• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.203-207
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• 2009

Copper is known as a replacement for aluminum wire which is used for semiconductor. Because specific resistance of Cu ($1.67{\mu}{\Omega}$-cm) is lower than that of Al ($2.66{\mu}{\Omega}$-cm), Cu reduce RC delay time. Although melting point of Cu($1085^{\circ}C$) is higher than melting point of Al, Cu have characteristic to easily react with Silicon(Si) in low temperature, and it isn't good at adhesive strength with Si. For above these reason, research of diffusion barrier to prevent reaction between Cu and Si and to raise adhesive strength is steadily advanced. Our study group have researched on W-C-N (tungsten-carbon-nitrogen) Diffusion barrier for preventing diffusion of Cu through semiconductor. By recent studies, It's reported that W-C-N diffusion barrier can even precent Cu and Si diffusing effectively at high temperature. In this treatise, we vaporized different proportion of N into diffusion barrier to research Cu's Electromigration based on the results and studied surface hardness in the heat process using nano scale indentation system. We gain that diffusion barrier containing nitrogen is more stable for Cu's electromigration and has stronger surface hardness in heat treatment process.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.5
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• pp.704-723
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• 2000

This study was undertaken to evaluate the tensile bond strength of In-Ceram alumina core treat-ed by ion assisted reaction(IAR). Ion assisted reaction is a prospective surface modification technique without damage by a keV low energy ion beam irradiation in reactive gas environments or reactive ion itself. 120 In-Ceram specimens were fabricated according to manufacturer's directions and divided into six groups by surface treatment methods of In-Ceram alumina core. SD group(control group): sandblasting SL group: sandblasting + silane treatment SC group: sandblasting + Siloc treatment IAR I group: sandblasting + Ion assisted reaction with argon ion and oxygen gas IAR II group: sandblasting + Ion assisted reaction with oxygen ion and oxygen gas IAR III group: sandblasting + Ion assisted reaction with oxygen ion only For measuring of tensile bond strength, pairs of specimens within a group were bonded with Panavia 21 resin cement using special device secured that the film thickness was $80{\mu}m$. The results of tensile strength were statistically analyzed with the SPSS release version 8.0 programs. Physical change like surface roughness of In-Ceram alumina core treated by ion assistad reaction was evaluated by Contact Angle Measurement, Scanning Electron Microscopy, Atomic Force Microscopy; chemical surface change was evaluated by X-ray Photoelectron Spectroscopy. The results as follows: 1. In tensile bond strength, there were no statistically significant differences with SC group, IAR groups and SL group except control group(P<0.05). 2. Contact angle measurement showed that wettability of In-Ceram alumina core was enhanced after IAR treatment. 3. SEM and AFM showed that surface roughness of In-Ceram alumina core was not changed after IAR treatment. 4. XPS showed that IAR treatment of In-Ceram alumina core was enabled to create a new functional layer. A keV IAR treatment of In-Ceram alumina core could enhanced tensile bond strength with resin cement. In the future, this ion assisted reaction may be used effectively in various dental materials as well as in In-Ceram to promote the bond strength to natural tooth structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.29-29
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• 2009

현재 고집적 비휘발성 메모리 소자로는 MRAM (Magnetic Random Access Memory)과 PRAM (Phase Magnetic Random Access Memory)이 활발하게 미국과 일본, 한국 등에서 다양한 연구가 진행되어 오고 있다. 이 중에서 MRAM은 DRAM과 비슷한 10 ns의 빠른 읽기/쓰기 속도와 비휘발성 특성을 가지고 있으며, 전하를 저장할 커패시터가 필요 없고, 두 개의 자성충에 약 10 mA 정도의 전류를 가하면 그때 발생하는 약 10 Oe의 자장을 개개의 비트를 write하고, read 시에는 각 비트의 자기저항을 측정함으로써 데이터를 저장하고 읽을 있으므로, 고집적화가 가능성하다 [1]. 현재 우수한 박막 재료가 개발 되었으나, 고집적 MRAM 소자의 양산에는 해결 하여야 하는 문제점이 있다. 특히 다층 박막으로 구성되어 있으므로 식각 공정의 개발이 필수적이다. 지금까지 MRAM 재료의 식각은 주로 Ion milling, ICP, ECR등의 플라즈마 장치를 되었고, 식각 가스로는 할로겐 기체와 금속카보닐 형성을 위한 Co/$NH_3$와 $Ch_3OH$ 기체가 이용되고 있다. 그러나 할로겐 계열의 기체를 사용할 경우, 식각 부산물들의 높은 끓는점 때문에 식각 부산물이 박막의 표면에서 열적 탈착에 의하여 제거되지 않기 때문에 높은 에너지를 가지는 이온의 도움에 의한 식각이 필요하다. 또한 Cl 계열의 기체를 사용할 경우, 식각 공정 후, 시료가 대기에 노출되면 대기 중의 수분과 식각 부산물이 결합하여 부식 현상이 발생하게 된다. 그러므로 이를 방지하기 위한 추가 공정이 요구된다. 최근에는 부식 현상이 없고, MTJ 상부에 사용되는 Ta 또는 Ti Hard mask와의 높은 선택비를 가지는 $CH_3OH$ 또는 CO/$NH_3$가 사용되고 있다. 하부 박막에 따른 식각 특성에 연구와 다층의 박막의 식각 공정에 발생에 관한 발표는 거의 없다. MRAM을 양산에 적용하기 위하여서는 Main etch 공정에서 빠른 식각 공정이 필요하고, Over etch 공정에서 하부박막에 대한 높은 선택비가 요구된다. 그러므로 본 논문에서는 식각 변수에 따른 플라즈마 측정과 표면 반응을 비교하여 각 공정의 식각 메커니즘을 규명하고, Main Etch 공정에서는 $Cl_2$/Ar 또는 $BCl_3$/Ar 가스를 이용하여 식각 실험을 수행하고, Over etch 공정에는 낮은 Ta 박막 식각 속도를 가지는 $Ch_4/O_2$/Ar 또는 $Ch_3OH$/Ar 가스를 이용하고자 한다. 플라즈마 내의 식각종과 Ta 박막과의 반응을 XPS와 AES를 이용하여 분석하고, 식각 공정 변수에 따른 식각 속도, 식각 선택비와 식각 프로파일 변화를 SEM을 이용하여 관찰한다.

• The Korean Nurse
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• v.37 no.2
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• pp.44-52
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• 1998

The purpose of this study is to inquire the people's views on nursing for nurses, correct the image of nurse and take it as basis to be applied on nursing education examining the image of nursing on Television drama playing important role of mass media. 22 nurses of the characters in drama is applied to the analysis object of this study by selecting 6 dramas of Television ones the nurse play on the prime time from June 1 to August 31 in 1997. Contents analysis method was used in Data Analysis, 4 items was used after Coders previously modify and compensate it based on research documents of 1m Milim(1996) 2 Coders made the Coding the article on each person by them seeing the recorded film making the Coding Paper each items is written by the character. The average of reliability degree was 90% which measured the reliability degree by the mathod of Holsti. The statisic method of frequency, percentage was used SPSS Program in data processing The results were as follows. 1. Relative importance of 86.2% nurses in drama was depicted as extra characters 2. The affair attitude of nurses shown on drama was revealed as mechanical(84.7%), passive(45.5%), dependent(54.4%) unkind(68.2%). 3. The activity of nurses was classified with professional! simple affair. The professional affairs such as I.V., Blood Pressure Check, Rounding, Nursing Recording, Patient Education, Assist of Operation, Assistant meal of Patient, etc is mainly depicted and the screen of simple affair such as Receiving telephone, Carrying Tray or Dragging, Stretcher Car, Dressing Car and or Wheel Chair than professional affair. 4. The appearance feature of nurses was shown on thin physique(68.2%), common stature(68.2), dirty costume(45.4%), common appearance(81.9%), unnoble action(63.6%). The image of nurses is illuminated as the exterial scene of technical affair such as assisting the doctors and affair focused on accident and educational activity of nureses or extended role is nor depicted on Television drama. Therefore, the people regard the nurse as sexual object with good appearance than professional worker working professional nursing We want the following, epigraph based on above conclusion. 1. The continuous research is required on the image of nurse shown on various mass media. 2. The later research is required on appliction strategy of mass media for advancing the image of nurse. 3. The research to strengthen the objectivity by comparing analyzed data on drama & analyzing it is required 4. Through the deep study, the standard to show a concrete and professional work of nurses to scenario writers of TV drama is suggested by the association. 5. The monitoring about the mass media must be activated, not by some nurses, on a national scale and much study on the basis of this is needed.

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.837-842
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• 1998

As the size of the integrated circuit is scaled down the importance of Si cleaning has been emphasized. One of the major concerns is abut the removal of metallic impurities such as Cu and Fe on Si surface. In this study, we intentionally contaminated Cu and Fe on the Si wafers and cleaned the wafer by cleaning splits of the chemical mixture of $\textrm{H}_2\textrm{O}_2$ and HF and the combination of HF treatment with UV/$\textrm{O}_3$ treatment. The contamination level was monitored by TXRF. Surface microroughness of the Si wafers was measured by AFM. The Si wafer surface was examined by SEM. AES analysis was carried out to analyze the chemical composition of Cu impurities. The amount of Cu impurities after intentional contamination was abut the level of $\textrm{10}^{14}$ atoms/$\textrm{cm}^2$. The amount of Cu was decreased down to the level of $\textrm{10}^{10}$ atoms/$\textrm{cm}^2$ by cleaning splits. The repeated treatment exhibited better Cu removal efficiency. The surface roughness caused by contamination and removal of Cu was improved by repeated treatment of the cleaning splits. Cu were adsorbed on Si surface not in a thin film type but in a particle type and its diameter was abut 100-400${\AA}$ and its height was 30-100${\AA}$. Cu was contaminated on Si surface by chemical adsorption. In the case of Fe the contamination level was $\textrm{10}^{13}$ atoms/$\textrm{cm}^2$ and showed similar results of above Cu cleaning. Fe was contaminated on Si surface by physical adsorption and as a particle type.

• Transactions on Electrical and Electronic Materials
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• v.8 no.3
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• pp.135-138
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• 2007

In this study, we investigated the electro-optical (EO) characteristic of fringe-field switching (FFS) mode cell by the two kinds of ultraviolet (UV) alignment method on the organic thin film (polyimide: PI). The suitable organic layers for FFS cell and the aligning capabilities of nematic liquid crystal (NLC) using the in-situ photoalignment method were studied; Disclination is observed after conventional photoalignment method for 1h, and in-situ photoalignment method for 1h. Monodomain alignment of the NLC can be observed via insitu photo alignment method for 2 h and 3 h. It is considered that NLC alignment is due to photo-depolymerization of the polymer with oblique non-polarized UV irradiation on PI surface. An unstable V-T curve of UV-aligned FFS-LCD with conventional photoalignment method can be achieved. However, a stable V-T curve of UV-aligned FFS-LCD with in-situ photoalignment method (1 h), and V-T curve of UV-aligned FFS-LCD with in-situ photo alignment method was much stable comparing with that of other UV-aligned FFSLCD's. As a result, more stable EO performance of UV-aligned FFS-LCD with in-situ photoalignment method for 3h is obtained than that of the other UV-aligned FFS-LCD's.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.3
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• pp.7-11
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• 2011

In this paper, we proposed a simple and high-yield printing process for source and drain electrodes of organic thin film transistor (OTFT). The surface energy of PVP (poly 4-vinylphenol) gate dielectric was decreased from 56 $mJ/m^2$ to 45 $mJ/m^2$ by adding fluoride of 3000ppm into it. Meanwhile the surface energy of source and drain (S/D) electrodes area on the PVP was increased to 87 $mJ/m^2$ by treating the areas, which was patterned by photolithography, with oxygen plasma, maximizing the surface energy difference from the other areas. A conductive polymer, G-PEDOT:PSS, was deposited on the S/D electrode areas by brushing painting process. With such a simple process we could obtain a high yield of above 90 % in $16{\times}16$ arrays of OTFTs. The performance of OTFTs with the fluoride-added PVP was similar to that of OTFTs with the ordinary PVP without fluoride, generating the mobility of 0.1 $cm^2/V.sec$, which was sufficient enough to drive electrophoretic display (EPD) sheet. The EPD panel employing the OTFT-backpane successfully demonstrated to display some patterns on it.

• Membrane Journal
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• v.13 no.3
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• pp.162-173
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• 2003

The pseudo n-type polyaniline was prepared by doping of camphorsulfonic acid(CSA) and dodecylbenzenesulfonic acid(DBSA) as the dopants in solvent of N-methyl-2-pyrrolidinone(NMP). The dopants in polymer structure was qualitatively analyzed using FT-IR. The influence on electrochemical properties with dopant concentration of PANI film were investigated. The electrochemical characteristics of the n-type PANI electrode that coated on ITO were evaluated by cyclic voltammetry(CV) and AC impedance method. The prepared PANI were confirmed as n-type PANI from FT-IR and CV. The charge transfer resistance of film on PANI/CSA electrode were measured as 1.14{\sim}1.09k{\mu}$by AC impedance. The charge transfer resistance of PANI/DBSA electrode decreased with increasing the mole ratio of DBSA as 27.73{\sim}8.37 k{\mu}$. The double layer capacitance of PANI/CSA electrode was showed almost constant value as $13.47{\sim}14.59 {\mu}F$ and that of PANI/DBSA electrode increased with increasing mole ratio of DBSA from 0.49 to $1.20 {\mu}F$.

• Journal of Periodontal and Implant Science
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• v.30 no.1
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• pp.187-203
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• 2000

The precipitation of calcium phosphate on implant surface has been known to accelerate osseointegration and to enhance osseous adaptation. The present study was performed to examine whether the precipitation of calcium phosphate on Ti-6Al-4V alloy could be affected by the immersion in NaOH solution and heat treatment. Ti-6Al-4V alloy plates of $15{\times}3.5{\times}1mm$ in dimension were polished sequentially from #240 to #2,000 emery paper and one surface of each specimen was additionally polished with $0.1{\mu}m$ alumina paste. Polished specimens were soaked in various concentrations of NaOH solution(0.1, 1.0, 3.0, 5.0, 7.0, 10.0 M) at $60^{\circ}C$ for 24 hours for alkali treatment, and 5.0 M NaOH treated specimens were heated for 1 hour at each temperature of 400, 500, 600, 700, $800^{\circ}C$. After the alkali and heat treatments, specimens were soaked in the Hank's solution with pH 7.4 at $36.5^{\circ}C$ for 30days.The surface ingredient change of Ti-6Al-4V alloy was evaluated by thin-film X-ray diffractometer(TF-XRD) and the surface microstructure was observed by scanning electron microscope(SEM), and the elements of surface were analyzed by X-ray photoelectron spectroscopy(XPS). The results were obtained as follows ; 1. The precipitation of calcium phosphate on Ti-6Al-4V alloy was accelerated by the immersion in NaOH solution and heat treatment. 2. In Alkali treatment for the precipitation of calcium phosphate on Ti-6Al-4V alloy, the optimal concentration of NaOH solution was 5.0 M. 3. In heat treatment after alkali treatment in 5.0 M NaOH solution, the crystal formation on alloy surface was enhanced by increasing temperature. In heat treated alloys at $600^{\circ}C$, latticed structure and prominences of calcium phosphate layer were most dense. On heat treated alloy surface at the higher temperature(${\geq}700^{\circ}C$), main crystal form was titanium oxide rather than apatite. The above results suggested that the precipitation of calcium phosphate on the surface of Ti-6Al-4V alloy could be induced by alkali treatment in 5.0 M-NaOH solution and by heat treatment at $600^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.253-261
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• 2005

Catalytic wet oxidation of ppm levels of trichloroethylene (TCE) in water has been conducted using $TiO_2$-supported cobalt oxides at a given temperature and weight hourly space velocity. 5% $CoO_x/TiO_2$ might be the most promising catalyst for the wet oxidation at $36^{\circ}C$ although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Characterization of the $CoO_x$ catalyst by acquiring XPS spectra of both fresh and used Co surfaces gave different surface spectral features of each $CoO_x$. Co $2p_{3/2}$ binding energy of Co species exposed predominantly onto the outermost surface of the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of $CoTiO_x$ such as $Co_2TiO_4$ and $CoTiO_3$. The spent catalyst possessed a 780.3 eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly $Co_3O_4$. XRD measurements indicated that the phase structure of Co species in 5% $CoO_x/TiO_2$ catalyst even before reaction is quite comparable to the diffraction lines of external $Co_3O_4$ standard. A model structure of $CoO_x$ present on titania surfaces would be $Co_3O_4$, encapsulated in thin-film $CoTiO_x$ species consisting of $Co_2TiO_4$ and $CoTiO_3$, which may be active for the decomposition of TCE in a flow of water.