Dr. Takumi Goto Profile

Dr. Takumi Goto

at Rigaku

SPIE Involvement:

Author

Publications (8)

Proceedings Article | 27 April 2023 Poster + Paper

Precise 3D profile measurement of high aspect ratio device patterns by small-angle x-ray scattering

R. Suenaga, Y. Ito, T. Goto, K. Omote

Proceedings Volume 12496, 124962A (2023) https://doi.org/10.1117/12.2657063

KEYWORDS: Tin, X-rays, Scattering, Transmission electron microscopy, Semiconducting wafers, 3D modeling, X-ray detectors, 3D metrology, Silicon, Film thickness

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Proceedings Article | 27 April 2023 Poster + Paper

Determination of deep hole structure for advanced semiconductor devices analyzed by transmission x-ray scattering

T. Goto, Y. Ito, R. Suenaga, K. Omote

Proceedings Volume 12496, 124962W (2023) https://doi.org/10.1117/12.2658129

KEYWORDS: Scattering, X-rays, Semiconducting wafers, Semiconductors, Etching, Critical dimension metrology, Process control, X-ray technology, Metrology

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Proceedings Article | 18 September 2018 Presentation

Precision Wolter mirrors for future x-ray observations of the Sun (Conference Presentation)

Taro Sakao, Satoshi Matsuyama, Takumi Goto, Jumpei Yamada, Takato Inoue, Kentaro Hata, Hiroyuki Yamaguchi, Kazuto Yamauchi, Yoshiki Kohmura, Ayumi Kime, Yoshinori Suematsu, Noriyuki Narukage, Shin-nosuke Ishikawa

Proceedings Volume 10760, 107600B (2018) https://doi.org/10.1117/12.2320861

KEYWORDS: Mirrors, X-rays, Sun, Scattering, Point spread functions, Solar processes, Coronagraphy, X-ray optics, Plasma, Polishing

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Proceedings Article | 23 August 2017 Paper

Development of precision Wolter mirrors for solar x-ray observations

Taro Sakao, Satoshi Matsuyama, Takumi Goto, Jumpei Yamada, Shuhei Yasuda, Kazuto Yamauchi, Yoshiki Kohmura, Ayumi Kime, Akira Miyake, Tadakazu Maezawa, Hirokazu Hashizume, Yoshinori Suematsu, Noriyuki Narukage, Shin-nosuke Ishikawa

Proceedings Volume 10386, 103860E (2017) https://doi.org/10.1117/12.2273507

KEYWORDS: Mirrors, X-rays, X-ray telescopes, Coronagraphy, X-ray imaging, Polishing, X-ray optics, Synchrotrons, X-ray astronomy, Synchrotron x-ray imaging

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High resolution imagery of the Sun's X-ray corona provides an essential clue in understanding dynamics and heating processes of plasma particles there. However, X-ray imagery of the Sun with sub-arcsecond resolution has so far never been conducted due to severe technical difficulty in fabricating precision Wolter mirrors. For future X-ray observations of the solar corona, we are attempting to realize precision Wolter mirrors with sub-arcsecond resolution by adopting advanced surface polish and metrology methods to sector mirrors which consist of a portion of an entire annulus, by direct polishing onto the mirror substrate. Based on the knowledge obtained through fabrication of the first (in 2013) and second (in 2014) engineering Wolter mirrors and subsequent evaluations on their X-ray focusing performance, the third engineering mirror was made in 2015−2016. The primary target of improvement over the second mirror was to suppress figure error amplitude especially for spatial frequencies around 1 mm^-1 and to suppress the large astigmatism that was present in the second mirror, by introducing improved deterministic polish and smoothing on the precision mirror surfaces (32.5 mm × 10 mm in area for both parabola and hyperbola segments), as well as by careful characterization of the systematic error in the figure measurement system for the precision polish. Measurements on the focusing performance of thus-fabricated third Wolter mirror at SPring-8 synchrotron facility with 8 keV X-rays demonstrated that the mirror attained sub-arcsecond focusing performance with its HPD (half-power diameter) size reaching as small as ~0.2 arcsec for meridional focusing while ~0.1 arcsec for sagittal focusing. The meridional focusing achieved nearly diffraction limited performance (~0.12 arcsec FWHM for the PSF core). We also confirmed that the large astigmatism noted in the second mirror was correctly removed in the third mirror with the correction of the above-mentioned systematic error.

Proceedings Article | 2 November 2016 Presentation

Progress in precision Wolter mirrors for soft x-ray observations of the sun (Conference Presentation)

Taro Sakao, Satoshi Matsuyama, Takumi Goto, Kazuto Yamauchi, Yoshiki Kohmura, Yoshinori Suematsu, Noriyuki Narukage

Proceedings Volume 9963, 99630L (2016) https://doi.org/10.1117/12.2237459

KEYWORDS: Mirrors, X-rays, X-ray imaging, Sun, Polishing, Coronagraphy, Image resolution, Solar processes, Point spread functions, X-ray astronomy

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Proceedings Article | 27 October 2016 Presentation + Paper

Size-changeable x-ray beam collimation using an adaptive x-ray optical system based on four deformable mirrors

T. Goto, S. Matsuyama, H. Nakamori, H. Hayashi, Y. Sano, Y. Kohmura, M. Yabashi, T. Ishikawa, K. Yamauchi

Proceedings Volume 9965, 996502 (2016) https://doi.org/10.1117/12.2238794

KEYWORDS: Mirrors, X-rays, Deformable mirrors, Beam shaping, X-ray optics, Collimation, Optical testing, Actuators, Electrodes, X-ray technology

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Proceedings Article | 4 September 2015 Paper

Development of precision Wolter mirrors for future solar x-ray observations

Taro Sakao, Satoshi Matsuyama, Ayumi Kime, Takumi Goto, Akihiko Nishihara, Hiroki Nakamori, Kazuto Yamauchi, Yoshiki Kohmura, Akira Miyake, Hirokazu Hashizume, Tadakazu Maezawa, Yoshinori Suematsu, Noriyuki Narukage

Proceedings Volume 9603, 96030U (2015) https://doi.org/10.1117/12.2188905

KEYWORDS: Mirrors, X-rays, Polishing, Coronagraphy, X-ray imaging, Sun, Surface finishing, Point spread functions, Scattering, Solar processes

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