Details of the Researcher

PHOTO

Kai Takeuchi
Section
Graduate School of Engineering
Job title
Assistant Professor
Degree
  • 博士(工学)(東京大学)

  • 修士(工学)(東京大学)

e-Rad No.
20896716

Research History 4

  • 2022/08 - Present
    Tohoku University Department of Electronic Engineering, Graduate School of Engineering Assistant Professor

  • 2021/10 - 2022/07
    The University of Tokyo System Design Lab, School of Engineering Project Researcher

  • 2020/08 - 2022/07
    The University of Tokyo Institute of Industrial Science Collaborative Researcher

  • 2020/04 - 2022/07
    Meisei University Collaborative Research Center Senior Researcher

Education 3

  • The University of Tokyo The Graduate School of Engineering Department of Precision Engineering

    2017/04 - 2020/03

  • The University of Tokyo The Graduate School of Engineering Department of Precision Engineering

    2015/04 - 2017/03

  • The University of Tokyo The Faculty of Engineering Department of Precision Engineering

    2011/04 - 2015/04

Committee Memberships 6

  • 一般社団法人 電子実装工学研究所 (IMSI) 接合界面創成技術研究会 幹事

    2024/06 - Present

  • International Conference on Electronics Packaging (ICEP) 論文副委員長

    2023/09 - Present

  • IEEE EPS Symposium Japan (ICSJ) 運営委員

    2023/01 - Present

  • 第41回「センサ・マイクロマシンと応用システム」シンポジウム運営委員 幹事

    2024/01 - 2024/12

  • 電気学会 第40回「センサ・マイクロマシンと応用システム」シンポジウム運営委員 副幹事

    2023/03 - 2023/12

  • International Conference on Electronics Packaging (ICEP) 2023 論文委員

    2022/08 - 2023/06

Show all ︎Show first 5

Professional Memberships 4

  • IEEE EPS

    2023/01 - Present

  • The Institute of Electrical Engineers of Japan

    2023/01 - Present

  • エレクトロニクス実装学会

    2021/03 - Present

  • 精密工学会

    2021/03 - Present

Research Interests 2

  • low temperature bonding

  • wafer bonding

Research Areas 1

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Electronic devices and equipment /

Awards 7

  1. ポスターアワード

    2025/03 第34回マイクロエレクトロニクスシンポジウム(MES2024) Au薄膜の転写とコイニングにより作製した平坦な Auマイクロバンプアレイ

  2. 優秀ポスター発表賞ファイナリスト

    2024/11 電気学会センサ・マイクロマシン部門 第41回「センサ・マイクロマシンと応用システム」シンポジウム 無機ポリマーを用いた水中でのSi基板間の接着

  3. Poster Award of ICEP 2024

    2024/04 The Japan Institute of Electronics Packaging Investigation of Plasma Gases for Polysilazane Conversion into SiO2 for Wafer Bonding

  4. IEEE EPS Japan Chapter Young Award of ICEP 2024

    2024/04 IEEE Electronics Packaging Society Japan Chapter Formation of SiO2 Bonding Interface using Perhydropolysilazane at Room Temperature

  5. 若手優秀研究賞

    2024/03 東北大学電気・情報系

  6. Best Presentation Award

    2021/10 The Organizing Committee of 2021 7th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D) Quantification of Wafer Bond Strength of Silicon Nitride under Controlled Atmosphere

  7. Outstanding Student Paper Award

    2016/10 The Electrochemical Society Modified Surface Activated Bonding Using Si Intermediate Layer for Bonding and Debonding of Glass Substrates

Show all ︎Show 5

Papers 56

  1. Room temperature wafer bonding through conversion of polysilazane into SiO2 Peer-reviewed

    Kai Takeuchi, Tadatomo Suga, Eiji Higurashi

    Scientific Reports 14 (1) 2024/01

    DOI: 10.1038/s41598-024-51800-6  

    eISSN: 2045-2322

  2. Room temperature bonding of Au assisted by self-assembled monolayer Peer-reviewed

    Kai Takeuchi, Junsha Wang, Beomjoon Kim, Tadatomo Suga, Eiji Higurashi

    Applied Physics Letters 122 (5) 051603-051603 2023/01/30

    Publisher: AIP Publishing

    DOI: 10.1063/5.0128187  

    ISSN: 0003-6951

    eISSN: 1077-3118

  3. Quantification of wafer bond strength under controlled atmospheres Peer-reviewed

    Kai Takeuchi, Tadatomo Suga

    JAPANESE JOURNAL OF APPLIED PHYSICS 61 (SF) 2022/06

    DOI: 10.35848/1347-4065/ac5e49  

    ISSN: 0021-4922

    eISSN: 1347-4065

  4. Microfluidic chip connected to porous microneedle array for continuous ISF sampling Peer-reviewed

    Kai Takeuchi, Nobuyuki Takama, Kirti Sharma, Oliver Paul, Patrick Ruther, Tadatomo Suga, Beomjoon Kim

    DRUG DELIVERY AND TRANSLATIONAL RESEARCH 12 (2) 435-443 2022/02

    DOI: 10.1007/s13346-021-01050-0  

    ISSN: 2190-393X

    eISSN: 2190-3948

  5. Sequential Plasma Activation for Low Temperature Bonding of Aluminosilicate Glass Peer-reviewed

    Kai Takeuchi, Fengwen Mu, Akira Yamauchi, Tadatomo Suga

    ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 10 (5) 2021/05

    DOI: 10.1149/2162-8777/abfd4b  

    ISSN: 2162-8769

    eISSN: 2162-8777

  6. Room Temperature Wafer Bonding of Glass Using Aluminum Oxide Intermediate Layer Peer-reviewed

    Kai Takeuchi, Fengwen Mu, Yoshiie Matsumoto, Tadatomo Suga

    ADVANCED MATERIALS INTERFACES 8 (5) 2021/03

    DOI: 10.1002/admi.202001741  

    ISSN: 2196-7350

  7. Flexible and porous microneedles of PDMS for continuous glucose monitoring Peer-reviewed

    Kai Takeuchi, Nobuyuki Takama, Rie Kinoshita, Teru Okitsu, Beomjoon Kim

    BIOMEDICAL MICRODEVICES 22 (4) 2020/11

    DOI: 10.1007/s10544-020-00532-1  

    ISSN: 1387-2176

    eISSN: 1572-8781

  8. Microfluidic chip to interface porous microneedles for ISF collection Peer-reviewed

    Kai Takeuchi, Nobuyuki Takama, Beomjoon Kim, Kirti Sharma, Oliver Paul, Patrick Ruther

    BIOMEDICAL MICRODEVICES 21 (1) 2019/03

    DOI: 10.1007/s10544-019-0370-4  

    ISSN: 1387-2176

    eISSN: 1572-8781

  9. Low pressure Au–Au bonding using flat-topped micro-bump Au arrays fabricated by Au film transfer and coining methods Peer-reviewed

    Shintaro Goto, Kai Takeuchi, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, Eiji Higurashi

    Japanese Journal of Applied Physics 64 (5) 05SP08-05SP08 2025/05/01

    Publisher: IOP Publishing

    DOI: 10.35848/1347-4065/adcc3a  

    ISSN: 0021-4922

    eISSN: 1347-4065

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    Abstract The fabrication of highly functional optical devices requires solid-state, low-pressure bonding techniques. In this study, we developed micro-bump Au arrays that come into close contact at low pressure and facilitate low-temperature bonding. The micro-bumps were fabricated by Au film transfer and coining methods. A high die shear strength was achieved between the Si chip with the micro-bumps and the Si substrate with an Au film under a low bonding pressure of 10 MPa in ambient air at 150 °C after Ar fast-atom beam irradiation. The close contact between the micro-bumps and Au film was confirmed via cross-sectional scanning electron microscopy. Using the micro-bumps, a GaAs laser diode chip with an active layer near the bonding interface was junction-down mounted without degradation. The study findings confirm that the proposed methods can bond dissimilar materials at low bonding pressures, thereby contributing to the integration of optical components.

  10. Wafer Bonding of GaAs and SiC via Thin Au Film at Room Temperature Peer-reviewed

    Kai Takeuchi, Eiji Higurashi

    Micromachines 2025/04/07

    DOI: 10.3390/mi16040439  

  11. Room temperature bonding of Au plating through surface smoothing using polyimide template stripping Peer-reviewed

    Kai Takeuchi, Shogo Koseki, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, Takahiro Tsuda, Tomoaki Tokuhisa, Toshikazu Shimizu, Eiji Higurashi

    Sensors and Actuators A: Physical 383 116211-116211 2025/03

    Publisher: Elsevier BV

    DOI: 10.1016/j.sna.2025.116211  

    ISSN: 0924-4247

  12. Room temperature wafer bonding via polysilazane for vacuum sealing bonding Peer-reviewed

    Kai Takeuchi, Eiji Higurashi

    Japanese Journal of Applied Physics 2025/02/12

    Publisher: IOP Publishing

    DOI: 10.35848/1347-4065/adb4fb  

    ISSN: 0021-4922

    eISSN: 1347-4065

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    Abstract This paper presents a novel room temperature wafer bonding method under vacuum using perhydropolysilazane (PHPS) as an adhesion layer. Vacuum wafer bonding is a critical technique for vacuum-sealed electronics packaging, such as MEMS sensors; however, conventional methods typically require high-temperature processes. In this study, we propose and demonstrate a room temperature wafer bonding approach via PHPS, enabling the formation of a robust SiO2 bonding interface. By utilizing plasma hydrophilic treatment to introduce adsorbed water at the bonding interface, the PHPS layer undergoes conversion to SiO2, even though the bonding is performed under vacuum at room temperature. While analysis of the bonding interface reveals partial desorption of the adsorbed water at the bonding interface due to the vacuum process, the achieved bond strength remains high at 3.98 J/m2. The proposed bonding method offers a promising solution for vacuum-sealing applications in electronics packaging.

  13. Plasma Hydrophilic Treatment for Improved Wafer Bonding Strength via Polysilazane

    Nemoto Daiki, Kai Takeuchi, Eiji Higurashi

    2024 International 3D Systems Integration Conference, 3DIC 2024 2024

    DOI: 10.1109/3DIC63395.2024.10830136  

  14. Formation of Au Hollow Micro-Bump Arrays for Low Temperature Au-Au Bonding

    Shintaro Goto, Kai Takeuchi, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, Eiji Higurashi

    13th IEEE CPMT Symposium Japan: Innovation of Packaging Technology for Advanced Heterogeneous Integration, ICSJ 2024 150-151 2024

    DOI: 10.1109/ICSJ62869.2024.10804723  

  15. Adhesion between Si Substrates in Liquid Water Using Inorganic Polymer

    Daiki Nemoto, Kai Takeuchi, Eiji Higurashi

    13th IEEE CPMT Symposium Japan: Innovation of Packaging Technology for Advanced Heterogeneous Integration, ICSJ 2024 168-169 2024

    DOI: 10.1109/ICSJ62869.2024.10804705  

  16. Sequential Surface Treatment Process with VUV light and Ar Plasma for Room Temperature Au-Au Bonding

    Mika Ogino, Kai Takeuchi, Eiji Higurashi

    13th IEEE CPMT Symposium Japan: Innovation of Packaging Technology for Advanced Heterogeneous Integration, ICSJ 2024 166-167 2024

    DOI: 10.1109/ICSJ62869.2024.10804698  

  17. Perhydropolysilazane as an Adhesion Layer for Vacuum Sealing Wafer Bonding

    Kai Takeuchi, Daiki Nemoto, Eiji Higurashi

    2024 8th International Workshop on Low Temperature Bonding for 3D Integration, LTB-3D 2024 2024

    DOI: 10.1109/LTB-3D64053.2024.10774106  

  18. Template Stripping Process Combined With Polyimide and SiO<inf>2</inf>/Si Templates for Obtaining Smooth Au Surfaces

    Shogo Koseki, Mika Ogino, Kai Takeuchi, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, Takahiro Tsuda, Tomoaki Tokuhisa, Toshikazu Shimizu, Eiji Higurashi

    2024 International Conference on Electronics Packaging, ICEP 2024 129-130 2024

    DOI: 10.23919/ICEP61562.2024.10535611  

  19. Investigation of Plasma Gases for Polysilazane Conversion into SiO<inf>2</inf> for Wafer Bonding

    Daiki Nemoto, Kai Takeuchi, Eiji Higurashi

    2024 International Conference on Electronics Packaging, ICEP 2024 289-290 2024

    DOI: 10.23919/ICEP61562.2024.10535633  

  20. Influence of Various Plasma and UV/O<inf>3</inf>Treatments on Au Surfaces for Au-Au Surface Activated Bonding

    Mika Ogino, Kai Takeuchi, Eiji Higurashi

    2024 International Conference on Electronics Packaging, ICEP 2024 331-332 2024

    DOI: 10.23919/ICEP61562.2024.10535697  

  21. Formation of SiO<inf>2</inf> Bonding Interface using Perhydropolysilazane at Room Temperature

    Kai Takeuchi, Daiki Nemoto, Tadatomo Suga, Eiji Higurashi

    2024 International Conference on Electronics Packaging, ICEP 2024 113-114 2024

    DOI: 10.23919/ICEP61562.2024.10535553  

  22. Optimization of Ag Thin Film Thickness with a Capping Layer for Ag-Ag Surface Activated Bonding

    Yuanhao Cai, Kai Takeuchi, Miyuki Uomoto, Takehito Shimatsu, Eiji Higurashi

    2024 International Conference on Electronics Packaging, ICEP 2024 117-118 2024

    DOI: 10.23919/ICEP61562.2024.10535599  

  23. Suppression of Surface Roughening of Ag Films by Capping Layer for Ag/Ag Surface Activated Bonding Peer-reviewed

    Yuanhao Cai, Kai Takeuchi, Miyuki Uomoto, Takehito Shimatsu, Eiji Higurashi

    2023 IEEE CPMT Symposium Japan (ICSJ) 135-136 2023/11/15

    Publisher: IEEE

    DOI: 10.1109/icsj59341.2023.10339608  

  24. Template Stripping of Au from Polyimide Film for Smoothing of Bonding Surface Peer-reviewed

    Shogo Koseki, Mika Ogino, Kai Takeuchi, Le Hac Huong Thu, Takashi Matsumae, Hideki Takagi, Yuichi Kurashima, Tomoaki Tokuhisa, Toshikazu Shimizu, Eiji Higurashi

    2023 IEEE CPMT Symposium Japan (ICSJ) 133-134 2023/11/15

    Publisher: IEEE

    DOI: 10.1109/icsj59341.2023.10339541  

  25. Conversion of Perhydropolysilazane into SiO2 using Plasma Treatment for Wafer Bonding Peer-reviewed

    Kai Takeuchi, Daiki Nemoto, Tadatomo Suga, Eiji Higurashi

    2023 18th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT) 2023/10/25

    Publisher: IEEE

    DOI: 10.1109/impact59481.2023.10348949  

  26. Hydrophilic Bonding of SiO2/SiO2 and Cu/Cu using Sequential Plasma Activation Peer-reviewed

    Kai Takeuchi, Takeki Ninomiya, Michitaka Kubota, Masaya Kawano, Takeshi Takagi, Niwa Masaaki, Tadahiro Kuroda, Tadatomo Suga

    ECS Transactions 112 (3) 95-101 2023/09/29

    Publisher: The Electrochemical Society

    DOI: 10.1149/11203.0095ecst  

    ISSN: 1938-5862

    eISSN: 1938-6737

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    Hybrid bonding is an indispensable technique for the 3D integration of electronic systems. Cu-to-Cu interconnections and SiO2-to-SiO2 dielectric layers should be bonded simultaneously in the wafer-to-wafer bonding process. In this study, sequential plasma activation (SPA) including O2 plasma, N2 plasma, and N radical is investigated for low-temperature bonding of Cu and TEOS SiO2 at 200°C. The SPA bonding improves the bond strength to more than 1 J/m2 compared to the conventional single gas plasma activation bonding. The surface analysis indicates that SPA forms oxynitrides on TEOS SiO2 surface and Cu oxide with adsorbed water on the Cu surface, facilitating the bonding interface formation. The presented technique will contribute to the hybrid bonding applications at lower temperatures.

  27. Protection of Activated Au Surface using Self-assembled Monolayer for Room Temperature Bonding Peer-reviewed

    Kai Takeuchi, Junsha Wang, Tadatomo Suga, Beomjoon Kim, Eiji Higurashi

    2023 International Conference on Electronics Packaging, ICEP 2023 173-174 2023

    Publisher: IEEE

    DOI: 10.23919/ICEP58572.2023.10129675  

  28. Removal of Adsorbed Water on Si Wafers for Surface Activated Bonding Peer-reviewed

    Kai Takeuchi, Eiji Higurashi, Junsha Wang, Akira Yamauchi, Tadatomo Suga

    2022 IEEE CPMT Symposium Japan (ICSJ) 61-64 2022/11/09

    Publisher: IEEE

    DOI: 10.1109/icsj55786.2022.10034710  

  29. A novel strategy for GaN-on-diamond device with a high thermal boundary conductance Peer-reviewed

    Fengwen Mu, Bin Xu, Xinhua Wang, Runhua Gao, Sen Huang, Ke Wei, Kai Takeuchi, Xiaojuan Chen, Haibo Yin, Dahai Wang, Jiahan Yu, Tadatomo Suga, Junichiro Shiomi, Xinyu Liu

    JOURNAL OF ALLOYS AND COMPOUNDS 905 2022/06

    DOI: 10.1016/j.jallcom.2022.164076  

    ISSN: 0925-8388

    eISSN: 1873-4669

  30. Polishing Diamond Substrates using Gas Cluster Ion Beam (GCIB) Irradiation for the Direct Bonding to Power Devices Peer-reviewed

    Junsha Wang, Kai Takeuchi, Izumi Kataoka, Tadatomo Suga

    2022 International Conference on Electronics Packaging (ICEP) 2022/05/11

    Publisher: IEEE

    DOI: 10.23919/icep55381.2022.9795483  

  31. Sequential Plasma Activation Bonding of Sapphire using SiO2 Intermediate Layer Peer-reviewed

    Kai Takeuchi, Tadatomo Suga

    2022 International Conference on Electronics Packaging (ICEP) 2022/05/11

    Publisher: IEEE

    DOI: 10.23919/icep55381.2022.9795608  

  32. Prolongation of the Surface Activation Effect using Self-Assembled Monolayer for Low Temperature Bonding of Au Peer-reviewed

    Kai Takeuchi, Beomjoon Kim, Tadatomo Suga

    2022 IEEE 72nd Electronic Components and Technology Conference (ECTC) 2022/05

    Publisher: IEEE

    DOI: 10.1109/ectc51906.2022.00103  

  33. Low-temperature bonding of surface-activated polyimide to Cu Foil in Pt-catalyzed formic acid atmosphere Peer-reviewed

    Ying Meng, Yang Xu, Runhua Gao, Xinhua Wang, Xiaojuan Chen, Sen Huang, Ke Wei, Dahai Wang, Haibo Yin, Kai Takeuchi, Tadatomo Suga, Fengwen Mu, Xinyu Liu

    JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS 33 (5) 2582-2589 2022/02

    DOI: 10.1007/s10854-021-07463-4  

    ISSN: 0957-4522

    eISSN: 1573-482X

  34. Demonstration of high thermal performance GaN-on-graphite composite bonded substrate for application in III-V nitride electronics Peer-reviewed

    Lei Li, Tomohiro Obata, Aozora Fukui, Kai Takeuchi, Tadatomo Suga, Atsushi Tanaka, Akio Wakejima

    Applied Physics Express 14 (9) 2021/09

    DOI: 10.35848/1882-0786/ac15c0  

    ISSN: 1882-0778

    eISSN: 1882-0786

  35. Low temperature bonding of GaN and carbon composite via Au capping layer activated by Ar fast atom bombardment Peer-reviewed

    Kai Takeuchi, Suga Tadatomo, Atsushi Tanaka, Akio Wakejima

    2021 International Conference on Electronics Packaging, ICEP 2021 43-44 2021/05/12

    DOI: 10.23919/ICEP51988.2021.9451955  

  36. Low temperature bonding of Cu bump to WBG device using the surface activation method Peer-reviewed

    Tadatomo Suga, Kai Takeuchi, Seongbin Shin, Nora Martinez, Yoshinari Ikeda, Akira Hirao, Motohito Hori

    2021 INTERNATIONAL CONFERENCE ON ELECTRONICS PACKAGING (ICEP 2021) 35 19-20 2021

    DOI: 10.11486/ejisso.35.0_17a3-02  

  37. Effect of Sequential Plasma Activation on Al2O3 for Low Temperature Bonding of Glass Peer-reviewed

    Kai Takeuchi, Tadatomo Suga

    2021 INTERNATIONAL CONFERENCE ON ELECTRONICS PACKAGING (ICEP 2021) 59-60 2021

  38. Surface Activated Bonding of Glass Wafers using Oxide Intermediate Layer Peer-reviewed

    Kai Takeuchi, Fengwen Mu, Yoshiie Matsumoto, Tadatomo Suga

    IEEE 71ST ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE (ECTC 2021) 2024-2029 2021

    DOI: 10.1109/ECTC32696.2021.00319  

    ISSN: 0569-5503

    eISSN: 2377-5726

  39. Evaluation of Wafer Bond Strength under Vacuum Peer-reviewed

    Kai Takeuchi, Tadatomo Suga

    2021 IEEE CPMT SYMPOSIUM JAPAN (ICSJ) 57-60 2021

    DOI: 10.1109/ICSJ52620.2021.9648866  

    ISSN: 2373-5449

  40. Surface Activated Bonding of Glass Using Aluminum Oxide Intermediate Layer for Microchannel Fabrication Peer-reviewed

    Kai Takeuchi, Fengwen Mu, Yoshiie Matsumoto, Beomjoon Kim, Tadatomo Suga

    ECS Meeting Abstracts MA2020-02 (22) 1631-1631 2020/11/23

    Publisher: The Electrochemical Society

    DOI: 10.1149/ma2020-02221631mtgabs  

    eISSN: 2151-2043

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    With a huge demand from the society on a more precise and rapid biological molecule detection in a reduced amount of biosamples, biomedical engineering technology has been in rapid development, resulting in a wide range of biosensors using microfluidic systems. For microfluidic structure, glass is still the main material owing to its chemical stability, cost efficiency, and optical characteristics. In order to seal the fluidic channel based on glass materials, glass substrates should be bonded to cover the channel grooves. Conventionally, glass materials are bonded by anodic bonding or hydrophilic bonding at high temperature process, in which the bonding surfaces are bonded via covalent bonds. However, these bondings of glass at high temperature lead to residual stress at the bonding interface and damage to the device on the substrate, especially the biomolecule sensors using enzymes. In addition to the process temperature, the bonding interface should be transparent as a wide range of biosensors utilizes optical measurements to detect biomarkers. For this reason, a room temperature bonding of glass is desirable for the microchannel sealing. As a room temperature direct bonding method of glass, modified surface activated bonding (mSAB) using Si intermediate layer has been reported to achieve a strong bond of glass via Si layers and Fe nano adhesion layers [1]. Although this approach enables the glass bonding at room temperature, the bonding interface is covered with the deposited Si layers, resulting in deteriorated optical characteristics at the bonding interface. Therefore, mSAB using Si intermediate layer is not suitable for the optical measurement of biomolecules in the microchannels. Recently, we reported a new SAB using aluminum oxide (AlO) intermediate layer instead of Si [2]. AlO has excellent optical characteristics such as low absorbance and refraction index uniformity. From the aspect of bonding, thin AlO membrane by ALD has been reported as intermediate layer for hydrophilic bonding [3]. Furthermore, it has been also reported that bulk sapphire is bonded by standard SAB process, where the sapphire surfaces are activated by Ar ion beam irradiation and bonded through amorphous-like AlO structure [4]. In this study, we apply mSAB using AlO intermediate layer for glass substrate and Si substrate with microchannel patterning. The bonding is evaluated from the perspective of the channel sealing. In order to evaluate the sealing by the proposed bonding method, microfluidic channels were realized on a 4 inch and 525 µm thick Si wafer. The patterning consists of 64x64 inlet ports 100 µm diameter, 46-142 µm wide microchannels, 4x4 mm2 cavity, and capillary pump. For the fabrication of the microfluidic components, inductively coupled plasma reactive ion etching (ICP-RIE) was employed. For the sealing of the microchannels on the Si wafer, mSAB using AlO intermediate layer was conducted. The substrates are activated by Ar ion beam and the AlO layers are deposited by ion beam sputtering, followed by contact and press. After sealing by the wafer bonding, through-glass holes were fabricated by sand blast etching to enable flow in the channels. In order to evaluate the sealing of the microfluidic system by the proposed bonding method, first, scanning acoustic tomography (SAT) was conducted. As shown in Figure, the whole structure is sealed without significant voids. Additionally, we also evaluated the sealing of the microfluidic structure by a flow test. A droplet of phosphate buffered-saline (PBS) as a model liquid of biosample was put on the inlet ports. As a result, PBS flow was observed through the microchannels and capillary pump without leakage. Therefore, it can be said that the proposed bonding method successfully sealed the microfluidic system and the bonding interface kept its transparency. From these result, it is indicated that the developed bonding method is suitable for the microchannel device fabrication by realizing a transparent bonding interface at room temperature. MMR Howlader, S. Suehara, and T. Suga. Sensors and Actuators A: Physical, 127(1):31–36, 2006. Takeuchi, F. Mu, Y. Matsumoto and T. Suga, 6th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D), Kanazawa, Japan, 2019, pp. 85-85. Ikku, M. Yokoyama, R. Iida, M. Sugiyama, Y. Nakano, M. Takenaka, and S. Takagi, 23rd International Conference on Indium Phosphide and Related Materials, May 2011, pp. 1–4. Takagi, Y. Kurashima, A. Takamizawa, T. Ikegami, and S. Yanagimachi, Jpn. J. Appl. Phys., Vol. 57, 02BA04, 2017. Figure 1 <p></p>

  41. Porous Microneedle Integrated in Paper based Glucose Sensor for Fluid Channel Interface Peer-reviewed

    Hakjae Lee, Kai Takeuchi, Yui Sasaki, Nobuyuki Takama, Tsuyoshi Minami, Beomjoon Kim

    2019 IEEE CPMT Symposium Japan (ICSJ) 39-42 2019/11

    DOI: 10.1109/icsj47124.2019.8998695  

    ISSN: 2373-5449

  42. Capillary driven porous pdms microneedle for naked-eye glucose sensor

    Hakjae Lee, Kai Takeuchi, Yui Sasaki, Nobuyuki Takama, Tsuyoshi Minami, Beomjoon Kim

    23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2019 654-656 2019

  43. Room Temperature Bonding of Quartz Glass using Aluminum Oxide Intermediate Layer Peer-reviewed

    Kai Takeuchi, Fengwen Mu, Yoshiie Matsumoto, Tadatomo Suga

    PROCEEDINGS OF 2019 6TH INTERNATIONAL WORKSHOP ON LOW TEMPERATURE BONDING FOR 3D INTEGRATION (LTB-3D) 85-85 2019

    DOI: 10.23919/ltb-3d.2019.8735327  

  44. Correction to: Functionalized microneedles for continuous glucose monitoring (Nano Convergence, (2018), 5, 1, (28), 10.1186/s40580-018-0161-2)

    Kai Takeuchi, Beomjoon Kim

    Nano Convergence 5 (1) 2018/12/01

    Publisher: Korea Nano Technology Research Society

    DOI: 10.1186/s40580-018-0169-7  

    ISSN: 2196-5404

  45. Functionalized microneedles for continuous glucose monitoring Peer-reviewed

    Kai Takeuchi, Beomjoon Kim

    Nano Convergence 5 (1) 2018/12

    DOI: 10.1186/s40580-018-0161-2  

    ISSN: 2196-5404

    eISSN: 2196-5404

  46. Mechanism of bonding and debonding using surface activated bonding method with Si intermediate layer Peer-reviewed

    Kai Takeuchi, Masahisa Fujino, Yoshiie Matsumoto, Tadatomo Suga

    JAPANESE JOURNAL OF APPLIED PHYSICS 57 (4) 2018/04

    DOI: 10.7567/JJAP.57.04FC11  

    ISSN: 0021-4922

    eISSN: 1347-4065

  47. Room temperature bonding and debonding of polyimide film and glass substrate based on surface activate bonding method Peer-reviewed

    Takeuchi Kai, Fujino Masahisa, Matsumoto Yoshiie, Suga Tadatomo

    Japanese Journal of Applied Physics 57 (2) 02BB05-02BB05 2018/01/15

    DOI: 10.7567/jjap.57.02bb05  

    ISSN: 0021-4922

    eISSN: 1347-4065

  48. A Porous Microneedle Array Connected to Microfluidic System for ISF Collection Peer-reviewed

    Kai Takeuchi, Nobuyuki Takama, Beomjoon Kim, Kirti Sharma, Patrick Ruther, Oliver Paul

    2018 IEEE CPMT SYMPOSIUM JAPAN (ICSJ) 85-88 2018

    DOI: 10.1109/icsj.2018.8602945  

    ISSN: 2373-5449

  49. Room Temperature Temporary Bonding of Glass Substrates Based on SAB Method Using Si Intermediate Layer Peer-reviewed

    Kai Takeuchi, Masahisa Fujino, Tadatomo Suga

    IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY 7 (10) 1713-1720 2017/10

    DOI: 10.1109/TCPMT.2017.2731621  

    ISSN: 2156-3950

    eISSN: 2156-3985

  50. Bonding and Debonding of Si/Glass based on SAB Method Combined with Hydrophilic Treatment Peer-reviewed

    K. Takeuchi, Y. Matsumoto, T. Suga

    Extended Abstracts of the 2017 International Conference on Solid State Devices and Materials 2017/09/21

    Publisher: The Japan Society of Applied Physics

    DOI: 10.7567/ssdm.2017.h-4-04  

  51. Room temperature bonding and debonding of PI film and glass substrate based on SAB method Peer-reviewed

    K. Takeuchi, M. Fujino, Y. Matsumoto, T. Suga

    2017 5th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D) 2017/05

    Publisher: IEEE

    DOI: 10.23919/ltb-3d.2017.7947434  

  52. Modified Surface Activated Bonding Using Si Intermediate Layer for Bonding and Debonding of Glass Substrates Peer-reviewed

    K. Takeuchi, M. Fujino, T. Suga

    ECS Transactions 75 (9) 185-189 2016/09/23

    Publisher: The Electrochemical Society

    DOI: 10.1149/07509.0185ecst  

    ISSN: 1938-6737

    eISSN: 1938-5862

  53. Direct Bonding and Debonding of Glass Wafers for Handling of Ultra-thin Glass Sheets Peer-reviewed

    Kai Takeuchi, Masahisa Fujino, Tadatomo Suga

    2016 International Conference on Electronics Packaging (ICEP) 298-301 2016

  54. Room Temperature Bonding and Debonding of Ultra-Thin Glass Substrates for Fabrication of LCD Peer-reviewed

    Kai Takeuchi, Masahisa Fujino, Tadatomo Suga

    2016 IEEE 66TH ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE (ECTC) 1284-1289 2016

    DOI: 10.1109/ECTC.2016.145  

    ISSN: 0569-5503

  55. Room temperature direct bonding and debonding of polymer film on glass wafer for fabrication of flexible electronic devices Peer-reviewed

    K. Takeuchi, M. Fujino, T. Suga, M. Koizumi, T. Someya

    2015 IEEE 65th Electronic Components and Technology Conference (ECTC) 2015/05

    Publisher: IEEE

    DOI: 10.1109/ectc.2015.7159668  

  56. Room temperature direct bonding and debonding of polyimide film on glass wafer using Si intermediate layer Peer-reviewed

    K. Takeuchi, M. Fujino, T. Suga, M. Koizumi, T. Someya

    2015 International Conference on Electronic Packaging and iMAPS All Asia Conference (ICEP-IAAC) 2015/04

    Publisher: IEEE

    DOI: 10.1109/icep-iaac.2015.7111037  

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Misc. 19

  1. Fabrication of hollow micro-bump arrays by Au thin film transfer

    後藤慎太郎, 竹内魁, 日暮栄治, LE Hac Huong Thu, 松前貴司, 高木秀樹, 倉島優一

    センサ・マイクロマシンと応用システムシンポジウム(CD-ROM) 41st 2024

  2. Room-temperature bonding of wafers with Au thin films using sequential surface treatment by VUV light and Ar plasma

    荻野美佳, 竹内魁, 日暮栄治

    センサ・マイクロマシンと応用システムシンポジウム(CD-ROM) 41st 2024

  3. Adhesion between Si Substrates in Liquid using Polymeric Precursor of SiO2

    根本大輝, 竹内魁, 日暮栄治

    センサ・マイクロマシンと応用システムシンポジウム(CD-ROM) 41st 2024

  4. Wafer bonding via Perhydropolysilazane at room temperature

    竹内魁, 根本大輝, 日暮栄治

    センサ・マイクロマシンと応用システムシンポジウム(CD-ROM) 41st 2024

  5. Au flat micro-bump arrays fabricated by transfer and coining of Au thin films

    後藤慎太郎, 竹内魁, LE Hac Huong Thu, 松前貴司, 高木秀樹, 倉島優一, 日暮栄治

    マイクロエレクトロニクスシンポジウム論文集 34th 2024

    ISSN: 2434-396X

  6. Surface smoothing of Au plated films by template stripping using polyimide films

    小関奨吾, 荻野美佳, 竹内魁, LE Hac Huong Thu, 松前貴司, 高木秀樹, 倉島優一, 津田貴大, 清水寿和, 徳久智明, 日暮栄治

    エレクトロニクス実装学会講演大会講演論文集(CD-ROM) 38th 2024

    ISSN: 1880-4616

  7. Effect of Water on Wafer Bonding Interface

    Kai Takeuchi

    Journal of The Japan Institute of Electronics Packaging 26 (5) 434-440 2023/08/01

    Publisher: Japan Institute of Electronics Packaging

    DOI: 10.5104/jiep.26.434  

    ISSN: 1343-9677

    eISSN: 1884-121X

  8. Passivation of Activated Au Surface for Low Temperature Bonding

    竹内魁, 日暮栄治, KIM Beomjoon, WANG Junsha, 須賀唯知

    センサ・マイクロマシンと応用システムシンポジウム(CD-ROM) 40th 2023

  9. 2nd quantized state oscillation in a gain switched 925nm-band QW-LD and its suppression

    古戸颯真, CUI Yuwen, 竹内魁, 山田博仁, 横山弘之, 日暮栄治

    応用物理学会秋季学術講演会講演予稿集(CD-ROM) 84th 2023

    ISSN: 2758-4704

  10. Progress and future perspective of room-temperature bonding technologies for heterogeneous integration

    日暮栄治, 竹内魁

    電子情報通信学会技術研究報告(Web) 123 (142(CPM2023 10-22)) 2023

    ISSN: 2432-6380

  11. Second-quantized-state laser oscillation dynamics of a 925nm-band QW-LD under strong pulsed excitation

    CUI Y., 安食聡一郎, 竹内魁, 竹内魁, 日暮栄治, 日暮栄治, 山田博仁, 山田博仁, 山田博仁, 横山弘之, 横山弘之

    応用物理学会春季学術講演会講演予稿集(CD-ROM) 70th 2023

    ISSN: 2436-7613

  12. GaN/カーボン材料の低熱抵抗界面を目的としたAu低温接合

    竹内 魁, 須賀 唯知, 田中 敦之, 分島 彰男

    精密工学会学術講演会講演論文集 2021S 699-700 2021/03/03

    Publisher: 公益社団法人 精密工学会

    DOI: 10.11522/pscjspe.2021s.0_699  

    More details Close

    GaNを用いたパワーデバイスの実装では、効率の良い放熱のためにカーボン材料をGaNに接合する必要がある。その際カーボン材料の表面粗さやGaNデバイスへのダメージ低減のため、接合荷重や接合温度に制限が生じる。本研究では、Ar原子ビームによって活性化した Au薄膜を介することで、GaN/カーボン材料の150°Cでの大気中接合を達成した。

  13. アルミシリケートガラスの低温接合のためのシーケンシャルプラズマ活性化のAl2O3への影響

    竹内 魁, 須賀 唯知

    エレクトロニクス実装学術講演大会講演論文集 35 18C4-05 2021

    Publisher: 一般社団法人エレクトロニクス実装学会

    DOI: 10.11486/ejisso.35.0_18c4-05  

  14. 表面活性化によるGaN/カーボン材のAu層を介した低温接合

    竹内 魁, 須賀 唯知, 田中 敦之, 分島 彰男

    エレクトロニクス実装学術講演大会講演論文集 35 17A3-03 2021

    Publisher: 一般社団法人エレクトロニクス実装学会

    DOI: 10.11486/ejisso.35.0_17a3-03  

  15. SiC/Ni中間層を用いたGaN基板の常温接合

    竹内 魁, 須賀 唯知, Mu Fengwen, 魚本 幸, 島津 武仁

    エレクトロニクス実装学術講演大会講演論文集 35 17A3-04 2021

    Publisher: 一般社団法人エレクトロニクス実装学会

    DOI: 10.11486/ejisso.35.0_17a3-04  

  16. 表面活性化による異種材料接合と界面形成—Bonding and Interfaces of Dissimilar Materials by Means of Surface Activation Method—特集 セラミックスコーティングの新潮流 : 界面制御が拓く新しい機能

    須賀 唯知, 竹内 魁

    Ceramics Japan = セラミックス : bulletin of the Ceramic Society of Japan 55 (10) 716-719 2020/10

    Publisher: 日本セラミックス協会

    ISSN: 0009-031X

  17. Functionalized microneedles for continuous glucose monitoring

    Kai Takeuchi, Beomjoon Kim

    NANO CONVERGENCE 5 2018/10

    DOI: 10.1186/s40580-018-0161-2  

    ISSN: 2196-5404

  18. Fabrication of biodegradable porous microneedle

    Morishita Yasuhisa, Takeuchi Kai, Takama Nobuyuki, Kim Beomjoon

    Proceedings of JSPE Semestrial Meeting 2018 734-735 2018

    Publisher: The Japan Society for Precision Engineering

    DOI: 10.11522/pscjspe.2018A.0_734  

  19. Direct Bonding and Debonding of PI film and Glass Wafer using Si intermediate layer for TFT fabrication

    Proceedings of JIEP Annual Meeting 29 537-540 2015

    Publisher: The Japan Institute of Electronics Packaging

    DOI: 10.11486/ejisso.29.0_537  

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Research Projects 5

  1. Creation of fundamental technology on room-temperature bonding through nano-interface control

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2024/04/01 - 2026/03/31

  2. ナノ界面制御による常温接合基盤技術の創出

    日暮 栄治, 竹内 魁

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(B)

    Institution: 東北大学

    2023/04/01 - 2026/03/31

  3. 常温接合技術に基づく耐腐食性接合界面の創出

    竹内 魁

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 若手研究

    Category: 若手研究

    Institution: 東北大学

    2023/04 - 2026/03

  4. 高出力用光学素子実装のための直接接合技術の開発

    竹内魁

    Offer Organization: 公益財団法人 天田財団

    System: 奨励研究助成(若手研究者枠)

    Institution: 明星大学

    2021/10 - 2024/03

  5. 光学素子実装のための酸化アルミニウム中間層を介したガラス材料の常温透明接合

    竹内魁

    Offer Organization: 公益財団法人 精密測定技術振興財団

    System: 研究助成

    Category: 助成金

    Institution: 明星大学

    2021/04 - 2022/03

Teaching Experience 2

  1. 学生実験A 東北大学

  2. 学生実験D 東北大学