• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1802-1806
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• 2007

Nowadays, many configurations and applications of small atmospheric plasma source have been investigated with growing interest, as it provides the bacteria inactivation, the surface modification and removal of unwanted small regions, and so on. In this paper, the non-thermal micro plasma source under atmospheric pressure by means of submicrosecond pulse voltage waveforms is suggested. Plasma operates in helium is appears as a small (sub-mm) glow at the tip of a plasma gun. Electrical measurements show that the plasma source operates at low voltage (about 500V) and the power consumption is about 1W at 25kHz. Moreover, the emission spectrum shows the relatively higher emission intensity of oxygen particles than those of helium and nitrogen.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1736-1741
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• 2003

The characteristics plasma flow of an atmospheric plasma torch used for thermal plasma processing is studied. In general, it is produced by the arc-gas interactions between a cathode tip and an anode nozzle. The performance of non-transferred plasma torch is significantly dependent on jet flow characteristics out of the nozzle. In this work, the distribution of gas flow that goes out to the atmosphere through a plenum chamber and nozzle is analyzed to evaluate the performance of atmospheric plasma torch. Numerical analysis is carried out with various angles of an inlet flow which can create different swirl flow fields. Moreover, the size of plasma plume is experimentally depicted.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.268-268
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• 2012

Atmospheric pressure microwave induced plasmas are used to excite and ionize chemical species for elemental analysis, for plasma reforming, and for plasma surface treatment. Microwave plasma differs significantly from other plasmas and has several interesting properties. For example, the electron density is higher in microwave plasma than in radio-frequency (RF) or direct current (DC) plasma. Several types of radical species with high density are generated under high electron density, so the reactivity of microwave plasma is expected to be very high [1]. Therefore, useful applications of atmospheric pressure microwave plasmas are expected. The surface characteristics of SUS304 stainless steel are investigated before and after surface modification by microwave plasma under atmospheric pressure conditions. The plasma device was operated by power sources with microwave frequency. We used a device based on a coaxial transmission line resonator (CTLR). The atmospheric pressure plasma jet (APPJ) in the case of microwave frequency (880 MHz) used Ar as plasma gas [2]. Typical microwave Pw was 3-10 W. To determine the optimal processing conditions, the surface treatment experiments were performed using various values of Pw (3-10 W), treatment time (5-120 s), and ratios of mixture gas (hydrogen peroxide). Torch-to-sample distance was fixed at the plasma edge point. Plasma treatment of a stainless steel plate significantly affected the wettability, contact angle (CA), and free energy (mJ/$m^2$) of the SUS304 surface. CA and ${\gamma}$ were analyzed. The optimal surface modification parameters to modify were a power of 10 W, a treatment time of 45 s, and a hydrogen peroxide content of 0.6 wt% [3]. Under these processing conditions, a CA of just $9.8^{\circ}$ was obtained. As CA decreased, wettability increased; i.e. the surface changed from hydrophobic to hydrophilic. From these results, 10 W power and 45 s treatment time are the best values to minimize CA and maximize ${\gamma}$.

• Transactions on Electrical and Electronic Materials
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• v.9 no.2
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• pp.79-83
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• 2008

The dampness by treating the surface with polyethylene terephthalate (PET) film was measured to grasp the plasma parameters and was observed the surface condition with an atomic force microscope (AFM) to find the causes of the dampness. Also, the vibrational and rotational temperatures in the plasma were calculated after identifying the radicals within the plasma by analyzing the emission spectral with an emission spectrum. The hydrophilic properties were enhanced, by treating the surface of the PET film with non-equilibrium atmospheric discharge plasma. When the rotational temperature was 0.22 to 0.31 eV within the plasma, surface modification control could be easily carried out to surface treatment of PET film on non-equilibrium atmospheric pressure plasma.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.148-152
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• 2005

Atmospheric low-temperature plasma was produced using dielectric barrier discharge (DBD) plate-type plasma reactor and high frequency of 13.56 Hz. The surfaces of polyimide films for insulating and packaging materials were treated by the atmospheric low-temperature plasma. The contact angle of 67$^{\circ}$ was observed before the plasma treatment. The contact angle was decreased with deceasing the velocity of plasma treatment. In case of oxygen content of 0.2 %, electrode gap of 2 mm, the velocity of plasma treatment of 20 mm/sec, and input power of 400 W, the minimum contact angle of 13$^{\circ}$ was observed. The chemical characteristics of polyimide film after the plama treatment were investigated using X-ray photoelectron spectroscopy (XPS), and new carboxyl group bond was observed. The surfaces of polyimide films were changed into hydrophilic by the atmospheric low-temperature plasma. The polyimide films having hydrophilic surface will be very useful as a packaging and insulating materials in electronic devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.56.2-56.2
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• 2015

Nonthermal Atmospheric Pressure Plasmas and their Applications to Plasma Bioscience and Medicines have been introduced for next generation human healthcare's quantum developments. Various kinds of nonthermal atmospheric pressure plasmas have been introduced and their electron temperature and plasma densities along with reactive oxygen and nitrogen species have been diagnosed and analyzed for biological cell interactions, especially, used in Plasma Bioscience Research Center (PBRC), Korea. Herein, we have also introduced the plasma-initiated ultraviolet photolysis, which might be a generation mechanism for the reactive oxygen and nitrogen species (RONS) intracellular and extracellular regions inside the liquid when the plasma has been bombarded onto the water. Finally we have investigated the interactions of these RONS with the various cancer cells resulting in apoptotic cell death.

• Korean Journal of Materials Research
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• v.27 no.4
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• pp.211-215
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• 2017

Reactive Ion Etching (RIE) and wet etching are employed in existing texturing processes to fabricate solar cells. Laser etching is used for particular purposes such as selective etching for grooves. However, such processes require a higher level of cost and longer processing time and those factors affect the unit cost of each process of fabricating solar cells. As a way to reduce the unit cost of this process of making solar cells, an atmospheric plasma source will be employed in this study for the texturing of crystalline silicon wafers. In this study, we produced the atmospheric plasma source and examined its basic properties. Then, using the prepared atmospheric plasma source, we performed the texturing process of crystalline silicon wafers. The results obtained from texturing processes employing the atmospheric plasma source and employing RIE were examined and compared with each other. The average reflectance of the specimens obtained from the atmospheric plasma texturing process was 7.88 %, while that of specimens obtained from the texturing process employing RIE was 8.04 %. Surface morphologies of textured wafers were examined and measured through Scanning Electron Microscopy (SEM) and similar shapes of reactive ion etched wafers were found. The Power Conversion Efficiencies (PCE) of the solar cells manufactured through each process were 16.97 % (atmospheric plasma texturing) and 16.29 % (RIE texturing).

• Journal of the Semiconductor & Display Technology
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• v.8 no.2
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• pp.15-21
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• 2009

Atmospheric pressure plasma equipment was successfully applied to the flip chip BGA manufacturing process to improve the uniformity of flux printing process. The problem was characterized as shrinkage of the printed flux layer due to insufficient surface energy of the flip chip BGA substrate. To improve the hydrophilic characteristics of the flip chip BGA substrate, remote DBD type atmospheric pressure plasma equipment was developed and adapted to the flux print process. The equipment enhanced the surface energy of the substrate to reasonable level and made the flux be distributed over the entire flip chip BGA substrate uniformly. This research was the first adaptation of the atmospheric pressure plasma equipment to the flip chip BGA manufacturing process and a lot of possible applications are supposed to be extended to other PCB manufacturing processes such as organic cleaning, etc.

• New & Renewable Energy
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• v.9 no.2
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• pp.23-29
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• 2013

Furnace and laser is currently the most important doping process. However furnace is typically difficult appling for selective emitters. Laser requires an expensive equipment and induces a structural damage due to high temperature using laser. This study has developed a new atmospheric pressure plasma source and research atmospheric pressure plasma doping. Atmospheric pressure plasma source injected Ar gas is applied a low frequency (a few 10 kHz) and discharged the plasma. We used P type silicon wafers of solar cell. We set the doping parameter that plasma treatment time was 6s and 30s, and the current of making the plasma is 70 mA and 120 mA. As result of experiment, prolonged plasma process time and highly plasma current occur deeper doping depth and improve sheet resistance. We investigated doping profile of phosphorus paste by SIMS (Secondary Ion Mass Spectroscopy) and obtained the sheet resistance using generally formula. Additionally, grasped the wafer surface image with SEM (Scanning Electron Microscopy) to investigate surface damage of doped wafer. Therefore we confirm the possibility making the selective emitter of solar cell applied atmospheric pressure plasma doping with phosphorus paste.

• Advanced Composite Materials
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• v.17 no.2
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• pp.167-175
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• 2008

Vapor grown carbon fibers (VGCF) were treated with atmospheric plasma enhancing the surface area in order to improve the bonding to the matrix in epoxy composites. The changes in the mechanical properties of VGCF/epoxy nanocompostes, such as tensile modulus and tensile strength were investigated in this study. VGCF with and without atmospheric plasma treatment for surface modification were used in this investigation. The interdependence of these properties on the VGCF contents and interfacial bonding between VGCF/epoxy matrix were discussed. The mechanical properties of atmospheric plasma treated (APT) VGCF/epoxy were compared with raw VGCF/epoxy. The tensile strength of APT VGCF/epoxy nanocomposites showed higher value than that of raw VGCF. The tensile strength was increased with atmospheric plasma treatment, due to better adhesion at VGCF/epoxy interface. The tensile modulus of raw VGCF and APT VGCF/epoxy matrix were of the similar value. The dispersion of the VGCF was investigated by scanning electron microscopy (SEM), SEM micrographs showed an excellent dispersion of VGCF in epoxy matrix by ultrasonic method.