (1998) https://doi.org/10.1117/12.308751

KEYWORDS: Calibration, Error analysis, Standards development, Metrology, Interferometers, Atomic force microscopy, Atomic force microscope, Resistance, Silicon, Heterodyning

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Because atomic force microscopes (AFMs) are capable of generating three dimensional images with nanometer level resolution, these instruments are being increasingly used in many industries as tools for dimensional metrology at sub- micrometer length scales. To achieve high accuracy, the scales of an AFM must be calibrated. Presently available standards for this purpose are commonly calibrated using stylus instruments and optical techniques. We have developed the calibrated AFM (C-AFM) in order to calibrate pitch and height standards using an AFM. Our instrument has metrology traceable to the wavelength of light for all three axes. This is accomplished through the integration of a flexure x-y translation stage, heterodyne laser interferometers, and a digital-signal-processor based closed-loop feedback system to control the x-y scan motion. The z-axis translation is accomplished using a piezoelectric actuator with an integrated capacitance sensor, which is calibrated using a heterodyne laser interferometer. When fully developed, this instrument will be a calibration tool for pitch and height standards for scanning probe microscopes. We have recently completed a reevaluation of the titling motions of the C-AFM scanner. This has allowed a refinement in our estimate of the Abbe error contribution to our measurement uncertainty. Our most recent pitch measurements are consistent with this new estimate and thus support our refined uncertainty budget. We have recently completed measurements of pitch on several samples, including both grid type and linear scale patterns, for an industrial user. We are also working toward the development of linewidth standards through the comparison of C-AFM width measurements with values obtained from other methods, including an electrical resistance techniques. In this paper, we will describe the current status of the C-AFM, discuss the use of the instrument for measurements of pitch and width, and describe our plans for future measurements.

Proceedings Article | 8 June 1998 Paper

Developing a method to determine linewidth based on counting the atom spacings across a line

Richard Silver, Carsten Jensen, Vincent Tsai, Joseph Fu, John Villarrubia, E. Clayton Teague

Proceedings Volume 3332, (1998) https://doi.org/10.1117/12.308754

KEYWORDS: Silicon, Scanning tunneling microscopy, Chemical species, Oxides, Calibration, Semiconducting wafers, Scanning electron microscopy, Crystals, Gallium arsenide, Atomic force microscopy

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Proceedings Article | 2 September 1997 Paper

Accurate force measurements for miniature mechanical systems: a review of progress

Lowell Howard, Joseph Fu

Proceedings Volume 3225, (1997) https://doi.org/10.1117/12.284543

KEYWORDS: Calibration, Microelectromechanical systems, Electromagnetism, Prototyping

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Proceedings Article | 21 May 1996 Paper

Calibration of scanning electron microscope magnification standards SRM484

Joseph Fu, Theodore Vorburger, David Ballard

Proceedings Volume 2725, (1996) https://doi.org/10.1117/12.240150

KEYWORDS: Calibration, Scanning electron microscopy, Electron microscopes, Interferometers, Gold, Standards development, Electron beams, Microscopes, Polishing, Nickel

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Showing 5 of 21 publications

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