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Jun Taniguchi - One of the best experts on this subject based on the ideXlab platform.

  • Fabrication of an Antireflective Structure on a Lenticular Lens
    JSME 2020 Conference on Leading Edge Manufacturing Materials and Processing, 2020
    Co-Authors: Katsuyuki Yatagawa, Jun Taniguchi, Masato Nakamura, Masaki Ono, Shin Hiwasa
    Abstract:

    Abstract In our previous study, various lenses with antireflective structures (ARSs) were fabricated by ultraviolet nanoimprint lithography (UV-NIL) and a thin flexible replica Mold, which had ARSs. However, in the case of a lens with a large uneven surface such a lenticular lens, it is difficult to transfer an ARS. In this paper, the improvement of the transfer process for a lenticular lens with an ARS is investigated. A Master Mold of ARSs was fabricated by irradiating glassy carbon with an oxygen ion beam. A flexible replica Mold with ARSs was transferred from the ARS Master Mold by UV-NIL. In this case, the thickness of the flexible replica Mold was 210 μm. A lenticular lens with the reverse shape was also transferred from the original lenticular lens by UV-NIL. To add an ARS to the lenticular lens with the reverse shape, it was covered with a flexible replica Mold coated with a UV-curable resin. In addition, the lenticular lens was placed on the back side of the flexible replica Mold to contact the lens curve properly. Afterwards, the setting samples were pressed with a roll press and simultaneously UV-cured. After this roll press method was carried out, a lenticular lens with the reverse shape and an ARS was obtained. Using this Mold, a lenticular lens with an ARS was replicated by UV-NIL and the reverse-shape Mold with an ARS.

  • Improvement of Transfer Durability of a Pillar-Shaped Release-Agent-Free Replica Mold in Ultraviolet Nanoimprint Lithography
    International journal of automation technology, 2018
    Co-Authors: Junpei Tsuchiya, Shin Hiwasa, Nakagawa, Jun Taniguchi
    Abstract:

    Ultraviolet nanoimprint lithography (UV-NIL) can be used to fabricate nanoscale patterns with high throughput. It is expected to serve as a low-cost technique for the production of items in large numbers. However, Master Molds for UV-NIL are expensive and laborious to produce, and there are problems associated with the deterioration of the Master Mold and damage to its nanopattern due to adhesion of the UV-curable resin. Consequently, the UV-curable resin has to combine low-viscosity characteristics for coatability with an antisticking property. Coating a Master Mold with a release layer is important in preventing damage to the Master Mold or adhesion between the Mold and the UV-curable resin. However, the released layer deteriorates as the Master Mold is repeatedly used to fabricate nanopatterns. By contrast, the use of a replica Mold is a valuable technique for preventing the deterioration of the Master Mold, and there have been several studies on the fabrication of replicas of Master Molds with the use of UV-curable resins. In many cases, the fabrication of nanopatterns with replica Molds requires the use of a release agent. In a previous study, we developed a material for replica Molds that does not require a release agent. This material consisted of a UV-curable resin with an antifouling effect that was prepared from cationically polymerizable UV-curable and epoxy-modified fluorinated resins. With the use of this material, replica Molds with patterns of pillars or holes were fabricated with UV-NIL. The lifetime of the Mold with the nanopattern of pillars was shorter than that with holes. In addition, the replica Mold with the pillar-shaped nanopattern had numerous defects and allowed adhesion of the transfer resin after repeated efforts. Herein, we describe an improved release-agent-free hard replica Mold. We transferred large numbers of nanopatterns of pillars from the replica Mold, and evaluated the error rate and contact angle of our improved release-agent-free hard replica Mold. The resulting release-agent-free replica Mold with a nanopattern of pillars was capable of transferring up to 1000 sequential imprints. In addition, to improve the release properties of the transfer resin, we included an additive to the transfer resin that contained a reactive fluorinated material. This material improved the release properties of the transfer resin and mitigated the deterioration of the contact angle and increase in the error rate.

  • Transfer durability and fidelity of hard release-agent-free replica Mold by repetition of ultraviolet nanoimprint lithography
    Microelectronic Engineering, 2018
    Co-Authors: Junpei Tsuchiya, Shin Hiwasa, Jun Taniguchi
    Abstract:

    Abstract Ultraviolet nanoimprint lithography provides a high-throughput and cost-effective method to fabricate nanopatterns. However, the Master Mold deteriorates owing to the adhesion of resin and the occurrence of defects. Prompted by the need to prevent deterioration of the Master Mold, we developed a new release-agent-free replica Mold with high toughness and high hardness. We evaluated the durability, error rate, and fidelity of the transfer patterns of the newly developed release-agent-free replica Molds of hard pillar- and hole-shaped patterns. As a result, the developed replica Mold with pillar-shaped patterns exposed to UV radiation at 50 J/cm2 has the best release properties, and the replica Mold with hole-shaped patterns can transfer up to 7000 imprint times under the same conditions.

  • Fabrication of a stretchable transparent electrode with jagged grid structure using silver ink
    Microelectronic Engineering, 2018
    Co-Authors: Naoyuki Sato, Jun Taniguchi
    Abstract:

    Abstract A metal nanogrid pattern with high aspect ratio was successfully fabricated on a stretchable substrate using silver ink. The Master Mold was fabricated by electron-beam lithography and dry etching, whereas the replica Mold was replicated from the Master Mold by ultraviolet nanoimprint lithography. The replica Mold was coated with silver ink and covered with a polyester film, which was then pressed using a roller to fill the Mold trenches with the silver ink. Next, the silver ink remaining in the bottom of the replica Mold was sintered at 120 °C for 5 min. Finally, the sintered silver ink at the bottom of the replica Mold was transferred onto a polyester film using an ultraviolet-curable resin. The resulting transparent electrode had a transmittance of 81% at a wavelength of 550 nm and resistance of 11.0 Ω. The strain on the electrode was 22.7% under a tensile load of 0.78 N.

  • Three-dimensional hologram-read-only memory duplication by nanoimprint lithography
    Journal of Vacuum Science & Technology B Nanotechnology and Microelectronics: Materials Processing Measurement and Phenomena, 2013
    Co-Authors: Noriyuki Unno, Shuhei Yoshida, Hideaki Akamatsu, Manabu Yamamoto, Shin-ichi Satake, Jun Taniguchi
    Abstract:

    Because the amount of multimedia data is continually increasing, there is growing demand for high-speed, large-capacity, read-only memory (ROM) to facilitate data distribution. Computer-generated hologram-ROM (CGH-ROM) has received considerable attention in relation to its potential to meet this rising demand. CGH-ROM requires a nanoscale-precision structure, as well as nanosteps. Because of its process simplicity, nanoimprint lithography (NIL) is a promising method for cost-effective fabrication of complex and high-precision patterns. The authors have demonstrated CGH-ROM duplication by ultraviolet NIL (UV-NIL) from a three-dimensional (3D) Master Mold fabricated by electron-beam lithography (EBL). The calculated depths of the CGH were converted into four tones to permit easy fabrication of the CGH while retaining a high diffraction efficiency. EBL using a spin-on glass and super-resolution technique with a postexposure bake was used to fabricate the 3D Master Mold. The developed depth was controlled by ...

Hyeon Bong Pyo - One of the best experts on this subject based on the ideXlab platform.

  • Study of SU-8 to make a Ni Master-Mold: Adhesion, sidewall profile, and removal
    Electrophoresis, 2006
    Co-Authors: Sungwoong Kim, Yong Taik Lim, Haesik Yang, Kyoung-nam Kim, Hyeon Bong Pyo
    Abstract:

    For disposable microfluidic devices, easy and inexpensive fabrication is essential. Consequently, replication of microfluidic devices, using injection Molding or hot embossing, from a Master-Mold is widely used. However, the conventional Master-Mold fabrication technique is unsatisfactory in terms of time and costs. In this regard, direct Ni growth (electroplating) from a back plate is promising when the photoresist is well-defined. Here, we demonstrate the use of SU-8 as a photoresist to define the Ni-growth region. We accomplish this application by focusing on the adhesion, the sidewall profile, and the removal of SU-8: the adhesion is enhanced by controlling the exposure dose, the soft-baking time, and by choosing the adhesion-promoting layer; the sidewall profile is regulated by selecting the intensity of each exposed wavelength, showing an aspect ratio of up to 20.9; and, easy removal is achieved by choosing a proper photoresist-stripper. Using the Master-Mold fabricated by this method, we test the mechanical stability of the features according to the aspect ratio and length; in the hot embossing process, the features are stable in the aspect ratio of up to 5.8 at a length of 200 microm. In addition, the plastic devices fabricated from this method are applied to the passive stop valves, showing a capillary pressure (-0.2 to -7.2 kPa).

Hiroaki Wakayama - One of the best experts on this subject based on the ideXlab platform.

  • Simple and scalable preparation of Master Mold for nanoimprint lithography.
    Nanotechnology, 2017
    Co-Authors: Yuri Yamada, Kota Ito, Atsushi Miura, Hideo Iizuka, Hiroaki Wakayama
    Abstract:

    Nanoimprint lithography (NIL) is one of the most prominent bottom-up techniques for duplicating nanostructures with a high throughput. However, fabrication of starting Master Mold commonly requires expensive equipment of top-down techniques, or additional steps to transfer the fabricated patterns from bottom-up methods. Here we demonstrate that a SiO2 nanostructure manufactured from a self-assembled block copolymer, polystyrene-b-polydimethylsiloxane (PS-b-PDMS), directly serves as a Master Mold for NIL without further modification. A hexagonally aligned pattern over the entire substrate is established using a simple technique; solvent annealing and etching. Etching also plays an important role in endowing fluorine on the surface of SiO2, thus promoting smooth deMolding upon imprinting. The obtained pattern of the SiO2 nanostructure is transferred to a polymer surface using UV nanoimprint. Identical patterns of the SiO2 nanostructure are elaborately reproduced on Ni and Cu nanodot arrays via electroplating on the polymer transcript, which was verified by morphological observations. The uniformity of the replicated Ni nanodot array is evaluated using spectroscopic ellipsometry. The measured optical response of the Ni nanodot is validated by electromagnetically simulated results, indicating that the pattern transfer is not limited to a small local area. In addition, the durability of the SiO2 Mold pattern is corroborated after the imprinting process, thus guaranteeing the reusability of the fabricated nanostructure as a Master Mold. The proposed approach does not require any high-end lithographic techniques; this may result in significant cost and time reductions in future nanofabrication.

Tsuyoshi Watanabe - One of the best experts on this subject based on the ideXlab platform.

  • A Master-Mold fabrication by electron beam lithography followed by nanoimprinting and self-aligned double patterning
    Japanese Journal of Applied Physics, 2014
    Co-Authors: Tsuyoshi Watanabe, Kouta Suzuki, Hiromasa Iyama, Takeshi Kagatsume, Shuji Kishimoto, Takashi Sato, Hideo Kobayashi
    Abstract:

    As a new scheme of Master-Mold fabrication, a half pitch (hp) 12 nm line and space (L/S) pattern was fabricated from hp 24 nm L/S resist mandrels, which were prepared by electron beam (EB) writing as well as nanoimprinting, followed by the self-aligned double-patterning (SADP) technique. It was observed that the line width roughness (LWR) was reduced and improved by single and multiple nanoimprintings in the new scheme of the Master-Mold fabrication to make hp 24 nm resist mandrels. We have studied the phenomena and revealed that the resist pattern of nanoimprinting had sharper and smoother shoulders and bottom edges in cross section than those of the EB resist. These shoulder shapes of nanoimprinting seemed to be reflected in its LWR improvement. The new scheme has advantages of resolution enhancement and better pattern quality of LWR on a Master Mold for nanoimprint lithography, in comparison with conventional optical and EB lithography technologies.

  • hsq process development for a superior resolution and a reasonable sensitivity for an eb Master Mold for nanoimprint lithography
    Photomask Technology 2013, 2013
    Co-Authors: Hideo Kobayashi, Hiromasa Iyama, Takeshi Kagatsume, Shuji Kishimoto, Takashi Sato, Tsuyoshi Watanabe
    Abstract:

    Half-pitch (hp) 11 to 7.5nm will be resolution requirement for 3 to 5 years later in lithography technology. In specific, hp16nm in 2015 and hp11nm in 2019 for flash memory, bit pitch (bp) 18nm in 2015, bp15nm in 2018 for HDD patterned media, such extremely fine patterning capability is expected. We have been studying a positive resist ZEP520A particularly on its developers and process for the last 5 years. And, its resolution limit is hp16nm in lines and spaces pattern and bp22nm bit patterns for patterned media, in a large and practical patterning area (Figure 1). ZE520A is an option to pursue the resolution limit for the future. However, since it is a positive-tone resist, dark erosion is significant between holes particularly on bp25nm and below, even when the highest resolution developer of an alcohol and a fluoro-carbon mixture is used. ZEP holes in the nearest were not isolated but connected due to excess dark erosion, which seemed to be caused by EB back-scattering and fogging. If a negative-tone resist is employed, it would cause residue instead between pillars. However, the residue can be eliminated by etching back to the bottom, and the pillars can be remained without defects (Figure 2).

  • Master Mold and working replica fabrication for nano-imprinting lithography for 1Tbit/inch2 and 25nm pitch bit patterned media
    Photomask and Next-Generation Lithography Mask Technology XIX, 2012
    Co-Authors: Hideo Kobayashi, Kouta Suzuki, Hiromasa Iyama, Shuji Kishimoto, Takashi Sato, Sakae Nakatsuka, Kazutake Taniguchi, Takaeshi Kagatsume, Tsuyoshi Watanabe
    Abstract:

    Bit Patterned Media (BPM) is essential of HDD media areal density increase, which will be combined with heatassisted magnetic recording (HAMR) eventually for thermal diffusion prevention. 1Tbit/inch 2 areal density is the first demonstration target, which is 25nm pitch hole array, for the BPM development. Nano-Imprinting Lithography (NIL) is indispensable too, so Molds as well, for the BPM large-scale production for throughput. At the beginning, 52nm pitch and below was successfully made on quartz Master-Mold. However, by our comprehensive development and improvement in material and process, we successfully fabricate 25nm pitch Master-Mold by EB Lithography, 25nm pitch working-replica by Nano-Imprinting Lithography as well.

  • 25nm pitch Master and replica Mold fabrication for nanoimprinting lithography for 1Tbit/inch 2 bit patterned media
    Alternative Lithographic Technologies IV, 2012
    Co-Authors: Hideo Kobayashi, Kouta Suzuki, Hiromasa Iyama, Shuji Kishimoto, Takashi Sato, Sakae Nakatsuka, Kazutake Taniguchi, Tsuyoshi Watanabe
    Abstract:

    Nanoimprint Lithography and a Mold, Mold replication from an EB Master Mold as well, those are essential for a large-scale production of bit patterned media. 1Tbit/inch2 (bit pitch 25nm) areal density on a 2.5inch HDD media, it is feasibility demonstration target all the media makers and the HDD makers are aiming at. This paper describes difficulties we faced, and solutions we established by designing and optimizing materials and process, to fabricate 25nm pitch Master Mold by EBL as well as working replica Mold by NIL.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  • 25nm pitch Master and replica Mold fabrication for nanoimprinting lithography for 1tbit inch 2 bit patterned media
    Proceedings of SPIE, 2012
    Co-Authors: Hideo Kobayashi, Kouta Suzuki, Hiromasa Iyama, Shuji Kishimoto, Takashi Sato, Sakae Nakatsuka, Kazutake Taniguchi, Tsuyoshi Watanabe
    Abstract:

    Nanoimprint Lithography and a Mold, Mold replication from an EB Master Mold as well, those are essential for a large-scale production of bit patterned media. 1Tbit/inch2 (bit pitch 25nm) areal density on a 2.5inch HDD media, it is feasibility demonstration target all the media makers and the HDD makers are aiming at. This paper describes difficulties we faced, and solutions we established by designing and optimizing materials and process, to fabricate 25nm pitch Master Mold by EBL as well as working replica Mold by NIL.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Hideo Kobayashi - One of the best experts on this subject based on the ideXlab platform.

  • A Master-Mold fabrication by electron beam lithography followed by nanoimprinting and self-aligned double patterning
    Japanese Journal of Applied Physics, 2014
    Co-Authors: Tsuyoshi Watanabe, Kouta Suzuki, Hiromasa Iyama, Takeshi Kagatsume, Shuji Kishimoto, Takashi Sato, Hideo Kobayashi
    Abstract:

    As a new scheme of Master-Mold fabrication, a half pitch (hp) 12 nm line and space (L/S) pattern was fabricated from hp 24 nm L/S resist mandrels, which were prepared by electron beam (EB) writing as well as nanoimprinting, followed by the self-aligned double-patterning (SADP) technique. It was observed that the line width roughness (LWR) was reduced and improved by single and multiple nanoimprintings in the new scheme of the Master-Mold fabrication to make hp 24 nm resist mandrels. We have studied the phenomena and revealed that the resist pattern of nanoimprinting had sharper and smoother shoulders and bottom edges in cross section than those of the EB resist. These shoulder shapes of nanoimprinting seemed to be reflected in its LWR improvement. The new scheme has advantages of resolution enhancement and better pattern quality of LWR on a Master Mold for nanoimprint lithography, in comparison with conventional optical and EB lithography technologies.

  • hsq process development for a superior resolution and a reasonable sensitivity for an eb Master Mold for nanoimprint lithography
    Photomask Technology 2013, 2013
    Co-Authors: Hideo Kobayashi, Hiromasa Iyama, Takeshi Kagatsume, Shuji Kishimoto, Takashi Sato, Tsuyoshi Watanabe
    Abstract:

    Half-pitch (hp) 11 to 7.5nm will be resolution requirement for 3 to 5 years later in lithography technology. In specific, hp16nm in 2015 and hp11nm in 2019 for flash memory, bit pitch (bp) 18nm in 2015, bp15nm in 2018 for HDD patterned media, such extremely fine patterning capability is expected. We have been studying a positive resist ZEP520A particularly on its developers and process for the last 5 years. And, its resolution limit is hp16nm in lines and spaces pattern and bp22nm bit patterns for patterned media, in a large and practical patterning area (Figure 1). ZE520A is an option to pursue the resolution limit for the future. However, since it is a positive-tone resist, dark erosion is significant between holes particularly on bp25nm and below, even when the highest resolution developer of an alcohol and a fluoro-carbon mixture is used. ZEP holes in the nearest were not isolated but connected due to excess dark erosion, which seemed to be caused by EB back-scattering and fogging. If a negative-tone resist is employed, it would cause residue instead between pillars. However, the residue can be eliminated by etching back to the bottom, and the pillars can be remained without defects (Figure 2).

  • Master Mold and working replica fabrication for nano-imprinting lithography for 1Tbit/inch2 and 25nm pitch bit patterned media
    Photomask and Next-Generation Lithography Mask Technology XIX, 2012
    Co-Authors: Hideo Kobayashi, Kouta Suzuki, Hiromasa Iyama, Shuji Kishimoto, Takashi Sato, Sakae Nakatsuka, Kazutake Taniguchi, Takaeshi Kagatsume, Tsuyoshi Watanabe
    Abstract:

    Bit Patterned Media (BPM) is essential of HDD media areal density increase, which will be combined with heatassisted magnetic recording (HAMR) eventually for thermal diffusion prevention. 1Tbit/inch 2 areal density is the first demonstration target, which is 25nm pitch hole array, for the BPM development. Nano-Imprinting Lithography (NIL) is indispensable too, so Molds as well, for the BPM large-scale production for throughput. At the beginning, 52nm pitch and below was successfully made on quartz Master-Mold. However, by our comprehensive development and improvement in material and process, we successfully fabricate 25nm pitch Master-Mold by EB Lithography, 25nm pitch working-replica by Nano-Imprinting Lithography as well.

  • ZEP520A cold-development technique and tool for ultimate resolution to fabricate 1Xnm bit pattern EB Master Mold for nano-imprinting lithography for HDD/BPM development
    Photomask and Next-Generation Lithography Mask Technology XIX, 2012
    Co-Authors: Hideo Kobayashi, Hiromasa Iyama
    Abstract:

    Poor solvent developers are effective for resolution enhancement on a polymer-type EB resist such as ZEP520A. Another way is to utilize "cold-development" technique which was accomplished by a dip-development technique usually. We then designed and successfully built a single-wafer spin-development tool for the cold-development down to -10degC in order to dissolve difficulties of the dip-development. The cold-development certainly helped improve ZEP520A resolution and hole CD size uniformity, and achieved 35nm pitch BPM patterns with the standard developer ZED-N50, but not 25nm pitch yet. By employing a poor solvent mixture of iso-Propyl Alcohol (IPA) and Fluoro-Carbon (FC), 25nm pitch BPM patterns were accomplished. However, the cold-development showed almost no improvement on the IPA/FC mixture developer solvent. This paper describes cold-development technique and a tool, as well as its results, for ZEP520A resolution enhancement to fabricate 1Xnm bits (holes) for EB Master-Mold for Nano-Imprinting Lithography for 1Tbit/inch 2 and 25nm pitch Bit Patterned Media development.

  • 25nm pitch Master and replica Mold fabrication for nanoimprinting lithography for 1Tbit/inch 2 bit patterned media
    Alternative Lithographic Technologies IV, 2012
    Co-Authors: Hideo Kobayashi, Kouta Suzuki, Hiromasa Iyama, Shuji Kishimoto, Takashi Sato, Sakae Nakatsuka, Kazutake Taniguchi, Tsuyoshi Watanabe
    Abstract:

    Nanoimprint Lithography and a Mold, Mold replication from an EB Master Mold as well, those are essential for a large-scale production of bit patterned media. 1Tbit/inch2 (bit pitch 25nm) areal density on a 2.5inch HDD media, it is feasibility demonstration target all the media makers and the HDD makers are aiming at. This paper describes difficulties we faced, and solutions we established by designing and optimizing materials and process, to fabricate 25nm pitch Master Mold by EBL as well as working replica Mold by NIL.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.