• 마이크로전자및패키징학회지
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• 제24권4호
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• pp.39-46
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• 2017

본 연구는 평판형 히터용 금속방열판상의 세라믹 절연층 제조, 즉 절연성 금속기판에 관한 것이다. 반도체나 디스플레이의 열처리 공정 등에 사용되는 평판형 히터를 제조함에 있어서, 온도 균일도를 높이기 위해 금속 방열판으로서 열전도율이 높고, 비교적 가벼우며, 가공성 좋은 알루미늄 합금 기판이 선호된다. 이 알루미늄 기판에 발열 회로 패턴을 형성하기 위해서는 금속 기판에 절연층으로서 고온 안정성이 우수한 세라믹 유전체막을 코팅하여야 한다. 금속 기판상에 세라믹 절연층을 형성함에 있어서 가장 빈번히 발생하는 첫 번째 문제는 금속과 세라믹의 이종재료 간의 큰 열팽창계수 차이와 약한 결합력에 의한 층간박리 및 균열발생이다. 두 번째 문제는 절연층의 소재 및 구조적 결함에 따른 절연파괴이다. 본 연구에서는 이러한 문제점 해소를 위해 금속소재 기판과 세라믹 절연층 사이에 완충층을 도입하여 이들 간의 기계적 매칭과 접합력 개선을 도모하였고, 다중코팅 방법을 적용하여 절연막의 품질과 내전압 특성을 개선하고자 하였다.

• 한국항행학회논문지
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• 제22권1호
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• pp.31-36
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• 2018

본 논문에서는 대역저지 특성을 갖는 초광대역(UWB: ultra wideband) 안테나를 설계 및 구현하였다. 제안된 안테나는 슬롯을 가진 평면 방사 패치와 패치 아래 양쪽과 뒷면 접지면으로 구성되어있다. 평면 방사 패치 내에 있는 슬롯들로써 대역을 저지하며 U-모양의 슬롯은 WLAN(wireless local area network, 5.15~5.825 GHz) 대역을, n-모양의 슬롯은 X-Band(7.25~8.395 GHz) 대역을 저지하는데 각각 기여한다. 그리고 저지 대역을 제외한 UWB(3.10~10.60 GHz) 전체 대역의 전압정재파비(VSWR: voltage standing wave ratio)를 2.0 이하로 만족시키기 위해 평면 방사 패치와 접지면에 변형을 주었다. 제안된 안테나의 설계과정과 전산모의실험에는 Ansoft사의 HFSS(high frequency structure simulator)를 사용하였다. 전산모의실험된 안테나는 3.10~10.60 GHz에서 저지 대역인 5.15~5.94 GHz, 7.02~8.45 GHz를 제외한 구간에서 전압정재파비는 2.0 이하를 만족하며, 구현된 안테나의 측정 결과는 저지 대역인 5.12~5.95 GHz, 7.20~8.58 GHz를 제외한 구간에서 전압정재파비는 2.0 이하를 만족한다.

• 한국정밀공학회지
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• 제29권12호
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• pp.1376-1381
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• 2012

Optical devices are used extensively in the field of information network. Increasing demand for optical device, optical interconnection has been a important issue for commercialization. However many problems exist in the interconnection between optical device and optical fiber, and in the case of the multi-channel, problems of the optical alignment and optical array arise. For solving the alignment and array problem of optical device and the optical fiber, we fabricated fiber alignment and array by using imprint technology. Achieved higher precision of optical fiber alignment and array due to fabricating using imprint technology. The silicon stamp with different depth was fabricated using the conventional photolithography. Using the silicon stamp, a nickel stamp was fabricated by electroforming process. We conducted imprint process using the nickel stamp with different depth. The optical alignment and array by fabricating the patterns of optical device and fiber alignment and array using imprint process, and achieved higher precision of decreasing the dimensional error of the patterns by optimization of process. The fabricated optical interconnection of PLC device was measured 3.9 dB and 4.2 dB, lower than criteria specified by international standard.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.135-135
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• 2003

The fast evolution in the fold of optical communication systems demands powerful optical information treatment. These functions can be performed by integrated optical systems. A key component of such systems is erbium doped waveguide amplifier(EDWA). The intra 4f radiative transition of Er at 1.5 $\mu\textrm{m}$ is particularly interesting because this wavelength is standard in optical telecommunications. The fabrication of waveguide amplifier for integrated optics using sol-gel process has received an increasing attention. Potential advantage of lower cost by less capital equipment and easy processing makes this process an attractive alternatives to conventional technologies like flame hydrolysis deposition, ion exchange and chemical vapor deposition, etc. In addition, sol-gel process has been found to be extremely suitable for the control of composition and refractive index related directly with optical properties. The main drawback of such an amplifier with respect to the EDWA is the need for a much higher Er3+ concentration to compensate for the smaller interaction length. However, the high doping of Er might be resulted in the non-radiative relaxation by clustering of Er ions End co-operative upconversion. In order to solve this problem, we investigate the possibility of avoiding short Er-Er distances by encapsulation of Er3+ ions in hosts such as organic-inorganic hybrid materials. For inorganic-organic hybrid sols, methacryloxypropyltrimethoxysilane (MPTS), zirconyl chloride octahydrate and erbium(III) chloride hexahydrate were used as starting materials, followed by conventional sol-gel process. It was observed by TEM that nano sols having core/shell toplology were formed, depending on the mole ratio of Zr/Er. The surface roughness for the coatings on Si substrate was investigated by AFM as a function of Zr/Er ratio. The local environment and vibrational Properties of Er3+ ions were studied using Near-IR, FT-IR, and UV/Vis spectroscopy. Nano hybrid coatings derived from polymer and Er doped encapsulation Eave the good luminescence at 1.55$\mu\textrm{m}$.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.433-434
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• 2002

Chemical mechanical polishing refers to a process by which silicon and partially-processed integrated circuits (IC's) built on silicon substrates are polished to produce planar surfaces for the continued manufacturing of IC's. Chemical mechanical polishing is done by pressing the silicon wafer, face down, onto a rotating platen that is covered by a rough polyurethane pad. During rotation, the pad is flooded with a slurry that contains nanoscale particles. The pad deforms and the roughness of the surface entrains the slurry into the interface. The asperities contact the wafer and the surface is polished in a three-body abrasion process. The contact of the wafer with the 'soft' pad produces a unique elastohydrodynamic situation in which a suction force is imposed at the interface. This added force is non-uniform and can be on the order of the applied pressure on the wafer. We have measured the magnitude and spatial distribution of this suction force. This force will be described within the context of a model of the sliding of hard surfaces on soft substrates.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1547-1552
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• 2003

In this paper, we present a planar single-crystalline silicon x-axis micro-gyroscope fabricated with a perfectly aligned vertical actuation combs on one silicon wafer, using the extended SBM technology. The fabricated x-axis micro-gyroscope has the resolution of 0.1 deg/sec, the bandwidth of 100 Hz. These research results allow integrating 6 axes inertial measurement (3 accelerations and 3 angular rates) on the same silicon substrate using the same process for the first time.

• 대한화학회지
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• 제41권5호
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• pp.239-245
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• 1997

광유로부터 polychlorinated biphenyls(PCBs)를 제거할 수 있는 가능성을 평가하기 위해 활성탄을 이용한 흡착반응을 연구하였다. 염소원자의 치환이 비교적 적은 PCBs로 구성되어 있는 Aroclor 1242의 흡착 효율은 95% 이상이었으나, 많은 염소원자들로 치환된 Aroclor 1260은 상당히 낮은 75%의 효율을 나타내었다. 관찰된 차이점은 평면이나 비평면 구조를 갖고 있는 PCBs의 기하학적인 구조에 기인한다. 실제로 평면구조 PCBs의 농도는 Aroclor 1260에서보다도 Aroclor 1242에서 훨씬 높다. PCBs의 독성은 주로 평면 구조와 관련되어 있기 때문에, 활성탄에 의한 평면구조 PCBs의 우선적인 흡착은 활성탄의 처리를 통해 독성의 감소가 성취될 수 있다는 것을 보여준다. 독성 감소의 효율은 Toxicity Equivalence Factor(TEF)를 써서 평가하였다.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.907-911
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• 2006

In this paper, we propose a new structure that improves the on-state voltage drop and switching speed in Insulated Gate Bipolar Transistors(IGBTs), which can be widely used in high voltage semiconductors. The proposed structure is unique in that the collector area is divided by $SiO_2$, whereas the conventional IGBT has a planar P+ collector structure. The process and device simulation results show remarkably improved on-state and switching characteristics. Also, the current and electric field distribution indicate that the segmented collector structure has increased electric field near the $SiO_2$ corner, which leads to an increase of electron current. This results in a decrease of on-state resistance and voltage drop to $30%{\sim}40%$. Also, since the area of the P+ region is decreased compared to existing structures, the hole injection decreases and leads to an increase of switching speed to 30 %. In spite of some complexity in process procedures, this structure can be manufactured with remarkably improved characteristics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.35-38
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• 1995

Indium Tin Oxide(ITO) thin film is transparent to visible ray and conductive in electricity. It is seen that the samples made by the sputtering process have high transmission rate to visible ray and high adhesion , but the planar type magnetron sputtering process with is very well known in industrial region have a defect of partial erosion on the surface of target and a high loss of target and also since the substrate is positioned in plasma, the damage on thin film surface is caused by the reaction with plasma. In cylindrical magnetron sputtering system. it is known that the loss of target is little , the damage of thin film is very little and the adhesion of thin film with substrate is strong. In this study, we have made ITO thin film in the cylindrical DC magnetron system with the variable of substrate temperature , magnetic field, vacuum condution and the applied voltage. The general temperature for formation on ITO is asked at 350 $^{\circ}C$~400$^{\circ}C$ but we have made ITO is low temperature(80-150$^{\circ}C$) By studing electrical and optical properties of ITO thin fims made by varing several condition, we have searched the optimal condition for formation in the best ITO in low temperature.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.303-306
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• 2009

High temperature solid oxide fuel cells (SOFCs) offer a clean, pollution-free technology to electrochemically generate electricity at high efficiencies. Solid oxide fuel cells in several different designs have been investigated; these include planar and tubular geometries. The tubular type cell is widely researched due to it have advantages about thermal expansion and sealing issues. Unfortunately, lab scale tubular cell for testing has thermal expansion and sealing problems. The previous Jig for lab scale tubular cell testing has many sealing problems. When we feed fuel gas to jig inlet, ceramic glue sealant has amount of gas expansion pressure, because temperature of feeding gas changes ambient temperature to high temperature ($700{\sim}900^{\circ}C$). Furthermore, when we carry out long time test, something like degradation test, crack of ceramic glue sealant due to weakness of mechanical properties can make stop working the test. Additionally, we reduce setting process for assembling, because micanite is not required drying or debinding process.