• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5434-5439
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• 2014

The surface management of metals was performed with a tool microscope or surface roughness measurement instruments. These methods were not efficient for checking the surface status of the die in the production field. For this reason, an analysis system or measurement system to monitor the wear, defects and surface status as a die ages is required. This study, developed surface analysis software for automatic analysis and standardization of a die or processed products. Software was designed to measure the basic features, such as circles, dots, and lines. The captured images were rendered as three-dimensional representations so that the depth of the grooves on the die and segmental profiles could be estimated. As a result of experimental analysis, the surface roughness was measured with an accuracy more than 93.2%, and the maximum deviation in the surface roughness for the brightness of the lighting was within $3{\mu}m$. The confidence in the device's precision was assured. These results show quality control through efficient surface analysis.

• Journal of Powder Materials
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• v.12 no.6 s.53
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• pp.399-405
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• 2005

Nanopowders of titanium dioxide $(TiO_2)$ incorporating the transition metal element(s) were synthesized by flame synthesis method. Single element among Fe(III), Cr(III), and Zn(II) was doped into the interior of $TiO_2$ crystal; bimetal doping of Fe and Zn was also made. The characteristics of transition-metal-doped $TiO_2$ nanopowders in the particle feature, crystallography and electronic structures were determined with various analytical tools. The chemical bond of Fe-O-Zn was confirmed to exist in the bimetal-doped $TiO_2$ nanopowders incorporating Fe-Zn. The transition element incorporated in the $TiO_2$ was attributed to affect both Ti 3d orbital and O 2p orbital by NEXAFS measurement. The bimetal-doped $TiO_2$ nanopowder showed light absorption over more wide wavelength range than the single-doped $TiO_2$ nanopowders.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.225-229
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• 2009

The front metal contact is one of the most important element influences in efficiency in the silicon solar cell. First of all selective of the material and formation method is important in metal contacts. Commercial solar cells with screen-printed contacts formed by using Ag paste process is simple relatively and mass production is easy. But it suffer from a low fill factor and a high shading loss because of high contact resistance. Besides Ag paste too expensive. because of depends income. This paper applied for Ni/Cu metallization replace for paste of screen printing front metal contact. Low cost Ni and Cu metal contacts have been formed by using electroless plating and electroplating techniques to replace the screen-printed Ag contacts. Ni has been proposed as a suitable silicide for the salicidation process and is expected to replace conventional silicides. Copper is a promising material for the electrical contacts in solar cells in terms of conductivity and cost. In experiments Ni/Cu metal contact applied same grid formation of screen-printed solar cell. And it has variation of different grid spacing. It was verified that the wide spacing of grid finger could increase the series resistance also the narrow spacing of grid finger also implies a grid with a higher density of grid fingers. Through different grid spacing found alteration of efficiency.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.32.2-32.2
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• 2011

반도체 생산공정에서 CMP (Chemical-mechanical planarization) 공정은 우수한 전기전도성 재료인 Cu의 사용과 다층구조의 소자를 형성하기 위해서 도입되었으며, 최근 소자의 집적도가 증가함에 따라 CMP 공정 비중은 점점 높아지고 있다. Cu CMP 공정에서 연마제인 슬러리는 금속 표면과의 물리적 화학적 반응을 동시에 사용하여 표면을 연마하게 되며, 연마특성을 향상시키기 위해 산화제, 부식방지제, 분산제 및 다양한 계면활성제가 첨가된다. 하지만 슬러리는 Cu 표면을 평탄화하는 동시에 오염입자, 유기오염물, 스크레치, 표면부식 등을 발생시키며 결과적으로 소자의 결함을 야기시킨다. 특히 부식방지제로 사용되는 BTA (Benzotriazole)은 Cu CMP 공정 중 Cu-BTA 형태로 표면에 흡착되어 오염원으로 작용하며 입자오염을 증가시시고 건조공정에서 물반점 등의 표면 결함을 발생시킨다. 이러한 문제점을 해결하기 위해 Cu 표면에서 식각과 부식반응을 최소화하며, 오염입자 제거 및 유기오염물을 효과적으로 제거하기 위한 Post-CMP 세정 공정과 세정액 개발이 요구된다. 본 연구에서는 오염입자 및 유기물 제거와 동시에 표면 거칠기와 부식현상을 제어할 수 있는 post Cu CMP 세정액을 개발 평가하였다. 오염입자 및 유기오염물을 제거하기 위해서 염기성 용액인 TMAH 사용하였으며, Cu 이온을 용해할 수 있는 Chelating agent와 표면 부식을 억제하는 부식 방지제를 사용하여 세정액을 합성하였다. 접촉각 측정과 FESEM(field Emission Scanning Electron Microscope) 분석을 통하여 CMP 공정에서 발생하는 유기오염물과 오염입자의 흡착과 제거를 확인하였으며 Cu 웨이퍼 세정 전후의 표면 거칠기의 변화와 식각량을 AFM(Atomic Force Microscope)과 4-point probe를 사용하여 각각 평가하였다. 또한 세정액 내에서의 연마입자의 zeta-potential을 측정 및 조절하여 세정력을 향상시켰다. 개발된 세정액과 Cu 표면에서의 화학반응 및 부식방지력은 potentiostat를 이용한 전기화학 분석법을 통해서 chelating agent와 부식방지제의 농도를 최적화 시켰다. 개발된 세정액을 적용함으로써 Cu-BTA 형태의 유기오염물과 오염입자들이 효과적으로 제거됨을 확인하였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.17.2-17.2
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• 2011

모든 생물은 늙어가면서 그 생물체를 이루고 있는 생체조직들이 낡게 되고 약해지기 마련이며, 이외에도 자동차 사고 등 재해에 의해 생체 장기의 손상을 가져올 수도 있다. 또한 인간의 평균수명 연장과 함께 소득 수준이 높아지고 또한 'quality of life'를 추구하는 고령화 시대로 접어듦에 따라, 인공골, 인공치아 또는 인공 고/슬관절 등의 골조직 대체재료의 수요가 빠르게 증가하고 있다. 이와 같은 골조직 대체, 즉 골이식은 크게 자기골 이식(autografting), 동종이식(allografing), 인공재료(man-made materials)의 이식으로 구분된다. 현재 대체물질의 약 58%를 차지하고 있는 자기골 이식의 경우, 거부면역 반응이 없어 임상성공율이 80%에 달한다는 장점을 가지고 있으나, 비용이 비싸고 감염과 통증의 위험이 있다. 또한 시신으로부터 골을 이식하는 동종이식의 경우 대체물질의 약 34%를 차지하고 있는데, 성공률이 떨어지고 질병 감염의 위험이 있는 단점이 있다. 이외에 약 8%를 차지하고 있는 인공재료 이식의 경우, 파단, 독성반응, 마모, 골조직의 remodeling 등이 일어나는 단점이 있으나, 앞에서 언급한 바와 같이 그 필요성이 급격히 증가함에 따라 보다 나은 치료법과 골이식 대체물질의 개발에 많은 노력이 경주되고 있다. 2003년 6월 미국 Financial Times에 의하면, 인체내 식립형 생체재료의 세계시장 규모는 약 650억 달러에 이르며, 매년 200% 이상씩 신장하고 있다고 한다. 따라서 세계 각국의 의학, 약학, 임상학, 생명과학, 공학 등의 관련 연구 분야에서는 이 수요를 충족시키기 위한 활발한 연구활동을 펼치고 있다. 한편 인체내 식립용 임플란트의 국내 시장규모는 치과 임플란트의 경우 2006년 현재 2000억원 규모로, 정형외과, 악안면 성형외과, 이비인후과를 포함하면 소위 'bone-anchored metal implant' 영역의 시장 규모는 4~5조원에 이를 것으로 추산 되고 있다. 또한 소비 신장률 10~15%를 감안하면 향후 시장 규모는 폭발적으로 증가될 것으로 예상된다. 이에 발맞추어, 최근 들어 선진국은 물론, 국내에서도 인체내 식립을 목적으로 하는 생체재료에 관한 연구개발이 활발히 진행되고 있으며, 일부는 실용화 단계에 진입하고 있다. 본 강연에서는 금속 임플란트의 시장현황과 앞으로의 추세에 대하여 조망하고, Ti 임플란트를 중심으로 이의 생체활성을 부여하는 표면개질 필요성 및 최근의 연구개발 동행에 대해 소개하고자 한다.

• Polymer(Korea)
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• v.25 no.6
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• pp.765-773
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• 2001

In In order to remove harmful trace elements such as $Co^{2+}$, $Ni^{2+}$ , $Cr_2O_7\;^{2-}$ from water, we synthesized AN-co-(MMA/IA) according to various mole ratio of monomers and spun by wet-spinning. And multi-functional PAN ion exchangers were prepared by hydrolysis. We observed structure, degree of functionalization, ion exchange capacity, distribution coefficient and mechanical properties for ion exchanger. Anion exchange capacity decreased in 4.5 ~ 4.2 meq/g with increasing of IA content and cation exchange capacity increased in 1.8 ~ 2.2 meq/g. Tensile strength of the ion exchanger increased up to 0.008 mol% IA content and appeared maximum value by 216$kg/cm^2$Distribution coefficient for AN-co-(MMA/IA) ion exchanger appeared maximum value for Co(II), Ni(II) in pH 5-6 range and for Cr(III) in pH 3-4 range. And the adsorption capacity was in the order of Cr(III) > Co(II) > Ni(II) for multicomponent in continuous process.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.73-76
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• 2020

Silver nanowires (AgNWs) intrinsically possess high conductivity, ductility, and network structure percolated in a low density, which have led to many advanced applications of transparent and flexible electronics. Most of these applications require patterning of AgNWs, for which photolithographic and printing-based techniques have been widely used. However, several drawbacks such as high cost and complexity of the process disturb its practical application with patterning AgNWs. Herein, we propose a novel method for the patterning of AgNWs by employing UV-curable adhesive tape with a structure of liner/adhesive layer/polyolefin (PO) film and UV irradiation to simplify the process. First, the UV-curable adhesive tape was attached to AgNWs/polyurethane (PU), and then selectively exposed to UV irradiation by using a photomask. Subsequently, the UV-curable adhesive tape was peeled off and consequently AgNWs were patterned on PU substrate. This facile method is expected to be applicable to the fabrication of a variety of low-cost, shape-deformable transparent and wearable devices.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.506-511
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• 2008

In this study sol-gel and combustion process was surveyed for the preparation of the red $Y_2O_3$: Eu phosphor, and the properties of phosphor was considered. Chelation and hydrolysis in amorphous citrate sol-gel process were completed in initial reaction stage, and water-forming condensation was superior to organic acid-forming condensation. The mole ratio of citric acid to metal ion had to be above to for the progress of sol-gel process. The dried gel powders are mostly amorphous, and crystallize completely at $700^{\circ}C$, and the crystallinity increases with increasing calcining temperature. The luminescence property of the phosphor was analyzed by measuring the emission spectra. The luminescence intensity increases when the calcination temperature and concentration of metal ions in solution increase.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.198-205
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• 2012

Carbon-supported manganese oxide composite were fabricated as an air cathode material for Li-air batteries by hydrothermal method. The composite materials of carbon and manganese oxide were investigated by the implementation of X-ray diffraction, FE-SEM and BET surface area measurer. The manganese oxide synthesized at $170^{\circ}C$ for 12 h has a rod like shape morphology with 40-50 nm long in size. A Lithium-air battery with coin type, of which electrodes are composed of cathode composite materials synthesized $170^{\circ}C$-12 h and lithium metal anode, reveals its first discharge capacity of 3,852 mAh/g and four discharge-charge cycles.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.239-244
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• 2009

This paper aims to report the effect of surface treatment on graphite and its effect on the improvement of $Al_2O_3$ and $nano-Li_4Ti_5O_{12}$. The structure and property of surface treatment on graphite were determined by scanning electron microscopy, transmission electron microscopy and electrochemical property and safety were determined by charge/discharge cycler, accelerating rate calorimeter. The composite with different metallic oxide exhibited the first efficiency of 82.5% and specific capacity of 350 mAh/g. Although the composite showed same efficiency and specific capacity at first cycle, surface treatment on graphite by $nano-Li_4Ti_5O_{12}$ exhibited a higher charge/discharge rate, cycle life and thermal stability.