• 한국정밀공학회지
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• 제21권5호
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• pp.38-45
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• 2004

As optical communication is being substituted for telecommunication, the demand of a large variety of fiber optic components is increasing. V-groove substrates, one of the module components, are used to connect optical fibers to optical planar circuits and to arrange fibers. Their applications are multi-channel optical connectors and optical waveguide fiber coupling, etc. Because these substrates are a critical part of the splitter in a multiplexer and a multi fiber connector, precise and reliable fabrication process is required. For precisely aligning core pitch between fibers, machined core pitch tolerance should be within sub-microns. Therefore, these are generally produced by state-of-the-art micro-fabrication like MEMS. However, most of the process equipment is very expensive. It is also difficult to change the process line for custom designs to meet specific requirements using various materials. For various design specifications such as different values of the V angle and low-priced process, the fabrication method should be flexible and low cost. To achieve this goal, we have suggested a miniaturized machine tool with high accuracy positioning system. Through this study, it is shown that this cutting process can be applied to produce V-groove subtracts. We also show the possibility of using a miniaturized machining system for producing small parts.

• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.37-43
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• 2022

In this study, we investigated the optical, electrical and exothermic characteristics of ITO/Ag/ITO multilayer structures prepared with various Ag thicknesses on quartz and PI substrates. The transparent conducting properties of the ITO/Ag/ITO multilayer films depended on the thickness of the mid-layer metal film. The ITO/Ag (14 nm)/ITO showed the highest Haccke's figure of merit (FOM) of approximately 19.3×10^-3 Ω^-1. In addition, the exothermic property depended on the substrate. For an applied voltage of 3.7 V, the ITO/Ag (14 nm)/ITO multilayers on quartz and PI substrates were heated up to 110℃ and 200℃, respectively. The bending tests demonstrated a comparable flexibility of the ITO/Ag/IT multilayer to other transparent electrodes, indicating the potential of ITO/Ag/ITO multilayer as a flexible transparent conducting heater.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.301.2-301.2
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• 2016

Metal-oxide thin-film transistors (TFTs) have gained a considerable interest in transparent electronics owing to their high optical transparency and outstanding electrical performance even in an amorphous state. Also, these metal-oxide materials can be solution-processed at a low temperature by using deep ultraviolet (DUV) induced photochemical activation allowing facile integration on flexible substrates [1]. In addition, high-dielectric constant (k) inorganic gate dielectrics are also of a great interest as a key element to lower the operating voltage and as well as the formation of coherent interface with the oxide semiconductors, which may lead to a considerable improvement in the TFT performance. In this study, we investigated the electrical properties of solution-processed high-k strontium-doped AlOx (Sr-AlOx) gate dielectrics. Using the Sr-AlOx as a gate dielectric, indium-gallium-zinc oxide (IGZO) TFTs were fabricated and their electrical properties are analyzed. We demonstrate IGZO TFTs with a 10-nm-thick Sr-AlOx gate dielectric which can be operated at a low voltage (~5 V).

• 센서학회지
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• 제25권4호
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• pp.247-251
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• 2016

Au/PDMS membranes are widely used to fabricate strain sensors which can detect input signals. An interfacial adhesion between metal films and polydimethylsiloxane (PDMS) substrates is one of the important factors determining the performance of strain sensors, in terms of robustness, reliability, and sensitivity. Here, we fabricate Au/PDMS membranes with (3-mercaptopropyl) trimethoxysilane (MPTMS) treatment. PDMS membranes were fabricated by spin-coating and the thickness was controlled by varying the spin rates. Au electrodes were deposited on the PDMS membrane by metal sputtering and the thickness was controlled by varying sputtering time. Owing to the MPTMS treatment, the interfacial adhesion between the Au electrode and the PDMS membrane was strengthened and the membrane was highly transparent. The Au electrode, fabricated with a sputtering time of 50 s, had the highest gauge factor at a maximum strain of ~0.7%, and the Au electrode fabricated with a sputtering time of 60 s had the maximum strain range among sputtering times of 50, 60, and 120 s. Our technique of using Au/PDMS with MPTMS treatment could be applied to the fabrication of strain sensors.

• 한국응용과학기술학회지
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• 제27권1호
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• pp.44-49
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• 2010

본 논문에서는 6,13-bis (triisopropylsily lethynyl)-pentacene (TIPS-pentacene) 유기 박막 트랜지스터에 니켈 버퍼층을 적층했을 때의 효과를 연구하였다. 니켈 (Nickel) / 은(Silver) 소스 드레인 전극은 은 (Silver) 전극이 단독으로 쓰일 때 보다 에너지 레벨차이를 줄여 캐리어의 주입이 더 잘되도록 도와주므로써 전기적 특성을 향상 시켜준다. 또한 유기 게이트 절연체의 추가로 TIPS-pentacene 은 규칙적 배열된 형태를 가지므로써 소자 성능의 향상을 가지고 온다. 제작한 유기박막트랜지스터 에서 $0.01\;cm^2$의 포화영역 이동도를 얻을 수 있었으며, 또한 드레인 전압을 50 V로 하고 게이트 전압을 20 V에서 -50 V 까지 인가하였을 때 $2{\times}10^4$의 전멸 비를 얻을 수 있었다. 이러한 결과를 polyethylene terephthalate (PET) 기판을 이용한 유연한 OTFTs 에 적용시켜본 결과 유리기판위에 제작했을 때와 비슷한 성능을 얻음을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.285-288
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• 2007

박막형 태양전지 및 플렉서블 태양전지 기판으로 사용되는 금속기판의 우수성은 잘 알려져 있다. 그러나 상용 금속기판이 직면하고 있는 문제점을 보완하기 위해서 전주법으로 제조된 2원합금 금속포일을 개발하였으며, 박막형 및 플렉서블 태양전지의 기판재로 적용가능성을 확인하였다. 일반적으로 태양전지를 제조할 때 열 공정이 수행되며, 이때 기판재와 cell을 구성하는 반도체의 열팽창 계수 차이에 의한 열변형으로 결함이 발생될 수 있고, 태양전지 효율 및 수명을 저하시키는 원인이 될 수 있다. 이러한 원인이 될 수 있는 구성 재료간의 열팽창계수 차이에 의한 cell 의 변형량을 추정하기 위해 유한요소해석 방법을 사용하였다. 유한요소해석을 수행하기 위해 ALGOR 라는 해석 tool 을 사용하였다. 유한요소해석 수행에 사용된 상용 금속인 Mo, Ti, Al, SUS 포일과 전주법으로 제조된 2원합금 금속포일의 열팽창 계수는 실험을 통한 측정치이며, cell을 구성하는 반도체의 열팽창 계수와 열특성은 참고 문헌에 있는 자료들이다. 이 값들을 기반으로 cell 의 구성을 단순화시킨 가상의 태양전지가 제조 공정 온도에서 상온으로 냉각될 때의 열변형량을 계산하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.30-34
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• 2008

The transfer assembly (or transfer printing) technique is a promising method for fabricating multi-scale structures on various substrates including semiconductors and polymers, and has been applied to fabrication of flexible devices with superior performance to conventional organic flexible devices. The mechanical behaviors of the structures fabricated by the transfer assembly is a very important information for design and reliability evaluation purpose, but the measurement of the behaviors is difficult since their critical-dimensions are very tiny. In this study, Au films with nano-scale thickness were fabricated on a silicon substrate and their mechanical properties were measured using micro-tensile test. The Au films on the silicon substrate were then transferred to a PDMS substrate using the transfer assembly technique. Self-assembled monolayer (SAM) with a thiol group was used to enhance the transfer of Au films, and the mechanical behaviors were characterized using wrinkle-based test. The test results from micro-tensile and wrinkle-based test are compared to each other, and their implication to the transfer assembly technique is discussed.

• 한국재료학회지
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• 제25권11호
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• pp.622-629
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• 2015

Cu circuits were successfully fabricated on flexible PET(polyethylene terephthalate) substrates using wettability difference and electroless plating without an etching process. The wettability of Cu plating solution on PET was controlled by oxygen plasma treatment and $SiO_x$-DLC(silicon oxide containing diamond like carbon) coating by HMDSO(hexamethyldisiloxane) plasma. With an increase of the height of the nanostructures on the PET surface with the oxygen plasma treatment time, the wettability difference between the hydrophilicity and hydrophobicity increased, which allowed the etchless formation of a Cu pattern with high peel strength by selective Cu plating. When the height of the nanostructure was more than 1400 nm (60 min oxygen plasma treatment), the reduction of the critical impalement pressure with the decreasing density of the nanostructure caused the precipitation of copper in the hydrophobic region.

• 한국표면공학회지
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• 제38권2호
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• pp.49-54
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• 2005

Flexible copper clad laminates (FCCL) fabricated by sputtering has advantages in fine pitch etching and dimensional accuracy than previous casting or laminating type FCCL, But its lower adhesion is inevitable technical challenge to solve for commercializing it. Chromium (Cr) which strongly reacts with O moiety was used as tie-coating layer in order to improve low adhesion between copper (Cu) and polyimide (PI). Sputtering raw polyimide (SRPI) and casting raw polyimide (CRPI) were used as substrates at this research. PI was pretreated by plasma before sputtering, and each sample was varied with RF power and Cr thickness on sputtering. Peel strength of the FCCL on SRPI was higher than that on CRPI. Adhesion had maximum value when 10 nm of Cr was deposited on SRPI by RF power of 50 W. It seems to be by the formation of Cu-Cr-O solid solution at the metal-PI interface.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.262-263
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• 2011

Flexible electronics, a future technology of electronics, require a low cost integrated circuit that can be built on various types of the flexible substrates. As a potential candidate for this application, a single walled carbon nanotube network is studied as an active device with a scheme of thin film transistor. Transistors are formed on a plastic foil by the Roll-to-Roll (R2R) and the Roll-to-Device (R2D) printing method. For both printing methods, electrical transports for the transistors are presented with the temperature dependence of threshold voltage (V_Th) and mobility from the measured transfer curves at temperatures ranging from 10 K to 300 K. It is observed that ${\mu}=0.044cm^2/V{\cdot}sec$ and V_Th=7.28V for R2R and ${\mu}=0.025cm^2/V{\cdot}sec$ and V_Th=3.10V for R2D, both for the temperature at 300K. Temperature dependence of mobility and V_Th is observed. However for R2R, the temperature dependence of V_Th is constant. It is the difference between, R2R and R2D.