• Journal of the Korean institute of surface engineering
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• v.53 no.3
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• pp.124-129
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• 2020

This study is for the development of high temperature ALD SiO₂ film process, optimized for gap-fill process in manufacturing memory products, using a space-divided PE-ALD system equipped with an independent control dual plasma system and orbital moving unit. Space divided PE-ALD System has high productivity, and various applications can be applied according to Top Lid Design. But space divided ALD system has a limitation to realize concentric deposition map due to process influence due to disk rotation. In order to solve this problem, we developed an orbit rotation moving unit in which disk and wafer. Also we used Independent dual plasma system to enhance thin film properties. Improve productivity and film density for gap-fill process by having deposition and surface treatment in one cycle. Optimize deposition process for gap-fill patterns with different depths by utilizing our independently controlled dual plasma system to insert N₂and/or He plasma during surface treatment, Provide void-free gap-fill process for high aspect ratio gap-fill patterns (up to 50:1) with convex curvature by adjusting deposition and surface treatment recipe in a cycle.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.277-283
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• 2001

This paper presents treatment efficiency and plant growth of a surface-flow constructed wetland system (30 meter in length and 10 meter in width) over one year after its establishment on a floodplain of a stream. Cattails (Typha angustiflora) grown on pots were transplanted on one half of its area from inlets and reeds (Phragmites australis) on another half from an outlet. Effluent discharged from a secondary-level treatment plant was funneled into the system. The stems of cattails and reeds emerging in April 2001 grew up to 165.9 cm and 95.3 cm, respectively until July 2001. The number of stems of cattails arid reeds in July 2001 increased by 65% and 100%, respectively, compared with that just after their planting. The growth of cattails was better than that of reeds during study period. The removal rates for SS, $BOD_5$, T-N and T-P was 33%, 43%, 31%, and 51%, respectively. The system was inundated seven times by storms over the monitoring period, which disturbed its environment and led to its lower treatment rates. The increase of SS concentration in effluent after inundation of the system was attributed to the falls of soil particles onto its water surface, which had been attached to the emergent plants by floods. Purification rates for T-N were relatively low for the period of late fall through winter until early spring due to lower water temperature which may have retarded microbial nitrification and denitrification mechanisms. Reduction in T-P concentration during fall and winter was relatively higher than that during summer and spring, which may have resulted from no system perturbations by floods and heavy storms during fall and winter.

• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.369-377
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• 2003

The aim of this study was to evaluate the effect of two polishing methods and chemical conditioning on the surface of hybrid composites. Ninety cylindrical specimens (diameter：8mm, depth：2mm) were made with three hybrid composites-Filtek Z250, Tetric Ceram. DenFil. Specimens for each composite were randomly divided into three treatment subgroups $^{\circled1}$ Mylar strip (no treatment). $^{\circled2}$ Sof-Lex XT system, $^{\circled3}$ PoGo system. Average surface roughness(Ra) was taken using a surface profilometer at the time of setting and after immersion into 0.02N lactic acid for 1 week and 1 month. Representative specimens were examined by scanning electron microscopy. The data were analyzed using ANOVA and Scheffe's tests at 0.05% significance level. The results were as follows：1. Mylar strip resulted in smoother surface than PoGo and Sof-Lex system (p<0.001). Sof-Lex system gave the worst results. 2. Tetric Ceram was smoother than DenFil and Z250 when cured under only mylar strip. However, it was significantly rougher than other materials when polished with PoGo system. 3. All materials showed rough surface after storage in 0.02N lactic acid, except groups polished with a PoGo system. The PoGo system gave a superior polish than Sof-Lex system for the three composites. However. the correlation to clinical practice may be limited, since there are several processes. such as abrasive, fatigue, and corrosive mechanisms. Thus. further studies are needed for polishing technique under in vivo conditions.

• Journal of the Semiconductor & Display Technology
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• v.12 no.4
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• pp.39-44
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• 2013

In the semiconductor heat-treatment process, the temperature uniformity determines the film quality of a wafer. This film quality effects on the overall yield rate. The heat transfer of the wafer surface in the heat-treatment process equipment is occurred by convection and radiation complexly. Because of this, there is the nonlinearity between the wafer temperature and reactor. Therefore, the accurate prediction of temperature on the wafer surface is difficult without the direct measurement. The thermal camera and the T/C wafer are general ways to confirm the temperature uniformity on the heat-treatment process. As above ways have limit to measure the temperature in the precise domain under the micro-scale. In this study, we developed the thin film type temperature sensor using the MEMS technology to establish the system which can measure the temperature under the micro-scale. We combined the experiment and numerical analysis to verify and calibrate the system. Finally, we measured the temperature on the wafer surface on the semiconductor process using the developed system, and confirmed the temperature variation by comparison with the commercial T/C wafer.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.6
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• pp.639-646
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• 2015

A treatment for improving the characteristics of a surface is very important in increasing the life of machine parts. Many studies have been carried out on the surface characteristics after such treatments. For enhanced eco-technology, an alternative to a conventional chemical surface treatment process is essential. Ultrasonic nano-crystal surface modification (UNSM) technology is a physical environmentally friendly surface treatment method. This technology was developed in domestic and currently being used. As the mechanism of UNSM technology, a ball tip attached to an ultrasonic vibration device strikes the metal surface at nearly 20,000 times per second. The resulting modified surface layer improves the surface characteristics. This paper describes a self-developed fast tool servo system applied to the UNSM process as a vibration module within a high-frequency bandwidth. After describing the surface modification process based on the material and process changes, the surface characteristics are compared.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1115-1119
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• 2014

In this article, a 20 kHz ultrasonic waveguide for nano-surface treatment was designed and manufactured. When designing the system, finite element analysis with ANSYS software was performed to find optimal dimensions of the waveguide, which can raise energy efficiency. Consequently an anti-resonance frequency of an Al waveguide with a piezoelectric actuator was 20 kHz, which predicted the experimentally obtained value of 18 kHz well. For the assessment of the performance, Steel Use Stainless (SUS) 304 and chromium molybdenum steel (SCM) 435 specimens were tested. Cross-sectional microscopies of SUS304 were taken and they showed that the treated thickness was $30{\mu}m$. Additionally, hardness tests of SCM435 were done and the hardness before the process was 14.0 Rockwell Hardness-C scale (HRC) and after the process was 20.5 HRC, respectively, which means 46% increase. Considering these results, the developed ultrasonic system is thought to be effective in the nano-surface treatment process.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.549-554
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• 2008

Nickel Chloride coated protein chip plates were developed by using a spin coating method after $H_2$ plasma treatment. The adsorption ability of histidine tagged protein was investigated at various times of plasma treatment. The properties of the nickel chloride and protein on the surface of the slides were assayed using particle size analysis and the extent of the protein adsorption was determined by using a bio imaging analyzer system. The results show that the ability of protein adsorption decreased as increasing the time of $H_2$ plasma treatment. The mechanism on the ability of protein adsorption at the plate surface is discussed on results and discussions. The results also suggest that the surface stabilization of protein chip plates treated by plasma technology may be applicable in biosensor markets.

• Macromolecular Research
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• v.15 no.3
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• pp.238-243
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• 2007

Nanofibers were prepared by electrospinning a solution of poly(lactic-co-glycolic acid) (PLGA) and their mean diameter was 340 nm. The PLGA nanofibers were treated with a plasma in the presence of either oxygen or ammonia gas to change their surface characteristics. The hydrophilicity of the electrospun PLGA nanofibers was significantly increased by the gas plasma treatment, as confirmed by contact angle measurements. XPS analysis demonstrated that the chemical composition of the PLGA nanofiber surface was influenced by the plasma treatment, resulting in an increase in the number of polar groups, which contributed to the enhanced surface hydrophilicity. The degradation behavior of the PLGA nanofibers was accelerated by the plasma treatment, and the adhesion and proliferation of mouse fibroblasts on the plasma-treated nanofibers were significantly enhanced. This approach to controlling the surface characteristics of nanofibers prepared from biocompatible polymers could be useful in the development of novel polymeric scaffolds for tissue engineering.

• Journal of the Korean institute of surface engineering
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• v.48 no.4
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• pp.163-168
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• 2015

Graphene has attracted much attention due to its remarkable physical properties and potential applications in many fields. In special, the electronic properties of graphene are influenced by the number of layer, stacking sequence, edge state, and doping of foreign elements. Recently, many efforts have been dedicated to alter the electronic properties by doping of various species, such as hydrogen, oxygen, nitrogen, ammonia and etc. Here, we report our recent results of plasma doping on graphene. We prepared mechanically exfoliated graphene, and performed the plasma treatment using ammonia gas for nitrogen doping. The direct-current plasma system was used for plasma ignition. The doping level was estimated from the number of peak shift of G-band in Raman spectra. The upshift of G-band was observed after ammonia plasma treatment, which implies electron doping to graphene.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.7
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• pp.517-521
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• 1998

After etching Al-Cu alloy films using $SiCl_4/Cl_2/He/CHF_3$ plasma, a corrosion phenomenon on the metal surface has been studied with XPS(X-ray pheotoelectron spectroscopy) and SEM (Scanning electron microscopy). In Al-Cu alloy system, the corrosion occurs rapidly on the etched surface by residual chlorine atoms. To prevent the corrosion, $CHF_3$ plasma treatment subsequent to the etch has been carried put. A passivation layer is formed by fluorine-related compounds on the etched Al-Cu surface after $CHF_3$ treatment, and the layer suppresses effectively the corrosion on the surface as the $CHF_3$treatment in the pressure of 300m Torr.