Dr. Norihito Fukugami Profile

Dr. Norihito Fukugami

at Toppan Printing Co Ltd

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Publications (14)

Proceedings Article | 12 June 2018 Paper

EUV mask with advanced hybrid black border suppressing EUV and DUV OOB light reflection

Genta Watanabe, Norihito Fukugami, Toru Komizo, Yutaka Kodera, Toshio Konishi

Proceedings Volume 10807, 108070N (2018) https://doi.org/10.1117/12.2501999

KEYWORDS: Extreme ultraviolet, Reflectivity, Photomasks, Deep ultraviolet, Semiconducting wafers, Reflection, Optical testing, Extreme ultraviolet lithography, Manufacturing, Atomic force microscopy

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EUV lithography is expected to be the most promising technology for semiconductor device manufacturing of the 7nm node and beyond. The EUV mask is a key element in the lithographic scanner optical path. The image border is a pattern free dark area around the die on the photomask serving as transition area between the parts of the mask that is shielded from the exposure light by the Reticle Masking (REMA) blades and the die. When printing a die at dense spacing on an EUV scanner, the reflection from the image border overlaps edges of neighboring dies, affecting CD and contrast in this area. This is related to the fact that EUV absorber stack reflects 1-3% of actinic EUV light. To reduce this effect several types of image border with reduced EUV light reflectance (<0.05%) have been proposed; such an image border is referred to as a black border (BB). In particular, an etched multilayer type black border was developed; it was demonstrated that CD impact at the edge of a die is strongly reduced with this type of the black border. However, wafer printing result still showed some CD change in the die influenced by the black border reflection. It was proven that the CD change was caused by DUV Out Of Band (OOB) light which is emitted from the EUV light source. In our previous study, a new types of multilayer etched BB called ‘Hybrid Black Border’ (HBB) had been developed and showed a good potential for DUV light suppression. OOB light reflection on HBB is ~3x lower than that of normal BB. Imaging performance was also demonstrated on NXE:3300 scanner system for N10 imaging structures of 16nm dense lines and 20nm isolated spaces. These results were compared to the imaging results obtained for a mask with the normal BB and 3x improvement was achieved; less than 0.2 nm CD changes were observed in the corners of the die. However, OOB light reflectance suppression was still not enough in short wavelength. In this study, we focused on OOB light reflectance reduction in short wavelength, and we developed a new HBB called ‘Advanced HBB’. We measured the OOB light reflectance of Advanced HBB by synchrotron radiation facility at PTB (Physikalisch- Technische Bundesanstalt, Germany). These results were compared to the results obtained from previous HBB. Then Advanced HBB achieved over 50% OOB light reflectance improvement in average wavelength 100nm to 270nm. Imaging performance also simulated in the edges and corners of the die. The CD-drop is expected to be more improved for Advanced HBB than previous HBB. As a result, it is expected the implementation of the Advanced HBB will help to mitigate the effects of possible increases of OOB light in the future higher power EUV sources.

Proceedings Article | 10 May 2016 Paper

Novel EUV mask black border suppressing EUV and DUV OoB light reflection

Shin Ito, Yutaka Kodera, Norihito Fukugami, Toru Komizo, Shingo Maruyama, Genta Watanabe, Itaru Yoshida, Jun Kotani, Toshio Konishi, Takashi Haraguchi

Proceedings Volume 9984, 99840O (2016) https://doi.org/10.1117/12.2242624

KEYWORDS: Extreme ultraviolet, Photomasks, Deep ultraviolet, Extreme ultraviolet lithography, Reflectivity, Semiconducting wafers, Neodymium, Reflection, Ultraviolet radiation, Manufacturing

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EUV lithography is the most promising technology for semiconductor device manufacturing of the 10nm node and beyond. The image border is a pattern free dark area around the die on the photomask serving as transition area between the parts of the mask that is shielded from the exposure light by the Reticle Masking (REMA) blades and the die. When printing a die at dense spacing on an EUV scanner, the reflection from the image border overlaps edges of neighboring dies, affecting CD and contrast in this area. This is related to the fact that EUV absorber stack reflects 1-3% of actinic EUV light. To reduce this effect several types of image border with reduced EUV reflectance (<0.05%) have been proposed; such an image border is referred to as a black border. In particular, an etched multilayer type black border was developed; it was demonstrated that CD impact at the edge of a die is strongly reduced with this type of the black border (BB). However, wafer printing result still showed some CD change in the die influenced by the black border reflection. It was proven that the CD shift was caused by DUV Out of Band (OOB) light from the EUV light source. New types of a multilayer etched BB were evaluated and showed a good potential for DUV light suppression. In this study, a novel BB called ‘Hybrid Black Border’ (HBB) has been developed to eliminate EUV and DUV OOB light reflection by applying optical design technique and special micro-fabrication technique. A new test mask with HBB is fabricated without any degradation of mask quality according to the result of CD performance in the main pattern, defectivity and cleaning durability. The imaging performance for N10 imaging structures is demonstrated on NXE:3300B in collaboration with ASML. This result is compared to the imaging results obtained for a mask with the earlier developed BB, and HBB has achieved ~3x improvement; less than 0.2 nm CD changes are observed in the corners of the die. A CD uniformity budget including impact of OOB light in the die edge area is evaluated which shows that the OOB impact from HBB becomes comparable with other CDU contributors in this area. Finally, we state that HBB is a promising technology allowing for CD control at die edges.

Proceedings Article | 18 March 2016 Paper

Novel EUV mask black border and its impact on wafer imaging

Yutaka Kodera, Norihito Fukugami, Toru Komizo, Genta Watanabe, Shin Ito, Itaru Yoshida, Shingo Maruyama, Jun Kotani, Toshio Konishi, Takashi Haraguchi

Proceedings Volume 9776, 977615 (2016) https://doi.org/10.1117/12.2218942

KEYWORDS: Photomasks, Extreme ultraviolet, Extreme ultraviolet lithography, Scanners, Deep ultraviolet, Imaging systems, Semiconducting wafers, Reflectivity, Printing, Semiconductor manufacturing, Reflection, Manufacturing

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Proceedings Article | 9 July 2015 Paper

Defectivity evaluation of EUV reticles with etched multilayer image border by wafer printing analysis

Rik Jonckheere, Erik Verduijn, Genta Watanabe, Norihito Fukugami, Yo Sakata, Yutaka Kodera, Emily Gallagher

Proceedings Volume 9658, 96580H (2015) https://doi.org/10.1117/12.2197682

KEYWORDS: Semiconducting wafers, Photomasks, Extreme ultraviolet, Reticles, Extreme ultraviolet lithography, Reflectivity, Scanning electron microscopy, Printing, Scanners, Opacity

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Proceedings Article | 17 October 2014 Paper

Black border, mask 3D effects: covering challenges of EUV mask architecture for 22nm node and beyond

Natalia Davydova, Eelco van Setten, Robert de Kruif, Brid Connolly, Norihito Fukugami, Yutaka Kodera, Hiroaki Morimoto, Yo Sakata, Jun Kotani, Shinpei Kondo, Tomohiro Imoto, Haiko Rolff, Albrecht Ullrich, Ramasubramanian Kottumakulal Jaganatharaja, Ad Lammers, Dorothe Oorschot, Cheuk-Wah Man, Guido Schiffelers, Joep van Dijk

Proceedings Volume 9231, 923102 (2014) https://doi.org/10.1117/12.2066299

KEYWORDS: Deep ultraviolet, Reflectivity, Extreme ultraviolet, Photomasks, Reticles, Scanners, Aluminum, Extreme ultraviolet lithography, Atomic force microscopy, Semiconducting wafers

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Proceedings Article | 28 July 2014 Paper

Achievements and challenges of EUV mask imaging

Proceedings Volume 9256, 925602 (2014) https://doi.org/10.1117/12.2072945

KEYWORDS: Reticles, Photomasks, Extreme ultraviolet, Semiconducting wafers, Reflectivity, 3D metrology, Deep ultraviolet, Neodymium, Atomic force microscopy, Scanners

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Proceedings Article | 28 July 2014 Paper

Simulation of image placement error due to fabrication of black border on EUV mask

Yasushi Nishiyama, Shinpei Kondo, Norihito Fukugami

Proceedings Volume 9256, 92560S (2014) https://doi.org/10.1117/12.2067965

KEYWORDS: Photomasks, Multilayers, Extreme ultraviolet, Etching, Finite element methods, Reflectivity, Device simulation, Distortion, Glasses, EUV optics

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Proceedings Article | 3 October 2013 Paper

Impact of an etched EUV mask black border on imaging: part II

Natalia Davydova, Robert de Kruif, Hiroaki Morimoto, Yo Sakata, Jun Kotani, Norihito Fukugami, Shinpei Kondo, Tomohiro Imoto, Brid Connolly, Dries van Gestel, Dorothe Oorschot, David Rio, John Zimmerman, Noreen Harned

Proceedings Volume 8880, 888027 (2013) https://doi.org/10.1117/12.2027596

KEYWORDS: Deep ultraviolet, Reflectivity, Reticles, Extreme ultraviolet, Semiconducting wafers, Scanners, Extreme ultraviolet lithography, Photomasks, Optical proximity correction, Aluminum

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Proceedings Article | 1 October 2013 Paper

Experimental approach to EUV imaging enhancement by mask absorber height optimization

Natalia Davydova, Robert de Kruif, Haiko Rolff, Brid Connolly, Eelco van Setten, Ad Lammers, Dorothe Oorschot, Norihito Fukugami, Yutaka Kodera

Proceedings Volume 8886, 88860A (2013) https://doi.org/10.1117/12.2030806

KEYWORDS: Photomasks, Extreme ultraviolet, Reflectivity, Critical dimension metrology, Reticles, Calibration, Phase shifts, Refractive index, Optical proximity correction, Etching

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EUV lithography performance is improved significantly by optimizing and fine-tuning of the EUV mask. The EUV mask is an active element of the scanner optical system influencing main lithographic figure of merits such as image contrast, critical dimension uniformity (CDU), focus and overlay. The mask stack consists of Mo/Si multilayer acting as a bright field and a patterned absorber stack. In this work we will concentrate on investigation of EUV absorber. Absorber topography that is pronounced compared to the imaging wavelength of 13.5 nm, will give rise to various mask 3d effects such as shadowing or dependence of CD on feature orientation, best focus shift of different resolution structures, etc. Light interference in the absorber layer results in swinging behavior of various lithography metrics as function of the absorber height. Optimization of the mask absorber allows mitigating mask 3d effects and improving imaging performance. In particular, reduction of the absorber height mitigates the shadowing effect and relaxes requirements on Optical Proximity Correction (OPC), but can result in smaller Process Window due to lower imaging contrast and larger best focus shifts. In this work we will show results of an experimental approach to absorber height optimization. A special mask with 27 different absorber heights in the range 40-70 nm is manufactured by Toppan Photomasks. EUV reflectivity spectra are measured for the different absorber heights and an experimental swing curve is constructed. For each absorber height various resolution features are present on the mask. Lines of 27 nm and 22 nm are imaged on the wafer using the ASML EUV scanner NXE:3300B with an NA of 0.33. The experimental CD swing curve is constructed as well as HV change as a function of absorber height. The impact of the absorber height on Exposure Latitude (EL) and Dose to Size (D2S) is investigated. EL improves with increasing absorber height in some cases, however there is no clear EL gain for a 70 nm absorber compared to for example 52 nm absorber. D2S does show a clear trend through absorber height. In particular, D2S can be reduced by absorber height reduction: e.g. for 52 nm absorber D2S is 5% or 1 mJ/cm2 smaller compared to 70 nm. The experimental results are used for calibration and verification of rigorous mask 3d simulations. This knowledge is crucial for accurate OPC of production masks and allows for accurate litho simulations of EUV user cases as a basis for lithography roadmaps towards High Volume Manufacturing and High NA EUV.

Proceedings Article | 8 November 2012 Paper

Impact of an etched EUV mask black border on imaging and overlay

Natalia Davydova, Robert de Kruif, Norihito Fukugami, Shinpei Kondo, Vicky Philipsen, Eelco van Setten, Brid Connolly, Ad Lammers, Vidya Vaenkatesan, John Zimmerman, Noreen Harned

Proceedings Volume 8522, 852206 (2012) https://doi.org/10.1117/12.964547

KEYWORDS: Semiconducting wafers, Reticles, Photomasks, Extreme ultraviolet, Etching, Reflectivity, Deep ultraviolet, Scanning electron microscopy, Optical proximity correction, Extreme ultraviolet lithography

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There are multiple mask parameters that can be tuned to optimize the lithographic performance of the EUV photo mask[1]. One of them is the absorber height. A reduction of the absorber height allows, for example, a higher resolution patterning on mask and reduces the OPC needed for shadowing correction[1][2][5]. Downside of a thinner absorber is the increased reflectivity which manifests itself not only in the image field (contrast loss) but also in the so called light shield area or image border. The image border is a pattern free (absorber covered) area around the die on the photo mask forming the transition area between the part on the mask that is completely shielded from the exposure light by the Reticle Masking (REMA) blades and the die. The image border accommodates the finite REMA placement accuracy and the half shadow of the REMA blades allowing close spaced die printing on the wafer. When printing a die at dense spacing, which is common practice in a production environment, the image border will overlap part of the neighboring die. This causes actinic EUV and DUV out of band light reflection from the image border exposing the overlapped die area and affecting CD and contrast at the edges of the dies. For a 44 nm thick absorber we found a CD impact of 8 nm for 32 nm dense lines[3] whereas for a 55 nm thick absorber the effect was 4 nm for 27 nm dense lines[7]. Increasing the die spacing would prevent this unwanted exposure but results in an unacceptable loss of valuable wafer real estate thereby reducing the yield per wafer and is thus not a viable manufacturing solution. Optical Proximity Correction (OPC) using ASML Brion’s Tachyon NXE model at the edges of the die was proposed as possible solution to this problem[3]. An alternative is to create a so called Black Border: the reflectivity in the image border is reduced to a sufficiently low level by for example increasing the absorber thickness, add a special coating or replace the absorber with a low reflective material[4][5]. The most radical solution is removal of the absorber and the underlying multilayer down to the low reflective substrate, so-called multilayer etching[4][6]. In this paper we will present the effects of such a Black Border created by a multilayer etch on features and their placement on the reticle and the impact on CD of 27 nm dense lines on the wafer. By comparing the wafer CDU printed with and without Black Border we will determine how well the image border effect is mitigated by the multilayer etching.

Proceedings Article | 30 June 2012 Paper

Black border with etched multilayer on EUV mask

Norihito Fukugami, Kazuaki Matsui, Genta Watanabe, Takeshi Isogawa, Shinpei Kondo, Yutaka Kodera, Yo Sakata, Shinji Akima, Jun Kotani, Hiroaki Morimoto, Tsuyoshi Tanaka

Proceedings Volume 8441, 84411K (2012) https://doi.org/10.1117/12.965536

KEYWORDS: Extreme ultraviolet, Reflectivity, Photomasks, Semiconducting wafers, Deep ultraviolet, Etching, Manufacturing, Inspection, Extreme ultraviolet lithography, Image processing

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Proceedings Article | 26 May 2010 Paper

Study of etching process for LER and resolution

Tomohiro Imoto, Yosuke Kojima, Norihito Fukugami, Takashi Haraguchi, Tsuyoshi Tanaka

Proceedings Volume 7748, 77480D (2010) https://doi.org/10.1117/12.866417

KEYWORDS: Line edge roughness, Etching, Photomasks, Chromium, Opacity, Semiconducting wafers, Inspection, Printing, Dry etching, Scanning electron microscopy

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Proceedings Article | 5 September 2001 Paper

Pattern shape analysis tool for quantitative estimate of photomask and process

Isao Yonekura, Yuhichi Fukushima, Fuyuhiko Matsuo, Masao Otaki, Norihito Fukugami

Proceedings Volume 4409, (2001) https://doi.org/10.1117/12.438360

KEYWORDS: Photomasks, Image processing, Scanning electron microscopy, Shape analysis, Image filtering, Etching, Ultraviolet radiation, Semiconducting wafers, Microscopes, Inspection

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Proceedings Article | 19 July 2000 Paper

Pattern shape analysis tool for defect judgement of photomask

Fuyuhiko Matsuo, Masao Otaki, Norihito Fukugami, Isao Yonekura, Yuhichi Fukushima

Proceedings Volume 4066, (2000) https://doi.org/10.1117/12.392036

KEYWORDS: Optical proximity correction, Head, Inspection, Image quality, Scanning electron microscopy, Photomasks, Shape analysis, Image processing, Semiconducting wafers, Image resolution

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Showing 5 of 14 publications

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