• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.61-66
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• 2012

Chemical Mechanical Planarization (CMP) is a polishing process used in the microelectronic fabrication industries to achieve a globally planar wafer surface for the manufacturing of integrated circuits. Pad conditioning plays an important role in the CMP process to maintain a material removal rate (MRR) and its uniformity. For metal CMP process, highly acidic slurry containing strong oxidizer is being used. It would affect the conditioner surface which normally made of metal such as Nickel and its alloy. If conditioner surface is corroded, diamonds on the conditioner surface would be fallen out from the surface. Because of this phenomenon, not only life time of conditioners is decreased, but also more scratches are generated. To protect the conditioners from corrosion, thin organic film deposition on the metal surface is suggested without requiring current conditioner manufacturing process. To prepare the anti-corrosion film on metal conditioner surface, vapor SAM (self-assembled monolayer) and FC (Fluorocarbon) -CVD (SRN-504, Sorona, Korea) films were prepared on both nickel and nickel alloy surfaces. Vapor SAM method was used for SAM deposition using both Dodecanethiol (DT) and Perfluoroctyltrichloro silane (FOTS). FC films were prepared in different thickness of 10 nm, 50 nm and 100 nm on conditioner surfaces. Electrochemical analysis such as potentiodynamic polarization and impedance, and contact angle measurements were carried out to evaluate the coating characteristics. Impedance data was analyzed by an electrical equivalent circuit model. The observed contact angle is higher than 90o after thin film deposition, which confirms that the coatings deposited on the surfaces are densely packed. The results of potentiodynamic polarization and the impedance show that modified surfaces have better performance than bare metal surfaces which could be applied to increase the life time and reliability of conditioner during W CMP.

• Journal of Fashion Business
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• v.2 no.1
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• pp.35-48
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• 1998

The purpose of this paper is to examine the street fashion, which is influenced by the youth culture in 1960s. Youth culture is the youth subculture which appeared multiform in the 1960s. It tried to create a new culture by subverting the ruling class culture with their combative life style and peculiar appearance which are distinguished from mother culture. Youth cultures as youth subculture are symbolically expressed in their style which had strong characteristics of sub-fashion and anti-fashion, and which are different from mother fashion in shape. Therefore youth subculture fashion had an effect on street fashion in the 60s. The influence that the youth culture fashion had had on the street fashion is summarized as follows: Beats fashion was intelligency look on black dress, black polo-neck shirts, black trousers, black glasses and heavy black eyeliner. Mods fashion was neat style on Edwardian suit with narrow trousers, pointer-toeshoes and smooth croped hair. Folkis fashion was ethnic look, middle east asian look, peasant look, Indian style, south america look, gypsy style, natural materials, natural dying, tie-dye, beads and hand made ornaments. Rockers fashion was violence appearance categorized 'blue collar' on black leather jacket decorated with metal studs and hand-painted insignia, blue jeans and boots for motor bike. Swinging London & the Psychedelics fashion was blend mods look with pschedelic color and motive pattern. Hippie fashion was intermix pschedelic and natural or ethnic style. It was appear to be a meaningless, unpredictable assortment of diverse items and style. Faded and tattered jeans, army jackets, vintage hat, beads, embroidered headband, white sheets, diverse theatrical costumes, sandals or bare feet, granny dress, peasant blouse, blanket cape, tie-dye T-shirts and long hair. Greasers fashion was adorned black leather jacket with chains, fringing, badges, insignia and sleeves had been crudely ripped off. They came to be known wore jeans so soaked with oil. Skinheads fashion was aggressive working class identity with donkey jacket, jeans rolled up, collarless union shirts, heavy boots, braces and hair cropped short.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.207-214
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• 2002

Nano adhesion between SPM (scanning probe microscope) tips and $DDPO_{4}$ (dodecylphosphoric acid ester) and $ODPO_{4}$ (octadecylphosphoric acid ester) SAM (self-assembled monolayer) was experimentally studied. Tests were performed to measure the nano adhesion and friction in both AFM(atomic force microscope) and LFM(lateral force microscope) modes with the applied normal load. $DDPO_{4}$ and $ODPO_{4}$ SAM were formed on TiMe and TiOx surfaces. TiMe and TiOx were coated on the Si wafer by ion sputtering. Adhesion and friction of $DDPO_{4}$ and $ODPO_{4}$ SAM surfaces were compared with those of OTS (octadecyltrichlorosilane) SAM and DLC surfaces. $DDPO_{4}$ and $ODPO_{4}$ SAM converted the TiMe and TiOx surfaces to be hydrophobic. When the surface was hydrophobic, the adhesion and friction forces were found lower than those of bare surfaces. Work of adhesion was also discussed to explain how the surface was converted into hydrophobic. Results also showed that tribological characteristics of $DDPO_{4}$ and $ODPO_{4}$ had good properties in the adhesion, friction, wetting angle and work of adhesion. $DDPO_{4}$ and $ODPO_{4}$ SAM could be one of the candidates for the bio-MEMS elements.

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.164-175
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• 2009

CFD is used to analyze gas flow characteristics, power absorption, electron temperature, electron density and chemical species profile of an internal antenna type inductively coupled plasma system. An optimized grid generation technology is used for a complex real-scale models for industry. A bare metal antenna shows concentrated power absorption around rf a feeding line. Skin depth of power absorption for a system is modeled to 50 mm, which is reported 53 mm by experiments. For an application of bipolar plates for hydrogen fuel cells, multi-sheet loading ICP nitriding system is proposed using an internal ICP antenna. It shows higher atomic nitrogen density than reported simple pulsed dc nitriding systems. Minimum gap between sheets for uniform nitriding is modeled to be 39 mm.

• Journal of KIISE
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• v.41 no.9
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• pp.605-610
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• 2014

Now, virtualization is no more emerging research area, and we can easily find its application in our circumstance. Nevertheless, I/O workloads are reluctant to be applied in virtual environment since they still suffer from unacceptable performance degradation due to virtualization latency. Many previous papers identified that virtual I/O overhead is mainly caused by exits and redundant I/O stack, and proposed several techniques to reduce them. However, they still have some limitations. In this paper, we introduce a novel I/O virtualization framework which improves I/O performance by exploiting multicore architecture. We applied our framework to the virtual network, and it improves TCP throughput up to 169%, and decreases UDP latency up to 38% on the network with the 10Gbps NIC.

• Journal of Plant Biology
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• v.17 no.4
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• pp.158-162
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• 1974

Some ecological attributes of perennial plants and Pb contamination were analyzed for study plots near an entrance of Nevade Test Site at Mercury Valley, Nye County, Nevada. The surface of the desert pavement soil was composed of stones (1 to 4cm diameter). The underside of each stone was coated with coarse and fine sand (about 90%). The profiles of soil were constituted with the A-horizon and C-horizon only. The soil pH at the plots ranges from 7.6 to 8.5, C/N was 13 and cation exchange capacity showed 15me/100g. Nine species and 42 number of individuals were found in all plots. Franseria dumosa and Larrea divaricata were dominant species. The discrete clumps of vegetation were consisted of 9 species of common perennials and these were covered about 25% on desert pavement, on the other words, bare area without vegetation was about 75%. The size and spacing of the plants was irregular. Community coefficient as comparison between shrub species in these study area and those in near the low elevation desert indicated a low degree of similarity. Density, cover and productivity in the study plots as compared with those in the nearest study areas in Mercury Valley showed a higher value. The soils in the studied area involved high heavy metal contents in the plant tissue was higher than those of its soil. The leavds of Lycium andersonii tended to accumulate more Zn and Mo than those of the other species. Larrea divaricata leaves accumulated very high leaves of Fe and Ephedra nevadensis were generally high in Mn. Lead contamination was apparent in foliage of desert vegetation collected alongside the roadway, reflecting the variation in traffic volume. Lead contents greater than fifteen-fold of normal (low traffic) were found in plant foliage alongside the heavily traveled roadway. Lead content of old foliage by the heavily traveled roadway was as much as 129 ppm but that of new foliage 17 ppm only.

• Korean Journal of Materials Research
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• v.17 no.3
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• pp.147-151
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• 2007

Cu-free multi-component sol, of which final oxide composition becomes $Bi_{1.9}Pb{0.35}SrCaO,\;Bi_{1.8}Pb_{0.2}SrCaO\;and\;Bi_{1.5}SrCaO$, respectively, was prepared through sol-gel route and coated on a bare Cu substrate. Starting materials were metal-alkoxides as follows.; [$Bi(OC_{2}H_{5})_{3}\;Pb(O^{1}C_{3}H_{7})_{2},\;Sr(O^{i}C_{3}H_{7})_{2},\;Ca(OC_{2}H_{5})_{2}$] as a reagent grade. Transparent light yellowish sol was obtained in the case of $Bi_{1.9}Pb_{0.35}SrCaO\;and\;Bi_{1.8}Pb_{0.2}SrCaO$ composition and $Bi_{1.5}SrCaO$ composition's sol was light greenish. Each sol was repeatedly dip-coated on Cu substrate four times and pre-heated at $400^{\circ}C$ and finally heat-treated in the range of $740{\sim}900^{\circ}C$. In the results, crystalline phases confirmed by XRD were (2201) orthorhombic and monoclinic phases. However, only $Bi_{1.9}Pb_{0.35}SrCaO_{x}$ composition showed pseudo-superconductive behavior after heat-treatment at $900^{\circ}C$ for 12 seconds and then onset temperature was 77 K, even though it did not exhibit zero resistance below Tc.

• Journal of the Korean institute of surface engineering
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• v.41 no.6
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• pp.255-263
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• 2008

Generally, deposition mechanism of diamond particle is mainly embedding effect in the kinetic spray process. Accordingly, in spite of high cost, helium gas was employed as process gas to get high diamond fraction in the composite coating. In this study, the deposition behavior of bronze/diamond by kinetic spray process was compared using different process gas (helium and nitrogen). Bare (mean size of $5{\mu}m$, $20{\mu}m$) and nickel coated diamond (mean size of $26{\mu}m$) were deposited on Al 6061-T6 substrate with fixed process temperature and pressure. For comparison with experimental results, plastic deformation behavior of nickel layer was simulated by finite element analysis (using ABAQUS/Explicit 6.7-2). The size, broken ratio, and fraction of diamond in the composite coating were analyzed through scanning electron microscopy and image analysis method. The uniform distribution and deposition efficiency of diamond particles in the coating layer could be achieved by tailoring the physical properties of the feedstock.

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.581-584
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• 2020

The effect of a chemical pretreatment on the surface carbon was investigated using a scanning electron microscope (SEM) and electrochemical methods. Primitive carbon has a reducing power likely due to incompletely oxidized functional groups on the surface. We aim to control this reducing power by chemical treatment and apply for the spontaneous deposition of nanoparticles (NPs). Highly ordered pyrolytic graphite (HOPG) was initially treated with a reducing agent, NaBH4 or an oxidizing agent, KMnO₄, for 5 min. Subsequently, the pretreated carbon was immersed in a platinum (Pt) precursor. Unexpectedly, SEM images showed that the reducing agent increased spontaneous PtNPs deposition while the oxidizing agent decreased Pt loading more as compared to that of using bare carbon. However, the amount of Pt on the carbon obviously decreased by NaBH₄ treatment for 50 min. Secondly, spontaneous reduction on pretreated glassy carbon (GC) was investigated using the catalytic hydrogen evolution reaction (HER). GC electrode treated with NaBH4 for a short and long time showed small (onset potential: -640 mV vs. MSE) and large overpotential for the HER, respectively. Although the mechanism is unclear, the electrochemistry results correspond to the optical data. As a proof-of-concept, these results demonstrate that chemical treatments can be used to design the shapes and amounts of deposited catalytic metal on carbon by controlling the surface state.

• Clean Technology
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• v.24 no.3
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• pp.249-254
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• 2018

In order to improve the photo conversion efficiency (${\eta}$) of dye-sensitized solar cells (DSSCs), the electrospun $TiO_2$, $SiO_2$, $ZrO_2$ and $SnO_2$ nanofibers were added into the hydrothermally prepared $TiO_2$ nanoparticles for application to a photoelectrode for DSSCs. The $TiO_2$ nanofiber added photoelectrode exhibited a higher photo current density ($J_{sc}$) compared to the bare $TiO_2$ nanoparticles, which is caused from acceleration of the transfer of excited electron from dye molecule due to the nanofiber structure. The DSSCs with $SiO_2$ nanofibers shows a higher open circuit voltage ($V_{oc}$) of 0.67 V and the highest photo conversion efficiency was found to be 6.24%.