• 한국전기전자재료학회논문지
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• 제13권2호
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• pp.131-136
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• 2000

We have investigated the slurry induced metallic contaminations of undoped and doped silicate oxides surface on CMP cleaning process. The metallic contaminations by CMP slurry were evaluated in four different oxide films, such as plasma enhanced tetra-ethyl-orthyo-silicate glass(PE-TEOS), O3 boro-phos-pho-silicate glass(O3-BPSG), PE-BPSG, and phospho-silicate glass(PSG). All films were polished with KOH-based slurry prior to entering the post-CMP cleaner. The Total X-Ray fluorescence(TXRF) measurements showed that all oxide surfaces are heavily contaminated by potassium and calcium during polishing which is due to a CMP slurry. The polished O3-BPSG films presented higher potassium and calcium contaminations compared to PE-TEOS because of a mobile ions gettering ability of phosphorus. For PSG oxides, the slurry induced mobile ion contamination increased with an increase of phosphorus contents. In addition, the polishing removal rate of PSG oxides had a linear relationship as a function of phosphorus contents.

• 한국진공학회지
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• 제9권1호
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• pp.30-35
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• 2000

Indium-Tin Oxide (ITO) thin films were deposited on the commercial glass substrate by rf-magnetron sputtering. The ITO films with the thickness of 2,000~2,400 $\AA$ were prepared by changing the oxygen partial pressures of 2, 3, and 5%, as well as by changing the substrate temperature of $300^{\circ}C$ and $500^{\circ}C$. spectrophotometer, XRD, SEM, AFM, 4-point probe and Hall effect system were employed to characterize the ITO films. The optimum deposition conditions were the substrate temperature of $500^{\circ}C$ and oxygen partial pressure of 2-3%. At theses conditions, the ITO film showed the transmittance of 91%, the resistivity of $5.4\times10^{-3}\Omega$cm, the carrier concentration of $1.0\times10^{19}\textrm{cm}^{-3}$, and the carrier mobility of 150$\textrm{cm}^2$/Vsec. In XRD spectra, the (222) and (400) $In_2O_3$ planes were dominant under the optimum deposition conditions When the substrate was cleaned only by the method of ultrasonic cleaning without both pre-annealing and chemical treatment of the substrate, the ITO film exhibited the transmittance of 86%, the carrier concentration of $5.4\times10^{19}\textrm{cm}^{-3}$ and the mobility of 24$\textrm{cm}^2$/Vsec.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.313.2-313.2
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• 2013

본 연구에서는 기존에 연구된 Solar Cell 보다 구조 및 제작이 단순한 $Al/Al_2O_3/Si$(100) Solar cell을 제작하여 평가하였다. 기판으로는 p-type Si(100), 0.5~2 ${\Omega}{\cdot}cm$을 사용하여 chemical cleaning 후 ALD(Atom Layer Deposition)법으로 Al2O3 터널링 절연막을 증착하였으며, 박막의 두께를 1~10 nm로 변화시켜 MIS 커패시터의 터널링 효과를 평가하였다. MIS 커패시터의 전기적 특성평가를 위해 누설전류 밀도-전계 특성은 pA meter/DC Voltage source를 사용하였고, 커패시턴스-전압특성, D-factor 특성은 precision LCR meter를 사용하였다. $Al/Al_2O_3/Si$(100) Solar cell의 특성평가를 위해 300~1100nm 파장영역에 따른 양자 효율을 평가하기 위해 Quantum Efficiency system (QE)을 사용하였고, Stanard Test Conditions 100 $mW/cm^2$, AM1.5, $25^{\circ}C$ 조건의 Voc, Isc, Jsc, FF (Fill Factor) 및 Efficiency(%)를 평가하기 위해 Solar simulator를 이용하였다.

• 한국물환경학회지
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• 제18권2호
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• pp.159-168
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• 2002

A lab-scale Reverse Osmosis(RO) membrane reactor was installed to investigate the membrane permeability, characteristics of membrane fouling at each conditions, and performance of elimination at different trans-membrane pressure(TMP) in the liquid fertilizer accumulated system. Experimental setup was divided to three different TMP conditions. As a result of experiment, permeability of RO membrane was proportional to the increase of TMP and temperature. After experiment was completed, two types chemical cleaning(remove the organic foulant and inorganic foulant) was done, and recover rate of permeability was each 99.8, 99.7 and 99.7%, respectively. From this experimental data, membrane fouling could be determined that the most of it was recoverable in this system, and major reason of fouling was concentration polarization. Elimination rate of solute substance in the liquid fertilizer indicated very stable(above 99%), except ammonia nitrogen, and the most stable elimination rate was investigated at the highest TMP condition (Run 3).

• 한국표면공학회지
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• 제32권3호
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• pp.428-432
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• 1999

As metallic surface has its unique lustrous appearance and optical reflectance in visible range of light, the metallization of plastic surface has been an essential drive toward weight reduction for fuel economy and decorations in transportation industry and has been put into practiced from wet chemical-electrochemial to dry vacuum process in view of an environmental effect. Electron-beam metallization was used in this work with an aim at improving the scratchproof surface hardness of plastic substrate with metallic finish character. Thin film of Al ($1000\AA$) and $SiO_2$($7000\AA$) were metallized on substrate of PC and PMMA and the films were evaluated by pencil test for surface hardness and by cross-cut tape test for adhesion. The ion beam treatment improved around twice as hard as non-treat surface. The ion beam is effect on its hardness and adhesion to surface hardened PC substrate.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.387-392
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• 2018

Various technical approaches and concepts have been proposed to develop conductive super-hydrophobic (SH) surfaces. However, most of these approaches are not usable in practical applications because of insufficient adhesion and cost issues. Additionally, durability and uniformity issues are still in need of improvement. The goal of this research is to produce a large-area conductive SH surface with improved adhesion performance and uniformity. To this end, carbon nanotubes (CNT) with a high aspect ratio and elastomeric polymer were utilized as a conductive filler and matrix, respectively, to form a coating layer. Additionally, nanoscale silica particles were utilized for stable implementation of the conductive SH surface. To improve the adhesion properties between the SH coating layer and substrate, pretreatment of the substrate was conducted by utilizing both wet and dry etching processes to create specific organic functional groups on the substrate. Following pretreatment of the surface, a zirco-aluminate coupling agent was utilized to enhance adhesion properties between the substrate and the SH coating layer. Raman spectroscopy revealed that adhesion was greatly improved by the formation of a chemical bond between the substrate and the SH coating layer at an optimal coupling agent concentration. The developed conductive SH coating attained a high electromagnetic interference (EMI) shielding effectiveness, which is advantageous in self-cleaning EMI shielding applications.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권5호
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• pp.39-45
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• 2013

Many researchers have studied the effectiveness of ultrasound in chemical and environmental engineering fields including material synthesis, pollutant removal, cleaning, extraction, and disinfection. Acoustic cavitation induced by ultrasound irradiation in aqueous phase can cause various sonophysical and sonochemical reactions without any chemicals. However most of the previous studies focused only on the relationships between ultrasonic conditions and the results of sonochemical reactions in lab-scale sonoreactors. As a results of this, only a few studies have been devoted to design and optimization of industrial scale sonoreactors. In this study, the effect of the distance between two opposite transducer modules on sonochemical reactions was investigated in single and dual irradiation systems (334 kHz) for four distances including 50, 100, 150, and 200 mm using KI dosimetry. It was found that the dual irradiation systems provided higher performance in terms of the zeroth reaction coefficient and the cavitation yield compared to the single irradiation systems. The sonochemiluminescence (SCL) images for the visualization of the cavitation field showed that cavitation active zone was larger and sonochemical reaction intensity was much higher in the dual irradiation system than in the single irradiation system.

• 한국안전학회지
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• 제36권4호
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• pp.62-70
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• 2021

Representative systematic accident analysis methods proposed so far include AcciMap, STAMP, and FRAM. This study used these three techniques to analyze a fire accident case that occurred during routine manufacturing work in a domestic chemical plant and compared the results. The methods used different approaches to identify the cause of the accident, but they all highlighted similar causal factors. In addition to technical issues, the three accident analysis methods identified factors related to safety education, risk assessment, and the operation of the process safety management system, as well as management philosophy and company culture as problems. The AcciMap and STAMP models play complementary roles because they use hierarchical structures, while FRAM is more effective in analyses centered on human and organizational functions than in technical analyses.

• Design & Manufacturing
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• 제15권4호
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• pp.57-64
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• 2021

In recent materials industry, researches on the technology to manufacture super hydrophobic surface by effectively controlling the wettability of solid surface are expanding. Research on the fabrication of super hydrophobic surface has been studied not only for basic research but also for self-cleaning, anti-icing, anti-friction, flow resistance reduction in construction, textile, communication, military and aviation fields. A super hydrophobic surface is defined as a surface having a water droplet contact angle of 150 ° or more. The contact angle is determined by the surface energy and is influenced not only by the chemical properties of the surface but also by the rough structure. In this paper, maskless lithography using DMD, electro etching, anodizing and hot embossing are used to make the polymer resin PMMA surface super hydrophobic. In the fabrication of microstructure, DMDs are limited by the spacing of microstructure due to the structural limitations of the mirrors. In order to overcome this, maskless lithography using a transfer mechanism was used in this paper. In this paper, a super hydrophobic surface with micro and nano composite structure was fabricated. And the wettability characteristics of the micro pattern surface were analyzed.

• 한국수소및신에너지학회논문집
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• 제33권4호
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• pp.437-445
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• 2022

This paper presents an experimental study on the main management factors of the condenser contamination such as fouling and corrosion for the R-134a turbo-chiller to save energy, reduce corrosion rates, and reduce maintenance costs through the application of condenser non-cleaning water treatment chemical. The series of experiment is conducted using combining oxidative microbial sterilizers, non-oxidizing microbial sterilizers, and anti-corrosion agents. The leaving temperature difference and corrosion rates for three different combination of chemicals are collected and analyzed. The experimental results show that the cost reduction (4,066,000 Won/year) of the disinfectant (FT-830) can be achieved by adding the oxidative disinfectant (NaOCl) and the non-oxidizing disinfectant (NX-1116). The LTD value is maintained at 1.9℃, and the corrosion rates of copper and carbon steel specimens are 0.07 mpy and 1.61 mpy, respectively.