• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.163-163
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• 2012

차세대 모바일용 전자디스플레이로 각광받고 있는 FOLED (flexible organic light emitting display)의 연구에서 display의 신뢰성과 수명은 매우 중요한 연구 테마이다. OLED의 수명단축에 영향을 미치는 요소는 수분에 의한 열화가 가장 치명적이다. Barrier layer를 통한 수분의 주요 침투경로는 pin-hole과 void 등과 같은 defect에 의한 것으로 보인다. 수분의 침투 경로를 제어하는 OLED용 barrier layer의 요구조건은 WVTR (water vapor transmission rate)이 $10^{-6}g/m^2{\cdot}day$ 이하로 낮아야 한다. Barrier layer가 가져야 할 핵심적인 조건은 유연성을 가지면서 동시에 WVTR 값이 매우 낮아야 하는데, 아직까지 이를 만족하는 barrier layer의 개발은 아직 덜된 실정이다. 본 연구에서는 PET (polyethylene terephthalate) 기판에 sputtering법으로 barrier layer를 제조하였다. 증착에 이용한 타겟은 두가지 종류인 Al과 $Al_2O_3$를 사용하였으며, 다층박막으로 제조하였다. 제조된 barrier layer의 수분침투 특성은 WVTR의 측정으로, 유연성의 평가는 in-situ fatigue test를 수행하여 측정하였다. 종합적인 특성 평가를 위하여 SEM과 AFM (atomic force microscope) 관찰도 하였다.

• Journal of the Semiconductor & Display Technology
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• v.5 no.4 s.17
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• pp.41-45
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• 2006

Micro vibration isolation, typically originated from ground, is always a prime concern for the nano-measurement instruments such as Atomic Force Microscopes. A four mount active vibration isolation system is proposed in this paper. Modeling and control of such a four mount system was analyzed. Combined active-passive isolation principle is used for vibration isolation by mounting the instrument on a passively damped isolation system made of Elastomer along with the active stage in parallel that consists of very soft actuation system, the Voice Coil Motor. The active stage works in combination with the passive stage for working as a very low frequency vibration attenuator.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.21-23
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• 2011

Uniformity of plasma etching processes critically depends on the wafer temperature and its distribution. The wafer temperature is affected by plasma, chucking force, He back side pressure and the surface temperature of ESC(electrostatic chuck). In this work, 3D mathematical modeling is used to investigate the influence of the geometry of coolant path and the temperature distribution of the ESC surface. The model that has the coolant path with less change of the cross-sectional area and the curvature shows low standard deviation of the ESC surface temperature distribution than the model with the coolant path of the larger surface area and more geometric change.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.112-115
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• 2017

ITO thin films were grown on the glass substrate under various oxygen gas flow and substrate temperature by using FTS (Facing Target Sputtering) system. To investigate properties of as-prepared films for transparent electrical devices, we employed four-point probe, UV-VIS spectrometer, X-ray diffractometer (XRD), scanning electron microscopy (SEM), Hall Effect measurement system and Atomic Force Microscope (AFM). As a results, all of prepared samples has high transmittance of over 80 % in the visible range (300-800 nm). Their resistivity increased as a function of oxygen gas flow and substrate temperature due to their crystal structure and oxygen defect in the films. As-prepared films have a resistivity of under $10^{-4}({\Omega}-cm)$.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.102-105
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• 2017

Currently, the size of the electronic device is in the nano area. In order to control the movements of these nanoscale devices, one should be able to understand the physical phenomena in the nano area. Recently, due to carbon nanotubes and mechanical outstanding electrical conductivity and mechanical characteristics of the carbon nanotubes and Graphene behaves to apply. Efforts have been active. There are various tubes with a radius of a in a compact mass in the form of a Multi walled carbon nanotubes in different between the radius. Van der Waals force can move smoothly without friction with each other by the nanoscale motor turning, using the properties, making. This is the lightest solids per unit area on the thickness is electrical atomic layer one of the substance and the electrical conductivity, the best material and mechanical characteristics are very much. Many studies because great is the ideal nanoelectromechanical device of material is being considered. In this study, electrical resonator for a new structure proposed and the nature and methodology would like to come up.

• Journal of the Semiconductor & Display Technology
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• v.4 no.2 s.11
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• pp.33-37
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• 2005

Bare-chip packaging becomes more popular along with the miniaturization of IT components. In this paper, we have studied flip-chip process, and developed automated bonding system. Among the several bonding method, NCP bonding is chosen and batch-type equipment is manufactured. The dual optics and vision system aligns the chip with the substrate. The bonding head equipped with temperature and force controllers bonds the chip. The system can be easily modified fer other bonding methods such as ACF.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.71-74
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• 2012

Uniformity of the wafer temperature is one of the important factors in etching process. Plasma, chucking force, backside helium pressure and the surface temperature of ESC(electrostatic chuck) affect the wafer temperature. ESC consists of several layers of structure. Each layer has own thermal resistance and the Si-adhesive layer has highest thermal resistance among them. In this work, the temperature distribution of ESC was analyzed by 3-D FEM with various defects and the thickness deviation of the Si-adhesive layer. The result with Si-adhesive layer with the low center thickness deviation shows modified temperature distribution of ESC surface.

• Journal of the Semiconductor & Display Technology
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• v.10 no.3
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• pp.61-65
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• 2011

The capabilities of finite elements codes allow now accurate simulations of blanking processes when appropriate materials modelling are used. Over the last decade, numerous numerical studies have focused on the influence of process parameters such as punch-die clearance, tools geometry and friction on blanking force and blank profile. In this study, three dimensional finite element analysis is carried out to design a lead frame blanking die using LS-Dyna3D package. After design of the blanking die, an experiment is also carried out to investigate the characteristics of blanking for nickel alloy Alloy42, a kind of IC lead frame material. In this paper, it has been researched the investigation to examine the influence of process parameters such as clearance and air cylinder pressure on the accuracy of sheared plane. Through the experiment results, it is shown that the quality of sheared plane is less affected by clearance and air cylinder pressure.

• Journal of the Semiconductor & Display Technology
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• v.10 no.3
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• pp.35-42
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• 2011

This paper describes the characteristics of high speed grinding and the influence of wheel surface speed V and a grindability of the grinding materials. The various fine ceramics pieces was ground by metal and vitrified bonded diamond wheel. The surface roughness of fine ceramics(Zirconia($ZrO_2$), Silicon Carbide(SiC), Silicon Nitride($Si_3N_4$), Alumina($Al_2O_3$)) decreases from $0.05{\mu}m(R_{max})$ to $0.025{\mu}m(R_{max})$ when the wheel speed at grinding point increases the wheel speed. Relation between the temperature at grinding point and surface roughness was linear. Abrasive jet machining(AJM), a specialized from of shot blasting, is considered one of the most helpful micro machining methods for hard and brittle materials such as glasses and ceramics by constant pressure grinding.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.144-149
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• 2019

This paper describes the results of a study on the unmanned maintenance robot that simultaneously performs the cleaning and inspection of the photovoltaic panels. The robot has a special adsorptive device, an infrared sensor, a vacuum level sensor and a camera. The robot uses two SSC (Sliding Suction Cup) adsorptive devices to move up and down the slope. First, the forces generated when the robot moves up the slope are mechanically analyzed, and the required design and control of the adsorption system are suggested. The robot was designed and manufactured to operate stably by using the presented results. Next, the normal force between the panel and the wheel was measured to confirm that the robot was manufactured and operated as intended, and the robot motion was tested on the inclined panel. It has been proven that robots are well designed and built to clean and inspect sloped panels.