• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 하계학술발표회 논문집
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• pp.387-388
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• 2006

• 한국산학기술학회논문지
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• 제14권9호
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• pp.4178-4184
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• 2013

최근 나노임프린트 리소그래피 공정이 마이크로/나노 스케일의 소자 개발에 있어서 경제적으로 대량 생산할 수 있는 기술로 주목 받고 있다. 최근 나노임프린트 기술은 공정의 고속화 및 대면적화를 통한 대량생산 기술로의 전환을 목표로 하고 있다. 자외선경화 방식의 나노임프린트의 경우 상온 및 저압의 장점과 함께 비진공 환경에서 공정이 가능하다면 진공챔버 및 고압 스테이지 등과 같은 고가의 장비가 필요 없게 됨으로써 설비비용을 낮추고 공정시간을 단축하는데 큰 기여를 할 수 있다. 그러나 비진공 환경에서는 기포결함이 종종 발생하게 된다. 본 연구에서는 비진공 환경에서의 자외선경화 방식의 나노임프린트 공정 중 레지스트의 액적도포 방법에 따른 기포형성을 연구하였다. 액적의 양과 액적의 수를 달리하여 도포한 레지스트에 대하여 충전 후 기포결함 발생을 분석하였다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.281-284
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• 2004

According to the National Space Program of Korea, KARI (Korea Aerospace Research Institute) has been developing a large space simulator (working dimension; $\Phi8m\;\times\;L10m$) to verify the performance of future large satellites under the space environment conditions. Especially, a very low temperature condition of space will be simulated by shrouds covering the inside surface of the vessel. The surface of shrouds will be cooled down to 17K by liquid nitrogen (LN2) from ambient temperature and hence, an optimal LN2 circulation system design is necessary to remove gaseous nitrogen (GN2) sufficiently and maintain the shrouds at the LN2 temperature.

• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.512-518
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• 2006

In this paper, we investigated the deposition of pentacene thin film on a large area substrate by Organic Vapor Phase Deposition(OVPD) and applied it to fabrication of Organic Thin Film Transistor(OTFT). We extracted the optimum deposition conditions such as evaporation temperature of $260^{\circ}C$, carrier gas flow rate of 10 sccm and chamber vacuum pressure of 0.1 torr. We fabricated 72 OTFTs on the 4 inch size Si Wafer, Which produced the average mobility of $0.1{\pm}0.021cm^2/V{\cdot}s$, average subthreshold slope of 1.04 dec/V, average threshold voltage of -6.55 V, and off-state current is $0.973pA/{\mu}m$. The overall performance of pentacene TFTs over 4 ' wafer exhibited the uniformity with the variation less than 20 %. This proves that OVPD is a suitable methode for the deposition of organic thin film over a large area substrate.

• 한국주조공학회지
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• 제37권6호
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• pp.181-185
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• 2017

In the present study, the effect of cooling rate on the formation of the porosity in the thick aluminum sand casting was investigated. Nowadays, due to considerations of weight and cost reduction, large scale thick aluminum casting has replaces steel frames for vacuum chambers for semiconductor production. Several thick aluminum castings were manufactured using chill with temperature measurements. The castings were inspected using 3D computed tomography in order to quantify the porosity defect density in the castings. Effects of the thickness of the chill on the porosity defect density were discussed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.230-235
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• 2011

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and was developed by KARI for communication, ocean and meteorological observations. COMS was tested under vacuum and very law temperature conditions in order to correlate thermal model and to verify thermal design. The test was performed by using KARI large thermal vacuum chamber. The COMS S/C thermal model was successfully correlated versus the 2 thermal balance test phases. After model correlation, temperatures deviation of all individual unit were less than $5^{\circ}C$ and global deviation and standard deviation also satisfied the requirements, less than $2^{\circ}C$ and $3^{\circ}C$. The final flight prediction was performed by using the correlated thermal model.

• 한국전산유체공학회지
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• 제16권3호
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• pp.59-65
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• 2011

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and was developed by KARI for communication, ocean and meteorological observations. COMS was tested under vacuum and very low temperature conditions in order to correlate thermal model and to verify thermal design. The test was performed by using KARI large thermal vacuum chamber. The COMS S/C thermal model was successfully correlated versus the 2 thermal balance test phases. After model correlation, temperatures deviation of all individual units were less than $5^{\circ}C$ and global deviation and standard deviation also satisfied the requirements, less than $2^{\circ}C$ and $3^{\circ}C$. The final flight prediction was performed by using the correlated thermal model.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.208-208
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• 2010

Zinc oxide (ZnO) is a functional material with interesting optical and electrical properties, a wide band gap (more than 3.3 eV), a high transmittance in the visible light region, piezoelectric properties, and a high n-type conductivity. This material has been investigated for use in many applications, such as transparent electrodes, blue light-emitting diodes, and ultra-violet detector. ZnO films grown under low oxygen pressure by thin film deposition methods show low resistivity and large free electron concentration. Therefore, reducing the background carrier concentration in ZnO films is one of the major challenges ahead of realizing high-performance ZnO-based optoelectronic devices. In this study, we deposited ZnO thin films on sapphire substrates by pulsed laser deposition (PLD) with employing an oxygen plasma source to decrease the background free-electron concentration and enhance the crystalline quality. Then, the substrate temperature was varied between 200 'C to 900 'C The vacuum chamber was initially evacuated to a pressure of $10^{-6}$ Torr, and then a pure $O_2$ gas was introduced into the chamber and the pressure during deposition was maintained at $10^{-2}$ Torr. Crystallinity and orientation of ZnO films were investigated by X-ray diffraction (XRD). The film surface was analyzed with atomic force microscope (AFM). And electrical properties were measured at room temperature by Hall measurement.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.247.1-247.1
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• 2014

The capacitive coupled plasma is used widely in the semiconductor industries. Especially, the uniformity of the industrial plasma is heavily related with defect ratio of devices. Therefore, the industries need the capacitive coupled plasma source which can generate the uniform plasma and control the plasma's uniformity. To achieving the uniformity of the large area plasma, we designed multi-powered electrodes. We controlled the uniformity by controlling the power of each electrode. After this work, we started to research another concept of the plasma device. We make the plasma chamber that has multi-ground electrodes imaginary (CST microwave studio) and simulate the electric field. The shape of the multi-ground electrodes is ring type, and it is same as the shape of the multi-power electrodes that we researched before. The diameter of the side electrode's edge is 300mm. We assumed that the plasma uniformity is related with the impedance of ground electrodes. Therefore we simulated the imaginary chamber in three cases. First, we connected L (inductor) and C (capacitor) at the center of multi-ground electrodes. Second, we changed electric conductivity of multi-ground electrode. Third, we changed the insulator's thickness between the center ground electrode and the side ground electrode. The driving frequency is 2, 13.56 and 100 MHz. We switched our multi-powered electrode system to multi-ground electrode system. After switching, we measured the plasma uniformity after installing a variable vacuum capacitor at the ground line. We investigate the effect of ground electrodes' impedance to plasma uniformity.

• 대한기계학회논문집B
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• 제22권5호
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• pp.563-572
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• 1998

An experimental study of hot filament chemical vapor deposition(HFCVD) has been carried out for the fabrication of diamond thin film. Of particular interest is the measurement of deposition uniformity on large substrates. Experimental apparatus including a vacuum chamber, heating elements, etc. has been designed and manufactured. Deposition profiles for different pretreatment powders and different flow rates have been measured in conjunction with the measurement of substrate temperature distribution on a large substrate surface. As the flow rate increases, deposition rate increases, however, the crystallinity becomes worse. Higher growth rate has been found on the region closer to the center location where substrate temperature is higher. The crystallinity has been improved as gas flow rate decreases. The growth rate and morphology of deposition were identified by SEM and the existence of diamond phase was proved by Raman spectroscopy.