• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.356-359
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• 2009

In recent years, flexible e-paper displays based on electrophorectic materials continue to attract enormous interest from technologists and are expected to be in the market soon. To realize a flexible e-paper, several key technologies for TFT backplane have been developed, while it still lacks good color reproduction and requires input function for use in its various applications. Thus, the technical issues for implementing color and touch functions in a flexible e-paper are discussed, and then our development status along with technology trend of it is described.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.87-90
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• 2007

VIATRON TECHNOLOGIES has developed an $\underline{A}$tmospheric $\underline{M}$etal $\underline{D}$oping (AMD) system which uniformly dopes metal species onto a substrate. The AMD system injects metal-organic vapor over substrate using an injection head with a scan motion. One of important application of this system is a metalinduced crystallization of amorphous Si for manufacturing AMOLED poly-Si panels. The AMD system with a use of Ni vapor source produces doping of trace amount of Ni onto amorphous Si, enabling uniform MIC crystallization. Also, the operation without vacuum condition offers advantages such as easy maintenance, low cost production, and large glass processes.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.255-256
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• 2007

A A4 size black and white reflective plastic display was developed for out door application. For document readability, high resolution of 180ppi plastic TFT backplane and high reflectance electrophoretic front panel sheet was used. Preparation of display was held near $100^{\circ}C$ process on PEN substrate.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.231-234
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• 2007

Advances in white OLED tandem architecture are discussed.With these structures, stable and low-power full color AMOLED displays can be fabricated that are anticipated to be suitable for large area applications such as TVs. With a tandem architecture, efficient (24 cd/A) OLED structures with exceptional stability (${\sim}100,000\;h$ at $1000\;cd/m^2$) are described. In addition, excellent color gamut (>100% NTSC) can be attained by incorporating advanced color filters into the AMOLED backplane in a typical bottom-emitting configuration.

• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.57-66
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• 2019

This paper compared the performance with an overview of channel equalization techniques used in high-speed serial transceivers, including the homogeneous architecture and associated components for the GHz interconnect of backplane and cable channels. It also used the MATLAB tool to present system analysis and simulation results for continuous time equivalent structures. In the case of conventional continuous equalization, high frequency deficits occur due to the use of a comparator that is difficult to implement as well as the low speed limit. In this paper, the channel equalization technique based on the power spectrum analysis of clocks was used to compensate for the frequency loss, and the application of the TX+Channel and TX+Equalizer filters enabled the measurement of attenuation and equivalence without comparators. The application of blender and band-pass filters at high speeds also showed significant effectiveness.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1261-1262
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• 2008

Laser-based crystallization techniques are ideally-suited for forming high-quality crystalline Si films on active-matrix display backplanes, because the highly-localized energy deposition allows for transformation of the as-deposited a-Si without damaging high-temperature-intolerant glass and plastic substrates. However, certain significant and non-trivial attributes must be satisfied for a particular method and implementation to be considered manufacturing-worthy. The crystallization process step must yield a Si microstructure that permits fabrication of thin-film transistors with sufficient uniformity and performance for the intended application and, the realization and implementation of the method must meet specific requirements of viability, robustness and economy in order to be accepted in mass production environments. In recent years, Low Temperature Polycrystalline Silicon (LTPS) has demonstrated its advantages through successful implementation in the application spaces that include highly-integrated active-matrix liquid-crystal displays (AMLCDs), cost competitive AMLCDs, and most recently, active-matrix organic light-emitting diode displays (AMOLEDs). In the mobile display market segment, LTPS continues to gain market share, as consumers demand mobile devices with higher display performance, longer battery life and reduced form factor. LTPS-based mobile displays have clearly demonstrated significant advantages in this regard. While the benefits of LTPS for mobile phones are well recognized, other mobile electronic applications such as portable multimedia players, tablet computers, ultra-mobile personal computers and notebook computers also stand to benefit from the performance and potential cost advantages offered by LTPS. Recently, significant efforts have been made to enable robust and cost-effective LTPS backplane manufacturing for AMOLED displays. The majority of the technical focus has been placed on ensuring the formation of extremely uniform poly-Si films. Although current commercially available AMOLED displays are aimed primarily at mobile applications, it is expected that continued development of the technology will soon lead to larger display sizes. Since LTPS backplanes are essentially required for AMOLED displays, LTPS manufacturing technology must be ready to scale the high degree of uniformity beyond the small and medium displays sizes. It is imperative for the manufacturers of LTPS crystallization equipment to ensure that the widespread adoption of the technology is not hindered by limitations of performance, uniformity or display size. In our presentation, we plan to present the state of the art in light sources and beam delivery systems used in high-volume manufacturing laser crystallization equipment. We will show that excimer-laser-based crystallization technologies are currently meeting the stringent requirements of AMOLED display fabrication, and are well positioned to meet the future demands for manufacturing these displays as well.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.53.2-53.2
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• 2010

지금까지 능동 구동 디스플레이의 TFT backplane에 사용하고 있는 채널 물질로는 수소화된 비정질 실리콘(a-Si:H)과 저온 폴리실리콘(low temperature poly-Si)이 대표적이다. 수소화된 비정질 실리콘은 TFT-LCD 제조에 주로 사용되는 물질로 제조 공정이 비교적 간단하고 안정적이며, 생산 비용이 낮고, 소자 간 특성이 균일하여 대면적 디스플레이 제조에 유리하다. 그러나 a-Si:H TFT의 이동도(mobility)가 1 cm2/Vs이하로 낮아 Full HD 이상의 대화면, 고해상도, 고속 동작을 요구하는 UD(ultra definition)급 디스플레이를 개발하는데 있어 한계 상황에 다다르고 있다. 또한 광 누설 전류(photo leakage current)의 발생을 억제하기 위해서 화소의 개구율(aperture ratio)을 감소시켜야하므로 패널의 투과율이 저하되고, 게이트 전극에 지속적으로 바이어스를 인가 시 TFT의 문턱전압(threshold voltage)이 열화되는 문제점을 가지고 있다. 문제점을 극복하기 위한 대안으로 근래 투명 산화물 반도체(transparent oxide semiconductor)가 많은 관심을 얻고 있다. 투명 산화물 반도체는 3 eV 이상의 높은 밴드갭(band-gap)을 가지고 있어 광 흡수도가 낮아 투명하고, 광 누설 전류의 영향이 작아 화소 설계시 유리하다. 최근 다양한 조성의 산화물 반도체들이 TFT 채널 층으로의 적용을 목적으로 활발하게 연구되고 있으며 ZnO, SnO2, In2O3, IGO(indium-gallium oxide), a-ZTO(amorphous zinc-tin-oxide), a-IZO (amorphous indium-zinc oxide), a-IGZO(amorphous indium-galliumzinc oxide) 등이 그 예이다. 이들은 상온 또는 $200^{\circ}C$ 이하의 낮은 온도에서 PLD(pulsed laser deposition)나 스퍼터링(sputtering)과 같은 물리적 기상 증착법(physical vapor deposition)으로 손쉽게 증착이 가능하다. 특히 이중에서도 a-IGZO는 비정질임에도 불구하고 이동도가 $10\;cm2/V{\cdot}s$ 정도로 a-Si:H에 비해 월등히 높은 이동도를 나타낸다. 이와 같이 a-IGZO는 비정질이 가지는 균일한 특성과 양호한 이동도로 인하여 대화면, 고속, 고화질의 평판 디스플레이용 TFT 제작에 적합하고, 뿐만 아니라 공정 온도가 낮은 장점으로 인해 플렉시블 디스플레이(flexible display)의 backplane 소재로서도 연구되고 있다. 본 실험에서는 rf sputtering을 이용하여 증착한 a-IGZO 박막에 대하여 열처리 조건 변화에 따른 a-IGZO 박막들의 광학적, 전기적 특성변화를 살펴보았고, 이와 더불어 a-IGZO 박막을 TFT에 적용하여 소자의 특성을 분석함으로써, 열처리에 따른 Transfer Curve에서의 우리가 요구하는 Threshold Voltage(Vth)의 변화를 관찰하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.209.1-209.1
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• 2015

Indium gallium zinc oxide (IGZO), indium zinc oxide (IZO) 그리고 zinc tin oxide (ZTO) 같은 zinc oxide 기반의 산화물 반도체는 높은 이동도, 투과도 그리고 유연성 같은 장점을 갖고 있어, display application의 backplane 소자로 적용되고 있다. 또한 최근에는 산화물 반도체를 이용한 thin-film transistor (TFT) 뿐만아니라 resistive random access memory (RRAM), flash memory 그리고 pH 센서 등 다양한 반도체 소자에 적용을 위한 연구가 활발히 진행 중이다. 그러나 zinc oxide 기반의 산화물 반도체의 전기 화학적 불안정성은 위와 같은 소자에 적용하는데 제약이 있다. 산화물 반도체의 안정성에 영향을 미치는 다양한 요인들 중 한 가지는, sputter 같은 plasma를 이용한 공정 진행 시 active layer가 plasma에 노출되면서 threshold voltage (Vth)가 급격하게 변화하는 plasma damage effect 이다. 급격한 Vth의 변화는 동작 전압의 불안정성을 가져옴과 동시에 누설전류를 증가시키는 결과를 초래 한다. 따라서 본 연구에서는, IGZO 기반의 TFT를 제작 후 plasma 분위기에 노출시켜, power와 노출 시간에 따른 전기적 특성 변화를 확인 하였다. 또한, thermal annealing을 적용하여 열처리 온도와 시간에 따른 Vth의 회복특성을 조사 하였다. 이러한 결과는 추후 산화물 반도체를 이용한 다양한 소자 설계 시 유용할 것으로 기대된다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.5
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• pp.374-380
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• 2011

In this paper a printing process for patterning electrodes on large area substrate was developed by combining screen printing with reverse off-set printing. Ag ink was uniformly coated by screen printing. And then etching resist (ER) was patterned in the Ag film by reverse off-set printing, and then the non-desired Ag film was etched off by etchant. Finally, the ER was stripped-off to obtain the final Ag patterns. We extracted the suitable conditions of reverse Using the process we successfully fabricated gate electrodes and scan bus lines of OTFT-backplane used for e-paper, in which the diagonal size was 6 inch, the resolution $320{\times}240$, the minimum line width 30 um, and sheet resistance 1 ${\Omega}/{\Box}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.6
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• pp.462-467
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• 2013

In this paper, we analyzed the effects of doctoring process on the patterns of Ag ink in gravure off-set printing. The parameters of doctoring process were the angle and the pressure, which was represented by the depth of blade movement to the gravure roll, of doctor blade to the surface of gravure roll, and the angle of patterns engraved on the gravure roll to the doctor blade moving direction. The proper parameters were extracted for the fine patterns and they were 15 mm for the pressure, $60^{\circ}$ for the blade angle. And the angle of patterns with respect to the blade movement should be less than $40^{\circ}$ for the best results. The gravure off-set printing with the above parameters was carried out to print gate electrodes and scan bus lines of OTFT-backplane for e-paper. The line width of $50{\mu}m$ was successfully obtained. The thickness of electrodes was $2.5{\mu}m$ and the surface roughness was $0.65{\mu}m$ and the sheet resistance was $15.8{\Omega}/{\Box}$.