NNFC

Conference General Chair of JCK MEMS/NEMS 2023
Ph. D., Jeongdai JOTitle:
Applications of MEMS piezo-resistive force sensors
Abstract:
Biography:[ To be announced on online. ]Title:Empowering MEMS: A journey towards self-powered MEMS technologies

Abstract:
Micro-Electro-Mechanical Systems (MEMS) play a vital role in wide range of industries,
including consumer electronics, healthcare and environmental monitoring. However, foractive operation of these system a content and steady energy supply is highly essential thatcan limit their functionality and make them less reliable. To address these challenges, selfpowered MEMS has emerged as a promising solution. These devices are capable generates
its own electrical energy and store it for later use, eliminating the need for external powersources and enhances the reliability and sustainability of MEMS devices. There are several
pathways to achieve self-powering in MEMS via the integration of various energy harvesters(such as triboelectric, piezoelectric, moisture electric devices) with flexible energy storage(planner and micro SCs) systems in both intrinsic and extrinsic configuration. Eachapproach has its own advantages and disadvantages, and the optimum solution will dependon the specific requirements of the MEMS device and its operating environment. Finally, we
provide an overview of the growing problems, tactics, and possibilities for the developmentof new and innovative self-powered MEMS, and IOT devices.

Biography:
Dr. Sang-Jae Kim is a professor in the Department of Mechatronics Engineering and theDepartment of Advanced Convergence Technology and Science at Jeju National
University, Republic of Korea. He received his Ph.D. degree in Electrical Communication
Engineering from Tohoku University, Japan.
He was a visiting research scholar in the materials science department at the University ofCambridge, UK, and the Georgia Institute of Technology, USA as well as a seniorresearcher at the National Institute of Materials Science (NIMS), Japan.
His research disciplines are based on nanomaterials and systems for energy andelectronics applications, covering Josephson devices, MEMS, and Nano biosensors.
He is member of Korea Academy of Science and Technology (KAST) and publishedresearch articles over 300 in SCI journal (with citation over 18,845 times, and an H-index
of 73 (by google scholar) and 30 patents (Int. Pat. 10).

Title:MEMS techniques towards self-powered sensing and human-machineinteraction
Abstract:
This talk will introduce our research on MEMS energy harvesting and sensing techniques
towards divisive self-powered sensing systems and intelligent human-machine interaction.
We integrated piezoelectric-based vibration energy harvester and vibration sensor as selfpowered wireless sensing nodes for status monitoring. We developed flexible andstretchable self-powered sensing skin for industrial and soft robot, thus realizing intelligent
feedback control systems. Intelligent skin with multi-information sensing can greatly
improve the environment adaptability and autonomous working ability of robot. We also
carried out in-depth innovation research on human-machine interface in 3D space based on
piezoresistive 3D force sensing, self-powered triboelectric parallel mechanism and silent
speech interaction based on epidermal electronic system, so as to provide technical support
for intelligent medical and healthcare fields.

Biography:
Huicong Liu is currently a Professor with the Robotics and Microsystems Center, Schoolof Mechanical and Electrical Engineering, Soochow University, China. She received theB.Eng. and M.Sc. Degrees from the Department of Mechanical Engineering, Universityof Science and Technology Beijing, China, in 2006 and 2008, respectively, and the Ph.D.
degree from the Department of Mechanical Engineering, National University ofSingapore (NUS), in 2013.
She was a Research Fellow with the Department of Electrical and Computer Engineering,
NUS, from 2012 to 2013. Her research interests are vibration-based MEMS/NEMS
energy harvesters, self-powered MEMS/NEMS system for IoTs, flexible and intelligent
sensing for human-machine interface. She has contributed two academic books. Morethan 110 academic papers have been published, including 42 SCI papers.
Her work has been cited for more than 4100 times. She was the co-chairman of the 2nd
International Conference on Vibration Energy Harvesting (VEH 2019), TPC member ofIEEE NEMS 2018, 2019 and 2021, TPC member of Bio4apps 2018/2019, TPC memberof Transducers 2021.

Empowering MEMS: A journey towards self-powered MEMS technologiesThe 14th Japan-China-Korea Joint Conference on MEMS/NEMS

CMP Technology for Heterogeneous Integration#

Haedo Jeong1

1 School of Mechanical Engineering, Pusan National University. Busan, 46241, Republic of Korea# Corresponding Author / E-mail: hdjeong@pusan.ac.kr, TEL: +82-51-510-2463, FAX: +82-51-518-8442

ABSTRACT
Semiconductor industry is facing the end of Moore's law and the emergence of a new paradigm of More-than-Moore
for the development of 3D heterogeneous integration. Recently, ChatGPT opened a new AI chip market by GPU with
HBM. When considering AI device chips, GPU with HBM is the one of the most optimal solutions to achieve highparallel processing ability. 3D heterogeneous integration with chiplet design and advanced packaging is accelerating
system diversification and industrial changes. The advanced packaging architecture has changed from 2D to RDL 2.1D
and TSV 2.5D and then microbump or bumpless 3D structure. This paper focuses on CMP technology to make planar
surfaces for 2.1D, 2.5D and 3D integration. An one step CMP was done on 2.1D large sized package for making RDL
directly using an optimized slurry. Chemical additives were adjusted to 2.5wt% H 2O2, 5wt% glycine and 0.2wt% BTA.
The step height was less than 1/1000 against both 160um and 370um copper patterns. Then, 2.5D TSV CMP also
successfully realized with 0.1um dishing amount in 2min by choosing TTA inhibitor. Planarization for 3D integration by
bumpless hybrid bonding is going on to realize dishing amount less than 5nm which is a rule of 1/1000 of pattern size.
Post CMP cleaning is another hot issue to realize ideal hybrid bonding for 3D heterogeneous integration.
Keywords : More-than-Moore, Heterogeneous integration, CMP, Dishing1.

Introduction
This study is focused on the development of a novel CMP process, which can maintain surface roughness below 10
nm on polymers and minimize the step height to less than 100 nm, which occurs from the simultaneous removal ofpolymer and copper patterns. For evaluating the CMP performance, RDL on a FCBGA substrate and Oscar-type CMP
tool developed by G&P Technology were used, as shown in Fig. 1 and 2.

Fig. 1. RDL on a FCBGA substateFig. 2. CMP tool for planarization of advanced packaging substrate2.

Chemical mechanical planarization
Fig.3 shows the cross-sectional images before and after CMP. The polymer on the copper patterns was removed withtime. The copper dishing occurred as the slurry was chemically strong, which requires chemical mechanical balance.

<Chemical attack ><Chemical attack >Fig.3 Cross-sectional images before and after CMP

Fig. 4. Dishing amount according to contents of H2O2
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2.1 Oxidizer
To study the effect of chemical reaction rate, the H 2O2 was used from 0 to 2 wt% as an oxidizer. For the case inwhich H2O2 was not added, approximately 4 µm of excessive polymer was observed, as shown in Fig. 4. However, theamount of excessive removal of copper increased with the amount of H2O2.
2.2 Complexing agent
Glycine (C2H5NO2) was used as a complexing agent from 0 to 3wt%. As shown in Fig. 5 (left), approximately 0.1µm of excessive removal of the polymer was observed when glycine was not added. As the added amount increased, thecopper removal rate increased and resulted in excessive removal of copper. This is because of the decrease in the copper
ions on the surface owing to their combination with glycine to produce stable complexes.
2.3 Corrosion inhibitor
The added amount of benzotriazole (BTA, C6H5N3) which is used as a corrosion inhibitor by varying BTA from 0 to
2 wt%. As shown in Fig. 5 (right), When BTA was added, a Cu-BTA layer was formed on the surface and inhibited
oxidation, resulting in reduction in excessive removal. However, with increase in the added amount of BTA, excessive
removal of polymer was observed. This was due to the formation of a thick Cu-BTA layer and the failure of effective
formation of a Cu oxide layer with the increase in the added amount of BTA.

Fig. 5. Dishing amount and chemical reaction mechanism according to glycine (Left), and BTA (Right)
3.

CONCLUSION
The selectivity between polymer and copper was controlled to investigate the possibility of creating microcircuits tomeet to increase in I/O per unit area of semiconductor chips and develop advanced package substrates for highspeed communication between dies. Polymer planarization was conducted focusing on mechanical elements to obtaina surface with a roughness of 10nm Ra or lower by controlling polishing abrasives. Then, the study investigated vari
ous selectivity between the polymer and copper according to contents of oxidizer, complexing agent, and corrosion inhibitor. Finally, the most optimal chemical compositions of 0.5, 1 and 0.5wt% of H2O2, glycine, and BTA, respective
ly, were achieved, resulting in a step height lower than 25nm. The obtained results could be effectively applied in theplanarization of the outer most layer of a substrate.

REFERENCES
1. S. Jang, H. Jeong, M. Yuh, I. Park and J. Park, Effect of glycine on copper CMP, Int. J. Precis. Eng. Manuf.-Green
Tech., 3 (2) (2016) 155-159.
2. H. Kim and H. Jeong, Effect of process conditions on uniformity of velocity and wear distance of pad and wafer
during chemical mechanical planarization, J. of Electronic Materials, 33 (1) (2004) 53-60.
3. A. Lancaster and M. Keswani, Integrated circuit packaging review with an emphasis on 3D packaging, Integration,
the VLSI Journal, 60 (2018) 204-212.
4. S. Jang, H. Jeong, M. Yuh and J. Park, Effect of surfactant on package substrate in chemical mechanicalplanarization, Int. J. Precis. Eng. Manuf.-Green Tech., 2 (1) (2015) 59-63.
5.
S. Pandija, D. Roy and S. V. Babu, Achievement of high planarization efficiency in CMP of copper at a reduced
down pressure, Microelectronic Engineering, 86 (3) (2009) 367- 373.
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MEMS Gas Sensor using Low Power Micro Platform andNano-structured Materials
Jun-gu Kang1,2, Tae-yil Eom1,2, Minwoo Cho2, Kwang-Bum Park1, #Hoo-Jeong Lee2, #Joon-Shik Park1
1

Smart Sensor Research Center, Korea Electronics Technology Institute, Seongnam, Kyunggi 13509, Rep. of Korea
2 School of Materials Science and Engineering, Sungkyunkwan University, Suwon, Kyunggi 16419, Rep. of Korea# Corresponding Author / E-mail: hlee@skku.edu, TEL: +82-31-290-7365#

Corresponding Author and Presenter / E-mail: jspark@keti.re.kr, TEL: +82-31-789-7278

ABSTRACT
In order to realize the portable type artificial or electronic nose system, micro gas sensor array is one ofindispensable components. Micro gas sensor array generally consists of various MEMS gas sensors to discriminate
versatile gases from environmental or human body. A MEMS gas sensor consists of MEMS platform to control
operation temperatures and functionalized nanostructured gas sensing materials. In this presentation, our research
results in terms of MEMS gas sensors using low power micro platforms and nano-structured materials such as thin films
and nanoparticles shapes will be presented and discussed in terms of operation temperature, gas response, andselectivity. Also, the gas sensing performance of designed and fabricated micro gas sensor array will be described.
Keywords : MEMS, Gas, Sensor, Array, Low power, Nano-structured materials
ACKNOWLEDGEMENTS
These researches were done through several research government projects, International Collaboration Program (No.
P0006858), ATC Program (No. 10076984), and partially K-Sensor Program RS-2022 00154983 supported by Ministryof Trade, Industry and Energy (MOTIE) in Rep. of Korea.
.
CURRICULUM VITAE

Joon-Shik Park received his B.S., M.S., and Ph.D degrees in Materials Science and Engineering from Hanyang
University, Seoul, Rep. of Korea in 1992, 1994, and 2004, respectively. Since 1994, he has researched piezoelectric
micro actuators, micro and nano gas sensors, micro fluidic devices for micro TAS, flexible sensors, and smart band forphysiological signal monitoring as a chief researcher at Korea Electronics Technology Institute (KETI) in Rep. of Korea.
From August 2007 to August 2009, he researched electrical and optical properties of individual Ge nanowires
synthesized using VLS mechanism as a visiting scholar at Dept. of Materials Science and Engineering of Stanford
University. Since 2002, he has worked in terms of the international standardization at IEC TC47/SC47F (MEMS),
TC119 (Printed Electronics), and SEG14 (Quantum Technologies).

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Vacuum Drying Process for High-Performance Inkjet-Printed
QLED/OLED Devices#

kwan Hyun Cho1, Jun Young Hwang1 and Sang-Ho Lee1

1 Digital Transformation R&D Dept., Korea Institute of Industrial Technology (KITECH), 143, Hanggaul-ro, Sangnok-gu, Ansan-si,
15588, Korea# Corresponding Author / E-mail: khcho@kitech.re.kr, TEL: +82-31-8040-6428, FAX: +82-31-8040-6430

ABSTRACTThe application of inkjet technology has already led to the commercialization of Thin Film Encapsulation and
Quantum Dot-Organic Light Emitting Diodes (QD-OLEDs) technologies. Recently, there has been a growing interest in
applying inkjet technology for the fabrication of Organic Light Emitting Diode (OLED) and Quantum Dot LightEmitting Diode (QLED) display pixels. To achieve improved performance in inkjet OLED/QLED devices, a uniform
drying process is indispensably required. In this work, our objective is to address enhancements in both intra-pixel andinter-pixel uniformity during the drying process of inkjet printing technology. We conducted a comprehensive analysisof the drying characteristics of various mixed solvent boiling points under atmospheric pressure (N2 conditions).
Additionally, we investigated the drying characteristics of high boiling point (BP) solvents under Gelation flow (GF)
condition control during the vacuum drying process. Optical microscope images, atomic force microscopy (AFM)
images, and thickness profiles were carefully examined in accordance with the printed positions, including the top,
center, bottom, and left parts of the inkjet-printed array. It is evident that achieving not only uniform thin film formation
but also the complete removal of residual solvents is crucial. This has been substantiated through the fabrication of
OLED devices.
Keywords: Inkjet, Drying, Vacuum, OLED, Quantum dot
1.

INTRODUCTION
Quantum dot light-emitting diode (QLED) displays have the potential to achieve high brightness, a wide color gamut,
and low power consumption. Thanks to the dedicated efforts of numerous researchers, the efficiency and lifetime ofself-emissive QLEDs using spin-coating techniques have nearly reached the level of commercialization [1-2]. In orderto realize high-resolution, full-color QLED displays for industrial applications, inkjet printing technology is crucial for
accurately depositing quantum dots (QDs) at the required pixels. However, the performance of inkjet-printed full-color
QLED devices falls significantly short of their spin-coated counterparts. This performance gap can be attributed to theissue of film non-uniformity that inevitably arises during the drying process of QD ink within the pixel after the inkjet
process. Overcoming this challenge of achieving uniform and high-resolution inkjet-printed patterns with robust
stability has proven complex, largely due to the coffee-ring effect during solvent evaporation [3-4].
In this study, we aim to investigate the technical challenges and current research trends associated with achieving
uniform OLED/QD film formation using inkjet printing technology. A significant amount of research is being
conducted to create uniform inkjet-printed patterns by balancing Capillary and Marangoni flows using a combination of
low and high vapor pressure solvents. Here, we will introduce a vacuum drying process aimed at enhancing theuniformity and overall film quality of the inkjet-printed layer. This process will involve employing a co-solvent systemwith an extremely low vapor pressure, particularly suited for QLED/OLED applications.
2.

Vacuum Drying Process using high BP mixed solvents

2.1 Drying characteristics of various mixed solvent boiling points under atmospheric pressure
Recently, high boiling point solvents have been widely adopted in the manufacturing of QLED/OLED using inkjet technology, as they contribute to improving the inkjet jetting stability. We carefully examined the drying characteristics under atmospheric pressure by utilizing various mixed solvent boiling points. As shown in Figure 1, the wicking phenom
enon decreased as the boiling point of the mixed solvent decreased, but positional nonuniformity within the printed array increased. On the other hand, higher boiling point solvents led to a reduction in positional nonuniformity, but an incre
ase in drying time resulted in an increased wicking phenomenon within the pixels, leading to significant internal nonuniformity.

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Figure 1. (a) Optical microscope (OM) images of the top, center, and bottom parts of inkjet-printed 48x16 pixel arrays withdifferent mixed solvents, (b) Drying outcomes of high boiling point and low boiling point solvents, (c) Vapor pressure distribution
prediction of inkjet-printed substrates using high boiling point and low boiling point solvents.

2.2 Drying characteristics of high-boiling point solvent
The inkjet printed ink on the pixel first undergoes microflow involving Capillary flow and Marangoni flow, followedby the cessation of microflow. However, the cessation of microflow does not necessarily indicate complete removal ofresidual solvents from the inkjet printed film. After the microflow comes to a halt, residual solvents evaporate in the drying environment, leading to the occurrence of Gelation flow. As depicted in Figure 2, various Gelation flow (GF) condit
ion controls show the thickness profile of the final film. As shown in Figure 2, it can be observed that compared
to applying vacuum pumping and heating in a state with a significant amount of residual solvent, applying va
cuum pumping and heating after sufficient evaporation of residual solvent leads to the complete removal of residual solvent, enabling the production of a uniform film.

Figure 2. 3D profile (left) images of center part and positional thickness profile (right) of high BP solvents under Gelation flow(GF) condition control during vacuum drying process; (a) HV, (b) Heat(LV), (c) HV+Heat(LV), and Heat(HV).

3.

CONCLUSION
The application of inkjet printing technology to OLED/QLED manufacturing holds the promise of advancing display
technology, improving production efficiency, and enabling new forms of displays that were previously challenging toachieve. For improved performance in inkjet OLED/QLED devices, a uniform drying process is indispensably required.
High boiling point solvents have favorable attributes for enhancing ink jetting capability and promoting the formationof large-area uniformly deposited ink films. In this study, we examined the necessary vacuum drying conditions using
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high boiling point solvents for the fabrication of high-performance QLED/OLED devices.
ACKNOWLEDGEMENT
This study was conducted with the support of the Ministry of Trade, Industry and Energy (MOTIE, Grant No. 20010
510) andkjet technology for self-luminous quantum dot display (kitech EM.
REFERENCES
1. Yu-Ho Won, Oul Cho, Taehyung Kim, Dae-Young Chung, Taehee Kim, Heejae Chung, Hyosook Jang, Junho Lee,
Dongho Kim & Eunjoo Jang, Highly efficient and stable InP/ZnSe/ZnS quantum dot light-emitting diodes. Nature
575, 634 638, 2019.
2. Taehyung Kim, Kwang-Hee Kim, Sungwoo Kim, Seon-Myeong Choi, Hyosook Jang, Hong-Kyu Seo, Hee
jae Lee, Dae-Young Chung & Eunjoo Jang, Efficient and stable blue quantum dot light-emitting diode, N
ature 586 (7829), 385-389, 2020.
3. Congbiao Jiang, Zhiming Zhong, Baiquan Liu, Zhiwei He, Jianhua Zou, Lei Wang, Jian Wang, JunBiao
Peng, and Yong Cao, Coffee-Ring-Free Quantum Dot Thin Film Using Inkjet Printing from a Mixed-Solv
ent System on Modified ZnO Transport Layer for Light-Emitting Devices, ACS Appl. Mater. Interfaces, 8,.
4. Siqi Jia, Haodong Tang, Jingrui Ma, Shihao Ding, Xiangwei Qu, Bing Xu, Zhenghui Wu, Guangyu Li, Pai Liu,
Kai Wang, Xiao Wei Sun, High Performance Inkjet-Printed Quantum-Dot Light-Emitting Diodes with HighOperational Stability, Adv. Optical Mater., 9, 2101069, 2021.

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Direct writing of elastic conductors for three-dimensional skinmountable electronics
Seungjun Chung1,2
Soft Hybrid Research Center, Korea Institute of Science and Technology, Seoul 02792, Korea
2
KU-KIST Graduate School of Converging Science & Technology, Korea University, Seoul 02841, Korea# Corresponding Author / E-mail: seungjun@kist.re.kr, TEL: +82-2-958-5305
1

ABSTRACT
Printing technologies have attracted tremendous attention in the realization of customized soft electronics due to theiradvantages, such as non-vacuum, low-temperature, and non-contact processability. In this work, we report printing ofsolid-state elastic conductors that can demonstrate self-standing three-dimensional (3D) geometries. A pneumatic direct
ink writing system is employed to deposit well-defined printed 3D patterns. For the ink preparation,
polydimethylsiloxane (PDMS), Ag particles, and multi-walled carbon nanotubes were used as the elastomeric matrix,
conductive fillers, and auxiliary fillers for improving their stretchability, respectively. Our omnidirectional printing
strategies achieve superior viscoelastic properties that provide the structural integrity of printed features, andpseudoplastic and lubrication behaviors that allow great printing stability simultaneously. It would promise the design
diversity of soft electronics.
Keywords : conductive composite, elastomer, stretchable, direct ink writing, wearable electronics
1. INTRODUCTION
Printing technologies have attracted tremendous attention in the realization of customized soft electronics due to theiradvantages, such as non-vacuum, low-temperature, and non-contact processability.[1-2] Three-dimensional (3D) direct
ink writing (DIW) has attracted substantial attention as a promising process due to its high degree of design freedom
upon demand which is beneficial from the perspective of manufacturing. In this frame, DIW has been employed torealize emerging customized stretchable applications, such as displays, sensors, and printed circuit boards.[2-3] To
demonstrate highly reliable stretchable devices, their interconnects which is a key building block must be sufficiently
stretchable maintaining their conductivity under mechanical deformation.
In this work, we report highly reliable, intrinsically stretchable solid-state composites patterned by using DIW
technologies. We successfully demonstrate printing of solid-state elastic conductors into self-supporting threedimensional (3D) geometries enabling complex, multifunctional, and tailored human-machine interfaces. To meet therequirements of stretchable conductors, e.g. stretchability, conductivity, and printability, we systematically investigatedthe electrical and mechanical performance of stretchable conductors and the rheological behaviors of elastomer
conductive composites depending on the amounts of conductive fillers. To illustrate the feasibility of our intrinsicallystretchable conductors, we demonstrate skin-mountable stretchable devices capable of operating reliably under various
mechanical deformations and believe that our results promise the design diversity of soft electronics.
2. RESULTS AND DISCUSSION
To prepare our elastic conductive composites, we used Polydimethylsiloxane (PDMS, a Sylgard 184 base and curing
agent kit), silver microparticles (AgMPs), and multi-wall carbon nanotubes (MWCNTs) as the matrix, conductive fillers,
170 nm and a length of 5
1PHR MWCNTs and 12 ml CHCl3 were added in this work, and then ultrasonic treatment was conducted for 1 h toprepare well-dispersed composites. After adding PDMS (0.91 g), AgMPs were mixed at 2000 rpm for 7 min using arotation/revolution mixer. Sequentially, magnetic stirring was performed for 3 h at room temperature, and then thesolvent was evaporated at room temperature for 24 h. After complete evaporation, 0.091 g of curing agent was added
and then 0.6 g of CHCl3 was added. Finally, 0.3 g of diethylene glycol (DEG) was added to the multi-solvent system.
The viscosity and elasticity of the pastes were measured with a modular compact rheometer system (MCR 702e, Anton
Paar) and conductivity was measured using a homemade 4-point probe measurement system. The reduced modulus wasevaluated by a nanoindenter (TI950 Triboindenter, Hysitron). For DIW, our inks were printed using a programmablepneumatic dispenser (ML-808GX associated with SHOTmini 200Sx, Musashi Eng.) with a nozzle ranging from 26 togram (AutoCAD 2020). The directly
printed elastic conductors were dried in a 180 °C oven for 2 h to eliminate the solvents.
To provide elasticity, PDMS was used as an elastic matrix of a conductive composite because it has beneficial
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properties of high elasticity, chemical stability, transparency, and biocompatibility. As a conductive filler, low-cost
AgMPs with a diameter of 2also mixed into the PDMS/AgMPs composites.[4] Finally, the PDMS-based paste was diluted by adding CHCl3 andDEG. Our AgMP elastomer composite exhibits excellent electrical conductivity and printability by creating surfacelocalized two-dimensional percolation paths and preventing energy dissipation between AgMPs, enabling better
extrusion without aggregation. The prepared paste was printed using a programmable pneumatic dispenser.
3. CONCLUSION
conductors simultaneously. In particular, DEG can form an immiscible dispersed phase in the paste which indicates ourpaste is an emulsion system. Using the elastomeric composites, we could demonstrate direct printing of the freestanding,filamentary, and out-of-plane 3D geometries, achieving a minimum feature with a width oprintability. The feasibility of our approach was visualized by demonstrating skin-mountable electronics including
matrix-type stretchable display based on omnidirectionally printed elastic interconnects.[5]ACKNOWLEDGEMENT
The author appreciates the support from the National R&D Program through the National Research Foundation of
Korea (NRF) funded by the Ministry of Science and ICT (NRF2020M3D1A2101799) and the Korea Institute of
Science and Technology (KIST) Future Resource Research Program (2E32501).
REFERENCES
1.
-integrated wireless haptic interfaces for virtual and augmented reali
479
2.
3. Y. Wang, Z. Yu, G. Mao, Y. Liu, G. Liu, J. Shang, S. Qu, Q. Chen, and R.4.
5.

Technol. 2019, 4, 1800435
Y. Ko, J. Oh,
Mater. Interfaces, 2019, 37043
B. Lee, H. Cho, S. Moon, Y. Ko, Y.-S. Ryu, H. Kim, J. Jeong, S.
conductors for threeNat. Electron. 2023, 6, 3072-378-Metal@PDMS

The 14th Japan-China-Korea Joint Conference on MEMS/NEMS

Advanced Characterization of the Active Materials for Lithium Ion
Batteries Using TEM Techniques to Promote Mechanism
Understanding#

Hyungcheoul Shim1, Minsub Oh1, Hye-Mi So1, Seungmin Hyun1,2,Young-Woon Byeon3, Hyun-Jeong Lee 4,5, Hong-Kyu Kim5 and Jae-Pyoung Ahn5
1 Department of Nano-Mechanics, Korea Institute of Machinery and Materials (KIMM), Daejeon, 34103, Republic of Korea
2 Department of Nanomechatronics, University of Science and Technology (UST), Daejeon, 34113 Republic of Korea
3 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
4 Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
5 Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea# Corresponding Author / E-mail: scafos@kimm.re.kr, TEL: +82-042-8687143, FAX: +82-042-8687884

ABSTRACTWith the rapid expansion of the electric vehicle (EV) market, an escalating demand has emerged for lithium-ion
batteries (LiBs) with high capacity and extended lifespan, ensuring consistent and dependable performance. In pursuitof achieving this objective, a precise comprehension of the operational and degradation mechanisms inherent to LiB
materials is imperative. This necessitates a comprehensive and multifaceted analysis of these materials, thereby
culminating in the advancement of robust and state-of-the-art LiB materials.
In this presentation, we will discuss the advanced analysis techniques using transmission electron microscope (TEM)
techniques to gain new insights into the operation and degradation mechanisms of active materials for LiBs frommultiple perspectives. We employ a combination of traditional TEM analysis methods including scanning TEM (STEM),
selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDS), and electron energy loss
spectroscopy (EELS) to identify the underlying reasons for the irreversible capacity reduction of high-capacity cathodematerials. To improve the accuracy of the diffraction pattern and achieve higher observation resolution, we also use
TEM analysis based on Precession Electron Diffraction (PED) and Nano-beam Diffraction (NED) to propose a novel
degradation mechanism of the cathode material for LiBs. Additionally, substantial emphasis is placed upon the solidelectrolyte interface (SEI) layer, an inherently sensitive component that exerts a pivotal influence upon the performanceof LiBs. The employment of cryogenic TEM examinations facilitates an incisive exploration of the SEI layer, thereby
elucidating the factors responsible for impeding the rate-limiting attributes intrinsic to LiBs.
Keywords : Transmission electron microscope, Lithium ion batteries, Advanced characterization

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Considerations on Conductor-Loss and Cross-Sectional Dimensions ofa Millimeter Wave Air-Based Microstrip Coupled-Line Filter

Kiyoka Takemoto1, Tamotsu Nishino2, Takeru Maeda1, Tomoaki Kageyama1, Tadao Matsunaga1 and #Sang-Seok Lee1
1 Faculty of Engineering, Tottori University,
4-101, Koyama-Minami, Tottori, Tottori 680-8552, JAPAN2 Graduate School of Engineering, Tohoku University, 6-6-1, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, JAPAN# Corresponding Author / E-mail: sslee@tottori-u.ac.jp, TEL: +81-857-31-5961

ABSTRACT
After 5G, communications using the millimeter wave band has been attracting a lot of attention. In addition, MIMOtype configurations are required to increase communication capacity. In a MIMO system consisting of multiple antenna
elements, one transmitter/receiver module is connected to one antenna element, so the module must be made smaller.
Particularly for filters, miniaturization and low loss are conflicting requirements, and the key point in design is to find acompromise that satisfies both specification values. The main causes of loss are loss in the dielectric, loss in the
conductor, and loss due to radiation. In this study, we propose a microstrip structure that removes silicon from thebottom of the line and utilizes the resulting air layer to reduce losses in the dielectric [1]. In order to reduce the loss inthe conductor, the relationship between the area of current flow (cross-sectional dimensions) and the transmission loss
is considered by simulation. Using the results, we derived a relationship between the value of transmission loss and thescale of the cross-sectional area.
Keywords : Millimeter-Wave Filters, Coupled-Line, RF-MEMS

1.

INTRODUCTION
The design process of analog filters in the millimeter-wave band always encounters conflicting demands for low loss
and miniaturization. For low loss, it is important to increase the cross-sectional area of the signal line to reduce
conductor loss by dispersing the current, and to reduce dielectric loss by using low-loss materials or adopting a structurethat prevents electromagnetic fields from penetrating into the lossy dielectric body as much as possible. Furthermore, in
MIMO systems, the spacing between antenna elements is often about half a wavelength, so the transmitter/receivermodule must also be as compact as possible.
In the above two approaches, increasing the cross-sectional area of the signal line directly results in an increase in the
cross-sectional dimensions of the module. Also, the use of low-loss materials results in an increase in the longitudinal
dimension of the signal line (proportional to the wavelength in the case of a filter), considering that low-loss materials
generally have a low dielectric constant.
In this paper, air is used as a low-loss material, ideally with zero dielectric loss. Although this increases thelongitudinal dimension of the signal line, one of the length, width, and height of the module is not restricted by theantenna element spacing, so the restriction is avoided by extending the signal line in that direction. In addition, somestructure to support the signal line is necessary to realize the circuit, but this is not considered here.
In the above structure, we have considered the cross-sectional dimensions to suppress the loss due to conductor loss,
while keeping the dielectric loss as close to zero as possible.
2. DESIGN AND SIMULATION
2.1 Design
In this study, a filter was designed with a center frequency of 40 GHz and a pass band width of 4 GHz. The filter typeis a coupled line type using a microstrip structure [2]. It was assumed that the filter would be fabricated by excavating a
portion of the silicon substrate, depositing gold on the bottom, layering a sacrificial layer and a thin oxide film, forminga circuit, and finally removing the sacrificial layer. However, the oxide film was not considered in the electromagnetic
field simulation, so that only the effect of losses due to conductors would be represented. Overview diagram of the filter
is shown in Figure 1.

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Figure 1 Overview diagram of the filter (Top view and cross-sectional view)

2.2 Simulation
Contents In this study, dielectric loss can be ignored by making the substrate an air layer. For the conductor loss, weused a model in which the thickness of the air layer (H) was set to 12.5 m, 25 m, 50 m, and 100 m, with the otherdimensions scaled by the same ratio, and calculated the passband characteristics using a high-frequency simulator. The
results are shown in Figure 2. The results show that the inverse of the air layer thickness (1/H) and the loss (dB) at thecenter of the passband have a roughly linear relationship (Figure 3).

Figure 2 Calculated pass band characteristics

Figure 3 Relation between 1/H and loss (S21)3.

CONCLUSION
We discussed the constraints on low-loss and miniaturization of analog filters in the millimeter-wave band. We
proposed an air-layer microstrip structure, in which the substrate silicon is processed using MEMS technology, as a
low-loss measure and examined the procedure for designing the thickness of the air layer to satisfy the use of a given
transmission loss. As a result, it was verified that there is a roughly linear relationship between the inverse of the crosssectional dimensions of the circuit and the loss (dB). Using this knowledge, the required air layer thickness can beobtained with a small number of trials.
ACKNOWLEDGEMENT
These research results were obtained from the commissioned research (No.06701) by National Institute ofInformation and Communication Technology (NICT), Japan.
REFERENCES
1. Sang-Seok Lee, Yukihisa Yoshida, Tamotsu Nishino, Yoshiyuki Suehiro, andimplementation of various RF passiv
Journal of Micromechanics and Microengineering 15(3), pp. 441-446, 2005.
2. Protap Pramanick and
2016.
2

277,

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Development of feasibility testing modules for smart sensing unit toobtain empirical dataset under various scenarios#

Chanhee Won1, Eunyeong Seong1,2 and Hye-jin Lee1

1 Digital Transformation R&D Department, Korea Institute of Industrial Technology, Republic of Korea, 143 Hanggaul-ro, Sangnokgu, Ansan-si, Gyeonggi-do, Republic of Korea
2 Department of Mechanical Design Engineering, Hanyang University, Republic of Korea, 55 Hanyangdaehak-ro, Sangnok-gu,
Ansan-si, Gyeonggi-do, Republic of Korea# Corresponding Author / E-mail: chan2@kitech.re.kr, TEL: +82-031-8040-6183, FAX: +82-031-8040-6820

ABSTRACT
Recently, smart sensing unit consisting of MEMS/NEMS components have been developed and widely applied in
manufacturing fields to predict the abnormal signal by analyzing the manufacturing process data. This research mainly
focused on the development of feasibility testing modules for various forming process, such as warm forging, warm
forming, machining process, to collect and refine empirical datasets under various process scenarios for developing thesmart sensing units and securing the reliability of their performances. Initially, the physical characteristics of eachmanufacturing process were analyzed based on the application cases of smart sensing units. Process features including
temperature ranges, acceptable temperature deviations, and process environment were examined. Subsequently,
feasibility testing modules were designed and fabricated to simultaneously simulate these physical characteristics, andvarious feasibility testing scenarios were devised to evaluate the performance of smart sensing units and analyze trends
in the acquired empirical datasets.
Keywords : Feasibility testing module, Smart sensing unit, Empirical dataset, Test scenarios, Manufacturing process
1.

INTRODUCTION
Smart sensors and smart sensing units consisting of MEMS/NEMS components, which have the capability to predictthe process abnormalities and assess product quality by analyzing process datasets, are widely applied to the various
manufacturing fields [1-2]. However, process conditions and tolerances can vary, even within the same manufacturing
process, especially when different components or shapes are involved. As a result, smart sensing units are developed
through optimization based on on-site data tailored to specific process applications [3-4]. Consequently, there is a
growing demand for reliability assessments through feasibility tests under similar process conditions in order toeffectively implement smart sensing units in practical settings.
In this study, we propose feasibility testing modules designed to simulate various forming processes: warm forging,sheet metal forming with heated sheets, and machining processes. These modules aim to gather empirical datasets undervarious process combinations and scenarios. The design of the feasibility testing modules and their specifications stemfrom the analysis of the physical characteristics of each manufacturing process, as well as insights from application
cases involving smart sensing units. This approach allows us to customize and configure process variables like
temperature, transfer time, and environmental conditions. Moreover, high-resolution sensors were applied at each stageof the process to facilitate a comparative analysis of the sensors being examined. Various feasibility testing scenarios
were designed to examine the performance of smart sensing unit and analyze tendency of various empirical datasets.
These modules enable the simultaneous simulation of the distinct physical attributes and process requirements relevantto the applied processes.
2. DEVELOPMENT OF FEASIBILITY TESTING MODULE
2.1 Procedures
To develop the feasibility testing modules, we proposed the following procedures to design the testing system andfeasibility testing scenarios. Initially, we identified and selected target processes that extensively utilize smart sensors
and smart sensing units, and which exhibit a significant demand for their integration into their respective facilities. Next,
we categorized key process parameters, such as cycle time, temperature, velocity, load, contact time, etc., based on their
physical significance in relation to product quality and process abnormalities. Detailed specifications and functions forthe feasibility testing system were determined through a combination of literature review and expert consultations. Thisapproach aimed to accurately replicate realistic anomalous characteristics. Building upon the conceptual design of thesystem, we devised detailed mechanisms and an automatic control system. This system was engineered to facilitate
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feasibility tests, simulating both continuous normal and abnormal states in accordance with the established feasibility
testing scenarios. Furthermore, we developed a user interface (UI) for the control system, which enables the extractionof sensor signals and related data. This interface was designed to enhance the system's capability to capture essential
information during testing and analysis."
2.2 Development results of feasibility testing modules
Based on the procedures as mentioned in Section 2.1, feasibility testing modules for warm forging process with highstrength aluminum alloy have been developed which is widely utilized to produce the automotive components as
depicted in Figure 1. This system applied induction heating system to obtain rapid heating of aluminum billets. Since
the heating temperature, transfer time and environmental temperature significantly affect to the formability and reaction
force on mold system, developed system can control the heating, transfer, cooling, and environmental temperature,
simultaneously. Additionally, a feasibility testing module for the machining process was developed. This module
facilitates the simulation of various abnormal conditions such as tool wear, collisions, and more as demonstrated on theright side of Figure 1. By attaching high-precision vibration and acoustic sensors, real-time collection of vibration andacoustic data is possible, which can be utilized for the validation of data reliability of developed smart sensing units.
This validation is achieved by comparing the collected high-resolution sensing data in real time with the data obtained
from the developed system.

Figure 1 Fabricated testing modules for simulating Heating/Transfer process and machining process

3.

CONCLUSION
In this study, we have outlined the procedures and outcomes related to the development of feasibility testing modules
aimed at obtaining empirical datasets under various feasility test scenarios. Through the creation of these modules, we
can not only identify the critical factors influencing product quality and equipment abnormality through feasibility tests
employing diverse process condition combinations, can utilize them for the development and guarantee the relability ofthe smart sensing unit. It is anticipated that these feasibility testing modules could significantly reduce theproductization timeline for the ongoing smart sensing unit development.
ACKNOWLEDGEMENT
This research was supported by Korea Evaluation Institute of Industrial Technology (KEIT) grant funded by Ministryof Trade, Industry and Energy (MOTIE, Korea) (No. 20016357, Demonstration platform development of smart sensingunit).
REFERENCES
1. P. Zheng, H. Wang, Z. Sang, R. Y. Zhong, Y. Liu, C. Liu X. Xu, Smart manufacturing systems for Industry 4.0:
Conceptual framework, scenarios, and future perspectives, Front. Mech. Eng., Vol. 13, pp. 137-150, 2018.
2. T. Kalsoom, N. Ramzan, S. Ahmed, M. Ur-Rehman, Advances in sensor technologies in the era of smart factoryand industry 4.0. Sensors, Vol. 20(23), 6783, 2020.
3. J. Wan, X. Li, H. N. Dai, A. Kusiak, M. Martinez-Garcia, D. Li, Artificial-intelligence-driven customized
manufacturing factory: key technologies, applications, and challenges. Proceedings of the IEEE, Vol. 109(4), pp.
377-398, 2020.
4. S. Aheleroff, X. Xu, Y. Lu, M. Aristizabal, J. P. Velásquez, B. Joa, Y Valencia, IoT-enabled smart appliances underindustry 4.0: A case study. Adv. Eng. Inform., Vol. 43, 101043, 20202

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Development of Miniaturized vibrationresistant physics package for chip-scale atomic clocks#

Munehisa Takeda, Akihisa Ueno, Isamu Kimura, Toshihiko Isokawa,Takeshi Harada, and Hiroshi Fukumoto
Micromachine Center,
MBR99 Bldg. 6F, 67 Kanda Sakumagashi, Chiyoda-ku, Tokyo 101-0026, JAPAN# Corresponding Author / E-mail: m_takeda@mmc.or.jp, TEL: +81-3-5835-1870, FAX: +81-3-5835-1873

ABSTRACTA miniaturized vibration-resistant physics package for in-vehicle chip-scale atomic clocks (CSAC) has beendeveloped. For miniaturization, the connection between the lower substrate and the ceramic package was changed fromwire-bonding to through hole wiring and bump-connection in the secondary prototype. Fabrication of lower substratewith through-hole wiring and the secondary prototype of the physics package was described. The secondary prototypeof the physics package was fabricated. It was realized that the package size is 14 mm × 14 mm × 10 mm for thesecondary prototype, which is about 60% smaller in installation area compared to the primary prototype (18 mm × 18
mm × 10 mm).
.
Keywords : Chip-scale atomic clocks, Physics package, MEMS gas cell, Vibration-resistant, Miniaturization
1.

INTRODUCTION
Precise timing is critical for numerous applications such as navigation, communications, surveillance, andsynchronization of sensors and systems.
assured PNT (Positioning, Navigation, and Timing) solutions
currently rely on acquiring GPS signals, it is desired to develop a small and highly accurate timing device that can beused even if GPS signals are interrupted. Since the early 2000s, the chip-scale atomic clock (CSAC) has beendeveloped1) and commercialized in 20112). However, commercially available CSAC is expensive, and its vibration
resistance and stability are not sufficient for in-vehicle use. We have been developing a vibration-resistant physics
package for in-vehicle CSAC3). In this report, we introduce the results of a study on vibration-resistant physics package
miniaturization and the prototype results.
2.

Miniturization of Physics Package for CSAC
The structure change of the physics package for CSAC is shown in Figure 1.

(a)Structure of primary prototype(b) Structure of secondary prototype
Figure 1 Structure change of the physics package for miniaturization

The left and right figures show the structures of the primary and secondary prototypes, respectively. The body of aphysics package of both the primary and the secondary prototype consists of an upper substrate with a photo diode (PD),a cesium vapor gas cell with an upper heater, a quarter wave plate, and a lower substrate with a vertical cavity surface
emitting laser (VCSEL), a thermistor, and a lower heater. The gas cell is fabricated using MEMS technology, is installed
in a gas cell holder and suspended by thermally isolated support legs. A structure with ribs on the thermally isolated
support legs was adopted so as to have vibration resistance. The body of the physics package is mounted on a ceramic
package. The ceramic package is vacuum sealed with a ceramic LID to block the heat that flows from the body ofphysics package through the air. For miniaturization, the connection between the lower substrate and the ceramic
package was changed from wire-bonding to through hole wiring and bump-connection in the secondary prototype.
3. Secondary Prototype Results of Physics Package
3.1 Fabrication of lower substrate with through-hole wiring
Figure 2 shows an observation images of a prototype wafer with through-hole electrodes. Forty-eight through1

The 14th Japan-China-Korea Joint Conference on MEMS/NEMS

electrodes are formed per chip at a pitch of 0.75 mm on the four sides of the outer circumference of the lower substrate
chip (size: 10.4 mm x 10.4 mm). As shown in the wafer appearance photograph (left photograph), through electrodes
for 208 chips are formed on an 8-inch wafer. It was confirmed that a through-hole electrode filled with Cu without gaps
was formed (right photograph). Furthermore, it was confirmed from the X-ray CT images (middle photographs) of thethrough-hole electrodes that were produced with good yield without lacking.

Figure 2 Observation images of a prototype wafer with through-hole electrodes
3.2 Fabrication of secondary prototype of physics package
Figure 3 shows the internal configuration and appearance of the secondary prototype of the physics package, which
incorporates the lower substrate with through-hole wiring, compared with the primary prototype. The main body ofphysics package (central part) supported by the support legs with ribs is common to both the primary and secondary
prototypes, but since through hole wiring was used in the second prototype, it is possible to mount in a smaller package.
The material of the outer frame that connects the upper and lower substrates has been changed from polycarbonate (PC)to polyimide (PI), which has higher heat resistance, in order to suppress deformation and outgassing due to heating
during the package vacuum sealing process. By changing the shape from a plane structure to a frame structure, the heatinsulation of the upper substrate was improved. As shown in Figure 3, It was realized that the package size is 14 mm ×
14 mm × 10 mm for the secondary prototype, which is about 60% smaller in installation area compared to the primary
prototype (18 mm × 18 mm × 10 mm).

Figure 3 Internal configuration and appearance of physics package
4.

CONCLUSION
A miniaturized vibration-resistant physics package for in-vehicle chip-scale atomic clocks has been developed. For
miniaturization, the connection between the lower substrate and the ceramic package was changed from wire-bonding
to through-hole wiring and bump-connection in the secondary prototype. The secondary prototype of the physics
package was fabricated. It was realized that the package size is 14 mm × 14 mm × 10 mm for the secondary prototype,which is about 40% smaller in installation area compared to the primary prototype (18 mm × 18 mm × 10 mm).
ACKNOWLEDGEMENT
This study was supported by Innovative Science and Technology Initiative for Security Grant No. JPJ004596, ATLA,Japan.
REFERENCES
1. S. Knappe, V. Shah, P. D. D. Schwindt, L. Hollberg, J. Kitching, L. A. Liew, and J. Moreland, A microfabricatedatomic clock, Applied Physics Letters Vol.85, No.9, pp1460–1462, 2004.
2. Symmetricom, Chip-Scale Atomic Clock User’s Guide, Document No.098-00055-000, Rev. 004, 2011
3. Munehisa Takeda, Akihisa Ueno, Isamu Kimura, Takeshi Harada, and Hiroshi Fukumoto, Introduction of thedevelopment on vibration-resistant physics package for chip-scale atomic clocks, JCK MEMS/NEMS 2022, pp5152, 2022
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Design of plasmonic nanostructure for optical intensity amplification
Jun Hyun Kim1, Tae Gyun Noh2, Ja Yeon Lee1,3 and Myung Yung Jeong1,3, #1 Cogno-mechatronics engineering,Pusan National University, Pusan, Geumjeong-gu, 46241, KOREA
2 Opto-mechatronics engineering,Pusan National University, Pusan, Geumjeong-gu, 46241, KOREA
3,ESPnMedic, ESPnMedic, Pusan, Geumjeong-gu, 46241, KR# Corresponding Author / E-mail: myjeong@pusan.ac.kr, TEL: +82-51-510-2970, FAX: +82-50-4436-4420

ABSTRACT
Nowdays, optics and photonic fields are interested field in various field such as bioimaging, sensor, and autonomous
driving. Many researchers studied plasmonic nanostructure that have various properties such as manipulating the opticalpathway, enhancing the electric field for enhancing the resolution and detect small signal. Surface plasmons are oscillations of free electron that arise from the interaction surface between metal and dielectric. When incident light excited insurface, free electron in metal made electron cloud and oscillated. Those effects occur the electric field enhancement due to resonance between free electron and incident light. In this paper, we proposed noble plasmonic nanostructure basedon FEM simulation and nanoimprint lithography with selective metal evaporation for enhancing optical signal. Proposed plasmonic nanostructure consists of the dipole nanoantenna and grating nanostructure which can occur the plasmonic
effects. These structures which have plasmonic characteristic can gather the optical and electric field in one place and en
hance transmittance of signals and so it can be enhance the signals. And through NIL process and metal evaporation, designed structure was transferred into polymeric surface, and formability and accuracy of fabricated structure was evalua
ted by SEM images. Also designed structures enhanced small optical signal 76 times than original signal applied in fNI
RS system and also can detect the small signal which cannot detect in original system due to similar with noise signal.
Keywords : Plasmonic, Electric field enhancements, Nanoimprint, Nanodevice, Selective deposition
1.

INTRODUCTION

2. Plasmonic nanostructure for enhancing electric field
2.1 Simulation
Proposed nanostructure was confirmed electric field by FEM simulation. As mentioned, plasmonic nanostructure hav
e a lot of parameters to get the plasmonic effect such as wavelength, dipole antenna length, depth, and metal s height. T
o optimize plasmonic nanostructure and figure out plasmonic properties, we use COMSOL Multiphysics simulation tool
which based on FEM. Depending on dipole antenna length, incident light angle, electric field and farfield gain of the plasmonic nanostructure was confirmed.

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2.2 Experiment
Noble plasmonic nanostructure which proposed and confirmed by simulation was fabricated by thermal nanoimprint
lithography. Compared to photolithography or e-beam lithography, the nanoimprint method has the advantage of fastand large-scale fabrication of nanostructures through a simple and easy process, resulting in uniform structure
fabrication.
And also, to confirm the plasmonic effect of nanostructure, the plasmonic nanostructure was applied in bio imaging system and also confirmed by optical signal enhancement.

3.

CONCLUSION
To verify the effectiveness of our proposed plasmonic nanostructure, we first performed FEM simulations (COMSOLMultiphysics 5.6a) to determine the possible electric field, far-field gain, and current density generated using thisnanostructure. According to the simulations, the optimal vertical length for the structure was 1177 nm, with transverse
lengths of 393 nm and 588 nm, which were applicable for a laser wavelength of 785 nm. For a structure with a height of
180 nm, an Ag layer with a height of 50 nm, and an incident laser angle of 30°, the electric field was observed to beconcentrated in the center and reached a value of 31.826 V/m, which was more than 15 times greater than that obtainedwith the dipole nanoantenna (DN) and grating nanostructure (GN). Moreover, a far-field gain of 1137.8 was obtained,
which is a significant improvement over existing optical imaging system.
Based on these design data, we fabricated a structure using thermal imprint lithography, followed by Ag deposition ontoa specific nanostructure. The results showed that the intensity in the MPN was approximately three times higher thanthat in a bare film. Furthermore, the intensity in the MPN was 2.24 times higher than the original laser intensity because
the laser photons were concentrated in the middle of the structure and had a high directivity toward the detector. Our
device significantly improves the signal-to-noise ratio and amplifies the optical signal by 106 times compared with theoriginal system, making it superior to existing functional near-infrared spectroscopy (fNIRS) systems.
In addition, amplifying the specific optical signal enhances the spatial resolution of the fluorescence optical imaging
system, making our device useful for enhancing the diagnosis, staging, and investigation of treatments for neurologicalailments such as Alzheimer's disease, dementia, and stroke, for which there are currently limited therapeutic options.
Overall, our plasmonic nanostructure-based optical application technology has the potential to advance the field of
optical imaging and contribute to the development of new diagnostic and therapeutic approaches for various
neurological conditions.
ACKNOWLEDGEMENT
or de-based film technology for securing all-fense Technology planning and advancemen
weather vision).

REFERENCES
1. Mahigir, Amirreza, et al. "Plasmonic nanohole array for enhancing the SERS signal of a single layer of graphene
in water." Scientific reports 7.1 (2017): 14044.
2. Chae, Jungseok, Basudev Lahiri, and Andrea Centrone. "Engineering near-field SEIRA enhancements in plasmonic resonators." Acs Photonics 3.1 (2016): 87-95.
3. Cui, Xiaoqiang, et al. "Tailored plasmonic gratings for enhanced fluorescence detection and microscopic imaging." Advanced Functional Materials 20.4 (2010): 546-553.
4. Minovich, Alexander E., et al. "Functional and nonlinear optical metasurfaces." Laser & Photonics Reviews 9.2(2015): 195-213.
5. Zhou, Wei, et al. "Lasing action in strongly coupled plasmonic nanocavity arrays." Nature nanotechnology 8.7(2013): 506-511.
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A Novel Structure of Bacteria Fuel Cell for Continuous Power
Generation in Rumen
Yasutaka Shimizu1, Yoshihiro Muneta2, Hiroshi Sawada2, Reina Nishiura2, Michitaka Yamamoto1, Seiichi Takamatsu1,
Shozo Arai2 and #Toshihiro Itoh1
1 Department of Precision Engineering, Graduate School of Engineering, The University of Tokyo,7-3-1, Hongo Bunkyo-ku, Tokyo
113-8654, JAPAN
2 National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki
305-0856, JAPAN# Corresponding Author / E-mail: itoh@pe.t.u-tokyo.ac.jp, TEL: +81-3-5841-6491, FAX: +81-3-5841-6485

ABSTRACTThis paper proposes the new structure of rumen bacteria fuel cell, that can overcome the problem of the present
rumen bacteria fuel cell by using the membrane filters to limit the bacteria distribution. The rumen bacteria fuel cell
designed in the previous research has a good performance. However, that does not work in ruminal environments. For
this problem, limiting the bacteria distribution with membrane filter, we succeeded in generating power constantly evenin the anaerobic environments. In this paper, we observed the influence of temperature and electrode size on theperformance of the rumen bacteria fuel cell. The results showed that the maximum of OCV was recorded around 0.3 V
regardless of any variables. While the MPP has a positive correlation with the electrode size, and the maximum power
per unit area was recorded around 100 mW/m2. From the results, it can be said that the proposed structure haspossibility to work in completely anaerobic environment.
Keywords: Cattle, Bacteria fuel cell, Rumen bacteria, Power supply.
1.

INTRODUCTION
Rumen bacteria fuel cell1 is a cell which generates power from bacteria s metabolic activity, and this technology is
paid attention as a solution to rumen sensor s2 short battery life. In the previous research, they generated power from thepotential difference between anaerobic reaction and aerobic one. The power was up to 1240 mW/m2 that is enough todrive MEMS sensor system. However, the previous research method can t work in ruminal environments because
those environments are anaerobic, and the aerobic reaction cannot occur. To apply rumen bacteria fuel cell to rumen
sensors, we need to invent the new structure that keeps potential difference even in anaerobic environments. We propose
the structure showed in Figure 1. In the structure, we used membrane filter to limit the bacteria distribution only on
negative electrode aiming to cause bacteria
ction in negative side and hydrogen reduction in positiveside. The objective of this study is to measure the performance of proposed structure and investigate how temperatureand electrode size influence the performance.
2.

EXPERIMENT METHODS
From healthy cows, rumen contents were taken and 2 parameters for generating power (electrode size S, temperatureT) were set, and several rumen bacteria fuel cells were fabricated (Figure 1). We used 2 cm2 or 6 cm2 for S and 22
or39. The used filter was made from cellulose, and its hole diameter was about 50 . In the measurements,
the voltage was measured while varying the additional resistance between 10 and. From the generated
Power-Current curve (Figure 2), open circuit voltage (OCV), which is the voltage when the resistor is not connected
and the maximum power point (MPP), which is the maximum value of power approximated by a quadratic curve, wereread and the relationship between these parameters was investigated. We measured each sample after following numberof days from fabrication, day 1, 3, 4, 5, 6, 8, 11, 15, 16, 17, 19 (11 measurements) for electrode size samples and day 1,
2, 5, 14, 15, 17 (6 measurements) for temperature samples. For the reference, we plotted the previous method s OCV
recorded in the anaerobic environment on the Figure 3 and Figure 4.

Figure 2. Power-Current Curve

Figure 1. Experimental fuel cell
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(b)

(a)

(a)

Figure 3. Relationship between electrode size and OCV (a) and MPP (b)(b)

Figure 4. Relationship between temperature and OCV (a) and MPP (b)3.

RESULTSThe results for the electrode size are shown in Figure 3. The OCV showed a constant maximum value of about 0.3 V(almost half of the previous method) regardless of the electrode size. On the other hand, MPP increased as the electrodesize increased, and a maximum value of 0.03 mW was obtained. While the MPP per unit area decreased as the electrodesize increased and a maximum value of 100 mW/m2. The results of samples whose temperature are changed (Figure 4)
suggest that, at least in the condition of T > 22
, the temperature influence on the bacteria s activity is nearly
negligible. Throughout the measurements, OCV of proposed structure decreased, however retained positive in allmeasurements. While the OCV drops to negative in the previous method by the day 3.
4. CONCLUSION
Measurements of the power performance of proposed structure cell revealed that the OCV was not affected by any
variables. The maximum of OCV were recorded around 0.3 V in all sample. The value is almost half of the previous
method. This is because proposed structure only uses anaerobic reaction s potential while the other also uses aerobic
one. After OCV recorded the maximum, it kept decreasing, however it kept positive in all measurements. This voltage
drop could be attributed to a change of chemical substrates which is caused by discharge which happen in eachmeasurement. On the other hand, MPP has positive correlation with electrode size but the MPP per unit area is weaknegative correlation with the electrode size. In addition, a maximum MPP per unit area was recorded 100 mW/m2,
which is about one-tenth of the previous reserch s method in the aerobic environments. Thinking the application in theruminal environment which is completely anaerobic, is maintained in around 39
and provide constant concentrationsof chemical substrates, those voltage drop may not occur, and the cell can generate power as efficient as 100 mW/m2
constantly. In other words, the results indicate that the propossed cell structure has good possibility to work incompletely anaerobic environements, but we need to improve the effficiency for the application to rumen sensors.
ACKNOWLEDGEMENT
This work was supported by JSPS KAKENHI Grant Number JP23H02336.
REFERENCES
1. Yashiro Y, Yamamoto M, Muneta Y, Sawada H, Nishiura R, Arai S, Takamatsu S, Itoh T. Comparative Studies on E
lectrodes for Rumen Bacteria Microbial Fuel Cells. Sensors (Basel). 2023 Apr 21;23(8):4162. doi: 10.3390/s23084
162.
2.
-Powerhighly sensitive pH senso
for monitoring rumen in cows in realIEEESensors, vol. 17, no. 22, pp. 7281 7289, 2017.

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Optimization of selective metal deposition process for plasmonicnanostructure

Tae Gyun Noh1 and Myung Yung Jeong1 2 #1 Department of Opto-Mechatronics Engineering, Pusan National University, Busan 46241, Korea
2 ESPn Medic, ESPn Medic cooperation, Busan 46241, Korea# Corresponding Author / E-mail: myjeong@pusan.ac.kr, TEL: +86-010-8727-6285

ABSTRACTThe selective deposition of metal thin films on polymeric patterns is a major challenge in flexible devices fabrication.
However, fabricating structures with precious metal thin films deposited on complex patterns at the nanoscales ischallenging. Here, we solve these problems using a process that combines UV-nanoimprint lithography (UV-NIL) withhalogenation of the metal and transfer printing. The fabricated plasmonic devices had a pattern tolerance of less than 3
percent and optical amplification efficiency of 2.85 times.
Keywords : : Flexible device, Nano Imprint Lithography (NIL), Nano Transfer Printing (NTP), Metal halide
1.

INTRODUCTION
The growing demand for flexible devices is requiring techniques to fabricate complex structures consisting of thinmetal films deposited on highly integrated polymeric nanopatterns. But traditional nanostructure fabrication techniquessuch as photolithography, plasma etching, and vacuum deposition directly on substrates are difficult to meet therequirements of non-traditional substrates with flexible features such as polymer films. Here, we propose a hybrid
process combining UV-NIL and NTP to achieve high yields and high stability of selective metal thin film deposition
with the precise formation of polymeric nanopatterns.
2. Methods and Materials
2.1 Photodissociation
The maximum wavelength of light for photodissociation of chloroform molecules has the value of 385 nm by the
proposed equation. The bond-dissociation energy of a single chlorine atom in the chloroform used is 311 kJ/mol, andthe activation energy is assumed to be zero since metal-chlorine bond formation occurs spontaneously.

2.2 Experiment
The process we propose in this work is summarized in Fig.1. It consists of a total of six steps, and the process of
fabricating the hard mold, Fig.1a, can be performed only once in an iterative process. First, Si mold was intaglio
fabricated by e-beam lithography (JBX-9300Fs, JEOL Ltd., USA) on a Si wafer coated with electron beam resist (AR-P
6200, Allresist GmbH, Germany). Then, 50nm thick metal film was deposited on the fabricated Si mold using DC
Sputtering and e-beam evaporation. DC sputter equipment (MCM-100, MJ Research Co., Ltd. Korea) was used todeposit Au film for 4min at operating power of 35-30mA, and the film thickness was confirmed to be 50nm using
atomic force microscopy. For the deposition of Ag thin film, e-beam evaporator (MEP5000, SNTEK Co.Ltd., Korea)
was used and deposited at a uniform rate of 5Å/s for uniform deposition. The halogenation of the metal was performedby coating with chloroform (>99.8%, SIGMA-ALDARICH, France) using a spin coater (Notel Delta 80, Suss
Mricrotec., Germany) at 500rpm 30s, a = 150rpm/s to uniformly coat the surface of the mold where metal film wasdeposited. Next, annealing was performed at 75ºC for 2 mins using hot plate (EC-1200, As-One, Japan) for removing
unwanted elements from the chemical reaction and improving the device performance. After Annealing, adhesive tape
(3M; St. Paul, MN, USA) was used to separate the metal film on the SI mold embossing and for the tape peel test. Oncethe tape removed the metal film on the embossed mold, UV-curing resin (MINS-311RM, Minuta Tech., Korea) was
coated on the mold, and the PMMA substrate was covered and exposed for 10 mins using a UV exposure equipment(CL-1000, UVP., USA) to obtain the final device.
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Figure 1 a, Si hard mold fabrication with e-beam lithography. b, Deposition of metal thin film on mold using sputtering or e-beam
evaporation. c, Halogen treatment of thin metal film using spin coating. d, apply enough heat to the mold to decompose molecules
into halogen atoms. e, Removing metal film from mold embossing with adhesive tape. f, UV-NIL for final device fabrication andmetal transfer on polymer nanopatterns.

3.

CONCLUSION
In this study, we optimized a selective deposition process for fabricating plasmonic structures. In the optimized
process, the wavelength of light to break the molecular structure of chloroform and halogenate the metal was 3 minutes
and 40 seconds at 365 nm, and the exposure time of the UV-NIL process was set to 12 minutes to accurately transfer thepattern. The device fabricated by this process showed an error of less than 3 percent, and the photomultiplier efficiencyof the fabricated device was 2.85 times, which improved the performance by 27% compared to the previous one.
ACKNOWLEDGEMENT
We gratefully acknowledge the support provided by Institute for Defense Technology Planning and Advancement for
their support through the Defense Venture Innovation Technology Support Project (V220021), which has enabled us topursue our research on nanostructure-based film technology for securing all-weather vision. And this research was
supported by Korea Basic Science Institute (National research Facilities and Equipment Center) grant funded by the
Ministry of Education. (Grant No. 2019R1A6C1010045)
REFERENCES
1. Kim, J.H. et al. Electric field enhancement of coupled plasmonic nanostructures for optical amplification.
PhotoniX 4, 8, 2023.
2. Alan K. Mo. et al. Understanding the mechanism of solvent-mediated adhesion of vacuum deposited Au andPt thin films onto PMMA substrates. Adv. Func. Mat. 23, 1349-1471,2013.

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Flexible thermoelectric generator with optimized structure
Fuchuan Zeng1, Meiye Liang1, Zhuqing Wang 1, Yuanlin Xia1, Cao Xia1
1 School of Mechanical Engineering, Sichuan University, Chengdu 610065, China
E-mail: wzhuqing@scu.edu.cn

ABSTRACTThis paper reported a flexible thermoelectric generator (FTEG) based on inorganic bulk thermoelectric materials,
which holds great prospects in wearable power sources. The developed FETG with optimized structure incorporating
aerogel thermal insulation and high thermal conductivity heat dissipation layer exhibits great flexibility and output
performance. The open circuit voltage of FTEG reaches 35 mV and its maximum power is 110.2 W by converting
human body heat at room temperature (23 ). Moreover, the open-circuit voltage, output power and power density
under 2 load resistance are 173 mV, 4.5 mW and 127 W/cm2 respectively at a temperature gradient of 50 K. The
developed FTEG shows great potential in converting waste heat into electricity, enabling the power supply forelectronic watches after voltage boosting with a DC booster.
Keywords : Flexible thermoelectric generator, thermal insulation, Waste heat harvesting
1.

INTRODUCTION
Thermoelectric generator shows great potential in converting waste heat into electricity and offering sustainable
power for electronic devices. This characteristic renders TEG becoming a highly promising candidate for self-powered
wearable application [1]. However, achieving a trade-off between flexibility and output performance is very challenging,and the exploration of the practical application for FTEG seems relatively rare [2]. Therefore, this work developed a
FTEG based on inorganic bulk TE materials [3]. The schematic diagram of the developed FTEG is shown in the Figure
1 (a). The developed FETG with optimized structure of aerogel thermal insulation layer and silicone-AlN heatdissipation layer exhibits great flexibility and power generation performance. A power management system based on the
FTEG is also proposed for waste heat harvesting in household environments to verify its practical application ability.
2. Method
2.1 Simulation
To investigate the effect of aerogel thermal insulation layer and high thermal conductivity silicone-AlN heatdissipation layer, we characterized the performances of FTEG with different thermal conductivity at middle and top
layer by finite element analysis (FEA). Figure 1 (b) presents the FEA results of FTEG showing open circuit voltage at atemperature difference of 10 K. Figure 1 (c), (d) and (e) show the temperature distribution on the cross-section, open
circuit voltage at different temperature differences and output power of the FTEG with different thermal conductivity at
middle and top layer.
2.2 Experiment
The current-voltage characteristic of FTEG is shown in Figure 2 (a), and the fitting results of the current-voltage
characteristic curve is shown in the Figure 2 (b). The voltage and current at different load resistance with thetemperature difference of 10 K is shown in the Figure 2 (c). Obviously, as the load resistance increases, the voltage andcurrent initially increase and then decrease until they reach a threshold and begin to stabilize. The voltage after
stabilizing is about 18 mV. Figure 2 (d)-(e) are output power and power density at different temperature difference witha load resistance of 2 . Figure 3 (a) shows the practical application of the FETG, and Figure 3 (b) presents the output
voltage of the FTEG and DC booster.
3. CONCLUSION
This paper reported a FTEG fabricated with inorganic bulk thermoelectric materials. The developed FTEG possesses
excellent flexibility and output performance. The conformal contact with arbitrary-shaped heat sources and highthermoelectric conversion efficiency make it become a good candidate as power sources for wearable devices tofacilitate the realization of self-powered wearable applications.
REFERENCES[1] Kuang N, Niu A, Wang W, et al. High performance flexible thermoelectric generator using bulk legs and integrated
electrodes for human energy harvesting. Energy conversion & management, Vol. 272, No. 15, 116337, 2022.
[2] Van Toan N, Tuoi T T K, Van Hieu N, et al. Thermoelectric generator with a high integration density for
portable and wearable self-powered electronic devices. Energy conversion & management, Vol. 27
5, No. 1, 114571, 2021.
[3] Lee B, Cho H, Park K T, et al. High-performance compliant thermoelectric generators with magnetically se
lf-assembled soft heat conductors for self-powered wearable electronics. Nature Communications, Vol. 11, No. 1,
5948, 2020.

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Figure 1. (a) The schematic diagram of the developed FTEG. (b) FEA results of FTEG showing open circuit voltage at atemperature difference of 10 K. (c) Temperature distribution on the cross-section, (d) open circuit voltage at different temperature
differences (e) and output power of the FTEG with different thermal conductivity at middle and top layer.

Figure 2. Experimental results. (a) Relationship between output voltage, power density and load resistance. (b) Fitting of the voltage-current curve and voltage-power density curve. (c) Voltage and current at different load resistance. (d) Output po
wer at different temperature differences. (e) Power density at different temperature difference. (f) Power density at different
load resistance and temperature difference.

Figure 3. Practical application of the FETG. (a) The FTEG Lights LED and supplies power for electronic watch. (b) Outp
ut voltage of the FTEG and DC booster.

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Self-assembled silicon cavity with polydimethysiloxane interface forliquid refractive index measurements via near-infrared interferometry

Taeyeong Kim, Minwoo Choi, Bong Jae Lee and # Jungchul Lee
Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology,
291, Daehak-ro, Yuseong-gu, Daejeon 34141, Korea# Corresponding Author / E-mail: jungchullee@kaist.ac.kr, TEL: +82-42-350-3212

ABSTRACTRefractive index (RI) can serve as an indicator for measuring the purity and concentration of different analytes within
microchannels. Hence, within biotechnology for cellular research and analytical chemistry for simultaneous sample
analysis, measuring the liquid refractive index in the Lab-on-a-Chip (LOC) systems have emerged as a pivotal tool inthese fields. Among various LOC systems, those based on silicon microchannels exhibit numerous advantages. Theyleverage semiconductor processes to integrate with on-board electronics and allow for miniaturization and batch
fabrication. The system boasts good mechanical and chemical stability, with surface modifications allowing tailoredadaptations for diverse applications. However, most are fabricated through bonding processes, leading to intricate
procedures and limitations in achieving desired structures. In this paper, we introduce a novel platform that integrates
near-infrared (NIR) interferometry with Silicon-on-Nothing (SON) microchannels to measure a RI of liquids. First, a
SON microchannel with ports is fabricated by annealing the hole array at 1150°C under a pressure of 2 10-6 torr for 150
minutes. We connect fluidic ports to the mm-scale SON microchannel by using PDMS interface and employed apressure regulator for computer-controlled liquid injection. By employing NIR interferometry, we execute a verticalpiezo scan within the SON microchannel to capture interference patterns [1]. The type of liquid influences the opticaldepth, enabling RI derivation based on these variations. Our platform allows for the successful measurement of RIs
across various solution.
Keywords : Near-infrared interferometry, Silicon-on-Nothing (SON), Refractive index, Microchannel

Figure 1 (a) 3D schematic of near-infrared interferometry and hybrid SON microchannel platform for measurement of liquid
refractive index. (b) Optical depth diagram as a function of the type of the liquid.

ACKNOWLEDGEMENT
This
researchwassupportedbyNational
Research
FoundationofKorea(NRF2020R1A2C3004885) funded by the Korean government (Ministry of Science and ICT). This work was also supportedby the Technology Innovation Program (00144157, Development of Heterogeneous Multi-Sensor MicroSystem Platform) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).
REFERENCES
1. M. G. Jeong, T. Kim, B. J. Lee, J. Lee, Subsurface Imaging of Microfabricated Silicon Membrane Cavity, Advanced Engineering Materials, Vol. 24, No. 10, p. 2200531,
2022.
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1.
2.

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Development of a Microfluidic system embedded with a drug
carrier for real-time monitoring of drug release
Hye Jin Choi1, Min Chul Shin1, Ji Hwan Han1, and Gyu Man Kim1#
1 School of Mechanical Engineering, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 41566, Korea,# Corresponding Author / E-mail: gyuman.kim@knu.ac.kr, TEL: +82-053-950-7570

ABSTRACT
We present a multi-system that integrates fluid chip technology for cell culture, microstructure fabrication as a drug
carrier, and real-time drug release analysis. The developed integrated multi-system (IMS) microfluidic chip consists ofthree parts that can capture drug-loaded microparticles, enable cell culture, and measure drug release concentration.
Using This, the release of drugs loaded onto microparticles was measured in real-time, and cell growth wasquantitatively analyzed simultaneously. The CCK-8 assay was used to determine the degree of cell viability by the drug
released from the microparticles. For this assay, standardized assays require commercialized well plates. However, in
this study, it was simply implemented, and the analysis was easily possible through the concentration measurement
chamber at the developed IMS microfluidic chip. Also, the shape changes of the drug-loaded microparticles wereobserved by FE-SEM. Accordingly, only a very small amount of microparticles was required. In addition, when
conducting additional research such as drug release of drug-loaded particles, there is a disadvantage in that there are a
lot of necessary accessories, and it is complicated. Therefore, it is possible to easily analyze the release behavior ofvarious cells and drugs by using this method, which is expected to apply to various fields.
Keywords: Microfluidic chip, Cell culture system, Multi-analysis, Real-time, Drug release,
1. INTRODUCTION
Microfluidic systems are attracting attention as a next-generation platform for experiments in the fields of medicine,
pharmacy, and biology that conduct research on cells, tissues, and organs. For example, there are organs on a chip for
observation by culturing cells on the fabricated device [1], drug screening for observing the reaction of a drug thereto[2], and preparation of a drug carrier [3]. As these are mutually interactive studies, it is important to research together
step-by-step. However, it is complicated because many steps are required for this. Here, we fabricated a multi-system
integrating cell culture device and microstructure fabrication as a drug carrier and real-time drug release analysis.
2. EXPEREIMENT AND RESULTThe developed microfluidic chip requires three areas that can capture drug-loaded microparticles, enable cell culture,and measure drug release concentration. Therefore, we designed a microfluidic chip that integrates all of them. Fig 1
shows the schematic diagram of the designed integrated multi-system (IMS) microfluidic chip. In the developed
microfluidic chip, two PDMS channels were formed at the top and bottom based on the intermediate PC membrane. The
lower layer was designed to have a supporter inside the chip to capture the drug-loaded particles. In addition, on theupper layer, a cell culture chamber and a drug concentration measurement chamber were configured based on the realtime drug measurement system [4] previously studied. Microparticles were prepared from PLGA, and doxorubicin(DOX), one of the anticancer drugs, was used as a model drug. In addition, A549 cells, one of the lung cancer cells,
were cultured. Using the developed IMS microfluidic chip, the drug release degree was measured in real-time and thecell growth degree was quantitatively analyzed. First, Fig 2(a) is a graph comparing and analyzing the concentration ofdrugs released from microparticles according to the presence or absence of cells. In the absence of cells, it was
confirmed that the drug was continuously released. On the other hand, when cells are present, it can be confirmed thatthe concentration of the drug measured by the cells acquiring the drug released from the particles is significantly lower
than that of the control group. In addition, the CCK-8 assay was used to determine the degree of cell viability by the
drug released from the microparticles. For this assay, standardized assays require well plates. However, in this study, it
was simply implemented using the developed IMS microfluidic chip. With the developed IMS microfluidic chip,analysis was easily possible through the concentration measurement chamber, and Fig2(b) is an absorbance analysis
graph of the observed cell growth. When there was a drug-loaded microparticle, it was confirmed that the cell viability
was 50% lower than that of the control group. Also, Fig3 shows the shape change of the drug-loaded microparticles
observed through the FE-SEM microscope. It was observed that the shape of the microparticles shrink as time passed
compared to before the test. It is considered that the shape of the DOX drug inside the PLGA microparticles is changed
as time passes. Therefore, when using this IMS microfluidic system, only a very small amount of microparticles was
required.
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Figure 1 Schematic of integrated multi system microfluidic chip

Figure 1 (a) Real-time concentration monitoring graph of drug with and without cells. (b) The cell viability of A549 cells with
DOX loaded particles

Figure 1 FE-SEM image of drug loaded particle

3.

CONCLUSION
Here, we fabricated a multi-system integrating cell culture device and microstructures as drug carriers and realtime drug release analysis. The developed device consists of three parts that can capture drug-loaded microparticles,
enable cell culture, and measure drug release concentration. Using this, the drug release was measured in real-time, andthe cell growth was quantitatively analyzed. In addition, the CCK-8 assay was used to determine the degree of cell
viability by the drug released from the microparticles. With the developed device, analysis was easily possible throughthe concentration measurement chamber. Finally, the shape change of the drug-loaded microparticles was observed
through the FE-SEM microscope. General, when conducting additional research such as drug release of drug-loaded
particles, there is a disadvantage in that there are a lot of necessary accessories, and it is complicated. However, it ispossible to easily analyze the release behavior of various cells and drugs by using this method, which is expected to be
applicable to various fields.
ACKNOWLEDGEMENT
This research was supported by National Research Foundation of Korea (2022R1A6A3A01087329 and RS-202300208717) and Korea Institute for Advancement of Technology grant (P0020616) funded by Korean Government (ME,MSIT and MOTIE).
REFERENCES
1. Caplin, J. D., Granados, N. G., James, M. R., Montazami, R., & Hashemi, N., Advanced healthcare materials.
4 (2015) 1426-1450.
2. Eduati, F., Utharala, R., Madhavan, D., Neumann, U. P., Longerich, T., Cramer, T., ... & Merten, C. A.,
Nature communications. 9 (2018) 1-13.
3. Xu, Q., Hashimoto, M., Dang, T. T., Hoare, T., Kohane, D. S., Whitesides, G. M., ... & Anderson, D. G.,
small. 5 (2009) 1575-1581.
4. Choi, H. J., Ngoc, T. B., Song, H., Chang, C. H., & Kim, G. M., IJPEM. 21 (2020) 2399-2405.

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Estimation of Static Characteristics of Frictionless Air Bearing System
Using CFD

Jahoon Moon1, Jinsoo Choi2, Kyung-Rok Kim1, Dongwoo Kang1, and #Seung-Hyun Lee1
1 Department of Flexible & Printed Electronics, Korea Institute of Machinery and Materials, 156, Gajeongbuk-ro, YuseongGu, Daejeon, Republic of Korea,
2 Department of Mechanical Engineering Korea Advanced Institute of Science and Technology, 291, Daehak-ro, Yuseong-gu,
Daejeon, Republic of Korea# Corresponding Author / E-mail: shlee79@kimm.re.kr

ABSTRACT
Bearings are crucially utilized in high-precision manufacturing processes due to their role in providing stable
operation and support for the overall system, relying on minimal frictional forces. Among various bearing systems, air
bearings, which are frictionless bearings offering numerous advantages, are attracting significant attention in the realmof high-precision manufacturing processes. In this study, we numerically analyzed the static characteristics of the air
film region generated by air bearings, specifically frictionless bearings driven by uniformly distributed air flow throughporous material. Numerical results were compared with experimental results conducted under similar conditions,demonstrating the effectiveness of utilizing computational fluid dynamics (CFD)-based numerical analysis for
examining the operational characteristics of frictionless bearings based on fluid force.
Keywords : Air bearing, Air film stiffness, Computational fluid dynamics, Static characteristic
1. INTRODUCTION
Various types of bearings, including ball bearings, magnetic bearings, and air bearings, represent notable categories.
Among these, ball bearings, which are commonly employed, exhibit imperfections due to ball friction and possess
higher friction coefficients compared to the aforementioned frictionless bearings. Additionally, periodic lubrication
inspections are required for maintenance, presenting a drawback. Magnetic bearings, on the other hand, mitigate noise
issues due to the absence of bearing friction and excel in operational performance under high-speed conditions.
Nonetheless, their magnetic fields can influence surrounding components, imposing limitations on the selection ofneighboring parts.
Air bearings, driven by the uniform dispersion of air passing through porous material, circumvent the disadvantagesof the aforementioned bearings and thus find applications in diverse fields. In this study, our aim was to establish an
analytical system for investigating the static characteristics of the air film region within an air bearing system based on
numerical analysis. Furthermore, we sought to calculate the buoyancy force based on the most stable bearing
performance parameters, including air injection pressure and float height, with the objective of assessing the stiffness of
the air film under stable operational conditions.
2. Experimental and Numerical Details
2.1 Experiment
A flat air bearing with a diameter of 50mm was used, and gap sensors were installed near the fluid outlet to measure
the floating height generated by the flow passing through the porous material. At the top of the guide where the bearing
was installed, a mass part based on a solenoid valve was positioned. The experiment involved injecting a certain
pressure of air into the air bearing while the mass was applied, and measuring the resulting floating height (gap). Thismeasurement aimed to establish a correlation between the floating height and the lifting force of the air bearing at
specific pressures.
2.2 Numerical modeling
Numerical simulation was conducted for incompressible 2-dimensional Newtonian fluid flow with aixs-rotating
periodic condition because the flat air bearing used in experiment has axisymmetric cylinderical structure. The
boundaries of the flow path were defined according to the dimensions observed in the internal disassembly of the actual
flat air bearing. The porous material region was specified accordingly. The governing equations, including the
momentum equation considering momentum sources arising from the passage through the porous material region andthe continuity equation, are represented as Figure 2 as follows.
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Figure 1 Flat air bearing(left) and experimental set-up(right)

Figure 2 Numerical model and governing equations

Figure 3 Measured and calculated lifting force for different gaps

3. CONCLUSION
By calculating the lifting force based on injection pressure and float height for various conditions representing themost stable bearing performance, the stiffness of the air film was assessed. The lifting force, obtained from numericalanalysis, was compared with experimental results. The comparison revealed a discrepancy of approximately 3% or lessin most cases. This result demonstrates the effectiveness of utilizing Computational Fluid Dynamics (CFD) for the
analysis of the static characteristics of air bearings.
ACKNOWLEDGEMENT
This research was supported by the National Research Council of Science & Technology (NST) granted by the Korea
government (MSIT) (No. CAP22082-300) and the principle research R&D program of the Korea Institute of Machineryand Materials (NK242E).
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Inkjet-printed Double Layer Mask Pattern for Area-selective Atomic
Layer Deposition Process

Jun Ho Yu1, Jae Wook Lee2, Kyung Hyun Choi2, #Sang-Ho Lee1
1 Korea Institute of Industrial Technology, Ansan, 15588, South Korea
2 Department of Mechatronics Engineering, Jeju University# Corresponding Author / E-mail: sholee7@kitech.re.kr

ABSTRACTThis study introduces a novel approach for Al2O3 area-selective atomic layer deposition (AS-ALD) using inkjetprinted inhibition patterns. ALD-inhibition patterns with two-layer structures of fluorocarbon (FC) thin film andphotoresist (PR) were patterned by inkjet printing. Low surface energy FC thin films were used to block the Al 2O3
nucleation and growth during the ALD process, and PR was patterned to easily remove ALD-inhibition patterns by alift-off process. To demonstrate AS-ALD, an Al2O3 thin film approximately 10 nm thick was deposited via an in-house
built system with a multiple-slit gas source. The proposed AS-ALD method was evaluated for topological analysis using
atomic force microscopy and surface composition analysis using a time of flight secondary ion mass spectrometry afterAl2O3 deposition and a lift-off process.
Keywords : Inkjet printing, Inhibition Pattern, Area-Selective Atomic Layer Deposition, Al2O3 Multilayer
1.

INTRODUCTION
Atomic layer deposition (ALD) is a nanoscale thin film deposition technique capable of producing highly conformal,
dense, and low porosity film. It relies on alternating pulses of precursor gases and vapors to the substrate surface andsubsequent chemisorption or surface reaction of the precursors [1]. Recently, area-selective atomic layer deposition(AS-ALD) has received considerable attention as an alternative method for nanoscale film patterning in the
microelectronics industry [2, 3]. Unlike ALD, which involves reactions occurring over the entire surface, AS-ALD
selectively inhibits thin film deposition on specific surfaces by utilizing surfaces with distinct chemical properties [4].
This paper presents the inkjet printing technique for fabricating a double-layer ALD suppression mask patterncomposed of a fluorocarbon (FC) thin film and photoresist (PR) for AS-ALD process.
2.

Experimentals
An inkjet printer (DMP2800, Dimatix-Fujifilm Inc.) was used to print the patterns with FC and PR inks. The FC ink(mixture of FC40 and FC722, 3M) was printed to form a low surface energy pattern. FC 40 was used as a solvent, andFC722 as a solute to prepare FC ink. The PR ink was prepared by mixing commercial PR (DSAM-3020, Dongjin
Semichem Co.) with ethyl lactate (EL) solvent. FC and PR inks were jetted using 1 and 10 pl cartridges (DMC-11610,
Fujifilm Dimatix Inc.), respectively. Si wafer was used as the substrate. We deposited the Al2O3 thin films via an inhouse built roll-to-roll ALD system with a multiple-slit head for gas source supply. The growth rate is determined by the
speed of the substrate that is continuously moving relative to the simultaneously delivered precursor sources (TMA and
H2O). The substrate moving speed was maintained at 5 mm/sec. Al2O3 thin films were grown on the substrates at room
-slithead and the moving substrate, and both the multiple-slit head and substrate were heated to 100 °C.
2.2

Results and Discussion
Figure 1 shows Schematic diagram of the proposed AS-ALD using the inkjet-printed ALD-inhibition mask patterns
and a lift-off process. To analyze the ALD inhibition effect of the mask patterns, surface analysis of the deposited layer
was conducted using an AFM. As a result of AFM analysis, all surfaces before Al 2O3 deposition showed fine-grain
spreading topology. Al2O3 deposition shows a tendency to increase RMS roughness (Rq) and decrease Peak-to-valley
roughness (Rp-v). In the cases of the PR surfaces, even after Al 2O3 deposition, surface morphology maintained a finegrain spreading topology. However, FC-covered PR showed lumped and undulating surface including cavities alongwith the abrupt increase of Rq. A 6.5 nm thick Al2O3 thin film was successfully patterned by the proposed lift-off
process using an inkjet-printed 1.28 µm thick FC/PR mask pattern (Figure 2).

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Figure 1. Graphical abstract of proposed AS-ALD method using inkjet-printed ALD-inhibition test patterns and lift-off process

Figure 2. Cross-sectional profile and three-dimensional image of patterned Al2O3 measured by AFM

3. CONCLUSION
In this study, AS-ALD of Al2O3 was successfully demonstrated using ALD inhibition patterns consisting of a two-layer
structure formed by inkjet printing. An FC thin film was coated to inhibit Al2O3 nucleation and growth during the ALD
process after thick PR was inkjet-printed to allow easy removal of ALD-inhibition patterns by the lift-off process. To
confirm the proposed AS-ALD process, FC, PR, and FC/PR were printed as ALD-inhibition test patterns on Si
substrates; thereafter, a ~10 nm thick Al2O3 thin film was deposited via an in-house built system with a multiple-slit gas
source. The Al2O3 film was successfully patterned by a lift-off process using an FC-thick PR
inhibition layer and ultrasonic agitation.
ACKNOWLEDGEMENT
This work was supported by the Industrial Fundamental Technology Development Program (20015123, Developmentof intelligent complex process manufacturing equipment for flexible flat cable for automobile harness) funded by the M
inistry of Trade, Industry & Energy (MOTIE) of Korea.
REFERENCES
1. M. Leskelä, M. Ritala,Thin Solid Films 409 (2002) 138-146.
2. M. Fang and J. C. Ho, ACS NANO 9 (2015) 8651-8654.
3. W. Lee, N. P. Dasgupta, O. Trejo, J. -R. Lee, J. Hwang, T. Usui, and F. B. Prinz, Langmuir 26 (2010)
6845-6852.
4. A. Haider, P. Deminskyi, T. M. Khan, H. Eren, and N. Biyikli, J. Phys. Chem. C 120 (2016) 26393-26
401.

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The 14th Japan-China-Korea Joint Conference on MEMS/NEMSHigh power vibration energy harvester for Smart Grid

Congsheng Duan 1,2, # Lu Wang 1,2,, Libo Zhao 1,2, Maeda Ryutaro 1,2
1 State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing andMe# Corresponding Author / E-mail: wang.lu@xjtu.edu.cn, TEL: +86-82668616, FAX: +86-82668616

ABSTRACT
Exploring a high power and highly reliable vibration energy harvester for widely existing vibration energy is of great
research significance for promoting energy collection applications. This paper first discusses the arrangement form ofpiezoelectric plates, and it can be seen that the prototype in vertical arrangement has an output of 0.36mW at 0.1g, whic
h is greater than the 0.21mW in horizontal arrangement. A L shaped piezoelectric energy harvester with wire cutting machining is proposed for the vibration of transformers in the power grid. The frequency modulation method of the prototy
pe is discussed to achieve maximum output power. Under 0.2g, 100Hz excitation, the output power can reach 6.4mW, w
hich can meet the needs of many wireless sensor nodes and is of great significance for promoting the development of smart grids.
Keywords : Adjustable frequency, Vibration energy harvesting, Smart grids
1.

INTRODUCTION
With the development of embedded system, MEMS, wireless communication network technology and sensor technol
ogy, the Internet of Things (IoT) technology, which is one of the main technical innovation directions in the future, is also developing vigorously. The Internet of Things technology obtains all kinds of information through many wireless nodes distributed in the environment. However, there are many problems in the power supply of wireless sensor nodes, su
ch as difficulty in long distance distribution of power lines, difficulty in replacing batteries, environmental pollution cau
sed by batteries, etc. Therefore, it is very important to explore the vibration energy collection technology in special scen
es[1].
2. PROTOTYPE DESIGN AND ANALYSIS
2.1 Comparison of the arrangement of piezoelectric plates
In order to realize the vibration energy harvester with high power output, a linear vibration energy harvester asshown in Fig. 1(a) is prepared. The upper and lower PZT-5H piezoelectric plates are connected in series, and an Lshaped tungsten mass is added at the free end to ensure compact and high input mechanical power. B comparing the output of the prototype under different layout forms, it can be seen that the vertically arranged prototype has an output of 0.36mW at 0.1g, which is greater than the 0.21mW at the horizontal arrangement. From the finite
element simulation of the two, it can be seen that the vertically arranged piezoelectric sheet forms an equal stress distribution during vibration, which not only increases the power generation effect of the piezoelectric she
et, but also avoids the problem of damage to the piezoelectric sheet caused by root stress concentration under
the horizontal layout.

Figure 1 Vertical and horizontal arrangement comparison
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2.2 L-shaped PVEH for Transformer of smart grids
Based on the above conclusions, a L shaped prototype as shown in Fig. 2(a) is proposed without complicated assembl
y process. At the same time, the influence of different adhesives on the output voltage was investigated, and 6101AB ad
hesive was determined as the binder of the prototype. To solve the problem of frequency offset in machining and assem
bly of the prototype, a frequency modulation scheme is proposed, which uses copper sheets of different thickness to increase frequency and adds mass blocks to decrease frequency, as can be seen in Fig. 2(g) , after bonding the copper plates,
the prototype achieves the resonant frequency of transformer standard 100Hz, output power 6.4 mW at 0.2 g excitation, and a limiter is used to ensure that the piezoelectric plates are not damaged at high acceleration for further protection of the prototype.

Figure 2 L-shaped PVEH for Transformer of smart grids

3.

CONCLUSION
In this research, a new type of PVEH with one-stage wire-cut is proposed, which is used to obtain the vibrationenergy of transformer in power grid, it can output 6.4 mW power under the excitation of 0.2 g, which is of greatsignificance to the development of smart grid
ACKNOWLEDGEMENT
This work is supported by the National Key Research & Development (R&D) Program of China (Grant No. 2022YF
B3206800), the R&D project of State Grid Corporation of China (5500-202158417A-0-0-00).
REFERENCES
1. Chongfeng Wei and Xingjian Jing. A comprehensive review on vibration energy harvesting: Modelling andrealization[J]. Renewable & Sustainable Energy Reviews, 2017, 74 : 1-18.

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[1]
[2]

Smart Mater. Struct., vol. 14, no. 1, pp. 197 214, 2005.
Z. Chen, T. I. Um, and H. Bart-inspired robotic manta ray powered by ionic polymer-metal
Int. J. Smart Nano Mater., vol. 3, no. 4, pp. 296 308, 2012.

[3]
Int. J. Smart Nano Mater., vol. 11, no. 2, pp. 117 128, 2020.

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A Compact Wireless Water Flow Speed Sensor

Michio Shimomura1,2, Fumikazu Mizutani1,2, Yukito Fukushima3, Shinsuke Ishii1, Yoshikazu Yoshida2,
Tomoaki Kageyama1, Tadao Matsunaga1 and #Sang-Seok Lee1
1 Graduate School of Engineering, Tottori University,
4-101 Koyama-Minami, Tottori, 680-8552, JAPAN2 Sakuragawa Pump MFG Co., Ltd.,
1-2-11 Itsukaichi, Ibaraki, Osaka, 567-0029, JAPAN
3 National Institute of Technology, Matsue College,
14-4Nishiikuma-cho, Matsue, 690-8518, JAPAN# Corresponding Author / E-mail: sslee@tottori-u.ac.jp, TEL: +81-857-315961

ABSTRACT
We propose a compact-size water flow sensor to monitor river or underground water flow speed. It consists of fourpressure sensors and wireless module. Measured pressure differences are converted into water flow speed. We designed,
fabricated and evaluated the water flow speed sensor. As a result, we confirmed that the water flow speed sensor could
measure lower water flow speed than previously proposed water flow sensor. We can measure the water flow speed
faster than 8.7 cm/sec. Moreover, by using wireless module, the measured water flow speeds were wirelessly transferred
to computer and we can obtain water flow speed automatically.
Keywords : compact-size, pressure sensor, water flow speed, wireless
1.

INTRODUCTION
For environment monitoring, measuring various physical quantities are necessary. One of them, water speed is an
important physical quantity to monitor river or underground water status. To measure liquid flow speed including water
flow, many sensors have been proposed. Among them, sensors using ultrasonic or electromagnetic induction method are
popular. However, those sensors are not suitable for wireless sensor network system sensor to measure and monitor
water flow remotely and continuously due to complicate output signal processing, large size sensor system caused fromphysical principle, high cost and high-power consumption. Therefore, small sized and low power consuming sensor isnecessary to monitor water flow using a wireless sensor network system. Furthermore, it is also indispensable toachieve environmental Internet of Things (IoT) society [1-3].
In this paper, we propose a sensor to measure river or underground water flow speed using commercial MEMS
pressure sensors. This water flow sensor is improved from our previously proposed sensor [4]. The water flow speed
sensor size and MEMS pressure sensors are redesigned more compactly and more precisely, respectively, to monitor
lower flow speed like underground water flow. Moreover, we added a wireless function in sensor system to obtain waterflow speed wirelessly and remotely. Four MEMS pressure sensors in the water flow sensor, which are positioned
perpendicularly each other in an octagon shaped housing to measure flow pressures of four different directions. FourMEMS pressure sensors measure pressure differences, which can be converted into water flow speed.
2.

DESIGN AND FABRICATION
We redesigned previously proposed water flow sensor, and we refabricated it. In the fabrication, four pressure
sensors are assembled on electronic circuit board and positioned perpendicularly each other, which measure flowpressures. To measure lower water flow speed than the previous flow speed sensor, we changed the MEMS pressure
sensor that can be measure lower pressure range and has higher resolution than those of MEMS pressure sensor used inprevious study. In this study, we added a new function to sensor system for wireless transfer acquired sensing data to PC.
To reduce sensor system size, we changed components on circuit board smaller sized ones. Moreover, we also changed
wiring design. Consequently, we achieved approximately 45% reduced area of the circuit board. On the new circuitboard, terminal is prepared to write Arduino boot loader as well.
After assembling four MEMS pressure sensor boards onto the main circuit board, we molded it with epoxy adhesive
to protect sensor system from water. Tiny spaces are buried with UV resin after molding the sensor system. In Fig. 1, weshow the fabricated sensor system consisted of four MEMS pressure sensor boards and main electronic circuit board.
Acquired sensing data from MEMS pressure sensors are temporally aggregated in the microcontroller via SPI
communication. Microcontroller is prepared outside of sensor system shown in Fig. 1. Furthermore, the data aggregatedin the microcontroller were wirelessly transferred to PC using Raspberry Pi.
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Pressure
sensors

Water
flow

S4

S2

S3

S1
Microcontroller

Pressure
sensors

Figure 1. Fabricated senor system consists of four MEMS pressure sensors and main electronic circuit board. It is molded by epoxy
adhesive, and it is connected to microcontroller.

3.

EXPERIMENT RESULTS
The water flow sensor was evaluated to verify working principle and availability. It was tested in experimentcirculating water channel. In experiment, we measured flow pressure using four pressure sensors to clarify thecorrelation between pressure variations and flow speed. Output data acquired by water flow speed sensor were
wirelessly transferred to PC once at every second via the Raspberry Pi. Water flow speed in the channel was confirmedby the commercial electromagnetic flowmeter.
In the experiment, to clarify the relationship between flow pressure value and speed, first, we measured staticpressure when the flow was 0. Then, by increasing the flow speed gradually, we acquired output data that were
calibrated with the static pressure value. Output data acquired every second were averaged every one minute. In Fig. 2,
experiment results are summarized.

Figure 2. Experiment results of water flow speed sensor. Positions of pressure sensors from S1 to S4 are represented in Fig. 1.

4.

CONCLUSION
We proposed a compact water flow speed sensor to monitor remotely and constantly river or underground water flow
speed. The flow speed was measured by measuring pressure variations and differences between installed four pressure
sensors. We successfully measured water flow speed when the speed was faster than 8.7 cm/sec.
REFERENCES
1. P. Kamalinejad, C. Mahapatra, Z. Sheng, S. Mirabbasi, V. C. M. Leung, Y. L. Guan,for the Internet of Things,-108, 2015.
2. K. Kuromori, S. Gotoh, Y. Matunaga,
Transactions of the Society of Instrument and Control Engineers, 30, pp. 1020-1026, 1994.
3. H. Ishikawa, M. Takamoto, K. Shimizu, H. Monji, G. Matsuiof ultrasonic flowmeter for very low liquids flow rate,
Engineers, 36, pp. 1071-1078, 2000.
4. Y. Fukushima, M. Taie, T. Kageyama, T. Tani, Y. Kajikawa, M. Kuroiwa, T. Seiyama, S.-y harvesting,
ControlthInternational Conference on Nano/Micro Engineered and Molecular System (NEMS), pp. 14-17, 2020.
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A Proposal of a Blockchain-Applied Framework
for Securing Process Logs in Semiconductor Manufacturing
Myoung Soo Choi1,2 and #Sang-Seok Lee1
1 Graduate School of Engineering, Tottori University,
4-101, Koyama-Minami, Tottori, Tottori 680-8552, JAPAN2 SK Hynix, 2091 Gyeongchung-daero, Bubal-eup, Icheon-si, Gyeonggi-do, 17336, KOREA# Corresponding Author / E-mail: sslee@tottori-u.ac.jp, TEL: +81-857-31-5961

ABSTRACT
Semiconductor equipment is an integrated system made up of components and sub-assemblies. This means thatsourcing erroneous components must be necessary to identify the root causes when something unexpected happens
during the processing of wafers. Fault Detection and Classification (FDC) is a classic system that detects malfunctionsin the equipment. However, it is well known that it is difficult to instantiate FDC in a way that watches for all potential
errors. Equipment engineers have to investigate process logs to source errors when FDC cannot show the errors.
However, the process logs are easy to tamper with, which could lead to a significant failure in resolving process
excursions. This paper proposes a framework to keep them tamper-resistant using blockchain technology.
Keywords : FDC, Process Log, DRAM, NAND, MEMS, Semiconductor Equipment, Blockchain
1.

INTRODUCTION
Semiconductor equipment is comprised of complex parts that degrade over time. Fault Detection and Classification(FDC) is widely used to monitor drifts in the health condition of these parts [1]. However, it's challenging to instantiate
FDC in a way that monitors all potential errors, and we often encounter drifts that FDC fails to detect. In such situations,investigating process logs can be a powerful means of understanding how the equipment has functioned, as they containhistorical state information of sensors and actuators that affect the equipment's operation. Nevertheless, process logs canbe unintentionally modified during investigation, leading to significant failures in resolving process excursions. To
prevent such failures, we need a method to make the process logs tamper-resistant. Blockchain technology inherently
supports tamper-resistant digital ledgers [2], which inspired us to secure the process log with blockchain technology.
Furthermore, if the process log is treated as a digital ledger, we can automate the investigation of the process log,
resulting in a productive resolution of process excursions. In this paper, we propose a framework called FIPL
(Framework Investigating Process Log) to transform the process log into a tamper-resistant digital ledger. The
framework utilizes essential components of blockchain and customizes them for its properties, which differ from theblockchain itself.
2.

FRAMEWORK DESIGNIn terms of its usage model, FIPL is limited to comparing process logs and identifying sensors with unusual values
compared to their normal states. Therefore, FIPL can be considered a very lightweight version of a blockchain
application. To exploit blockchain, FIPL uses transactions, blocks, and digital ledgers as its data structures, which areessential components of blockchain. However, they are modified to adjust to its simpler usage model in comparison to
the blockchain, which balances input-output of cryptocurrencies [3]. In terms of protocol, FIPL is not required tosupervise the competition of creating new blocks, whereas blockchain must solve hash puzzles to fairly organize thecompetition among block miners [4]. With FIPL, the transactions are instantiated to collect sensor data from distributed
process logs to be investigated. Gathering sensor data requires one transaction request and multiple transaction
responses. Figure 1 shows an example of a transaction list with collected sensor data. A block is created to build theledger of sensor data from transactions. The block includes TrID (Transaction ID) that specifies the transactions
containing sensor data. Once a block is created, FIPL compiles sensor data of interest from the transaction list andgenerates a digital ledger of the compiled sensor data. Figure 2 shows an example of the ledger.

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Figure 1 An example of transaction list

Figure 2 An example of the ledger

3.

FRAMEWORK USAGE
With FIPL, equipment engineers can invoke the BuildLedgerCommand to construct a digital ledger of sensor data forinvestigation. Once the BuildLedgerCommand is initiated, FIPL generates a transaction and a block in turn to build thedigital ledger. When needed, equipment engineers can securely investigate sensor data maintained in the digital ledger
using the InvestigationCommand. The InvestigationCommand conducts comparisons of the sensor data by default. If
necessary, the engineers can pre-enroll several comparison methods and select one of them with an OPCODE.
Additionally, FIPL can support a GUI (Graphical User Interface) to visualize the investigation results.
4.

CONCLUSION
There is a strong requirement for early detection of performance drifts in semiconductor equipment. However, thedrifts that cannot be identified by FDC still pose an annoying problem for semiconductor manufacturing.While
investigating process logs is typically used to uncover these undetected drifts, it can lead to failure dueto accidental
modifications of the process logs. In this paper, we propose a framework to transform the process log into a tamperresistant digital ledger. The paper demonstrates how blockchain technology can be adoptedto build the digital ledger forthe process log. While FIPL was originally devised for manufacturing memory devices such as DRAM and NAND, it
can be applied to diverse devices such as CPU, GPU, CIS, and MEMS. FIPL will undoubtedly contribute to enhancing
the capabilities for early detection of performance drifts in semiconductor equipment.
REFERENCES
1. H. Shinozaki and T. Tanaka,
Proc. of IEEE
International Symposium on Semiconductor Manufacturing, p.1, 2018.
2. https://doi.org/10.6028/NIST.IR.8202.
3. A. M. Antonopoulos, Mastering Bitcoin (2nd ed.),Sebastopol, CA, USA, 2017.
4. A. M. Antonopoulos and G.Wood, Mastering Ethereum,
Sebastopol, CA, USA, 2019.

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Process Development Utilizing Two-Photon Polymerization (TPP) andDigital Micro Mirror Device (DMD) for High-Resolution Digital
Patterning4#

Hyunmin Cho1 , Won-Sup Lee1and Won Seok Chang1,2*

1 Department of Nano Manufacturing Technology, Korea Institute of Machinery and Materials (KIMM), Daejeon, Republic ofKorea)
2 Department of Nano-mechatronics, University of Science and Technology (UST), Daejeon, Republic of Korea# Won Seok Chang / E-mail: paul@kimm.re.kr, TEL: +86-10-6403-9488

ABSTRACTIn traditional photo lithography processes, the fabrication of patterns necessitates the production of masks.
However, the utilization of a Digital Micro Mirror Device (DMD) enables real-time implementation of desired
shapes, eliminating the need for mask production. Mask-less photolithography equipment based on DMD tech
nology relies on optical systems for projecting DMD images, limiting pattern resolution to the Rayleigh criteri
on. Such pattern distortions are undesirable in conventional projection imaging systems. Therefore, this study a
ims to dramatically enhance the pattern resolution in the Depth of Focus direction using femtosecond laser-bas
ed two-photon polymerization. Additionally, we investigate the production of desired patterns by simulating the
Point Spread Function of distorted images implemented through an optical system with high magnification an
d diffraction-limited performance. Through this research, we explore innovative techniques to advance high-reso
lution digital patterning, eliminating the constraints associated with traditional mask-based lithography processes.
Keywords : Two-Photon Polymerization (TPP), Digital Micro Mirror Device (DMD), High-Resolution Digital
Patterning

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Flexible thermoelectric generator with optimized structure
Fuchuan Zeng1, Meiye Liang1, Zhuqing Wang 1, Yuanlin Xia1, Cao Xia1
1 School of Mechanical Engineering, Sichuan University, Chengdu 610065, China
E-mail: wzhuqing@scu.edu.cn

ABSTRACTThis paper reported a flexible thermoelectric generator (FTEG) based on inorganic bulk thermoelectric materials,
which holds great prospects in wearable power sources. The developed FETG with optimized structure incorporating
aerogel thermal insulation and high thermal conductivity heat dissipation layer exhibits great flexibility and output
performance. The open circuit voltage of FTEG reaches 35 mV and its maximum power is 110.2 W by converting
human body heat at room temperature (23 ). Moreover, the open-circuit voltage, output power and power density
under 2 load resistance are 173 mV, 4.5 mW and 127 W/cm2 respectively at a temperature gradient of 50 K. The
developed FTEG shows great potential in converting waste heat into electricity, enabling the power supply forelectronic watches after voltage boosting with a DC booster.
Keywords : Flexible thermoelectric generator, thermal insulation, Waste heat harvesting
1.

INTRODUCTION
Thermoelectric generator shows great potential in converting waste heat into electricity and offering sustainable
power for electronic devices. This characteristic renders TEG becoming a highly promising candidate for self-powered
wearable application [1]. However, achieving a trade-off between flexibility and output performance is very challenging,and the exploration of the practical application for FTEG seems relatively rare [2]. Therefore, this work developed a
FTEG based on inorganic bulk TE materials [3]. The schematic diagram of the developed FTEG is shown in the Figure
1 (a). The developed FETG with optimized structure of aerogel thermal insulation layer and silicone-AlN heatdissipation layer exhibits great flexibility and power generation performance. A power management system based on the
FTEG is also proposed for waste heat harvesting in household environments to verify its practical application ability.
2. Method
2.1 Simulation
To investigate the effect of aerogel thermal insulation layer and high thermal conductivity silicone-AlN heatdissipation layer, we characterized the performances of FTEG with different thermal conductivity at middle and top
layer by finite element analysis (FEA). Figure 1 (b) presents the FEA results of FTEG showing open circuit voltage at atemperature difference of 10 K. Figure 1 (c), (d) and (e) show the temperature distribution on the cross-section, open
circuit voltage at different temperature differences and output power of the FTEG with different thermal conductivity at
middle and top layer.
2.2 Experiment
The current-voltage characteristic of FTEG is shown in Figure 2 (a), and the fitting results of the current-voltage
characteristic curve is shown in the Figure 2 (b). The voltage and current at different load resistance with thetemperature difference of 10 K is shown in the Figure 2 (c). Obviously, as the load resistance increases, the voltage andcurrent initially increase and then decrease until they reach a threshold and begin to stabilize. The voltage after
stabilizing is about 18 mV. Figure 2 (d)-(e) are output power and power density at different temperature difference witha load resistance of 2 . Figure 3 (a) shows the practical application of the FETG, and Figure 3 (b) presents the output
voltage of the FTEG and DC booster.
3. CONCLUSION
This paper reported a FTEG fabricated with inorganic bulk thermoelectric materials. The developed FTEG possesses
excellent flexibility and output performance. The conformal contact with arbitrary-shaped heat sources and highthermoelectric conversion efficiency make it become a good candidate as power sources for wearable devices tofacilitate the realization of self-powered wearable applications.
REFERENCES[1] Kuang N, Niu A, Wang W, et al. High performance flexible thermoelectric generator using bulk legs and integrated
electrodes for human energy harvesting. Energy conversion & management, Vol. 272, No. 15, 116337, 2022.
[2] Van Toan N, Tuoi T T K, Van Hieu N, et al. Thermoelectric generator with a high integration density for
portable and wearable self-powered electronic devices. Energy conversion & management, Vol. 27
5, No. 1, 114571, 2021.
[3] Lee B, Cho H, Park K T, et al. High-performance compliant thermoelectric generators with magnetically se
lf-assembled soft heat conductors for self-powered wearable electronics. Nature Communications, Vol. 11, No. 1,
5948, 2020.

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Figure 1. (a) The schematic diagram of the developed FTEG. (b) FEA results of FTEG showing open circuit voltage at atemperature difference of 10 K. (c) Temperature distribution on the cross-section, (d) open circuit voltage at different temperature
differences (e) and output power of the FTEG with different thermal conductivity at middle and top layer.

Figure 2. Experimental results. (a) Relationship between output voltage, power density and load resistance. (b) Fitting of the voltage-current curve and voltage-power density curve. (c) Voltage and current at different load resistance. (d) Output po
wer at different temperature differences. (e) Power density at different temperature difference. (f) Power density at different
load resistance and temperature difference.

Figure 3. Practical application of the FETG. (a) The FTEG Lights LED and supplies power for electronic watch. (b) Outp
ut voltage of the FTEG and DC booster.

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1.
2.

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1Contact
General : micro@kimm.re.kr
Accounting : master@micronanos.org