• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.18-22
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• 2002

CMP(chemical mechanical polishing) process has attracted as an essential technology of multilevel interconnection. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, slurry dominates more than 40%. So, we focused that it has how to reduce the consumption of raw slurry. In this paper, we presented the pH changes of diluted slurry and pH control as a function of KOH contents. Also, the removal rates of slurry with different dilution ratio was investigated. Finally, CMP the characteristics as a function of silica($SiO_2$) abrasive contents were discussed.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.156-157
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• 2000

낮은 도핑의 silicon은 광통신에서 사용하는 1.3 및 1.55 um의 광파장 영역에서 0.01dB/cm 이하의 낮은 흡수 손실을 가짐으로 인해, core 층으로 silicon을 사용하며 상부 및 하부 cladding 층으로 SiO$_2$와 같은 유전체 박막 구조를 갖는 SOI (Silicon on Insulator)를 사용한 수동광소자에 대한 연구가 1990년대부터 진행되고 있다. 또한 silicon의 특성상 SOI는strain에 의한 영향이 낮고, 광학적 비등방성이 적어서 polymer 및 silica를 이용한 광소자에 비해 편광의존도가 낮은 광소자를 구현할 수 있는 장점이 있다. 현재까지 연구되어온 SOI 수동광소자의 연구결과는 TE/TM 편광차에 따른 채널분리도가 약 0.04nm, 누화특성이 23dB 인 8채널 AWG의 연구결과가 있었으며, 스위칭시간 < 1msec, 소광비 17 dB의 광결합기와 마하젠더가 혼합된 광변조기 및 Bookham사에서 개발한 RX/TX 양방향 송수신 광모듈에 적용된 1.3/l.55 um 파장선택적 분리기, Silicon-CMOS 증폭기와 집적화된 4channel 광다중 수신기등에 대한 연구결과가 있었다. (중략)

• Transactions on Electrical and Electronic Materials
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• 제5권6호
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• pp.233-236
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• 2004

Copper metallization has been used in high-speed logic ULSI devices instead of the conventional aluminum alloy metallization. One of the key issues in copper CMP is the development of slurries that can provide high removal rates. In this study, the effects of slurry chemicals and pH for slurry dispersion stability on Cu CMP process characteristics have been performed. The experiments of copper slurries containing each different alumina and colloidal silica particles were evaluated for their selectivity of copper to TaN and $SiO_{2}$ films. Furthermore, the stability of copper slurries and pH are important parameters in many industries due to problems that can arise as a result of particle settling. So, it was also observed about several variables with various pH.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.551-552
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• 2007

Coating films were prepared from silane-terminated Colloidal silaca(CS) and UV-curable acrylate resin. The silane-terminated CSs were synthesized from CS and methyltrimethoxysilane(MTMS) and then treated with 3-methacryloxypropyltrimethoxysilane(MAPTMS)/3-glycidoxypropyltrimethoxysilane( GPTMS)/vinyltrimethoxysilane(VTMS) by sol-gel process, respectively. The silane-terminated CS and acrylate resin were hybridized using UV-curing system. Thin films of hybrid material were prepared using spin coater on the glass. Their hardness, contact angle and transmittance improved with the addition of silane-terminated CS.

• International Journal of Concrete Structures and Materials
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• 제9권3호
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• pp.381-390
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• 2015

Investigating the microstructure of hardened cement mixtures with the aid of advanced technology will help the concrete industry to develop appropriate binders for durable building materials. In this paper, morphological, mineralogical and thermogravimetric analyses of autoclave-cured mixtures incorporating ground dune sand and ground granulated blast furnace slag as partial cementing materials were investigated. The microstructure analyses of hydrated products were conducted using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), differential thermal analysis (DTA), thermo-graphic analysis (TGA) and X-ray diffraction (XRD). The SEM and EDX results demonstrated the formation of thin plate-like calcium silicate hydrate plates and a compacted microstructure. The DTA and TGA analyses revealed that the calcium hydroxide generated from the hydration binder materials was consumed during the secondary pozzolanic reaction. Residual crystalline silica was observed from the XRD analysis of all of the blended mixtures, indicating the presence of excess silica. A good correlation was observed between the compressive strength of the blended mixtures and the CaO/$SiO_2$ ratio of the binder materials.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1621-1625
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• 2015

Power quality has always been a concern of power engineers. Certainly an argument can be successfully made that most parts of power engineering have the ultimate objective to improve power quality. AC motors were widely used in industrial and domestic applications. Generally, AC motors were of two types: Induction and Synchronous motors. In motor many parameters like different load cycling, switching, working in hot weather and unbalances creates harmonics which creates major reasons for temperature rise of the motors. Due to high peak value of voltage, harmonics can weaken insulation in cables, windings and capacitors and different electronic components. Higher value of harmonics increase the motor current and decrease the power factor which will reduce the life time of the motor and increase the overall rating of all electrical equipments. Harmonics reduction of all the motors in India will save more power. Coating of windings of the motor with nano fillers will reduce the amount of harmonics in the motor. Based on the previous project works, actions were taken to use the enamel filled with various nano fillers for the coating of the windings of the different AC motors. Ball mill method was used to convert the micro particles of Al₂O₃, SiO₂, TiO₂, ZrO₂ and ZnO into nano particles. SEM, TEM and XRD were used to augment the particle size of the powder. The synthesized nano powders were mixed with the enamel by using ultrasonic vibrator. Then the enamel mixed with the nano fillers was coated to the windings of the several AC motors. Harmonics were measured in terms of various indices like THD, VHD, CHD and DIN by using Harmonic analyzer. There are many other measures and indices to describe power quality, but none is applicable in all cases and in many instances, these indices may hide more than they show. Sometimes power quality indices were used as a basis of comparison and standardization. The efficiency of the motors was increased by 5 – 10 %. The thermal withstanding capacity of the motor was increased by 5º to 15º C. The harmonics of the motors were reduced by 10 – 50%.

• 한국전기전자재료학회논문지
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• 제25권8호
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• pp.646-650
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• 2012

Multifunctional structures with two kinds of materials have been intensively investigated in order to improve their electrical characteristic with two functions simultaneously. However, the research regarding of multifunctional ceramic sensor is still in a preliminary stage and how to integrate them with low-cost and high-yield mass production process remains a challenge issue. In this study, we fabricated the multifunctional ceramic sensor composed of temperature and gas sensors. Moreover, we investigated the CO sensing properties of three dimensional nanostuctured $Nb_2O_5$ thin film gas sensors fabricated with silica ($SiO_2$ nanosphere (${\O}$= 750 nm). Compared to plain films, the nanostructured films show enhanced gas sensing of greater sensitivity and a faster response. This result reveals that significantly increased sensitivity is an increase in the effective surface area for the adsorption of gas molecules.

• 공업화학
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• 제22권2호
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• pp.161-166
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• 2011

이산화탄소를 수소와 일산화탄소로 전환시키는 이산화탄소 건조 개질반응은 대표적인 흡열반응이며 열역학적으로 불리한 반응으로 알려져 있다. 이러한 문제를 극복하기 위해 높은 열적 내구성과 수명 최적화에 적합한 귀금속계 촉매 개발 연구가 활발히 진행되고 있으나 경제적인 어려움을 지니고 있다. 본 연구에서는 $Co/SiO_2$ 촉매에 Pt (0.02~0.2 wt%)와 La (2~20 wt%)을 각각 담지시켜 이산화탄소 건조 개질반응을 통해 우수한 활성과 경제적인 사용을 할 수 있는 함량을 확인 할 수 있었다. 그 결과, 0.04 wt% Pt 또는 9 wt% La을 담지하였을 경우에 각각 57%와 55%의 가장 높은 활성도를 보여주었다. 촉매 특성화에 의하여 0.04 wt% Pt와 9 wt% La이 첨가된 촉매의 코발트 입자 크기는 이 연구에서 가장 작은 입자 크기를 가진다는 것을 확인하였다. 그러므로 코발트의 입자 크기가 Pt와 La의 함량 때문에 촉매의 안정성과 반응성에 영향을 주는 것을 알 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.306-308
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• 2007

Poly(ethylene glycol) dimethyl ether (PEGDME)/fumed silica/ 1-methyl -3-propylimidazolium iodide (MPII)/$I_2$ mixtures were used as polymer electrolytes in solid state dye-sensitized solar cells (DSSCs). The contents of MPII were changed and the concentration of $I_2$ was fixed at 0.1 mole% with respect to the MPII. The maximum ionic conductivity was obtained at [EG]:[MPII]:[$I_2$]=10:1.5:0.15. It was supposed that the maximum of ionic conductivities would match with that of cell efficiencies, if the ionic conductivity is a rate determining step in the sol id state DSSCs. However, the maximum composition did not show the maximum solar cell performance, indicating the mismatch between ionic conductivity and cell performance. This suggests that the ionic conductivity may not be the rate controlling step in determining the cell efficiency in these experimental conditions, whereas other parameters such as the electron recombination might play an important role. Thus, we tried to modify the surface of the $TiO_2$ particles by coating a thin metal oxide such as $Al_2O_3$ or $Nb_2O_5$ layer to prevent electron recombination. As a result, the maximum of the cell efficiency was shifted to that of the ionic conductivity. The peak shifts were also attempted to be explained by the diffusion coefficient and the lifetime of electrons in the $TiO_2$ layer.

• 대한화학회지
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• 제47권6호
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• pp.608-613
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• 2003

Post-Oxide CMP(Chemical-Mechanical Polishing) 결과 실리콘 웨이퍼를 오염 시키고 있는 슬러리 입자의 세정 가능성을 조사하기 위하여DHF(Diluted HF)에 비이온성 계면 활성제인 PAAE(Polyoxyethylene Alkyl Aryl Ether), 비양성자성 용제인 DMSO(Dimethylsulfoxide) 와 초순수의 혼합물인 새로운 세정액을 제조하였다. 세정력을 평가하기 위해서 세정제 내에서 각각 다른 제타 포텐셜을 갖는 실리카($SiO_2$), 알루미나($Al_2O_3$)와 PSL(polystylene latex) 입자를 실리콘 웨이퍼 표면의 산화막에 인위적으로 오염시킨 후 실험에 이용하였다. 초음파하에서 세정액의 성능 평가 결과 본 세정기술은 효과적인 입자의 세정능력과 금속이온에 대한 세정 능력을 나타내고 있음을 확인하였다. 즉 기존의 APM($NH_4OH,\;H_2O_2$와 D.I.W의 혼합물)과 달리 상온에서 세정이 가능하고 세정과정이 단축 되었으며, 낮은 농도의 HF를 사용함으로써 최소의 에칭에 의하여 표면 거칠기를 감소시킬 수 있음을 보여주고 있다. 또한 주요 CMP 금속 배선 물질들에 대한 낮은 부식력으로 기존의 CMP 후 세정공정에 뿐만 아니라 차세대CMP 공정으로 각광 받고 있는 Copper CMP 에 대한 Brush 세정 공정의 보조 세정제로 본 세정제가 적용될 가능성이 있음을 확인하였다.