Dr. Christopher Neil Anderson Profile

Dr. Christopher Neil Anderson

Vice President of Photon Systems at xLight Inc

SPIE Involvement:

Conference Program Committee | Author

Publications (35)

Proceedings Article | 10 April 2024 Presentation + Paper

On the compatibility of free-electron lasers with EUV scanners

Christopher Anderson

Proceedings Volume 12953, 129530T (2024) https://doi.org/10.1117/12.3012412

KEYWORDS: Speckle, Light sources and illumination, Free electron lasers, Photomasks, Scanners, Picosecond phenomena, Speckle pattern, Extreme ultraviolet lithography, Laser scanners, Projection systems

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Proceedings Article | 9 April 2024 Presentation + Paper

Advanced processes in metal-oxide resists for high-NA EUV lithography

Cong Que Dinh, Seiji Nagahara, Kayoko Cho, Hikari Tomori, Yuhei Kuwahara, Tomoya Onitsuka, Soichiro Okada, Shinichiro Kawakami, Arisa Hara, Seiji Fujimoto, Makoto Muramatsu, Reiko Tsuzuki, Xiang Liu, Arame Thiam, Yannick Feurprier, Kathleen Nafus, Michael Carcasi, Lior Huli, Kanzo Kato, Alexandra Krawicz, Michael Kocsis, Peter De Schepper, Lauren McQuade, Kazuki Kasahara, Jara Garcia Santaclara, Rik Hoefnagels, Bruno La Fontaine, Ryan Miyakawa, Chris Anderson, Patrick Naulleau

Proceedings Volume 12957, 1295705 (2024) https://doi.org/10.1117/12.3010207

KEYWORDS: Extreme ultraviolet lithography, Extreme ultraviolet, Inspection, Tin, Lithography, Etching

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One of the key steps in the pattern formation chain of extreme ultraviolet (EUV) lithography is the development process to resolve the resist pattern after EUV exposure. The traditional development process might be insufficient to achieve the requirements of ultra-high-resolution features with low defect levels. The aim of this paper is to establish a process to achieve a good roughness, a low defectivity at a low EUV dose, and capability for extremely-high-resolution for high numerical aperture (NA) and hyper-NA EUV lithography. A new development method named ESPERT™ (Enhanced Sensitivity develoPER Technology™) has been introduced to improve the performance of metal oxide-resists (MOR). ESPERT™ as a chemical super resolution technique effectively apodized the MOR chemical image, improving chemical gradient (higher exposure latitude (EL)) and reducing scums (fewer bridge defects). This new development method can also keep the resist profile vertical to mitigate the break defects. The performances of the conventional development and ESPERT™ were evaluated and compared using 0.33 NA EUV, 0.5 NA EUV, and electron beam (EB) exposures, for all line-space (LS), contact hole (CH), and pillar (PL) patterns. Using 0.33 NA EUV scanners on LS patterns, both bridge and break defects were confirmed to be reduced for all 32-nm-pitch, 28-nm-pitch, 26-nm-pitch LS patterns while reducing the EUV dose to size (DtS). In the electrical yield (1 meter length) test of breaks/bridges of 26-nm pitch structures, ESPERT™ reduced EUV dose while its combo yield was almost 100% over a wide dose range of 20mJ/cm². For CH patterns, in the case of 32-nm-pitch AEI (after etch inspection), EL was increased 7.5% up to 22.5%, while failure free latitude (FFL) was widened from 1-nm to 4-nm. A 16-nm-pitch LS pattern was successfully printed with 0.5 NA tool, while a 16-nm-pitch PL and an 18-nm-pitch CH patterns were also achieved with an EB lithography by ESPERT™. With ESPERT™, there was no pillar collapse observed for 12-nm half-pitch PL by 0.5 NA and 8-nm half-pitch PL by EB. With all the advantages of having a high exposure sensitivity, a low defectivity, and an extremely-high-resolution capability, this advanced development method is expected be a solution for high-NA EUV towards hyper-NA EUV lithography.

Proceedings Article | 1 May 2023 Paper

Advanced development methods for high-NA EUV lithography

Cong Que Dinh, Seiji Nagahara, Yuhei Kuwahara, Arnaud Dauendorffer, Soichiro Okada, Seiji Fujimoto, Shinichiro Kawakami, Satoru Shimura, Makoto Muramatsu, Kayoko Cho, Xiang Liu, Kathleen Nafus, Michael Carcasi, Ankur Agarwal, Mark Somervell, Lior Huli, Kanzo Kato, Michael Kocsis, Peter De Schepper, Stephen Meyers, Lauren McQuade, Kazuki Kasahara, Jara Garcia Santaclara, Rik Hoefnagels, Chris Anderson, Patrick Naulleau

Proceedings Volume 12498, 1249806 (2023) https://doi.org/10.1117/12.2655928

KEYWORDS: Extreme ultraviolet lithography, Extreme ultraviolet, Line width roughness, Line edge roughness, Lithography, Etching

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One of the key steps in the pattern formation chain of (extreme ultraviolet) EUV lithography is the development process to resolve the resist pattern after EUV exposure. A simple traditional development process might not be sufficient to achieve the requirements of an ultra-high-resolution feature with low defect levels in high numerical aperture (NA) EUV lithography. In our previous literature, a new development method named ESPERT^TM (Enhanced Sensitivity develoPER Technology^TM) has been introduced to improve the performance of metal oxide resists (MOR) for 0.33 NA EUV lithography by breaking the dose-roughness trade-off. In this work, this development technique was optimised for high-NA lithography to not only keep the advantages of previous ESPERT^TM version, but also reduce the defect levels at a higher EUV sensitivity. This is made possible thanks to the capability of the new version of ESPERT^TM that can easily remove the residue (undeveloped resist) at low exposure dose area to enhance the developing contrast. Using 0.33 NA EUV scanners at imec on 16-nm half-pitch (HP) line/space (L/S) patterns, with the new development method, EUV dose-to-size (DtS) was reduced roughly 16%, and total after-development-inspection (ADI) defects was reduced by a factor of approximately 7, simultaneously. In another condition, DtS was reduced from 44.2 to 28.4 mJ/cm² (an improvement of 36%), while the number of after-etch-inspection (AEI) single-bridge defects was reduced by half, simultaneously. Using the 0.5 NA exposure tool at Lawrence Berkeley National Laboratory with this new development method, the exposure sensitivity and line-width-roughness (LWR) were both improved by 30% and 21%, respectively. An 8-nm-HP L/S pattern was also successfully printed by this high NA tool. Using a 150 kV electron-beam (EB) lithography system, a 12-nm-HP of pillars was successfully printed on a 22-nm-thick MOR resist with ESPERT^TM. With all the advantages of having a high exposure sensitivity, a low defectivity, and an ultra-high-resolution capability, this new development method is expected to be a solution for high-NA EUV lithography.

Proceedings Article | 1 December 2022 Presentation + Paper

The trade-off between local critical dimension uniformity and sensitivity for contact hole high-NA printing in chemically amplified resists

Chawon Koh, Jinkyu Han, Jinmo Kim, Cheolhong Park, Eunju Kim, Tsunehiro Nishi, Chris Anderson, Patrick Naulleau

Proceedings Volume 12292, 1229203 (2022) https://doi.org/10.1117/12.2641648

KEYWORDS: Scanning electron microscopy, Nanoimprint lithography, Photomasks, Optical lithography, Printing, Extreme ultraviolet, Chemically amplified resists, Stochastic processes, Extreme ultraviolet lithography, Diffusion

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Proceedings Article | 11 November 2022 Presentation

Berkeley MET5 enters mature phase of research

Christopher Anderson

Proceedings Volume PC12292, PC1229206 (2022) https://doi.org/10.1117/12.2643076

KEYWORDS: Semiconducting wafers, Optical alignment, Metrology, Image processing, Ecosystems, Diagnostics, Computer security, Calibration

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Proceedings Article | 22 February 2021 Presentation + Paper

EUV dark field lithography: extreme resolution by blocking 0th order

Timothy Brunner, Jara Santaclara, Gerardo Bottiglieri, Chris Anderson, Patrick Naulleau

Proceedings Volume 11609, 1160906 (2021) https://doi.org/10.1117/12.2582751

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We have used the MET5 exposure system using “dark field” lithography, where a small σ=0.1 source is wholly contained in the 30% Central Obscuration of the 0.5NA mirror optics. One goal of this paper is to quantify and explain the superior image contrast of dark field lithography over normal dipole imagery. We demonstrate that almost ideal grating images can be obtained over the pitch range from 15 to 25nm. With the x-polarized source, gratings with Horizontal lines (TE polarized) have the best image contrast, while Vertical lines (TM polarized) have lesser contrast, showing less contrast as pitch decreases. By comparing lines of different orientation, the impact of polarization on lithography can be assessed. At the 16nm pitch, the experimental data showed roughly 20% improvement of the LWR metric for TE over TM. Besides the image contrast, we also calculate the effective contrast C_eff by folding in a Gaussian resist blur. These calculations highlight the need to find resist processes with small blur, e.g. with σ < 3nm. Exposure latitude scales with C_eff, as does LWR, LCDU and stochastic defect levels. Therefore optimization of C_eff, at the small pitches needed for production, is of high importance. We have also looked at dense arrays of bright spots produced with dark field imaging, which can produce either dense contact holes or dense pillars depending on the resist process tone. Our experimental results used a negative tone Metal Oxide resist process to print pillar arrays with pitches of 22, 24 and 26nm. Our experiments, and most of our simulations, were done with a standard EUV mask using a Ta-based absorber. Additional simulations explored the use of alternative absorber materials which can increase the dark field image intensity. For example, 25nm thick Ru absorber can more than double the image intensity relative to Ta absorber. The MET5 dark field litho imaging method is well-suited for testing resist processes in advance of the high NA tool availability. Both dense line gratings and dense hole/pillar array images can be imaged with good image contrast. However, pure dark field imaging is not capable of producing all the patterns needed for production, such as the larger pitch structures needed for overlay and alignment marks. On the other hand, there is a kind of “partial” dark field imagery that is very promising for production imaging with the high NA tool. Allowing Source Mask Optimization (SMO) software to include source points within the obscured part of the pupil, i.e. “dark field source points”, implements this capability in a very natural way and seems attractive for High Volume Manufacturing (HMV) applications with the high NA tool in the near future.

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 | 16 October 2019 Presentation

Status and performance of the 0.5-NA EUV microfield exposure tool at Berkeley Lab (Conference Presentation)

Christopher Anderson

Proceedings Volume 11147, 1114712 (2019) https://doi.org/10.1117/12.2538717

KEYWORDS: Extreme ultraviolet lithography, Lithography, Photoresist materials, Robotic systems, Robotics, Printing

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SPIE Journal Paper | 3 May 2019 Open Access

Reconstructing the three-dimensional latent image of extreme ultraviolet resists with resonant soft x-ray scattering

Guillaume Freychet, Isvar Cordova, Terry McAfee, Dinesh Kumar, Ronald Pandolfi, Chris Anderson, Scott Dhuey, Patrick Naulleau, Cheng Wang, Alexander Hexemer

JM3, Vol. 18, Issue 02, 024003, (May 2019) https://doi.org/10.1117/12.10.1117/1.JMM.18.2.024003

KEYWORDS: Scattering, X-rays, 3D image reconstruction, Extreme ultraviolet, X-ray imaging, Extreme ultraviolet lithography, 3D image processing, Modulation, Carbon, Image enhancement

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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 | 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 | 12 October 2018 Presentation

Berkeley MET5 update: commissioning, interferometry, and first prints (Conference Presentation)

Ryan Miyakawa, Wenhua Zhu, Geoff Gaines, Chris Anderson, Patrick Naulleau

Proceedings Volume 10809, 1080911 (2018) https://doi.org/10.1117/12.2501953

KEYWORDS: Wavefronts, Error analysis, Interferometry, Data modeling, Extreme ultraviolet, Shearing interferometers, Monochromatic aberrations, Projection lithography, Objectives, Optical resolution

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The Berkeley MET5, funded by EUREKA, is the world’s highest-resolution EUV projection lithography tool. With a 0.5-numerical aperture (NA) Schwartzchild objective, the Berkeley MET5 is capable of delivering 8-nm resolution for dense line/space patterns. In order to achieve this resolution, optical aberrations must be accurately characterized and compensated, a task that is complicated by the difficulty in finding a bright, high quality reference wave, and nonlinear effects associated with high incident angles on interferometry targets. The Berkeley MET5 was designed with an in-situ lateral shearing interferometer (LSI) to provide real-time wavefront diagnostics alongside its imaging capabilities. The geometry of the MET5 makes it a particularly difficult optical system to measure interferometrically. Unlike EUV production tools, the 2-bounce Schwartzchild design is non-telecentric at the image, with an image plane whose normal vector is tilted 1.12 degrees with respect to the optical axis. Shearing interferometers have shown good results measuring EUV wavefronts at low to medium NAs (0.1 - 0.33) with telecentric geometry. However, to accommodate the MET5 geometry, a generalized model of LSI was developed to inform the design and build of a lateral shearing interferometer capable of operating at high-NA and with a tilted image plane. This model predicts non-negligible systematic errors that must be compensated in the analysis. Specialized pinhole arrays were patterned onto the mask to fill the pupil with spatially filtered light that is incoherently multiplexed from multiple apertures. Due to the relatively large amount of DC flare compared with the signal in the interferograms, illumination profiles were chosen to match the NA of the obscuration so that zero-order light coming through the mask absorber is blocked in the pupil, which results in a finite coherence function width. Because of this, the design of the arrays required balancing the efficiency of the pattern while maintaining enough separation between apertures to accommodate the coherence function width. Analysis of the interferometric data shows a total RMS wavefront error of 0.6 nm after removal of systematic errors predicted by the LSI model. The bulk of this error lies in astigmatism and coma terms which can be corrected by field position and small adjustments to the alignment of the Schwartzchild optic respectively. The aberration signature of this wavefront is in good agreement with preliminary print data of aberration targets according to aerial image modeling of these features. The interferometric capability of the Berkeley MET5 is an indispensable part of commissioning the tool, and will allow for the diagnosing and monitoring of tool performance as it begins user operations in the coming months.

Proceedings Article | 9 October 2018 Presentation + Paper

Using resonant soft x-ray scattering to image patterns on undeveloped resists

Guillaume Freychet, Isvar Cordova, Terry McAfee, Dinesh Kumar, Ronald Pandolfi, Chris Anderson, Patrick Naulleau, Cheng Wang, Alexander Hexemer

Proceedings Volume 10809, 108090V (2018) https://doi.org/10.1117/12.2502769

KEYWORDS: Scattering, X-rays, Extreme ultraviolet lithography, Modulation, Extreme ultraviolet, Carbon, X-ray imaging, Absorption, 3D image reconstruction, Laser scattering

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Proceedings Article | 27 March 2017 Presentation + Paper

High-NA metrology and sensing on Berkeley MET5

Ryan Miyakawa, Chris Anderson, Patrick Naulleau

Proceedings Volume 10143, 101430N (2017) https://doi.org/10.1117/12.2261893

KEYWORDS: Wavefronts, Metrology, Interferometry, Extreme ultraviolet, Optical testing, Wavefront sensors, Sensors, Inspection, Semiconducting wafers, Shearing interferometers, Monochromatic aberrations

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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 | 23 March 2012 Paper

The SEMATECH Berkeley MET: demonstration of 15-nm half-pitch in chemically amplified EUV resist and sensitivity of EUV resists at 6.x-nm

Chris Anderson, Dominic Ashworth, Lorie Mae Baclea-An, Suchit Bhattari, Rikos Chao, Rene Claus, Paul Denham, Ken Goldberg, Andrew Grenville, Gideon Jones, Ryan Miyakawa, Ken Murayama, Hiroki Nakagawa, Senajith Rekawa, Jason Stowers, Patrick Naulleau

Proceedings Volume 8322, 832212 (2012) https://doi.org/10.1117/12.917386

KEYWORDS: Chemically amplified resists, Extreme ultraviolet, Mass attenuation coefficient, Optical lithography, Chemical elements, Extreme ultraviolet lithography, Phase shifts, Photomasks, Printing, Reticles

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Proceedings Article | 16 April 2011 Paper

Critical challenges for EUV resist materials

Patrick Naulleau, Christopher Anderson, Lorie-Mae Baclea-an, Paul Denham, Simi George, Kenneth Goldberg, Gideon Jones, Brittany McClinton, Ryan Miyakawa, Seno Rekawa, Nate Smith

Proceedings Volume 7972, 797202 (2011) https://doi.org/10.1117/12.882955

KEYWORDS: Line edge roughness, Extreme ultraviolet, Chemically amplified resists, Extreme ultraviolet lithography, Photons, Printing, Synchrotrons, Imaging spectroscopy, Stochastic processes, Light sources

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Proceedings Article | 8 April 2011 Paper

Photoresist shrinkage effects at EUV

Thomas Pistor, Thomas Wallow, Christopher Anderson, Patrick Naulleau

Proceedings Volume 7969, 796917 (2011) https://doi.org/10.1117/12.879554

KEYWORDS: Distortion, Extreme ultraviolet lithography, 3D modeling, Photoresist materials, Extreme ultraviolet, Lithography, Silicon, Lanthanum, Current controlled current source, Electron beams

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Proceedings Article | 8 April 2011 Paper

Low-speckle holographic beam shaping of high-coherence EUV sources

Christopher Anderson, Ryan Miyakawa, Patrick Naulleau

Proceedings Volume 7969, 796938 (2011) https://doi.org/10.1117/12.881553

KEYWORDS: Holograms, Speckle, Extreme ultraviolet, Holographic optical elements, Diffraction, Speckle pattern, Holography, Binary data, Beam shaping, Modulation

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Proceedings Article | 7 April 2011 Paper

Directly patterned inorganic hardmask for EUV lithography

Jason Stowers, Alan Telecky, Michael Kocsis, Benjamin Clark, Douglas Keszler, Andrew Grenville, Chris Anderson, Patrick Naulleau

Proceedings Volume 7969, 796915 (2011) https://doi.org/10.1117/12.879542

KEYWORDS: Etching, Extreme ultraviolet lithography, Semiconducting wafers, Metals, Extreme ultraviolet, Oxides, Absorption, Coating, Photons, Photoresist processing

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Proceedings Article | 5 April 2011 Paper

The SEMATECH Berkeley MET: extending EUV learning down to 16nm half pitch

Christopher Anderson, Lorie Mae Baclea-An, Paul Denham, Simi George, Kenneth Goldberg, Michael Jones, Nathan Smith, Thomas Wallow, Warren Montgomery, Patrick Naulleau

Proceedings Volume 7969, 79690R (2011) https://doi.org/10.1117/12.881573

KEYWORDS: Printing, Illumination engineering, Metals, Oxides, Extreme ultraviolet, Chemically amplified resists, Image resolution, Optical lithography, Phase shifts, Modulation

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Proceedings Article | 2 April 2011 Paper

Using synchrotron light to accelerate EUV resist and mask materials learning

Patrick Naulleau, Christopher Anderson, Lorie-Mae Baclea-an, Paul Denham, Simi George, Kenneth Goldberg, Gideon Jones, Brittany McClinton, Ryan Miyakawa, Iacopo Mochi, Warren Montgomery, Seno Rekawa, Tom Wallow

Proceedings Volume 7985, 798509 (2011) https://doi.org/10.1117/12.885420

KEYWORDS: Extreme ultraviolet lithography, Line edge roughness, Extreme ultraviolet, Photomasks, Synchrotrons, Light sources, Printing, Chemically amplified resists, Image resolution, Imaging systems

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Proceedings Article | 23 March 2010 Paper

The SEMATECH Berkeley MET pushing EUV development beyond 22nm half pitch

Patrick Naulleau, Christopher Anderson, Lorie-Mae Baclea-an, David Chan, Paul Denham, Simi George, Kenneth Goldberg, Brian Hoef, Gideon Jones, Chawon Koh, Bruno La Fontaine, Brittany McClinton, Ryan Miyakawa, Warren Montgomery, Seno Rekawa, Tom Wallow

Proceedings Volume 7636, 76361J (2010) https://doi.org/10.1117/12.848438

KEYWORDS: Line edge roughness, Photomasks, Extreme ultraviolet, Printing, Phase shifts, Lithographic illumination, Extreme ultraviolet lithography, Image resolution, Mask cleaning, Resolution enhancement technologies

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Proceedings Article | 20 March 2010 Paper

Corner rounding in EUV photoresist: tuning through molecular weight, PAG size, and development time

Christopher Anderson, Joe Daggett, Patrick Naulleau

Proceedings Volume 7636, 763617 (2010) https://doi.org/10.1117/12.848362

KEYWORDS: Photoresist developing, Extreme ultraviolet lithography, Photoresist materials, Polymers, Extreme ultraviolet, Scanning electron microscopy, Semiconducting wafers, Metrology, X-ray optics, Lithography

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Proceedings Article | 1 April 2009 Paper

Correlation of EUV resist performance metrics in micro-exposure and full-field EUV projection tools

Thomas Wallow, Bill Pierson, Hiroyuki Mizuno, Anita Fumar-Pici, Karen Petrillo, Chris Anderson, Patrick Naulleau, Steven Hansen, Yunfei Deng, Koen van Ingen Schenau, Chiew-Seng Koay, Linda Ohara, Sang-In Han, Robert Watso, Lior Huli, Martin Burkhardt, Obert Wood, Joerg Mallmann, Bart Kessels, Robert Routh, Kevin Cummings

Proceedings Volume 7273, 72733T (2009) https://doi.org/10.1117/12.814457

KEYWORDS: Optical proximity correction, Extreme ultraviolet lithography, Extreme ultraviolet, Data modeling, Lithography, Diagnostics, Photoresist processing, Nanoimprint lithography, Diffusion, Reticles

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Proceedings Article | 23 March 2009 Paper

MOSAIC: a new wavefront metrology

Christopher Anderson, Patrick Naulleau

Proceedings Volume 7272, 72720B (2009) https://doi.org/10.1117/12.814303

KEYWORDS: Wavefronts, Wavefront metrology, Diffraction, Metrology, Spherical lenses, Optical lithography, Model-based design, Monochromatic aberrations, Photomasks, Diffraction gratings

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Proceedings Article | 18 March 2009 Paper

The SEMATECH Berkeley microfield exposure tool: learning at the 22-nm node and beyond

Patrick Naulleau, Christopher Anderson, Lorie-Mae Baclea-an, Paul Denham, Simi George, Kenneth Goldberg, Michael Goldstein, Brian Hoef, Russ Hudyma, Gideon Jones, Chawon Koh, Bruno La Fontaine, Brittany McClinton, Ryan Miyakawa, Warren Montgomery, John Roller, Thomas Wallow, Stefan Wurm

Proceedings Volume 7271, 72710W (2009) https://doi.org/10.1117/12.814232

KEYWORDS: Line edge roughness, Photomasks, Extreme ultraviolet, Extreme ultraviolet lithography, Semiconducting wafers, Printing, Lithography, Computer aided design, Synchrotrons, Surface roughness

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Proceedings Article | 3 April 2008 Paper

Advanced extreme ultraviolet resist testing using the SEMATECH Berkeley 0.3-NA microfield exposure tool

Patrick Naulleau, Christopher Anderson, Jerrin Chiu, Kim Dean, Paul Denham, Kenneth Goldberg, Brian Hoef, Sungmin Huh, Gideon Jones, Bruno LaFontaine, Andy Ma, Dimitra Niakoula, Joo-on Park, Tom Wallow

Proceedings Volume 6921, 69213N (2008) https://doi.org/10.1117/12.773833

KEYWORDS: Line edge roughness, Monochromatic aberrations, Extreme ultraviolet, Photomasks, Printing, Lithography, Extreme ultraviolet lithography, Semiconducting wafers, Projection systems, Wafer-level optics

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Proceedings Article | 28 March 2008 Paper

Film quantum yields of EUV and ultra-high PAG photoresists

Elsayed Hassanein, Craig Higgins, Patrick Naulleau, Richard Matyi, Gregg Gallatin, Gregory Denbeaux, Alin Antohe, Jim Thackeray, Kathleen Spear, Charles Szmanda, Christopher Anderson, Dimitra Niakoula, Matthew Malloy, Anwar Khurshid, Cecilia Montgomery, Emil Piscani, Andrew Rudack, Jeff Byers, Andy Ma, Kim Dean, Robert Brainard

Proceedings Volume 6921, 69211I (2008) https://doi.org/10.1117/12.774099

KEYWORDS: Quantum efficiency, Extreme ultraviolet lithography, Photoresist materials, Extreme ultraviolet, X-rays, Absorbance, Photons, Coating, Reflectometry, Line edge roughness

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Proceedings Article | 26 March 2008 Paper

A high-throughput contact-hole resolution metric for photoresists: full-process sensitivity study

Christopher Anderson, Patrick Naulleau

Proceedings Volume 6923, 69230Z (2008) https://doi.org/10.1117/12.768551

KEYWORDS: Scanning electron microscopy, Electron beams, Extreme ultraviolet lithography, Data modeling, Image resolution, Image analysis, Finite element methods, Extreme ultraviolet, Photoresist materials, Printing

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Proceedings Article | 12 February 2008 Paper

Spin-on-glass smoothing of diamond turned optics for use in the extreme ultraviolet regime

Farhad Salmassi, Christopher Anderson, Eric Gullikson, Patrick Naulleau

Proceedings Volume 6883, 68830F (2008) https://doi.org/10.1117/12.769625

KEYWORDS: Extreme ultraviolet, Reflectivity, Mirrors, Multilayers, EUV optics, Silicon, Diamond, Atomic force microscopy, Surface finishing, Diamond turning

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Proceedings Article | 3 May 2007 Paper

Progress in EUV photoresist technology

Thomas Wallow, Ryoung-han Kim, Bruno LaFontaine, Patrick Naulleau, Chris Anderson, Richard Sandberg

Proceedings Volume 6533, 653317 (2007) https://doi.org/10.1117/12.737189

KEYWORDS: Extreme ultraviolet, Line width roughness, Extreme ultraviolet lithography, Photoresist processing, Modulation transfer functions, Diffusion, Point spread functions, Line edge roughness, Cadmium sulfide, Photoresist technology

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Resist resolution remains a significant issue for EUV. Strong concerns persist regarding the use of chemically amplified resists owing to their diffusion characteristics. Current EUV resist development is focused on a) large-scale screening efforts in an attempt to identify promising platforms and b) refinement and optimization of the processing of these formulations. Resolution arguably remains the parameter of highest importance at this time. The intrinsic resist resolution limit has been claimed to be determined by the resist diffusion length and various metrics have been proposed to characterize this diffusion length as well as resist resolution. Characterization of the intrinsic resolution limit of resists, however, is not a trivial issue due to practical complications such as pattern collapse and top-loss. Here we investigate a variety of resolution and diffusion length metrics and study the correlation between these metrics and observed resist performance when applied to a variety of leading EUV resists. The metrics we study include resist modulation transfer function, corner rounding, through-dose sub-resolution contact printing, iso-focal bias, line-edge-roughness correlation length, and mask error factor. We present an analogous study of resist process refinements. Process refinements are capable of significantly enhancing resolution, expanding process latitude, mitigating resist failure mechanisms, and attenuating line-edge and line-width roughness. Metrics used for correlation of resolution and diffusion length with resist performance show significant utility when applied to process refinement studies as well. Additionally, we show that LWR mitigation can be accomplished in selected EUV resists using post-development surface conditioner rinses. A similar post-development rinse apprach is also demonstrated to reduce pattern collapse at sub-40 nm CDs. Such strategies may become increasingly attractive as CDs shrink toward 32 nm and 22 nm nodes.

Proceedings Article | 21 March 2007 Paper

Extreme ultraviolet interference lithography with incoherent light

Patrick Naulleau, Christopher Anderson, Stephen Horne

Proceedings Volume 6517, 65172T (2007) https://doi.org/10.1117/12.715069

KEYWORDS: Extreme ultraviolet, Lithography, Interferometers, Extreme ultraviolet lithography, Diffraction gratings, Fiber optic illuminators, Spatial coherence, Fringe analysis, Lithographic illumination, Prisms

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Proceedings Article | 20 March 2007 Paper

Lithographic metrics for the determination of intrinsic resolution limits in EUV resists

Patrick Naulleau, Christopher Anderson, Bruno La Fontaine, Ryoung-han Kim, Tom Wallow

Proceedings Volume 6517, 65172N (2007) https://doi.org/10.1117/12.712363

KEYWORDS: Extreme ultraviolet, Point spread functions, Line edge roughness, Modulation transfer functions, Diffusion, Lithography, Extreme ultraviolet lithography, Photoresist processing, Printing, Chemically amplified resists

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Proceedings Article | 15 March 2007 Paper

Recent results from the Berkeley 0.3-NA EUV microfield exposure tool

Patrick Naulleau, Chris Anderson, Kim Dean, Paul Denham, Kenneth Goldberg, Brian Hoef, Bruno La Fontaine, Tom Wallow

Proceedings Volume 6517, 65170V (2007) https://doi.org/10.1117/12.713440

KEYWORDS: Monochromatic aberrations, Line edge roughness, Extreme ultraviolet lithography, Extreme ultraviolet, Fiber optic illuminators, Lithography, Line width roughness, Eye, Critical dimension metrology, Photomasks

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Showing 5 of 35 publications

Conference Committee Involvement (2)

Optical and EUV Nanolithography XXXVIII

24 February 2025 | San Jose, California, United States

Optical and EUV Nanolithography XXXVII

26 February 2024 | San Jose, California, United States

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