Dr. Weilun Chao Profile

Dr. Weilun Chao

Research Scientist at Lawrence Berkeley National Lab

SPIE Involvement:

Author

Publications (63)

Proceedings Article | 13 November 2024 Presentation

A SHARP look at mask-side hyper-NA EUV imaging

Markus Benk, Ryan Miyakawa, Weilun Chao, Bruno La Fontaine

Proceedings Volume PC13215, PC132150L (2024) https://doi.org/10.1117/12.3034709

KEYWORDS: Image sharpness, Extreme ultraviolet lithography, Extreme ultraviolet, Scanners, Refractive index, Photomasks, Multilayers, Coating, Semiconducting wafers, Optical testing

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SPIE Journal Paper | 18 October 2024 Open Access

Characterization of latent image of electron beam resist via critical-dimension resonant soft X-ray scattering

Qi Zhang, Kas Andrle, Weilun Chao, Zhengxing Peng, Warren Holcomb, Ryan Miyakawa, Dinesh Kumar, Alexander Hexemer, Patrick Naulleau, Bruno La Fontaine, Ricardo Ruiz, Cheng Wang

JM3, Vol. 23, Issue 04, 044003, (October 2024) https://doi.org/10.1117/12.10.1117/1.JMM.23.4.044003

KEYWORDS: Scattering, X-rays, X-ray imaging, Stochastic processes, Atomic force microscopy, Extreme ultraviolet lithography, Electron beams, Simulations, Laser scattering, Finite element methods

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Proceedings Article | 8 October 2024 Presentation + Paper

Binary pseudo-random array standards for calibration of 3D optical surface profilers used for metrology with significantly curved x-ray optics

K. Munechika, K. Yamada, S. Rochester, H. Barnard, W. Chao, I. Lacey, C. Pina-Hernandez, P. Takacs, V. Yashchuk

Proceedings Volume 13150, 1315007 (2024) https://doi.org/10.1117/12.3028493

KEYWORDS: Calibration, Fizeau interferometers, Distortion, Mirrors, Metrology, Optical surfaces, Design, Wavefront errors, X-ray optics, X-rays

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High-accuracy metrology is vitally important in manufacturing ultra-high-quality free-form mirrors designed to manipulate x-ray light with nanometer-scale wavelengths. The current capabilities and possibility for improvements in x-ray mirror manufacturing are limited by inherent imperfections of the integrated metrology tools. In the case of Fizeau interferometry, metrology tools are currently calibrated with super-polished flat test-standard/reference mirrors. This is acceptable for measuring slightly curved x-ray optics. However, for even moderately curved aspherical x-ray mirrors the flat-reference calibration is not sufficiently accurate and stitching Fizeau interferometer-based surface metrology is used to mitigate the problem. But still, the retrace and aberration errors, as well as the limited spatial resolution, described with the instrument transfer function (ITF), can be transferred into the optical surface topography of x-ray mirrors obtained in stitching metrology. For ITF calibration, we have developed an original technique, based on test standards structured as two-dimensional (2D) highly-randomized (HR) binary pseudo-random arrays (BPRAs). The technique employs the unique properties of the HR BPRA patterns in the spatial frequency domain., i.e. the inherent 2D power spectral density of the HR BPRA pattern has a deterministic white-noise-like character that allows direct determination of the ITF with uniform sensitivity over the entire spatial frequency range and field-of-view of an instrument. Here, we explore technological, metrological, and analytical aspects essential for calibration of the retrace and aberration errors of Fizeau interferometers using different types of tilted test samples, including a super-polished reference mirror for the re-trace calibration and the uniformly redundant array (URA) BPRA standards for the geometrical distortion (aberration) calibration. While the first method was previously demonstrated by researchers at DIAMOND Light Source, a method based on the URA BPRA is described and demonstrated here for the first time. We outline the design and fabrication process used in fabrication of URA BPRA test standards, and present the results of application of the URA BPRA standards demonstrating the high efficacy of our approach to geometrical distortion calibration of Fizeau interferometers. We also discuss the possible sources of unexpected peculiarities of the systematic errors, including an astigmatic character of the retrace error, observed with Fizeau interferometers at the Advanced Light Source X-Ray Optics Laboratory.

Proceedings Article | 30 September 2024 Paper

Binary pseudo-random array for calibration of interferometers with transmission spheres and cylinders

K. Munechika, S. Rochester, W. Chao, I. Lacey, C. Pina-Hernandez, K. Yamada, M. Biskach, P. Takacs, U. Griesmann, V. Yashchuk

Proceedings Volume 13135, 1313505 (2024) https://doi.org/10.1117/12.3028496

KEYWORDS: Computer generated holography, Fizeau interferometers, Spherical lenses, Fabrication, Microscopes, Calibration, Interferometry, Design, Reflection, Optical surfaces

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SPIE Journal Paper | 20 August 2024

Zone plate-based extreme ultraviolet mask microscope with through-pellicle imaging capability

Markus Benk, Dmytro Zaytsev, Chris Orman, Brandon Vollmer, Daniel Santos, Jeffrey Gamsby, Jeremy Mentz, Farhad Salmassi, Arnaud Allezy, Senajith Rekawa, Ryan Miyakawa, Weilun Chao, Eric Gullikson, Scott Chegwidden, Guojing Zhang, Patrick Naulleau, Bruno La Fontaine

JM3, Vol. 23, Issue 04, 041404, (August 2024) https://doi.org/10.1117/12.10.1117/1.JMM.23.4.041404

KEYWORDS: Microscopes, Extreme ultraviolet, Pellicles, Photomasks, Mirrors, Zone plates, Modulation, Imaging systems, Nanoimprint lithography, Microelectromechanical systems

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Proceedings Article | 10 April 2024 Presentation

Characterization of chemical/structural information of latent image via critical-dimension resonant soft x-ray scattering

Qi Zhang, Weilun Chao, Warren Holcomb, Ryan Miyakawa, Dinesh Kumar, Ricardo Ruiz, Andrew Neureuther, Patrick Naulleau, Cheng Wang

Proceedings Volume 12955, 129550A (2024) https://doi.org/10.1117/12.3010967

KEYWORDS: Scattering, X-rays, X-ray imaging, X-ray characterization, Photoresist materials, X-ray sources, Data modeling, Light scattering, Laser scattering, Extreme ultraviolet lithography

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Proceedings Article | 22 November 2023 Poster

Metrology development on latent images via critical-dimension resonant soft x-ray scattering

Qi Zhang, Weilun Chao, Warren Holcomb, Ryan Miyakawa, Ricardo Ruiz, Dinesh Kumar, Andrew Neureuther, Patrick Naulleau, Cheng Wang

Proceedings Volume PC12750, PC1275012 (2023) https://doi.org/10.1117/12.2689943

KEYWORDS: Scattering, X-rays, X-ray imaging, Metrology, Systems modeling, X-ray sources, X-ray characterization, Time metrology, Spatial resolution, Simulations

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Proceedings Article | 4 October 2023 Presentation + Paper

Binary pseudo-random array (BPRA) for inspection and calibration for cylindrical wavefront interferometry

K. Munechika, S. Rochester, W. Chao, I. Lacey, C. Pina-Hernandez, Kaito Yamada, M. Biskach, A. Numata, V. Yashchuk

Proceedings Volume 12677, 1267708 (2023) https://doi.org/10.1117/12.2677966

KEYWORDS: Metrology, Calibration, Optical surfaces, Microscopes, X-rays, Fabrication, Wavefronts, Mirror surfaces, Interferometry, Semiconducting wafers

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Proceedings Article | 31 October 2022 Poster

Ruthenium attenuated phase-shifting structure fabrication for contact-hole applications

Weilun Chao, Dong-Seok Nam, Sharon Oh, Sarath Samdurala, Eric Gullikson, Farhad Salmassi, Anthony Yen, Patrick Naulleau

Proceedings Volume PC12292, PC122920Y (2022) https://doi.org/10.1117/12.2645263

KEYWORDS: Extreme ultraviolet, Ruthenium, Phase shifts, Photomasks, Stochastic processes, Resolution enhancement technologies, Extreme ultraviolet lithography, Double patterning technology, Reticles, Optical lithography

Proceedings Article | 4 October 2022 Presentation + Paper

Reliability investigation of the instrument transfer function calibration technique based on binary pseudo-random array standards

Valeriy Yashchuk, Keiko Munechika, Simon Rochester, Weilun Chao, Ian Lacey, Carlos Pina-Hernandez, Peter Takacs

Proceedings Volume 12240, 122400D (2022) https://doi.org/10.1117/12.2633476

KEYWORDS: Microscopes, Calibration, Zoom lenses, Interferometry, Spatial frequencies, Deconvolution, Reflectivity, Metrology, Objectives, Binary data

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Proceedings Article | 3 October 2022 Presentation + Paper

Binary pseudo-random array standards for calibration of 3D optical surface profilers used for metrology with aspheric x-ray optics

Keiko Munechika, Weilun Chao, Scott Dhuey, Ian Lacey, Carlos Pina-Hernandez, Simon Rochester, Valeriy Yashchuk

Proceedings Volume 12223, 1222307 (2022) https://doi.org/10.1117/12.2633163

KEYWORDS: Calibration, Metrology, Distortion, Microscopes, X-ray optics, Standards development, X-rays, Mirrors, Interferometry, Spherical lenses

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High-accuracy surface metrology is vitally important in manufacturing ultra-high-quality free-form mirrors designed to manipulate x-ray light with nanometer-scale wavelengths. The current capabilities and possibility for improvements in x˗ray mirror manufacturing are limited by inherent imperfections of the integrated metrology tools. Metrology tools are currently calibrated with super-polished flat test-standard/reference mirrors. This is acceptable for fabrication of slightly curved x-ray optics. However, for even moderately curved aspherical x-ray mirrors the flat-reference calibration is not sufficiently accurate. In the case of micro-stitching interferometry developed for surface measurements with curved xray mirrors, the tool aberration errors are known to be transferred into the optical surface topography of x-ray mirrors. Our approach to improvement of the metrology is to thoroughly calibrate the measuring tool and apply the results of the calibration to gain the reliability of the metrology via calibration-based deconvolution of the measured data. Thus, we explore the application of a recently developed technique for calibrating the instrument’s transfer function (ITF) of 3D optical surface profilers to the metrology with significantly curved x-ray optics. The technique, based on test standards structured as two-dimensional (2D) binary pseudo-random arrays (BPRAs), employs the unique properties of the BPRA patterns in the spatial frequency domain. The inherent 2D power spectral density of the pattern has a deterministic whitenoise-like character that allows direct determination of the ITF with uniform sensitivity over the entire spatial frequency range and field-of-view of an instrument. The high efficacy of the technique has been previously demonstrated in application to metrology with flat and slightly curved optics. Here, we concentrate on development of an efficient fabrication process for production of highly randomized (HR) BPRA test standards on flat and 500-mm spherical optical substrates. We also compare and discuss the results of the ITF calibration of an interferometric microscope when using the HR BPRA standards on flat and curved substrates.

Proceedings Article | 3 October 2022 Presentation + Paper

Characterization of surface texture-measuring optical microscopes using a binary pseudo-random array standard

Ulf Griesmann, Keiko Munechika, T. Brian Renegar, X. Alan Zheng, Johannes Soons, Thomas Germer, Weilun Chao, Ian Lacey, Carlos Pina-Hernandez, Peter Takacs, Valeriy Yashchuk

Proceedings Volume 12223, 1222306 (2022) https://doi.org/10.1117/12.2633411

KEYWORDS: Microscopes, Spatial frequencies, Standards development, Confocal microscopy, Interferometry, Optical microscopes

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Proceedings Article | 13 June 2022 Presentation

Development of a standalone zoneplate based EUV mask defect review tool

Chami Perera, Gi Sung Yoon, Ryan Carlson, Baorui Yang, Mike Hermes, Dave Houser, Alexander Khodarev, Chuck Murray, Travis Grodt, Arnaud Allézy, Weilun Chao, Farhad Salmassi, Eric Gullikson, Patrick Naulleau

Proceedings Volume PC12051, PC120510E (2022) https://doi.org/10.1117/12.2617277

KEYWORDS: Extreme ultraviolet, Photomasks, Reticles, Microscopes, Imaging systems, Zone plates, Semiconductors, Semiconducting wafers, Patents, Metrology

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Proceedings Article | 5 August 2021 Presentation + Paper

Binary pseudo-random array test standard optimized for characterization of interferometric microscopes

Keiko Munechika, Stefano Cabrini, Weilun Chao, Ian Lacey, Carlos Pina-Hernandez, Simon Rochester, Valeriy Yashchuk

Proceedings Volume 11817, 1181704 (2021) https://doi.org/10.1117/12.2594995

KEYWORDS: Microscopes, Calibration, Metrology, Spatial frequencies, Interferometry, Binary data, Deconvolution, Point spread functions, Zoom lenses, X-ray optics

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Proceedings Article | 8 July 2021 Open Access

Single-shot picosecond resolution Fourier transform holographic microscopy with large field of view using a compact soft x-ray laser

Shoujun Wang, Alex Rockwood, Yong Wang, Wei-Lun Chao, Patrick Naulleau, Huanyu Song, Carmen Menoni, Mario Marconi, Jorge Rocca

Proceedings Volume 11886, 118860O (2021) https://doi.org/10.1117/12.2594832

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Proceedings Article | 21 August 2020 Paper

Binary pseudorandom array test standard optimized for characterization of large field-of-view optical interferometers

Valeriy Yashchuk, Sergey Babin, Stefano Cabrini, Weilun Chao, Ulf Griesmann, Ian Lacey, Stefano Marchesini, Keiko Munechika, Carlos Pina-Hernandez, Allen Roginsky

Proceedings Volume 11490, 114900W (2020) https://doi.org/10.1117/12.2568309

KEYWORDS: Modulation transfer functions, Fizeau interferometers, Calibration, Light sources, Interferometers, Spatial frequencies, Metrology, Zoom lenses, Binary data

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Proceedings Article | 23 March 2020 Presentation + Paper

How we are making the 0.5-NA Berkeley mirco-field exposure tool stable and productive

Chris Anderson, Arnaud Allezy, Weilun Chao, Lucas Conley, Carl Cork, Will Cork, Rene Delano, Jason DePonte, Michael Dickinson, Geoff Gaines, Jeff Gamsby, Eric Gullikson, Gideon Jones, Lauren McQuade, Ryan Miyakawa, Patrick Naulleau, Seno Rekawa, Farhad Salmassi, Brandon Vollmer, Daniel Zehm, Wenhua Zhu

Proceedings Volume 11323, 113230B (2020) https://doi.org/10.1117/12.2552125

KEYWORDS: Mirrors, Scanners, Semiconducting wafers, Scanning electron microscopy, Camera shutters, Image processing, Vibration isolation, Projection systems

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Proceedings Article | 9 September 2019 Presentation + Paper

Collaborative development of diffraction-limited beamline optical systems at US DOE light sources

Kenneth Goldberg, Antoine Wojdyla, Diane Bryant, Weilun Chao, Daniele Cocco, Corey Hardin, Daniel Morton, May Ling Ng, Lance Lee, Lahsen Assoufid, Walan Grizolli, Xianbo Shi, Steve Kearney, Michael Wojcik, Yuri Shvyd'ko, Deming Shu, Mourad Idir, Lei Huang

Proceedings Volume 11109, 111090C (2019) https://doi.org/10.1117/12.2530817

KEYWORDS: Mirrors, Wavefronts, Wavefront sensors, Sensors, X-rays, Optical alignment, Monochromatic aberrations, Hard x-rays, Diffraction, Crystals, Adaptive optics

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Proceedings Article | 26 March 2019 Paper

Achieving diffraction-limited performance on the Berkeley MET5

Ryan Miyakawa, Chris Anderson, Wenhua Zhu, Geoff Gaines, Jeff Gamsby, Carl Cork, Gideon Jones, Michael Dickenson, Seno Rekawa, Weilun Chao, Sharon Oh, Patrick Naulleau

Proceedings Volume 10957, 109571X (2019) https://doi.org/10.1117/12.2516384

KEYWORDS: Wavefronts, Diffraction gratings, Interferometry, Shearing interferometers, Optical alignment, Diffraction, Optical design, Sensors, Multiplexing, Monochromatic aberrations

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Proceedings Article | 26 March 2019 Paper

Upgrade to the SHARP EUV mask microscope

Markus Benk, Weilun Chao, Ryan Miyakawa, Kenneth Goldberg, Patrick Naulleau

Proceedings Volume 10957, 109570V (2019) https://doi.org/10.1117/12.2516387

KEYWORDS: Microscopes, Sensors, Extreme ultraviolet, Photomasks, CCD image sensors, Image sensors, Charge-coupled devices, Diffraction, Fiber optic illuminators, Mirrors

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Proceedings Article | 26 March 2019 Presentation + Paper

Overview and status of the 0.5NA EUV microfield exposure tool at Berkeley Lab

Christopher Anderson, Arnaud Allezy, Weilun Chao, Carl Cork, Will Cork, Rene Delano, Jason DePonte, Michael Dickinson, Geoff Gaines, Jeff Gamsby, Eric Gullikson, Gideon Jones, Stephen Meyers, Ryan Miyakawa, Patrick Naulleau, Senajith Rekawa, Farhad Salmassi, Brandon Vollmer, Daniel Zehm, Wenhua Zhu

Proceedings Volume 10957, 1095708 (2019) https://doi.org/10.1117/12.2516339

KEYWORDS: Scanning electron microscopy, Critical dimension metrology, Semiconducting wafers, Extreme ultraviolet lithography, Optical lithography, Monochromatic aberrations, Line width roughness, Photoresist materials, Image processing, Projection systems

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Proceedings Article | 17 September 2018 Presentation + Paper

Design and demonstration of tunable soft x-ray lateral shearing and Hartmann wavefront sensors

Antoine Wojdyla, Diane Bryant, Weilun Chao, Lahsen Assoufid, Daniele Cocco, Mourad Idir, Kenneth Goldberg

Proceedings Volume 10760, 1076003 (2018) https://doi.org/10.1117/12.2321642

KEYWORDS: Wavefronts, Wavefront sensors, Sensors, X-rays, Cameras, Interferometry, Diffraction, Scintillators, Calibration, Diffraction gratings

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Proceedings Article | 13 March 2018 Presentation + Paper

Characterization and imaging of nanostructured materials using tabletop extreme ultraviolet light sources

Robert Karl, Joshua Knobloch, Travis Frazer, Michael Tanksalvala, Christina Porter, Charles Bevis, Weilun Chao, Begoña Abad Mayor, Daniel Adams, Giulia Mancini, Jorge Hernandez-Charpak, Henry Kapteyn, Margaret Murnane

Proceedings Volume 10585, 105850N (2018) https://doi.org/10.1117/12.2297223

KEYWORDS: Acoustics, Extreme ultraviolet, Nanostructures, Diffraction, Coherence imaging, Nickel, Thin films, Wave propagation, Silicon, Nanostructuring

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Proceedings Article | 27 October 2017 Paper

Taking a SHARP look at mask 3D effects

Markus Benk, Weilun Chao, Ryan Miyakawa, Kenneth Goldberg, Patrick Naulleau

Proceedings Volume 10450, 104500Y (2017) https://doi.org/10.1117/12.2281109

KEYWORDS: Photomasks, Extreme ultraviolet, Extreme ultraviolet lithography, Imaging systems, Lenses, Modulation, Reticles, Microscopes, Scanners, EUV optics

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Proceedings Article | 16 October 2017 Presentation

Fabrication and performance of transmission engineered molybdenum-rich phase structures in the EUV regime (Conference Presentation)

Farhad Salmassi, Weilun Chao, Eric Gullikson, Julia Meyer-Ilse, Patrick Naulleau

Proceedings Volume 10450, 104501B (2017) https://doi.org/10.1117/12.2281487

KEYWORDS: Extreme ultraviolet, Molybdenum, Silicon, Atomic layer deposition, Optical components, Phase shifts, Structural engineering, Electron beam lithography, Optical design, Reflection

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For applications in the Extreme Ultraviolet (EUV) region, phase-shift structures play an important role in pushing the throughput and performance of optical systems. While EUV optical elements are typically designed and fabricated for use in reflection, there are important applications in transmission as well where phase shift structures can provide substantial throughput gains. Examples are EUV microscopy and interferometry using gratings or zone plates. In the EUV regime, few materials offer a better combination of phase shift and absorption properties than molybdenum (Mo), however, drawbacks for Mo include crystalline growth complicating the etch process, and ease of oxidation which leads to diminished performance with time. Here we develop a fabrication process for transmission optical elements made of an engineered molybdenum-rich film on free-standing silicon membranes and show the performance of these phase structures in the EUV regime. We chose the fabrication of simple binary gratings of 72nm half pitch (Fig. 1) in order to establish a baseline for performance. We further addressed the oxidation concerns for Mo by developing a process to passivate the surface using atomic layer deposition (ALD) to coat a thin and conformal layer of silicon nitride while incurring minimum throughput loss. The gratings were measured for efficiency in three stages of fabrication at Lawrence Berkeley Laboratory’s Advance Light Source (Beamline 6.3.2) in Berkeley California (Fig. 2). The first measurement was prior to ALD passivation, the second measurement was immediately after passivation, and the third measurement was performed after exposure of the gratings to UV ozone used as an accelerated oxidation test. The conformal coating of silicon nitride was effective in passivating the surface of Mo features. The measurement results show that we were able to achieve a grating efficiency of approximately 18% in the 1st and -1st orders (compared to 8% possible with a conventional absorber grating on Si membrane). The results also demonstrate the effectiveness of the ALD passivation process in mitigating oxidation effects with minimal effect on performance.

Proceedings Article | 16 June 2017 Presentation + Paper

Soft x-ray ablation mass spectrometry: high sensitivity elemental trace analysis

I. Kuznetsov, T. Green, W. Chao, A. Duffin, J. Rocca, C. Menoni

Proceedings Volume 10243, 102430G (2017) https://doi.org/10.1117/12.2267159

KEYWORDS: Laser ablation, Ions, Oxides, Zone plates, Scandium, Nickel, Argon, Glasses, X-ray lasers, Mass spectrometry

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Proceedings Article | 9 September 2016 Paper

Design and implementation of precise x-ray metrology to control a 45-cm long x-ray deformable mirror

Lisa Poyneer, Jaime Ruz Armendariz, Jun Feng, Weilun Chao, Jessie Jackson, James Nasiatka, Todd Decker

Proceedings Volume 9965, 99650G (2016) https://doi.org/10.1117/12.2236568

KEYWORDS: X-rays, Metrology, X-ray optics, Charge-coupled devices, Sensors, Photons, Signal to noise ratio, Calibration, Fringe analysis, Interferometers

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SPIE Journal Paper | 12 July 2016

Emulation of anamorphic imaging on the SHARP extreme ultraviolet mask microscope

Markus Benk, Antoine Wojdyla, Weilun Chao, Farhad Salmassi, Sharon Oh, Yow-Gwo Wang, Ryan Miyakawa, Patrick Naulleau, Kenneth Goldberg

JM3, Vol. 15, Issue 03, 033501, (July 2016) https://doi.org/10.1117/12.10.1117/1.JMM.15.3.033501

KEYWORDS: Photomasks, Extreme ultraviolet, Microscopes, Extreme ultraviolet lithography, Semiconducting wafers, Scanners, Modulation, Multilayers, Fiber optic illuminators, Nickel

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Proceedings Article | 10 May 2016 Paper

Ultrahigh efficiency EUV contact-hole printing with chromeless phase shift mask

Patrick Naulleau, Christopher Anderson, Weilun Chao, Kenneth Goldberg, Eric Gullikson, Farhad Salmassi, Antoine Wojdyla

Proceedings Volume 9984, 99840P (2016) https://doi.org/10.1117/12.2243321

KEYWORDS: Photomasks, Phase shifts, Optical lithography, Extreme ultraviolet, Printing, Chromium, Extreme ultraviolet lithography, Etching, Multilayers, Microscopes

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Proceedings Article | 21 April 2016 Paper

Reliable characterization of materials and nanostructured systems <<50nm using coherent EUV beams

Jorge Hernandez-Charpak, Travis Frazer, Joshua Knobloch, Kathleen Hoogeboom-Pot, Damiano Nardi, Weilun Chao, Lei Jiang, Marie Tripp, Sean King, Henry Kapteyn, Margaret Murnane

Proceedings Volume 9778, 97780I (2016) https://doi.org/10.1117/12.2219434

KEYWORDS: Nanowires, Extreme ultraviolet, Thin films, Metrology, Nanostructuring, Nanostructures, Photoacoustic spectroscopy, Acoustics, Nanostructured thin films, Physics, Laser optics, Phonons, Dielectrics, Thermal effects, Thermal modeling

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Proceedings Article | 18 March 2016 Paper

Emulation of anamorphic imaging on the SHARP EUV mask microscope

Markus Benk, Antoine Wojdyla, Weilun Chao, Farhad Salmassi, Sharon Oh, Yow-Gwo Wang, Ryan Miyakawa, Patrick Naulleau, Kenneth Goldberg

Proceedings Volume 9776, 97761J (2016) https://doi.org/10.1117/12.2219294

KEYWORDS: Photomasks, Extreme ultraviolet lithography, Lenses, Extreme ultraviolet, Microscopes, Scanners, EUV optics, Semiconducting wafers, Modulation, Multilayers, Nickel

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Proceedings Article | 22 September 2015 Paper

Soft x-ray laser ablation mass spectrometry for materials study and nanoscale chemical imaging

Ilya Kuznetsov, Tomas Burian, Libor Juha, Regina Soufli, Jorge Filevich, M. Woolston, Elliot Bernstein, Dean Crick, D. Carlton, W. Chao, E. Anderson, Jorge Rocca, Carmen Menoni

Proceedings Volume 9589, 958905 (2015) https://doi.org/10.1117/12.2188645

KEYWORDS: Laser ablation, Ions, Mass spectrometry, Magnesium, Corrosion, Crystals, X-ray lasers, Laser induced fluorescence, Molecules, Oxides

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Proceedings Article | 20 March 2015 Paper

Revealing beam-induced chemistry using modulus mapping in negative-tone EUV/e-beam resists with and without cross-linker additives

Prashant Kulshreshtha, Ken Maruyama, Scott Dhuey, Dominik Ziegler, Weilun Chao, Paul Ashby, Deirdre Olynick

Proceedings Volume 9425, 94250I (2015) https://doi.org/10.1117/12.2086045

KEYWORDS: Electron beam lithography, Scanning electron microscopy, Scanning probe microscopy, Chemistry, Calibration, Line scan image sensors, Electron beams, Atomic force microscopy, Lithography, Line edge roughness

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Proceedings Article | 19 March 2015 Paper

Mechanical and thermal properties of nanomaterials at sub-50nm dimensions characterized using coherent EUV beams

Kathleen Hoogeboom-Pot, Jorge Hernandez-Charpak, Travis Frazer, Xiaokun Gu, Emrah Turgut, Erik Anderson, Weilun Chao, Justin Shaw, Ronggui Yang, Margaret Murnane, Henry Kapteyn, Damiano Nardi

Proceedings Volume 9424, 942417 (2015) https://doi.org/10.1117/12.2085615

KEYWORDS: Phonons, Extreme ultraviolet, Acoustics, Nanostructures, Tantalum, Nanostructuring, Nickel, Diffraction, Thermal effects, Nanowires

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Proceedings Article | 16 March 2015 Paper

Enhancing defect detection with Zernike phase contrast in EUV multilayer blank inspection

Yow-Gwo Wang, Ryan Miyakawa, Weilun Chao, Markus Benk, Antoine Wojdyla, Alex Donoghue, David Johnson, Kenneth Goldberg, Andy Neureuther, Ted Liang, Patrick Naulleau

Proceedings Volume 9422, 94221C (2015) https://doi.org/10.1117/12.2087532

KEYWORDS: Signal to noise ratio, Phase contrast, Phase shifts, Apodization, Extreme ultraviolet, Inspection, Microscopes, Interference (communication), Absorption, Defect detection

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Proceedings Article | 16 March 2015 Paper

Analysis of shot noise limitations due to absorption count in EUV resists

Suchit Bhattarai, Weilun Chao, Shaul Aloni, Andrew Neureuther, Patrick Naulleau

Proceedings Volume 9422, 942209 (2015) https://doi.org/10.1117/12.2087303

KEYWORDS: Line edge roughness, Extreme ultraviolet, Absorption, Extreme ultraviolet lithography, Electron beam lithography, Plasmons, Lithography, Photons, Photomasks, Spectroscopy

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SPIE Journal Paper | 23 February 2015 Open Access

Broader view on extreme ultraviolet masks: adding complementary imaging modes to the SHARP microscope

Markus Benk, Ryan Miyakawa, Weilun Chao, Yow-Gwo Wang, Antoine Wojdyla, David Johnson, Alexander Donoghue, Kenneth Goldberg

JM3, Vol. 14, Issue 01, 013507, (February 2015) https://doi.org/10.1117/12.10.1117/1.JMM.14.1.013507

KEYWORDS: Phase contrast, Extreme ultraviolet, Microscopes, Digital image correlation, Photomasks, Silicon, Scanning electron microscopy, Phase shifts, Lenses, Point spread functions

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Proceedings Article | 8 October 2014 Paper

Phase-enhanced defect sensitivity for EUV mask inspection

Yow-Gwo Wang, Ryan Miyakawa, Weilun Chao, Kenneth Goldberg, Andy Neureuther, Patrick Naulleau

Proceedings Volume 9235, 92350L (2014) https://doi.org/10.1117/12.2069291

KEYWORDS: Signal to noise ratio, Inspection, Phase shifts, Phase contrast, Photomasks, Apodization, Speckle, Extreme ultraviolet, Interference (communication), Defect inspection

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Proceedings Article | 8 October 2014 Paper

A broader view on EUV-masks: adding complementary imaging modes to the SHARP microscope

Markus Benk, Ryan Miyakawa, Weilun Chao, Yow-Gwo Wang, Antoine Wojdyla, David Johnson, Alexander Donoghue, Kenneth Goldberg

Proceedings Volume 9235, 92350K (2014) https://doi.org/10.1117/12.2065513

KEYWORDS: Phase contrast, Microscopes, Photomasks, Digital image correlation, Extreme ultraviolet, Silicon, Lenses, Scanning electron microscopy, Phase shifts, Point spread functions

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Proceedings Article | 17 April 2014 Paper

Comparative analysis of shot noise in EUV and e-beam lithography

Suchit Bhattarai, Weilun Chao, Andrew Neureuther, Patrick Naulleau

Proceedings Volume 9048, 90481H (2014) https://doi.org/10.1117/12.2048248

KEYWORDS: Extreme ultraviolet, Line edge roughness, Electron beam lithography, Extreme ultraviolet lithography, Point spread functions, Absorption, Binary data, Scattering, Lithography, Laser scattering

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Proceedings Article | 17 April 2014 Paper

Actinic mask imaging: recent results and future directions from the SHARP EUV microscope

Kenneth Goldberg, Markus Benk, Antoine Wojdyla, Iacopo Mochi, Senajith Rekawa, Arnaud Allezy, Michael Dickinson, Carl Cork, Weilun Chao, Daniel Zehm, James Macdougall, Patrick Naulleau, Anne Rudack

Proceedings Volume 9048, 90480Y (2014) https://doi.org/10.1117/12.2048364

KEYWORDS: Photomasks, Extreme ultraviolet, Microscopes, Lithographic illumination, Mirrors, Fiber optic illuminators, Coherence (optics), Lenses, Extreme ultraviolet lithography, Lithography

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Proceedings Article | 12 March 2014 Paper

Flash extreme ultraviolet holographic microscopy in a table top setup

Nils Monserud, Erik Malm, Przemyslaw Wachulak, Huiwen Xu, Ganesh Balakrishnan, Weilun Chao, Erik Anderson, Mario Marconi

Proceedings Volume 8949, 89490K (2014) https://doi.org/10.1117/12.2041698

KEYWORDS: Holography, Extreme ultraviolet, Holograms, Microscopy, Zone plates, Fourier transforms, Scanning electron microscopy, Spatial resolution, Temporal resolution, Oscillators

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Proceedings Article | 7 March 2014 Paper

Periodic nanostructures fabricated by Talbot extreme ultraviolet lithography

W. Li, D. Patel, C. Menoni, A. Stein, W. Chao, E. Anderson, M. Marconi

Proceedings Volume 8973, 89730D (2014) https://doi.org/10.1117/12.2041688

KEYWORDS: Photomasks, Lithography, Nanostructures, Nanolithography, Extreme ultraviolet lithography, Extreme ultraviolet, Imaging systems, Nanoimprint lithography, Photoresist materials, X-ray optics

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Proceedings Article | 30 September 2013 Paper

Analysis of spatial resolution and coherence demands in soft x-ray image-plane holographic microscopy with two zone plates

Jaroslav Nejdl, Isela Howlett, David Carlton, Erik Anderson, Weilun Chao, Mario Marconi, Jorge Rocca, Carmen Menoni

Proceedings Volume 8849, 88490X (2013) https://doi.org/10.1117/12.2024274

KEYWORDS: Zone plates, Holograms, Diffraction, Holography, X-rays, Microscopy, Sensors, Spatial resolution, X-ray microscopy, Digital holography

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Proceedings Article | 27 September 2013 Paper

Coherent nanopatterning with table-top soft x-ray lasers

W. Li, V. Martinez Esquiroz, D. Patel, L. Urbanski, C. Menoni, J. Rocca, A. Stein, W. Chao, E. Anderson, M. Marconi

Proceedings Volume 8849, 88490W (2013) https://doi.org/10.1117/12.2024472

KEYWORDS: Photomasks, Lithography, Nanolithography, Nanostructures, X-ray lasers, Photoresist materials, Extreme ultraviolet, Coherence imaging, Printing, Imaging systems

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Proceedings Article | 27 September 2013 Paper

Composition depth profiling by soft x-ray laser-ablation mass spectrometry

Ilya Kuznetsov, Jorge Filevich, M. Woolston, Elliot Bernstein, Dean Crick, D. Carlton, W. Chao, E. Anderson, Jorge Rocca, Carmen Menoni

Proceedings Volume 8849, 88490G (2013) https://doi.org/10.1117/12.2024535

KEYWORDS: Mass spectrometry, Laser ablation, Profiling, X-ray lasers, Multilayers, Ions, Tin, Aluminum, Metals, Gold

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Proceedings Article | 20 September 2013 Paper

Increased depth of field through wave-front coding: using an off-axis zone plate lens with cubic phase modulation in an EUV microscope

Markus Benk, Kenneth Goldberg, Iacopo Mochi, Weilun Chao, Erik Anderson

Proceedings Volume 8880, 88801R (2013) https://doi.org/10.1117/12.2025954

KEYWORDS: Zone plates, Microscopes, Phase modulation, Wavefronts, Point spread functions, Imaging systems, Extreme ultraviolet, Visible radiation, Optical transfer functions, Modulation

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Proceedings Article | 20 September 2013 Paper

The SEMATECH high-NA actinic reticle review project (SHARP) EUV mask-imaging microscope

Kenneth Goldberg, Iacopo Mochi, Markus Benk, Chihcheng Lin, Arnaud Allezy, Michael Dickinson, Carl Cork, James Macdougall, Erik Anderson, Weilun Chao, Farhad Salmassi, Eric Gullikson, Daniel Zehm, Vamsi Vytla, William Cork, Jason DePonte, Gino Picchi, Ahmet Pekedis, Takeshi Katayanagi, Michael Jones, Elizabeth Martin, Patrick Naulleau, Senajith Rekawa

Proceedings Volume 8880, 88800T (2013) https://doi.org/10.1117/12.2026496

KEYWORDS: Photomasks, Extreme ultraviolet, Microscopes, Coherence (optics), Reticles, Mirrors, Lithographic illumination, Coherence imaging, Optical proximity correction, Diffraction

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Proceedings Article | 1 April 2013 Paper

Commissioning an EUV mask microscope for lithography generations reaching 8 nm

Kenneth Goldberg, Iacopo Mochi, Markus Benk, Arnaud Allezy, Michael Dickinson, Carl Cork, Daniel Zehm, James Macdougall, Erik Anderson, Farhad Salmassi, Weilun Chao, Vamsi Vytla, Eric Gullikson, Jason DePonte, M. S. Gideon Jones, Douglas Van Camp, Jeffrey Gamsby, William Ghiorso, Hanjing Huang, William Cork, Elizabeth Martin, Eric Van Every, Eric Acome, Veljko Milanovic, Rene Delano, Patrick Naulleau, Senajith Rekawa

Proceedings Volume 8679, 867919 (2013) https://doi.org/10.1117/12.2011688

KEYWORDS: Photomasks, Mirrors, Microscopes, Extreme ultraviolet, Fiber optic illuminators, Lenses, Reflectivity, Charge-coupled devices, Coating, Extreme ultraviolet lithography

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Proceedings Article | 29 September 2009 Paper

Advances in full field microscopy with table-top soft x-ray lasers

Carmen Menoni, Fernando Brizuela, Yong Wang, Courtney Brewer, Bradley Luther, Francesco Pedaci, Przemeslaw Wachulak, Mario Marconi, Jorge Rocca, Weilun Chao, Erik Anderson, Yanwei Liu, Kenneth Goldberg, David Attwood, Alexander Vinogradov, Igor Artyukov, Yuri Pershyn, Viktor Kondratenko

Proceedings Volume 7451, 74510I (2009) https://doi.org/10.1117/12.826419

KEYWORDS: Microscopes, Zone plates, Extreme ultraviolet lithography, Objectives, Photomasks, Spatial resolution, X-ray lasers, Microscopy, Modulation, Modulation transfer functions

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Proceedings Article | 18 March 2009 Paper

Inspection 13.2-nm table-top full-field microscope

F. Brizuela, Y. Wang, C. Brewer, F. Pedaci, W. Chao, E. Anderson, Y. Liu, K. Goldberg, P. Naulleau, P. Wachulak, M. Marconi, D. Attwood, J. Rocca, C. Menoni

Proceedings Volume 7271, 72713F (2009) https://doi.org/10.1117/12.814320

KEYWORDS: Microscopes, Spatial resolution, Extreme ultraviolet lithography, Zone plates, Photomasks, Extreme ultraviolet, Image resolution, Inspection, Objectives, Modulation transfer functions

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Proceedings Article | 12 February 2008 Paper

Toward sub-10-nm resolution zone plates using the overlay nanofabrication processes

Weilun Chao, Erik Anderson, Peter Fischer, Dong-Hyun Kim

Proceedings Volume 6883, 688309 (2008) https://doi.org/10.1117/12.768878

KEYWORDS: Zone plates, Optical alignment, Overlay metrology, X-rays, Plating, Diffraction, X-ray imaging, Gold, Nanofabrication, X-ray microscopy

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Proceedings Article | 12 October 2007 Paper

High spatial resolution full-field microscopy using a desktop-size soft x-ray laser

Courtney Brewer, Fernando Brizuela, Dale Martz, Georgiy Vaschenko, Mario Marconi, Weilun Chao, Erik Anderson, David Attwood, Alexander Vinogradov, Igor Artioukov, Yuriy Pershyn, Valeriy Kondratenko, Jorge Rocca, Carmen Menoni

Proceedings Volume 6702, 67020M (2007) https://doi.org/10.1117/12.733422

KEYWORDS: Microscopes, Zone plates, Spatial resolution, X-ray lasers, Microscopy, Image processing, Capillaries, Charge-coupled devices, Objectives, Silicon

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Proceedings Article | 12 October 2007 Paper

Nanoscale ablation with soft x-ray lasers

Fernando Brizuela, Herman Bravo, Georgiy Vaschenko, Mark Berrill, Benjamin Langdon, Carmen Menoni, Oscar Hemberg, Scott Bloom, Weilun Chao, Erik Anderson, David Attwood, Jorge Rocca

Proceedings Volume 6702, 67020L (2007) https://doi.org/10.1117/12.733401

KEYWORDS: Laser ablation, X-ray lasers, Zone plates, Polymethylmethacrylate, Diffraction, Signal attenuation, Silver, Laser induced breakdown spectroscopy, Spectroscopy, Atomic force microscopy

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Proceedings Article | 23 March 2006 Paper

EUV imaging with a 13nm tabletop laser reaches sub-38 nm spatial resolution

Georgiy Vaschenko, Fernando Brizuela, Courtney Brewer, Miguel Larotonda, Yong Wang, Bradley Luther, Mario Marconi, Jorge Rocca, Carmen Menoni, Weilun Chao, Erik Anderson, Yanwei Liu, David Attwood

Proceedings Volume 6151, 61510X (2006) https://doi.org/10.1117/12.656588

KEYWORDS: Extreme ultraviolet, Zone plates, Spatial resolution, Microscopes, Photomasks, Imaging systems, Extreme ultraviolet lithography, Inspection, Plasma, Reflectivity

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Proceedings Article | 23 January 2006 Paper

New nanofabrication technique using overlay for 15-nm zone plate

Weilun Chao, Bruce Harteneck, Erik Anderson, David Attwood, J. Alexander Liddle

Proceedings Volume 6110, 61100D (2006) https://doi.org/10.1117/12.647164

KEYWORDS: Zone plates, Fabrication, Overlay metrology, Spatial resolution, X-ray microscopy, X-rays, Electron beam lithography, Nanofabrication, X-ray imaging, Diffraction

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Proceedings Article | 14 September 2005 Paper

Nanometer-scale imaging with compact soft x-ray lasers

Fernando Brizuela, Georgiy Vaschenko, Courtney Brewer, Michael Grisham, Carmen Menoni, Hector Mancini, Mario Marconi, Jorge Rocca, Weilun Chao, J. Alexander Liddle, Erik Anderson, David Attwood, Alexander Vinogradov, Igor Artioukov, Yuriy Pershyn, Valeriy Kondratenko

Proceedings Volume 5919, 59190N (2005) https://doi.org/10.1117/12.614646

KEYWORDS: Zone plates, Image resolution, X-ray lasers, Imaging systems, Capillaries, Microscopes, X-rays, Spatial resolution, Objectives, Modulation

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Proceedings Article | 23 May 2005 Paper

Direct spatial-temporal observation of Barkhausen avalanche in low-dimensional ferromagnetic system

Dong-Hyun Kim, Bosun Kang, Weilun Chao, Peter Fischer, Erik Anderson, Sug-Bong Choe, Mi-Young Im, Sung-Chul Shin

Proceedings Volume 5843, (2005) https://doi.org/10.1117/12.609637

KEYWORDS: Magnetism, Statistical analysis, Visualization, Spatial resolution, Thin films, Stochastic processes, Microscopes, X-rays, Anisotropy, Ferromagnetics

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Proceedings Article | 10 May 2005 Paper

Nano-imaging with compact extreme ultraviolet laser sources

G. Vaschenko, F. Brizuela, C. Brewer, M. Grisham, Y. Wang, M. Larotonda, B. Luther, C. Menoni, M. Marconi, J. Rocca, W. Chao, J. Liddle, E. Anderson, D. Attwood, A. Vinogradov, I. Artioukov, Y. Pershyn, V. Kondratenko

Proceedings Volume 5752, (2005) https://doi.org/10.1117/12.601899

KEYWORDS: Zone plates, Extreme ultraviolet, Imaging systems, Image resolution, Microscopes, Laser sources, Silicon, Spatial resolution, Objectives, Reflectivity

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Proceedings Article | 13 December 2001 Paper

Experimental analysis of high-resolution soft x-ray microscopy

Weilun Chao, Erik Anderson, Gregory Denbeaux, Bruce Harteneck, Angelic Pearson, Deirdre Olynick, Gerd Schneider, David Attwood

Proceedings Volume 4499, (2001) https://doi.org/10.1117/12.450231

KEYWORDS: Zone plates, X-rays, Microscopes, Gold, Plating, Scanning electron microscopy, X-ray imaging, Mirrors, Silicon, Nickel

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Proceedings Article | 20 August 2001 Paper

Equivalent multilayer bandwidth and comparison between 13.4 nm and 14.4 nm for EUV throughput calculation

Weilun Chao, Eric Gullikson, David Attwood

Proceedings Volume 4343, (2001) https://doi.org/10.1117/12.436637

KEYWORDS: Reflectivity, Mirrors, Extreme ultraviolet, Semiconducting wafers, Photons, Extreme ultraviolet lithography, Interfaces, Integration, Oxides, Chaos

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Proceedings Article | 8 November 2000 Paper

XM-1: the high-resolution soft x-ray microscope at the Advanced Light Source

Angelic Pearson, Weilun Chao, Gregory Denbeaux, Thomas Eimueller, Peter Fischer, Lewis Johnson, Matthias Koehler, Carolyn Larabell, Mark LeGros, Deborah Yager, David Attwood

Proceedings Volume 4146, (2000) https://doi.org/10.1117/12.406672

KEYWORDS: X-rays, Magnetism, Microscopes, Zone plates, Gold, Silver, Spectral resolution, Imaging systems, Absorption, X-ray imaging

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Proceedings Article | 8 November 2000 Paper

High-resolution soft x-ray microscopy

Weilun Chao, Erik Anderson, Gregory Denbeaux, Bruce Harteneck, Mark LeGros, Angelic Pearson, Deirdre Olynick, David Attwood

Proceedings Volume 4146, (2000) https://doi.org/10.1117/12.406671

KEYWORDS: Microscopes, Zone plates, X-rays, X-ray imaging, Scanning electron microscopy, X-ray microscopy, Objectives, Lenses, Mirrors, Nanofabrication

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