Mr. Ryouichirou Naitou Profile

Ryouichirou Naitou

Staff Engineer at Tokyo Electron Kyushu Ltd

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Publications (8)

Proceedings Article | 4 April 2008 Paper

Process manufacturability evaluation for next generation immersion technology node

M. Enomoto, T. Shimoaoki, T. Otsuka, S. Hatakeyama, K. Nafus, R. Naito, Y. Terashita, T. Shibata, H. Kosugi, M. Jyousaka, J. Mallmann, R. Maas, M. Blanco Mantecon, E. van Setten, J. Finders, S. Wang, C. Zoldesi

Proceedings Volume 6923, 69231W (2008) https://doi.org/10.1117/12.772552

KEYWORDS: Semiconducting wafers, Critical dimension metrology, Manufacturing, Inspection, Standards development, Scanners, Bridges, Particles, Metrology, High volume manufacturing

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Proceedings Article | 1 April 2008 Paper

Random 65nm..45nm C/H printing using optimized illumination source and CD sizing by post processing

Jo Finders, Eddy Van der Heijden, Gert-Jan Janssen, Rik Vangheluwe, Tsuysohi Shibata, Ryouichirou Naitou, Hitoshi Kosugi, Hisanori Sugimachi

Proceedings Volume 6924, 69242Y (2008) https://doi.org/10.1117/12.773595

KEYWORDS: Reticles, Optical proximity correction, Printing, Lithographic illumination, Photoresist processing, Critical dimension metrology, Semiconducting wafers, Lithography, Scanning electron microscopy, Double patterning technology

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Proceedings Article | 2 April 2007 Paper

Impact of airborne NH3 and humidity against wafer-to-wafer CD variation in ArF lithography through 45-nm technology node

Ryoichiro Naito, Yoshitaka Matsuda, Masaharu Shioguchi, Tsuyoshi Shibata

Proceedings Volume 6519, 65193D (2007) https://doi.org/10.1117/12.711334

KEYWORDS: Critical dimension metrology, Humidity, Carbon, Polymers, Lithography, Diffractive optical elements, Control systems, Photoresist processing, Environmental sensing, Fermium

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Proceedings Article | 29 March 2006 Paper

Defect reduction by using a new rinse solution for 193-nm conventional and immersion lithography

Osamu Miyahara, Takeshi Shimoaoki, Ryoichiro Naito, Kousuke Yoshihara, Junichi Kitano

Proceedings Volume 6153, 61533K (2006) https://doi.org/10.1117/12.656361

KEYWORDS: Photoresist processing, Etching, Immersion lithography, Semiconducting wafers, Lithography, Thin film coatings, Laser processing, Satellites, Scanning electron microscopy, Liquids

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Semiconductor manufacturing technology has progressed remarkably in recent years. This progress has been accompanied by demands to reduce the feature size used in photolithography processing, resulting in a reduction of the exposure wavelength from 248 nm (KrF laser) to 193 nm (ArF laser). ArF immersion lithography is now being actively researched and developed with the aim of implementing the 45-nm technology node. Chemically amplified (CA) resists have been introduced to cope with these reduced feature sizes, making it all the more important to reduce defects produced in the lithography process. In recent years, the behavior of defects in a CA resist has been clarified by studies involving various microprobe analysis techniques. Basically, it has been reported that water-soluble defects such as "satellites" and water-insoluble defects such as "resist residues" are generated by various factors. Furthermore, the reduction in pattern sizes has led to the identification of new types of resist-related defects such as "missing-hole" defects in contact-hole (C/H) patterns and "bridging" defects in line-and-space (L/S) patterns. Although the satellite, resist-residue, and missing-hole problems have been addressed by implementing new ideas such as extended rinse times, improved development recipes, and the introduction of post-development rinse stages and improved rinse recipes, it cannot be said that these measures are sufficient in terms of processing throughput or effectiveness. In this paper, we investigate the effect of adding chemical additives to the de-ionized water (DIW) rinse used in the development rinse process. Our studies confirm that these additives significantly reduce the quantity of minute defects generated on the wafer without degrading lithography performance, and thus help to improve process throughput. We also investigate the application of this method to immersion lithography, and confirm that this additive procedure also reduces the quantity of defects in immersion lithography processes.

Proceedings Article | 14 May 2004 Paper

Mechanisms of defect generation in chemically amplified resist processes

Takeshi Shimoaoki, Ryoichiro Naito, Junichi Kitano

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.535088

KEYWORDS: Lithography, Polymers, Photoresist processing, Chemically amplified resists, Excimers, Reflectivity, Particles, Control systems, Excimer lasers, Satellites

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Proceedings Article | 14 May 2004 Paper

Behavior of chemically amplified resist defects in TMAH solution: III

Yuko Ono, Takeshi Shimoaoki, Ryoichiro Naito, Junichi Kitano

Proceedings Volume 5376, (2004) https://doi.org/10.1117/12.534982

KEYWORDS: Polymers, Particles, Semiconducting wafers, Photoresist processing, Chemically amplified resists, Defect detection, Manufacturing, Lithography, Infrared radiation, Arsenic

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Proceedings Article | 16 June 2003 Paper

Improvement of resist pattern collapse

Manabu Watanabe, Yoichi Tomo, Masaki Yamabe, Yukio Kiba, Keiichi Tanaka, Ryoichiro Naito

Proceedings Volume 5037, (2003) https://doi.org/10.1117/12.484978

KEYWORDS: Semiconducting wafers, Photoresist processing, Lithography, Ultraviolet radiation, Liquids, Extreme ultraviolet lithography, Capillaries, Scanning electron microscopy, Lithium, Fabrication

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Proceedings Article | 12 June 2003 Paper

Improvement of pattern collapse issue by additive-added D.I. water rinse process

Keiichi Tanaka, Ryoichiro Naito, Tomohiro Kitada, Yukio Kiba, Yoshiaki Yamada, Masakazu Kobayashi, Hiroyuki Ichikawa

Proceedings Volume 5039, (2003) https://doi.org/10.1117/12.485069

KEYWORDS: Photoresist processing, Interfaces, Semiconducting wafers, Capillaries, Ions, Water, Photoresist materials, Lithography, Etching, Polymers

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Reduction of critical dimension in lithography technology is aggressively promoted. At the same time, further resist thickness reduction is being pursued to increase the resolution capabilities of resist. However, thin film has its limitation because of etch requirements etc. As that result, the promotion of reduction results in increasing the aspect ratio, which leads to pattern collapse. It is well known that at drying step in developing process the capillary effect operates the photoresist pattern. If the force of the capillary effect is greater than the aggregation force of the resist pattern, the pattern collapse is generated. And the key parameters of the capillary effect are the space width between patterns, the aspect ratio, the contact angle of the D.I water rinse and the surface tension of rinse solution. Among these parameters the surface tension of rinse solution can be controlled by us. On the other hand, we've already reported that the penetration of TMAH and D.I water into the resist plays an important role on the lithographic latitude. For example, when we use the resist which TMA ion can be easily diffuse into, D.I water and TMA ion which are penetrated in the resist decreases the aggregation force of resist pattern and causes the pattern collapse even by the weak force against resist pattern. These results indicate that the swelling of photoresist by TMA ion and water is very important factor for controlling the pattern collapse. Currently, two methods are mainly tried to reduce the surface tension of rinse solution: SCF (Super Critical Fluid) and addition of additive to D.I water rinse. We used the latter method this time, because this technique has retrofittability and not special tool. And in this evaluation, we found that the degree of suppressing pattern collapse depends on the additive chemistry or formulation. With consideration given to process factors such as above, we investigated what factors contribute to suppressing pattern collapse for each resist platform when using additive-added rinse solutions. This report describes the results of our examinations and discussions of the pattern collapse mechanism.

Showing 5 of 8 publications

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