• Journal of the Korean institute of surface engineering
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• v.51 no.2
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• pp.133-137
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• 2018

Plasma devices such as jets, pencils, and torches have been developed as new tools that help penetration of target agents and applied to plasma medicine. However, these devices cannot be used in a large area. Therefore, we introduced a flexible plasma device, which can be treated of large area and designed as bendable plasma. In additional, in vitro model based on agarose gel was prepared that can be show effectiveness in the depth of penetration. Plasma treatment conditions such as power, time and distance can be optimized on the agarose gel wound model. The chemical structure of changed polysaccharides was predicted due to reactive excited atoms and molecules, UV photons, charged particles and reactive oxygen and nitrogen species (RONS).

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.148-148
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• 2011

Recently, there have been many research activities to develop the large-area plasma source, which is able to generate the high-density plasma with relatively good uniformity, for the plasma processing in the thin-film solar cell and display panel industries. The large-area CCP sources have been applied to the PECVD process as well as the etching. Especially, the PECVD processes for the depositions of various films such as a-Si:H, ${\mu}c$-Si:H, Si3N4, and SiO2 take a significant portion of processes. In order to achieve higher deposition rate (DR), good uniformity in large-area reactor, and good film quality (low defect density, high film strength, etc.), the application of VHF (>40 MHz) CCP is indispensible. However, the electromagnetic wave effect in the VHF CCP becomes an issue to resolve for the achievement of good uniformity of plasma and film. Here, we propose a new electrode as part of a method to resolve the standing wave effect in the large-area VHF CCP. The electrode is split up a series of strip-type electrodes and the strip-type electrodes and the ground ones are arranged by turns. The standing wave effect in the longitudinal direction of the strip-type electrode is reduced by using the multi-feeding method of VHF power and the uniformity in the transverse direction of the electrodes is achieved by controlling the gas flow and the gap length between the powered electrodes and the substrate. Also, we provide the process results for the growths of the a-Si:H and the ${\mu}c$-Si:H films. The high DR (2.4 nm/s for a-Si:H film and 1.5 nm/s for the ${\mu}c$-Si:H film), the controllable crystallinity (~70%) for the ${\mu}c$-Si:H film, and the relatively good uniformity (1% for a-Si:H film and 7% for the ${\mu}c$-Si:H film) can be obtained at the high frequency of 40 MHz in the large-area discharge (280 mm${\times}$540 mm). Finally, we will discuss the issues in expanding the multi-electrode to the 8G class large-area plasma processing (2.2 m${\times}$2.4 m) and in improving the process efficiency.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.550-551
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• 2013

Large-area RF-driven ion source is being developed at Germany for the heating and current drive of ITER plasmas. Negative hydrogen (deuterium) ion sources are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER and DEMO. RF ion sources for the production of positive hydrogen ions have been successfully developed at IPP (Max-Planck- Institute for Plasma Physics, Garching) for ASDEX-U and W7-AS neutral beam injection (NBI) systems. In recent, the first NBI system (NBI-1) has been developed successfully for the KSTAR. The first and second long-pulse ion sources (LPIS-1 and LPIS-2) of NBI-1 system consist of a magnetic bucket plasma generator with multi-pole cusp fields, filament heating structure, and a set of tetrode accelerators with circular apertures. There is a development plan of large-area RF ion source at KAERI to extract the positive ions, which can be used for the second NBI (NBI-2) system of KSTAR, and to extract the negative ions for future fusion devices such as ITER and K-DEMO. The large-area RF ion source consists of a driver region, including a helical antenna (6-turn copper tube with an outer diameter of 6 mm) and a discharge chamber (ceramic and/or quartz tubes with an inner diameter of 200 mm, a height of 150 mm, and a thickness of 8 mm), and an expansion region (magnetic bucket of prototype LPIS in the KAERI). RF power can be transferred up to 10 kW with a fixed frequency of 2 MHz through a matching circuit (auto- and manual-matching apparatus). Argon gas is commonly injected to the initial ignition of RF plasma discharge, and then hydrogen gas instead of argon gas is finally injected for the RF plasma sustainment. The uniformities of plasma density and electron temperature at the lowest area of expansion region (a distance of 300 mm from the driver region) are measured by using two electrostatic probes in the directions of short- and long-dimension of expansion region.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.271-271
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• 2012

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance, Inductively Coupled Plasma, Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. In this presentation, we will propose the new concept of the multiple source, which consists of a parallel connection of ICP sources and helicon plasma sources. For plasma uniformity, equivalent power (especially, equivalent current in ICP & Helicon) should distribute on each source. We design power feeding line as coaxial transmission line with same length of ground line in each source for equivalent power distribution. And we confirm the equivalent power distribution with simulation and experimental result. Based on basic study, we develop the plasma source for oxidation in semiconductor process. we will discuss the relationship between the processing parameters (With or WithOut magnet, operating pressure, input power ). In ICP, plasma density uniformity is uniform. In ICP with magnet (or Helicon) plasma density is not uniform. As a result, new design (magnet arrangement and gas distributor and etc..) are needed for uniform plasma density in ICP with magnet and Helicon.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.94-94
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• 2010

As a new plasma source for the plasma enhanced chemical vapor deposition (PCVD) of ${\mu}c$-Si deposition, we have demonstrated a microwave-excited plasma source, which can produce high density (${\sim}10^{12}\;cm^{-3}$) plasma with low electron temperature (~1 eV) and low plasma potential (~10 V). In this plasma source, microwave power radiated from slot antenna is distributed along the plasma-dielectric interface in large area and this enables us to produce uniform high-density plasma in large area. To optimize deposition conditions, deep understanding of gas phase chemistry is indispensable. In this presentation, we will discuss on the gas phase diagnostics of microwave $SiH_4/H_2$ plasma such as $SiH_4$ dissociation or $SiH_3$ radical profile as well as deposited film properties.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.282-285
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• 2000

Four helical resonators are distributed in a 2 ${\times}$ 2 array by modifying upper part of the conventional reactive ion etching(RIE) type LCD etcher in order to prepare a large area plasma source. Since the resonance condition of the RF signal to the helical antenna, one RF power supply is used for delivering the power efficiently to all four helical resonators without an impedance matching network Previous work of 2 ${\times}$ 2array inductively coupled plasma(ICP)requires one matching circuit to each ICP antenna for more efficient power deliverly Distributions of ion density and electron temperature are measured in terms of chamber pressure, gas flow rate and RF power . By adjusting the power distribution among the four helical resonator units, argon plasma density of higher than 10$\^$17/㎥ with the uniformity of better than 7％ can be obtained in the 620 ${\times}$ 620$\textrm{mm}^2$ chamber.

• Journal of Information Display
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• v.3 no.2
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• pp.26-30
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• 2002

Large area plasma source has been built for LCD etcher by an array of $2{\times}2$ ICP sources. Since only one RF power supply and one impedance matching network is used in this configuration, any difference in impedances of unit RF antennas causes unbalanced power delivery to the unit ICP. In order to solve this unavoidable unbalance, unit antenna is designed to have a movable tap, with which the inductance of each unit can be adjusted individually. The plasma density becomes symmetric and etch rate becomes more uniform with the impedance adjustment. The concept of adding axial time-varying magnetic field to the single ICP source is applied to the array ICP source, and is found to be effective in terms of etch rate and uniformity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.145-148
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• 2001

A large area plasma source using parallel $2{\times}2$ ICP antennas showed improved etching uniformity by the E-ICP operation. ITO etching process with $CH_4$ gas chemistry is optimized with the DOE (Design of Experiment) based on Taguchi method. Various methane ratios in methane and argon mixture are compared to confirm the effect of polymerization. The analysis shows that the effect of bias power is the largeset. We obtained higher ITO etching rate and better uniformity on $350{\times}300mm$ substrate at the 50Hz magnetization frequency of the E-ICP operation technique,

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.145-148
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• 2001

A large area plasma source using parallel 2x2 ICP antennas showed improved etching uniformity by the E-ICP operation. ITO etching process with CH$_4$ gas chemistry is optimized with the DOE(Design of Experiment) based on Taguchi method. Various methane ratios in methane and argon mixture are compared to confirm the effect of polymerization. The analysis shows that the effect of bias power is the largeset. We obtained higher ITO etching rate and better uniformity on 350x300mm substrate at the 50Hz magnetization frequency of the E-ICP operation technique.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.241.1-241.1
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• 2014

The large-area high-power radio-frequency (RF) driven ion sources based on the negative hydrogen (deuterium) ion beam extraction are the major components of neutral beam injection (NBI) systems in future large-scale fusion devices such as an ITER and DEMO. Positive hydrogen (deuterium) RF ion sources were the major components of the second NBI system on ASDEX-U tokamak. A test large-area high-power RF ion source (LAHP-RaFIS) has been developed for steady-state operation at the Korea Atomic Energy Research Institute (KAERI) to extract the positive ions, which can be used for the NBI heating and current drive systems in the present fusion devices, and to extract the negative ions for negative ion-based plasma heating and for future fusion devices such as a Fusion Neutron Source and Korea-DEMO. The test RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of RF discharge. The characteristics and uniformities of the plasma parameter in the RF ion source were measured at the lowest area of the expansion bucket using two RF-compensated electrostatic probes along the direction of the short- and long-dimensions of the expansion region. The plasma parameters in the expansion region were characterized by the variation of loaded RF power (voltage) and filling gas pressure.