• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.214-214
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• 1999

다이아몬드를 반도체용 열방산용기판 등으로 사용하기 위해서는 수백 $\mu\textrm{m}$ 두께의 대면적 웨이퍼가 요구된다. 이를 위해서 DC are jet CVD, MW PACVD, DC PACVD 등이 개발되어, 현재 4"에서 8"까지의 많은 문제를 일으키고 있다. 본 연구에서는 multi-cathode DC PACVD법에 의한 4" 다이아몬드 웨이퍼의 합성과 합성된 막의 특성변화에 대한 연구를 수행하였다. 또한, 웨이퍼의 휨과 crack 발생거동과 대한 고찰을 통래 휨과 crack이 없는 웨이퍼의 제작방법을 고안하였다. 사용된 음극의 수는 일곱 개이며, 투입된 power는 각 음극 당 약 2.5kW(4.1 A-600V)이었다. 사용된 기판의 크기는 직경 4"이었다. 합성압력은 100Torr, 가스유량은 150sccm, 증착온도는 125$0^{\circ}C$~131$0^{\circ}C$, 수소가스네 메탄조성은 5%~8%이었다. 합성 중 막에 인가되는 응력은 합성 중 증착온도의 변화에 의해 제어하였다. 막의 결정도는 Raman spectroscopy 및 열전도도를 측정을 통해 분석하였다. 성장속도 및 다이아몬드 peak의 반가폭은 메탄조성 증가(5%~8%)에 따라 증가하여 각각 6.6~10.5$\mu\textrm{m}$/h 및 3.8~5.2 cm-1의 분포를 보였다. 6%CH4 및 7%CH4에서 합성된 웨이퍼에서 측정된 막의 열전도도는 11W/cmK~13W/cmK 정도로 높게 나타났다. 막두께의 uniformity는 최대 3.5%로 매우 균일하였다. 막에 인가되는 응력의 제어로 직경 4"k 합성면적에서 두께 1mm 이상의 균열 및 휨이 없는 다이아몬드 자유막 웨이퍼를 합성할 수 있었다.다이아몬드 자유막 웨이퍼를 합성할 수 있었다.active ion에 의해 sputtering 이 된다. 이때 plasma 처리기의 polymer 기판 후면에 magnet를 설치하여 높은 ionization을 발생시켜 처리 효과를 한층 높여 주었다. 이 plasma 처리는 표면 청정화, 표면 etching 이 동시에 행하는 것과 함께 장시간 처리에 의해 표면에서는 미세한 과, C=C기, -C-O-의 극성기의 도입에 의한 표면 개량이 된다는 것을 관찰할 수 있다. OPP polymer 표면을 Ar 100%로 plasma 처리한 경우 C-O, C=O 등의 carbonyl가 발생됨을 알 수 있었다. C-O, C=O 등의 carbynyl polor group이 도입됨에 따라 sputter된 Al의 접착력이 향상됨을 알 수 있으며, TEM 관찰 결과 grain size도 상당히 작아짐을 알 수 있었다.onte-Carlo 방법으로 처리하였다. 정지기장해석의 경우 상용 S/W인 Vector Fields를 사용하였다. 이를 통해 sputter 내 플라즈마 특성, target으로 입사하는 이온에너지 및 각 분포, 이들이 target erosion 형상에 미치는 영향을 살펴보았다. 또한 이들 결과로부터 간단한 sputtering 모델을 사용하여 target으로부터 sputter된 입자들이 substrate에 부착되는 현상을 Monte-Carlo 방법으로 추적하여 성막특성도 살펴보았다.다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상

• Elastomers and Composites
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• v.40 no.2
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• pp.93-103
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• 2005

In this study, surface treatment of the elastomeric matrix was investigated to develop a substituting material for steel dynamic damper of automobile. The key technology is to get ultra high density elastomeric compound in order to substitute steel dynamic damper. The optimum matrix material(chloroprene rubber) and filler(metal powder) were selected for this. The several properties of elastomeric compound were examined. According to the results, the $t_{s2}$ of filled elastomeric compound was decreased with increasing the filler loading whereas the $t_{90}$ was increased. Also, tensile strength and rebound resilience were decreased with filler loading. To solve the problem of high filler loading, the photo grafting technique was employed on elastomeric matrix. The degree of grafting was determined by FTIR-ATR. Also, the filler surface was modified by chemical etching and the surface morphology was examine by SEM. After chemical treatment of filler, the particle size analyzer was used to examined the particle size, size distribution, and morphology of the modified filler.

• Transactions on Electrical and Electronic Materials
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• v.14 no.3
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• pp.133-138
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• 2013

Acrylonitrile-butadiene-styrene (ABS) plastic is a polymer material extensively used in electrical and electronic applications. Nickel (Ni) thin film was deposited on ABS by electroless plating, after its surface was treated and modified with atmospheric plasma generated by means of dielectric barrier discharges (DBDs) in air. The method in this study was developed as a pre-treatment for electroless plating using DBDs, and is a dry process featuring fewer processing steps and more environmentally friendliness than the chemical method. After ABS surfaces were modified, surface morphologies were observed using a scanning electron microscope (SEM) to check for any physical changes of the surfaces. Cross-sectional SEM images were taken to observe the binding characteristics between metallic films and ABS after metal plating. According to the SEM images, the depths of ABS by plasma are shallow compared to those modified by chemically treatment. The static contact angles were measured with deionized (DI) water droplets on the modified surfaces in order to observe for any changes in chemical activities and wettability. The surfaces modified by plasma showed smaller contact angles, and their modified states lasted longer than those modified by chemical etching. Adhesion strengths were measured using 3M tape (3M 810D standard) and by 90° peel-off tests. The peel-off test revealed the stronger adhesion of the Ni films on the plasma-modified surfaces than on the chemically modified surfaces. Thermal shock test was performed by changing the temperature drastically to see if any detachment of Ni film from ABS would occur due to the differences in thermal expansion coefficients between them. Only for the plasma-treated samples showed no separation of the Ni films from the ABS surfaces in tests. The adhesion strengths of metallic films on the ABS processed by the method developed in this study are better than those of the chemically processed films.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1857-1863
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• 2010

We present the fabrication and characterization of transparent carbon nanotube film (CNF) piezoresistors. CNFs were fabricated by vacuum filtration methods with 65?92% transmittance and patterned on Au-deposited silicon wafer by photolithography and dry etching. The patterned CNFs were transferred onto poly-dimethysiloxane (PDMS) using the weak adhesion property between the silicon wafer and the Au layer. The transferred CNFs were confirmed to be piezoresistors using the equation of concentrated-force-derived resistance change. The gauge factor of the CNFs was measured to range from 10 to 20 as the resistance of the CNFs increased with applied pressure. In polymer microelectromechanical systems, CNF piezoresistors are the promising materials because of their high sensitivity and low-temperature process.

• Textile Coloration and Finishing
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• v.1 no.1
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• pp.7-18
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• 1989

The distinguishing characteristic of the glow discharge is that chemical reaction induced by partially ionized gases are limited only to the substrate surface. Most studies have been done on the plasma etching and polymerization. The graft polymerization in vapour phase by cold plasma has been rarely investigated. In this study the system of tub3ar reaction chamber with capacitively coupled electrode of alternative current of 60 Hz was employed for the graft polymerization. The graft polymerization of Acylic Acid(AA) onto the poly (ethylene terephthalate) (PET) was carried out by treatment of PET film and fabric by cold plasma (glow discharge of argon gas), followed by the supply of AA vapour. The graft yield was about 1 wt%. The surface property was determined by contact angle, the surface tension was evaluated by zisman’s plot and equation of surface tension mesurement. The results were as follows: 1. In order to obtain lower contact angle, it was effective to avoid the vicinity of electrodes for a setting position of substrate. 2. Contact angle affected on the monomer pressure and its duration of exposure to the acid vapour. 3. Polymer radical formation was influenced by the changes of the value of current density and plasma treatment time. 4. Total surface tension of plasma grafted PET film increased. With an increase in the carboxylic acid content, the dispersion force decreased, while, the polar force and hydrogen bonding force increased. 5. The contact angle decreased from $75^\circ$ to around $30^\circ$ by plasma grafting. There was no ageing effect on the contact angle after 4 months.

• The Journal of Advanced Prosthodontics
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• v.9 no.6
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• pp.439-446
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• 2017

PURPOSE. To evaluate the effects of different surface treatments on the bond strength of novel CAD/CAM restorative materials to resin cement by four point bending test. MATERIALS AND METHODS. The CAD/CAM materials under investigation were e.max CAD, Mark II, Lava Ultimate, and Enamic. A total of 400 bar specimens ($4{\times}1.2{\times}12mm$) (n=10) milled from the CAD/CAM blocks underwent various pretreatments (no pretreatment (C), hydrofluoric acid (A), hydrofluoric acid + universal adhesive (Scotchbond) (AS), sandblasting (Sb), and sandblasting + universal adhesive (SbS)). The bars were luted end-to-end on the prepared surfaces with a dual curing adhesive resin cement (Variolink N, Ivoclar Vivadent) on the custom-made stainless steel mold. Ten test specimens for each treatment and material combination were performed with four point bending test method. Data were analyzed using ANOVA and Tukey's test. RESULTS. The surface treatment and type of CAD/CAM restorative material showed a significant effect on the four point bending strength (FPBS) (P<.001). For LDC, AS surface treatment showed the highest FPBS results ($100.31{\pm}10.7MPa$) and the lowest values were obtained in RNC ($23.63{\pm}9.0MPa$) for control group. SEM analyses showed that the surface topography of CAD/CAM restorative materials was modified after treatments. CONCLUSION. The surface treatment of sandblasting or HF acid etching in combination with a universal adhesive containing MDP can be suggested for the adhesive cementation of the novel CAD/CAM restorative materials.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.54-59
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• 2006

Biophotonic sensors based on polymer waveguide with Bragg reflection grating are demonstrated in this work. Waveguide Bragg reflectors were designed by using the effective index method and the transmission matrix method. The grating pattern was formed by exposing the laser interference pattern on a photoresist. On top of the inverted rib waveguide, the Bragg reflection grating was inscribed by the O2 plasma etching. In order to perform the bio-molecule detection experiment, a calixarene molecule was self-assembled on top of thin Au film deposited on the waveguide Bragg reflector. To measure the response of the sensor, several PBS solutions with different concentrations of potassium ion from 1 pM to $100\;{\mu}M$ were dropped on the sensor surface. The shift of Bragg reflection wavelength was observed from the fabricated sensor device, which was proportional to the concentration of potassium ion ranging from 1 pM to 108 pM.

• The Journal of Advanced Prosthodontics
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• v.12 no.1
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• pp.22-32
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• 2020

PURPOSE. The aim of this study was to evaluate the microshear bond strength (µSBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols. MATERIALS AND METHODS. Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, µSBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests. RESULTS. The findings revealed that silane application yielded higher µSBS values (P<.05). All surface treatments were showed a significant increase in µSBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05). CONCLUSION. Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.502-502
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• 2007

Current thin film process using memory device fabrication process use expensive processes such as manufacturing of photo mask, coating of photo resist, exposure, development, and etching. However, direct printing technology has the merits about simple and cost effective processes because inks are directly injective without mask. And also, this technology has the advantage about fabrication of fine pattern line on various substrates such as PCB, FCPB, glass, polymer and so on. In this work, we have fabricated the fine and thick metal pattern line for the electronic circuit board using metal ink contains Ag nano-particles. Metal lines are fabricated by two types of printing methods. One is a conventional printing method which is able to quick fabrication of fine pattern line, but has various difficulties about thick and high resolution DPI(Dot per Inch) pattern lines because of bulge and piling up phenomenon. Another(Second) methods is sequential printing method which has a various merits of fabrication for fine, thick and high resolution pattern lines without bulge. In this work, conductivities of metal pattern line are investigated with respect to printing methods and pattern thickness. As a result, conductivity of thick pattern is about several un.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.72-77
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• 2021

The radial distribution of etch rate was analyzed using the ion energy flux model in VHF-CCP. In order to exclude the effects of polymer passivation and F radical depletion on the etching. The experiment was performed in Ar/SF6 plasma with an SF6 molar ratio of 80% of operating pressure 10 and 20 mTorr. The radial distribution of Ar/SF6 plasma was diagnosed with RF compensated Langmuir Probe(cLP) and Retarding Field Energy Analyzer(RFEA). The radial distribution of ion energy flux was calculated with Bohm current times the sheath voltage which is determined by the potential difference between the plasma space potential (measured by cLP) and the surface floating potential (by RFEA). To analyze the etch rate uniformity, Si coupon samples were etched under the same condition. The ion energy flux and the etch rate show a close correlation of more than 0.94 of R² value. It means that the etch rate distribution is explained by the ion energy flux.