Dr. Hiroki Yamamoto Profile

Dr. Hiroki Yamamoto

Researcher at National Institutes for Quantum Science and Technology

SPIE Involvement:

Author

Publications (33)

Proceedings Article | 9 April 2024 Poster + Paper

Study on resist performance of inorganic-organic resist materials for EUV and EB lithography

Hiroki Yamamoto, Yuko Tsutsui Ito, Kazumasa Okamoto, Takahiro Kozawa

Proceedings Volume 12957, 129572F (2024) https://doi.org/10.1117/12.3025195

KEYWORDS: Extreme ultraviolet lithography, Lithography, Metals, Annealing, Extreme ultraviolet, Etching, Reactive ion etching, Particles, Miniaturization, Design

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Proceedings Article | 21 November 2023 Poster + Paper

Comparison of photoresist sensitivity between KrF, EB, and EUV exposure

Yosuke Ohta, Atsushi Sekiguchi, Shinji Yamakawa, Tetsuo Harada, Takeo Watanabe, Hiroki Yamamoto

Proceedings Volume 12750, 1275018 (2023) https://doi.org/10.1117/12.2691211

KEYWORDS: Extreme ultraviolet lithography, Photoresist materials, Photoresist developing, Quantum correlations, Film thickness, Chemically amplified resists, Quantum experiments, Ultraviolet radiation, Quantum numbers, Electrons

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Proceedings Article | 1 May 2023 Poster + Paper

Study on irradiation effects by femtosecond-pulsed extreme ultraviolet in resist materials

Yuji Hosaka, Hiroki Yamamoto, Masahiko Ishino, Thanh-Hung Dinh, Masaharu Nishikino, Akira Kon, Shigeki Owada, Yuichi Inubushi, Yuya Kubota, Yasunari Maekawa

Proceedings Volume 12498, 1249827 (2023) https://doi.org/10.1117/12.2670220

KEYWORDS: Polymethylmethacrylate, Extreme ultraviolet, Extreme ultraviolet lithography, Lithography, Attenuation, Free electron lasers, Film thickness, X-ray lasers, Zirconium, X-rays

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Proceedings Article | 23 March 2020 Paper

Fundamental study on lithographic characteristics of metal oxo clusters for KrF, ArF, and electron beam lithography

Hiroki Yamamoto, Yasunari Maekawa

Proceedings Volume 11326, 113261W (2020) https://doi.org/10.1117/12.2565717

KEYWORDS: Thin films, Silicon, Electron beams, Silicon films, Scanning electron microscopy, Extreme ultraviolet

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SPIE Journal Paper | 12 December 2018

Sensitizers in extreme ultraviolet chemically amplified resists: mechanism of sensitivity improvement

Yannick Vesters, Jing Jiang, Hiroki Yamamoto, Danilo De Simone, Takahiro Kozawa, Stefan De Gendt, Geert Vandenberghe

JM3, Vol. 17, Issue 04, 043506, (December 2018) https://doi.org/10.1117/12.10.1117/1.JMM.17.4.043506

KEYWORDS: Absorption, Photoresist materials, Photons, Extreme ultraviolet, Electrons, Optical lithography, Chemically amplified resists, Extreme ultraviolet lithography, Photoresist developing, Metals

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Proceedings Article | 12 October 2018 Presentation

Pattern formation mechanism of zirconia nanoparticle resist used for extreme-ultraviolet lithography (Conference Presentation)

Takahiro Kozawa, Teppei Yamada, Satoshi Ishihara, Hiroki Yamamoto, Yusa Muroya, Julius J. Santillan, Toshiro Itani

Proceedings Volume 10809, 108090I (2018) https://doi.org/10.1117/12.2501647

KEYWORDS: Nanoparticles, Zirconium dioxide, Extreme ultraviolet lithography, Metals, Oxides, Chemically amplified resists, Line edge roughness, Diffusion, Polymers, Stochastic processes

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The performance of chemically amplified resist is approaching its physical limit with the reduction of feature sizes due to the acid diffusion needed for the solubility change of resist polymer. The line edge roughness (LER) of chemically amplified resists rapidly increases in the sub-10-nm-half-pitch region when the half-pitch is decreased. Also, the stochastic defect (pinching and bridges) generation is a significant concern for the high resolution patterning with high throughput. To solve these problems, the increase of the density of resist films is an important strategy. Metal oxide nanoparticle resists have attracted much attention as the next generation resist used for the high-volume production of semiconductor devices because of their high density property. However, the sensitization mechanism of the metal oxide nanoparticle resists is unknown. Understanding the sensitization mechanism is important for the efficient development of resist materials. In the previous study[1], the numbers of electron-hole pairs required for the solubility change of the resist films were estimated for a zirconia nanoparticle and a ligand shell, respectively. In this study, the pattern formation mechanism of zirconia nanoparticle resist was investigated. The elementary reactions possibly induced in the zirconia nanoparticle resist were investigated using a pulse radiolysis method. The pulse radiolysis is a powerful method to directly observe the kinetics of short-lived intermediates produced by an ionizing radiation. The pattern formation mechanism was assumed by integrating the elementary reactions. The resist patterns fabricated using an EUV exposure tool were analyzed on the basis of the assumed pattern formation mechanism. In the material design of metal oxide nanoparticle resists, it is important to efficiently use the electron-hole pairs generated in nanoparticles for the chemical change of ligand molecules. Acknowledgement This work was partially supported by Ministry of Economy, Trade and Industry (METI) and the New Energy and Industrial Technology Development Organization (NEDO). Reference [1] T. Kozawa, J. J. Santillan, and T. Itani, “Electron–hole pairs generated in ZrO2 nanoparticle resist upon exposure to extreme ultraviolet radiation”, Jpn. J. Appl. Phys. 57, 026501 (2018).

Proceedings Article | 19 March 2018 Presentation + Paper

Sensitizers in EUV chemically amplified resist: mechanism of sensitivity improvement

Yannick Vesters, Jing Jiang, Hiroki Yamamoto, Danilo De Simone, Takahiro Kozawa, Stefan De Gendt, Geert Vandenberghe

Proceedings Volume 10583, 1058307 (2018) https://doi.org/10.1117/12.2297627

KEYWORDS: Absorption, Photoresist materials, Electrons, Photons, Photoresist developing, Extreme ultraviolet lithography, Metals, Extreme ultraviolet, Polymers, Yield improvement

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Proceedings Article | 19 March 2018 Presentation

Sensitization and reaction mechanisms of ZrO2 nanoparticle resist used for extreme-ultraviolet lithography (Conference Presentation)

Takahiro Kozawa, Satoshi Ishihara, Hiroki Yamamoto, Julius Joseph Santillan, Toshiro Itani

Proceedings Volume 10583, 105831O (2018) https://doi.org/10.1117/12.2297654

KEYWORDS: Nanoparticles, Zirconium dioxide, Extreme ultraviolet lithography, Metals, Oxides, Chemically amplified resists, Line edge roughness, Diffusion, Polymers, Stochastic processes

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Proceedings Article | 13 March 2018 Paper

Synthesis of metal nanoparticle and patterning in polymeric films induced by electron beam

Hiroki Yamamoto, Takahiro Kozawa, Seiichi Tagawa, Jean-Louis Marignier, Mehran Mostafavi, Jacqueline Belloni

Proceedings Volume 10586, 105861G (2018) https://doi.org/10.1117/12.2297331

KEYWORDS: Polymers, Metals, Electron beams, Silver, Nanoparticles, Polymer thin films, Picosecond phenomena, Ions, Absorption, Absorbance

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Proceedings Article | 27 March 2017 Presentation + Paper

Lamellar orientation of block copolymer using polarity switch of nitrophenyl self-assembled monolayer induced by electron beam

Hiroki Yamamoto, Guy Dawson, Takahiro Kozawa, Alex P. Robinson

Proceedings Volume 10146, 1014613 (2017) https://doi.org/10.1117/12.2257953

KEYWORDS: Directed self assembly, Self-assembled monolayers, Lithography, Switches, Electron beams, NOx, Reactive ion etching, Process control, Nanostructures, Nanolithography, Chemistry, Gold, Silicon, Annealing, Optical lithography, Polymethylmethacrylate

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Proceedings Article | 18 March 2016 Paper

Fundamental study on dissolution behavior of poly(methyl methacrylate) by quartz crystal microbalance

Akihiro Konda, Hiroki Yamamoto, Shusuke Yoshitake, Takahiro Kozawa

Proceedings Volume 9776, 977629 (2016) https://doi.org/10.1117/12.2218965

KEYWORDS: Silicon films, Quartz, Crystals, Lithography, Line width roughness, Photoresist processing, Extreme ultraviolet, Optical filters, Polymers, Polymer thin films

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Proceedings Article | 9 July 2015 Paper

Dynamics of radical ions of fluorinated polymer for Extreme Ultraviolet (EUV) lithography

Naoya Nomura, Kazumasa Okamoto, Hiroki Yamamoto, Takahiro Kozawa, Ryoko Fujiyoshi, Kikuo Umegaki

Proceedings Volume 9658, 96581C (2015) https://doi.org/10.1117/12.2193060

KEYWORDS: Fluorine, Extreme ultraviolet, Polymers, Chemical species, Extreme ultraviolet lithography, Absorption, Radiation effects, Lithography, Chemical reactions, Ions

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Proceedings Article | 20 March 2015 Paper

Evaluation of novel lactone derivatives for chemically amplified EUV resists

Hiroyasu Tanaka, Tetsuhiko Mizusaka, Hiroyuki Tanagi, Kikuo Furukawa, Hiroki Yamamoto, Takahiro Kozawa

Proceedings Volume 9425, 94251R (2015) https://doi.org/10.1117/12.2083755

KEYWORDS: Extreme ultraviolet lithography, Polymers, Line edge roughness, Extreme ultraviolet, Lithography, Photoresist materials, Optical lithography, Diffusion, Statistical modeling, Photopolymers

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Proceedings Article | 19 March 2015 Paper

Effects of low-molecular weight resist components on dissolution behavior of chemically amplified resists for extreme ultraviolet lithography studied by quartz crystal microbalance

Masaki Mitsuyasu, Hiroki Yamamoto, Takahiro Kozawa

Proceedings Volume 9422, 94222D (2015) https://doi.org/10.1117/12.2085482

KEYWORDS: Extreme ultraviolet lithography, Extreme ultraviolet, Polymers, Quartz, Crystals, Photoresist processing, Lithography, Chemically amplified resists, Thin films, Silicon

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Proceedings Article | 13 March 2015 Paper

Acid generation mechanism in anion-bound chemically amplified resists used for extreme ultraviolet lithography

Yoshitaka Komuro, Hiroki Yamamoto, Kazuo Kobayashi, Katsumi Ohomori, Takahiro Kozawa

Proceedings Volume 9422, 94220O (2015) https://doi.org/10.1117/12.2085749

KEYWORDS: Extreme ultraviolet lithography, Extreme ultraviolet, Polymers, Double positive medium, Chemically amplified resists, Quantum efficiency, Lithography, Diffusion, Line width roughness, Ionization

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Proceedings Article | 17 April 2014 Paper

Electron and hole transfer in anion-bound chemically amplified resists used in extreme ultraviolet lithography

Yoshitaka Komuro, Hiroki Yamamoto, Yoshiyuki Utsumi, Katsumi Ohmori, Takahiro Kozawa

Proceedings Volume 9048, 90481F (2014) https://doi.org/10.1117/12.2046627

KEYWORDS: Polymers, Chemically amplified resists, Extreme ultraviolet lithography, Absorption, Diffusion, Extreme ultraviolet, Ionization, Line edge roughness, Electron beams, Matrices

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