• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.210-210
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• 2008

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.144-144
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• 2011

Diagnostics of plasma density and temperature play an important role for monitoring plasma processing and Laser Thomson scattering is a one of the most accurate diagnostic technique for measuring plasma density and temperature because of none-perturbation to plasma among various diagnostic techniques invented to measure plasma density and temperature. I will briefly review Laser Thomson scattering experiment performed in KRISS and difficulties for measuring the electron velocity distribution such as Gaussian due to low signal-to-noise ratio with showing results that we got until now. This work is an intermediate step in a process that we will get a reliable data which shows physical phenomenon of plasma compared with other diagnostic techniques and results.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.21-23
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• 2011

Uniformity of plasma etching processes critically depends on the wafer temperature and its distribution. The wafer temperature is affected by plasma, chucking force, He back side pressure and the surface temperature of ESC(electrostatic chuck). In this work, 3D mathematical modeling is used to investigate the influence of the geometry of coolant path and the temperature distribution of the ESC surface. The model that has the coolant path with less change of the cross-sectional area and the curvature shows low standard deviation of the ESC surface temperature distribution than the model with the coolant path of the larger surface area and more geometric change.

• Journal of the Semiconductor & Display Technology
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• v.6 no.2 s.19
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• pp.41-44
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• 2007

Optical simulation of the rear and front panel geometries were needed to improve the luminance and efficiency in PDP cells. The 3-dimensional optical code can be used to analyze the variation of geometries and changing of optical properties. In order to improve the accuracy of simulated results, a new UV source, called a multi-cubes UV source, was designed. To design the source, at first UV distribution was calculated with the plasma fluid code and then the UV distribution was transformed to the multi-cube structures in the optical code. Compared to the results from existing UV source, called a planar UV source, could be improved the accuracy of visible light distribution. Simulated results were also compared to the visible distribution measured with the ICCD in a real PDP cell.

• Journal of Environmental Science International
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• v.26 no.6
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• pp.711-717
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• 2017

Dielectric Barrier Discharge (DBD) plasma is a new technique for use in environmental pollutant degradation, which is characterized by the production of hydroxyl radicals as the primary degradation species. Due to the short lifetime of the chemically active species generated during the plasma reaction, the dissolution of the plasma gas has a significant effect on the reaction performance. The plasma reaction performance can be enhanced by combining the basic plasma reactor with a homogenizer system in which the bubbles are destroyed and turned into micro-bubbles. For this purpose, the improvement of the dissolution of plasma gas was evaluated by measuring the RNO (N-dimethyl-4-nitrosoaniline, an indicator of the generation of OH radicals). Experiments were conducted to evaluate the effects of the diameter, rotation speed, and height of the homogenizer, pore size, and number of the diffuser and the applied voltage on the plasma reaction. The results showed that the RNO removal efficiency of the plasma reactor combined with a homogenizer is two times higher than that of the conventional one. The optimum rotor size and rotation speed of the homogenizer were 15.1 mm, and 19,700 rpm, respectively. Except for the lowest pore size distribution of $10-16{\mu}m$, the pore size of the diffuser showed little effect on RNO removal.

• Journal of the Korean Magnetics Society
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• v.13 no.2
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• pp.47-52
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• 2003

Ferromagnetic tunnel junctions were fabricated by dc magnetron sputtering and plasma oxidation process. The local transport properties of the ferromagnetic tunnel junctions were studied using contact-mode Atomic Force Microscopy (AFM) and the local current-voltage analysis. Tunnel junctions with the structure of sub./Ta/Cu/Ta/NiFe/Cu/Mn$\_$75/Ir$\_$25//Co$\_$70/Fe$\_$30//Al-oxide were prepared on thermally oxidized Si wafers. Al-oxide layers were formed with microwave excited plasma using radial line slot antenna (RLSA) for 5 and 7 sec. Kr gas was used as the inert gas mixed with $O_2$ gas for the plasma oxidization. No correlation between topography and current image was observed while they were measured simultaneously. The local current distribution was well identified with the distribution of local barrier height. Assuming the gaussian distribution of the local barrier height, the ferromagnetic tunnel junction with longer oxidation time was well fitted with the experimental results. As contrast, in the case of the shorter time oxidation junction, the current mainly flow through the low barrier height area for its insufficient oxygen. Such leakage current might result in the decrease of tunnel magnetoresistance (TMR) ratio.

• 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.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1996.11a
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• pp.63-66
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• 1996

Electron temperature and electron density were measured in a radio-frequency(rf) inductively coupled plasma using probe measurements. Measurements were made in an argon discharge for pressures from 10 to 100mTorr and input rf power from 100 to 800W. Spatial distribution Electron temperature and electron density were measured for discharge with same aspect ratio. Electron temperature and Electron density were found to depend on both pressure and power. Electron density was creased with increasing pressure, but peaked in a 70mTorr discharge. Radial distribution of the electron density was peaked in the plasma fringes. These results were compared to a simple model of inductively coupled plasmas.

• Journal of Korean Society for Atmospheric Environment
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• v.1 no.1
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• pp.9-15
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• 1985

For the purpose of obtaining the index that represents the contaminated status due to polychlorinated biphenyls (PCB) in the human body, the authors investigated the contents of PCB in the plasma of 183 subjects who were not exposured to the massive amount of PCB occupationaly in the past. The obtained results were as follows; 1. The mean contents of PCB in plasma were 3.35 $\pm$ 1.48 ppb in male and 3.04 $\pm$ 1.06 ppb in female. $Cl_4$ and $Cl_3$ were the main isomers in both sexes. 2. The distribution of total-PCB by the age group was showed increasing tendency with the age in both sexes. 3. The tendency of freqyency distribution of total-PCB level were skewed to the higher level in malo and skewed to the lower level in female. 4. There was satistically significant interrelationship between age and total-PCB in plasma in both sexes.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1361-1366
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• 2009

This study is to see the internal flow for the plasma cutting fume collector. Plasma cutters are widely used in the canning industry and Fume cause the device because it will affect the performance of the design of dust collector. Therefore, to determine the distribution of the internal flow using CFD and Solver was used for calculated with commercial CFD code STAR-CCM+. The results show that design of chamber was incorrect after passed the filter for exhaust to the fan. And the location of the duct to the influx of dust collector and the design was incorrect. In addition, an array of filter was also inappropriate. As a result, present fume collector need to improvement.