Dr. John S. Villarrubia Profile

Dr. John S. Villarrubia

Physicist at National Institute of Standards and Technology

SPIE Involvement:

Author

Area of Expertise:

SEM modeling & simulation , Dimensional metrology

Publications (39)

Proceedings Article | 10 April 2024 Presentation

Simulation insights: can we measure buried gate-all-around features with backscattered electrons?

John Villarrubia, Shari Klotzkin, Benjamin Bunday

Proceedings Volume 12955, 129551H (2024) https://doi.org/10.1117/12.3013044

KEYWORDS: Monte Carlo methods, Transistors, Gallium arsenide, Scanning electron microscopy, Optical simulations, Transparency, Spatial resolution, Nanowires, Nanosheets, Electron microscopes

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Proceedings Article | 30 April 2023 Presentation

A total shift show: submilliradian tilt goniometry in scanning electron microscopy

Andrew Madison, John Villarrubia, Daron Westly, Ronald Dixson, Craig Copeland, John Gerling, Katherine Cochrane, Alan Brodie, Lawrence Muray, J. Alexander Liddle, Samuel Stavis

Proceedings Volume 12496, 1249606 (2023) https://doi.org/10.1117/12.2673963

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Proceedings Article | 27 April 2023 Presentation + Paper

Model validation for scanning electron microscopy

O. Yu Ridzel, W. Yamane, I. Mansaray, J. Villarrubia

Proceedings Volume 12496, 124960T (2023) https://doi.org/10.1117/12.2661103

KEYWORDS: Critical dimension metrology, Electron transport, Dimensional metrology, Scanning electron microscopy, Data modeling, Silicon, Scanning transmission electron microscopy, Vacuum chambers, Physics

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Proceedings Article | 24 March 2016 Paper

Virtual rough samples to test 3D nanometer-scale scanning electron microscopy stereo photogrammetry

J. Villarrubia, V. Tondare, A. Vladár

Proceedings Volume 9778, 977809 (2016) https://doi.org/10.1117/12.2219777

KEYWORDS: Scanning electron microscopy, 3D metrology, Photogrammetry, 3D modeling, Metrology, 3D scanning, Critical dimension metrology, Electron microscopes, 3D image processing, Data processing, Scattering, Skin, Virtual reality, Error analysis, Clouds

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SPIE Journal Paper | 12 November 2015 Open Access

Optimizing hybrid metrology: rigorous implementation of Bayesian and combined regression

Mark-Alexander Henn, Richard Silver, John Villarrubia, Nien Fan Zhang, Hui Zhou, Bryan Barnes, Bin Ming, András Vladár

JM3, Vol. 14, Issue 04, 044001, (November 2015) https://doi.org/10.1117/12.10.1117/1.JMM.14.4.044001

KEYWORDS: Scanning electron microscopy, Metrology, Error analysis, Data modeling, Standards development, 3D metrology, Monte Carlo methods, Indium arsenide, Electron microscopes, Calibration

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Proceedings Article | 19 March 2015 Paper

Optimizing hybrid metrology: rigorous implementation of Bayesian and combined regression

Mark-Alexander Henn, Richard Silver, John Villarrubia, Nien Fan Zhang, Hui Zhou, Bryan Barnes, Bin Ming, András Vladár

Proceedings Volume 9424, 94241J (2015) https://doi.org/10.1117/12.2175653

KEYWORDS: Scanning electron microscopy, Error analysis, Metrology, Data modeling, Standards development, 3D metrology, Indium arsenide, Calibration, Inverse problems, Monte Carlo methods

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Proceedings Article | 16 September 2014 Paper

3D Monte Carlo modeling of the SEM: Are there applications to photomask metrology?

J. Villarrubia, A. Vladár, M. Postek

Proceedings Volume 9236, 923602 (2014) https://doi.org/10.1117/12.2069324

KEYWORDS: Electrons, Scanning electron microscopy, Photomasks, Model-based design, Monte Carlo methods, 3D modeling, Metrology, Scattering, Statistical modeling, Sensors

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Proceedings Article | 14 April 2014 Paper

10nm three-dimensional CD-SEM metrology

András Vladár, John Villarrubia, Jasmeet Chawla, Bin Ming, Joseph Kline, Scott List, Michael Postek

Proceedings Volume 9050, 90500A (2014) https://doi.org/10.1117/12.2045977

KEYWORDS: Scanning electron microscopy, 3D metrology, 3D modeling, Transmission electron microscopy, Model-based design, Electron beams, Metrology, Monte Carlo methods, 3D image processing, Process control

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Proceedings Article | 14 April 2014 Paper

Optimizing hybrid metrology through a consistent multi-tool parameter set and uncertainty model

R. Silver, B. Barnes, N. Zhang, H. Zhou, A. Vladár, J. Villarrubia, J. Kline, D. Sunday, A. Vaid

Proceedings Volume 9050, 905004 (2014) https://doi.org/10.1117/12.2048225

KEYWORDS: Metrology, Scanning electron microscopy, 3D modeling, Error analysis, Atomic force microscopy, Data modeling, 3D metrology, Model-based design, Critical dimension metrology, Uncertainty analysis

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Proceedings Article | 5 April 2012 Paper

Scanning electron microscopy imaging of ultra-high aspect ratio hole features

Aron Cepler, Benjamin Bunday, Bradley Thiel, John Villarrubia

Proceedings Volume 8324, 83241N (2012) https://doi.org/10.1117/12.916552

KEYWORDS: Particles, Electrons, Signal detection, Scanning electron microscopy, Silicon, Copper, Selenium, Metrology, Interference (communication), Oxides

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Proceedings Article | 5 April 2012 Open Access

Can we get 3D-CD metrology right?

András Vladár, Petr Cizmar, John Villarrubia, Michael Postek

Proceedings Volume 8324, 832402 (2012) https://doi.org/10.1117/12.916537

KEYWORDS: Scanning electron microscopy, Metrology, 3D metrology, Dimensional metrology, Monte Carlo methods, Signal detection, 3D modeling, Critical dimension metrology, Model-based design, Physics

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Proceedings Article | 2 April 2010 Paper

Proximity-associated errors in contour metrology

John Villarrubia, Ronald Dixson, András Vladár

Proceedings Volume 7638, 76380S (2010) https://doi.org/10.1117/12.848406

KEYWORDS: Scanning electron microscopy, Metrology, Scattering, Monte Carlo methods, Atomic force microscopy, Silicon, Critical dimension metrology, Interfaces, Laser scattering, Electron microscopes

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SPIE Journal Paper | 1 July 2009

Sensitivity of scanning electron microscope width measurements to model assumptions

John Villarrubia, Zejun Ding

JM3, Vol. 8, Issue 03, 033003, (July 2009) https://doi.org/10.1117/12.10.1117/1.3190168

KEYWORDS: Monte Carlo methods, Scattering, Scanning electron microscopy, Silicon, Data modeling, Copper, Electron microscopes, Dielectrics, Model-based design, Binary data

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Proceedings Article | 23 March 2009 Paper

Sensitivity of SEM width measurements to model assumptions

J. Villarrubia, Z. J. Ding

Proceedings Volume 7272, 72720R (2009) https://doi.org/10.1117/12.814300

KEYWORDS: Scattering, Monte Carlo methods, Scanning electron microscopy, Silicon, Copper, Data modeling, Binary data, Dielectrics, Model-based design, Physics

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Proceedings Article | 25 March 2008 Paper

Accurate and traceable dimensional metrology with a reference CD-SEM

András Vladár, John Villarrubia, Petr Cizmar, Martin Oral, Michael Postek

Proceedings Volume 6922, 69220H (2008) https://doi.org/10.1117/12.773806

KEYWORDS: Scanning electron microscopy, Semiconducting wafers, Interferometers, Metrology, Signal detection, Electron beams, Laser interferometry, Dimensional metrology, 3D modeling, Calibration

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Proceedings Article | 24 March 2008 Paper

Linewidth roughness and cross-sectional measurements of sub-50 nm structures with CD-SAXS and CD-SEM

Chengqing Wang, Kwang-Woo Choi, Ronald Jones, Christopher Soles, Eric Lin, Wen-li Wu, James Clarke, John Villarrubia, Benjamin Bunday

Proceedings Volume 6922, 69221Z (2008) https://doi.org/10.1117/12.773558

KEYWORDS: Line width roughness, Line edge roughness, Diffraction, X-rays, Critical dimension metrology, Scattering, Sensors, Laser scattering, Extreme ultraviolet lithography, Extreme ultraviolet

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Proceedings Article | 5 April 2007 Paper

Monte Carlo modeling of secondary electron imaging in three dimensions

John Villarrubia, Nicholas Ritchie, Jeremiah Lowney

Proceedings Volume 6518, 65180K (2007) https://doi.org/10.1117/12.712353

KEYWORDS: Scattering, Monte Carlo methods, 3D modeling, Interfaces, Plasmons, Silicon, Scanning electron microscopy, Sensors, Physics, Metrology

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Proceedings Article | 5 April 2007 Paper

Image simulation and surface reconstruction of undercut features in atomic force microscopy

Xiaoping Qian, John Villarrubia, Fenglei Tian, Ronald Dixson

Proceedings Volume 6518, 651811 (2007) https://doi.org/10.1117/12.712399

KEYWORDS: 3D image reconstruction, Atomic force microscopy, 3D image processing, 3D modeling, 3D metrology, Mathematical morphology, Critical dimension metrology, Reconstruction algorithms, Algorithm development, Device simulation

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Proceedings Article | 5 April 2007 Paper

Line edge roughness characterization of sub-50nm structures using CD-SAXS: round-robin benchmark results

Chengqing Wang, Ronald Jones, Eric Lin, Wen-li Wu, John Villarrubia, Kwang-Woo Choi, James Clarke, Bryan Rice, Michael Leeson, Jeanette Roberts, Robert Bristol, Benjamin Bunday

Proceedings Volume 6518, 65181O (2007) https://doi.org/10.1117/12.725380

KEYWORDS: Line width roughness, Line edge roughness, Diffraction, Critical dimension metrology, Photoresist materials, X-rays, Scattering, Satellites, Extreme ultraviolet lithography, Sensors

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SPIE Journal Paper | 1 July 2005

Simulation study of repeatability and bias in the critical dimension scanning electron microscope

John Villarrubia, András Vladár, Michael Postek

JM3, Vol. 4, Issue 03, 033002, (July 2005) https://doi.org/10.1117/12.10.1117/1.2037447

KEYWORDS: Monte Carlo methods, Line scan image sensors, Spatial resolution, Scanning electron microscopy, Microscopy, Device simulation, Manufacturing, Precision measurement, Computer simulations, Electron microscopes

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Proceedings Article | 10 May 2005 Paper

Unbiased estimation of linewidth roughness

J. Villarrubia, B. Bunday

Proceedings Volume 5752, (2005) https://doi.org/10.1117/12.599981

KEYWORDS: Line width roughness, Metrology, Line edge roughness, Scanning electron microscopy, Critical dimension metrology, Error analysis, Edge detection, Semiconductors, Line scan image sensors, Transistors

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Proceedings Article | 10 May 2005 Paper

Influence of focus variation on linewidth measurements

Maki Tanaka, John Villarrubia, Andras Vladar

Proceedings Volume 5752, (2005) https://doi.org/10.1117/12.599741

KEYWORDS: Beam shaping, Critical dimension metrology, Scanning electron microscopy, Gold, Carbon, Mathematical modeling, Line scan image sensors, Data modeling, Spatial resolution, Detection and tracking algorithms

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Proceedings Article | 24 May 2004 Paper

Determination of optimal parameters for CD-SEM measurement of line-edge roughness

Benjamin Bunday, Michael Bishop, Donald McCormack, John Villarrubia, Andras Vladar, Ronald Dixson, Theodore Vorburger, N. Orji, John Allgair

Proceedings Volume 5375, (2004) https://doi.org/10.1117/12.535926

KEYWORDS: Line edge roughness, Line scan image sensors, Line width roughness, Edge roughness, Image segmentation, Critical dimension metrology, Metrology, Edge detection, Image quality, Tolerancing

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The measurement of line-edge roughness (LER) has recently become a topic of concern in the litho-metrology community and the semiconductor industry as a whole. The Advanced Metrology Advisory Group (AMAG), a council composed of the chief metrologists from the International SEMATECH (ISMT) consortium’s Member Companies and from the National Institute of Standards and Technology (NIST), has a project to investigate LER metrics and to direct the critical dimension scanning electron microscope (CD-SEM) supplier community towards a semiconductor industry-backed, standardized solution for implementation. The 2003 International Technology Roadmap for Semiconductors (ITRS) has included a new definition for roughness. The ITRS envisions root mean square measurements of edge and width roughness. There are other possible metrics, some of which are surveyed here. The ITRS envisions the root mean square measurements restricted to roughness wavelengths falling within a specified process-relevant range and with measurement repeatability better than a specified tolerance. This study addresses the measurement choices required to meet those specifications. An expression for the length of line that must be measured and the spacing of measurement positions along that length is derived. Noise in the image is shown to produce roughness measurement errors that have both random and nonrandom (i.e., bias) components. Measurements are reported on both UV resist and polycrystalline silicon in special test patterns with roughness typical for those materials. These measurements indicate that the sensitivity of a roughness measurement to noise depends importantly both on the choice of edge detection algorithm and the quality of the focus. Measurements are less sensitive to noise when a model-based or sigmoidal fit algorithm is used and when the images are in good focus. Using the measured roughness characteristics for UV resist lines and applying the ITRS requirements for the 90 nm technology node, the derived expression for sampling length and sampling interval implies that a length at least 8 times the node (i.e., 720 nm) must be measured at intervals of 7.5 nm or less.

Proceedings Article | 24 May 2004 Paper

Dimensional metrology of resist lines using a SEM model-based library approach

John Villarrubia, Andras Vladar, Benjamin Bunday, Michael Bishop

Proceedings Volume 5375, (2004) https://doi.org/10.1117/12.536871

KEYWORDS: Scanning electron microscopy, Electron beams, Model-based design, Silicon, Dimensional metrology, Statistical modeling, Metrology, Monte Carlo methods, Manufacturing, Semiconducting wafers

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Proceedings Article | 15 July 2003 Paper

CD-SEM measurement line-edge roughness test patterns for 193 nm lithography

Benjamin Bunday, Michael Bishop, John Villarrubia, Andras Vladar

Proceedings Volume 5041, (2003) https://doi.org/10.1117/12.485234

KEYWORDS: Line edge roughness, Reticles, Line width roughness, Scanning electron microscopy, Line scan image sensors, Edge roughness, Signal to noise ratio, Binary data, Lithography, Semiconductors

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Proceedings Article | 2 June 2003 Paper

New way of handling dimensional measurement results for integrated circuit technology

Andras Vladar, John Villarrubia, Michael Postek

Proceedings Volume 5038, (2003) https://doi.org/10.1117/12.485021

KEYWORDS: Metrology, Standards development, Scanning electron microscopy, Integrated circuits, Dimensional metrology, Electron microscopes, Process control, Error analysis, Semiconducting wafers, Precision measurement

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Proceedings Article | 2 June 2003 Paper

CD-SEM measurement line-edge roughness test patterns for 193-nm lithography

Benjamin Bunday, Michael Bishop, John Villarrubia, Andras Vladar

Proceedings Volume 5038, (2003) https://doi.org/10.1117/12.485007

KEYWORDS: Line edge roughness, Reticles, Line width roughness, Edge roughness, Line scan image sensors, Scanning electron microscopy, Signal to noise ratio, Binary data, Lithography, Metrology

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Proceedings Article | 2 June 2003 Paper

Simulation study of repeatability and bias in the CD-SEM

John Villarrubia, Andras Vladar, Michael Postek

Proceedings Volume 5038, (2003) https://doi.org/10.1117/12.485012

KEYWORDS: Monte Carlo methods, Line scan image sensors, Spatial resolution, Microscopy, Device simulation, Manufacturing, Model-based design, Precision measurement, Computer simulations, Scanning electron microscopy

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Proceedings Article | 16 July 2002 Paper

Scanning electron microscope analog of scatterometry

John Villarrubia, Andras Vladar, Jeremiah Lowney, Michael Postek

Proceedings Volume 4689, (2002) https://doi.org/10.1117/12.473470

KEYWORDS: Scanning electron microscopy, Scatterometry, Scattering, Model-based design, Line edge roughness, Light scattering, Electron microscopes, Monte Carlo methods, Silicon, Edge roughness

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Proceedings Article | 22 August 2001 Paper

Edge determination for polycrystalline silicon lines on gate oxide

John Villarrubia, Andras Vladar, Jeremiah Lowney, Michael Postek

Proceedings Volume 4344, (2001) https://doi.org/10.1117/12.436738

KEYWORDS: Scanning electron microscopy, Silicon, Monte Carlo methods, Oxides, Line scan image sensors, Electron beams, Metrology, Statistical modeling, Signal to noise ratio, Mathematical modeling

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Proceedings Article | 2 June 2000 Paper

Is a production-level scanning electron microscope linewidth standard possible?

Michael Postek, Andras Vladar, John Villarrubia

Proceedings Volume 3998, (2000) https://doi.org/10.1117/12.386452

KEYWORDS: Scanning electron microscopy, Standards development, Metrology, Semiconductors, Electron microscopes, Instrument modeling, Calibration, Semiconducting wafers, Manufacturing, Visual process modeling

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Proceedings Article | 2 June 2000 Paper

Linewidth measurement intercomparison on a BESOI sample

John Villarrubia, Andras Vladar, Jeremiah Lowney, Michael Postek, Richard Allen, Michael Cresswell, Rathindra Ghoshtagore

Proceedings Volume 3998, (2000) https://doi.org/10.1117/12.386488

KEYWORDS: Scanning electron microscopy, Bridges, Silicon, Statistical modeling, Instrument modeling, Oxides, Contamination, Image segmentation, Resistance, Crystals

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Proceedings Article | 30 November 1999 Paper

Grating pitch measurements with the molecular measuring machine

John Kramar, Jau-Shi Jun, William Penzes, Fredric Scire, E. Clayton Teague, John Villarrubia

Proceedings Volume 3806, (1999) https://doi.org/10.1117/12.371144

KEYWORDS: Motion measurement, Metrology, Interferometers, Scanning tunneling microscopy, Chromium, Standards development, Distance measurement, Actuators, Vibration isolation, Optical alignment

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Proceedings Article | 14 June 1999 Paper

Toward nanometer accuracy measurements

John Kramar, Edward Amatucci, David Gilsinn, Jau-Shi Jun, William Penzes, Fredric Scire, E. Clayton Teague, John Villarrubia

Proceedings Volume 3677, (1999) https://doi.org/10.1117/12.350791

KEYWORDS: Interferometers, Metrology, Scanning tunneling microscopy, Motion measurement, Digital signal processing, Control systems, Temperature metrology, Chromium, Actuators, Data acquisition

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Proceedings Article | 14 June 1999 Paper

Intercomparison of SEM, AFM, and electrical linewidths

John Villarrubia, Ronald Dixson, Samuel Jones, Jeremiah Lowney, Michael Postek, Richard Allen, Michael Cresswell

Proceedings Volume 3677, (1999) https://doi.org/10.1117/12.350846

KEYWORDS: Scanning electron microscopy, Atomic force microscopy, Bridges, Image segmentation, Silicon, Resistance, Crystals, Oxides, Metrology, Contamination

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Proceedings Article | 8 June 1998 Paper

Strategy for faster blind reconstruction of tip geometry for scanned probe microscopy

John Villarrubia

Proceedings Volume 3332, (1998) https://doi.org/10.1117/12.308727

KEYWORDS: Microscopy, Scanning probe microscopy, Particles, Scanning tunneling microscopy, Thin films, Spherical lenses, Polishing, Atomic force microscopy, Metrology, Semiconductors

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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 | 21 May 1996 Paper

Electrical test structures replicated in silicon-on-insulator material

Michael Cresswell, Jeffry Sniegowski, Rathindra Ghoshtagore, Richard Allen, Loren Linholm, John Villarrubia

Proceedings Volume 2725, (1996) https://doi.org/10.1117/12.240117

KEYWORDS: Silicon, Etching, Semiconducting wafers, Metrology, Photomasks, Crystals, Oxides, Silicon films, Calibration, Optical lithography

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Proceedings Article | 22 May 1995 Paper

Progress on accurate metrology of pitch, height, roughness, and width artifacts using an atomic force microscope

Jason Schneir, Thomas McWaid, Ronald Dixson, Vincent Tsai, John Villarrubia, Ellen Williams, E. Fu

Proceedings Volume 2439, (1995) https://doi.org/10.1117/12.209224

KEYWORDS: Calibration, Metrology, Atomic force microscopy, Surface roughness, Interferometers, Atomic force microscope, Standards development, Polarization, Capacitance, Digital signal processing

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