• Journal of Electrical Engineering and Technology
• /
• v.9 no.1
• /
• pp.307-312
• /
• 2014

We present a full finite element analysis for plasma discharge in etching process of semiconductor circuit. The charge transport equations of hydrodynamic diffusion-drift model and the electric field equation were numerically solved in a fully coupled system by using a standard finite element procedure for transient analysis. The proposed method was applied to a real plasma reactor in order to characterize the plasma sheath that is closely related to the yield of the etching process. Throughout the plasma discharge analysis, the base electrode of reactor was tested and modified for improving the uniformity around the wafer edge. The experiment and numerical results were examined along with SEM data of etching quality. The feasibility and usefulness of the proposed method was shown by both numerical and experimental results.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.36 no.6
• /
• pp.625-632
• /
• 2012

The objective of this paper is to demonstrate the cathode channel flooding effects at different stoichiometries in proton exchange membrane (PEM) fuel cells by using visualization techniques. The phenomena of liquid water formation and removal caused by current variations were also examined experimentally. Tests were conducted at cathode stoichiometries of 1.5 and 2.0, and the anode stoichiometry was fixed at 1.5. It is found that at an air-side stoichiometry of 2.0, liquid water begins to form and the flooding occurs faster than at an air-side stoichiometry of 1.5. Also, when the air-side stoichiometry of 1.5 is maintained, the dry-out phenomena is observed in the dry-out area 7.8 A following the field of flooding. Thus, a stoichiometry of 1.5 produced better performance in terms of membrane electrode assembly (MEA) durability and hydrogen ion conductivity than did a stoichiometry of 2.0, in which dry-out occurs beyond 8A.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.10
• /
• pp.86-92
• /
• 2013

In studies on an alternative insulating gas of $SF_6$ gas, the section of the alternative gas and an insulation technique to improve its low dielectric strength have been reported, but very few attempts have been made at the dependence of a gas pressure and a gap as well as the medium effect in the alternative gas. The purpose of this paper is to analyze the dependence of the gas pressure and the gap at surface flashover voltage in dry air. The dependence is analyzed based on the medium effect. The medium effect by the gas pressure and the gap can be explained by surface roughness of a solid dielectric and an electrode as well as an electric field which decreases due to the correlation between the collision ionization coefficient and the gap, respectively. In addition, an insulation technique which can fabricate a compact eco-friendly gas insulated switchgear is proposed by the results of this paper.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.33 no.6
• /
• pp.490-494
• /
• 2020

Sulphur hexafluoride (SF₆) is mostly used as a current-insulating medium in gas-insulated switchgears (GIS), owing to its excellent dielectric strength and arc-extinguishing performance. The global warming potential (GWP) of SF₆, however, is 23,900 times that of CO₂, and its life time in the atmosphere is 3,200 years. For these reasons, new eco-friendly gases to replace SF₆ are required. In this study, the partial discharge (PD) characteristics of green gas for grid (g³) and dry air (N₂/O₂) were analyzed to compare with those of SF₆. A PD electrode system was designed to simulate the protrusion defect in GISs and fabricated for experimentation. To compare the PD characteristics of each gas, the discharge inception voltage (DIV), discharge extinction voltage (DEV), discharge magnitude, discharge pulse number, and phase pattern were analyzed. Results from this study are expected to provide fundamental materials for the design of eco-friendly GISs.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.129-129
• /
• 2015

Dry etcher, PECVD등의 플라즈마 공정 장비의 구조물에는 유전체로 절연된 금속판들이 사용된다. 플라즈마 이론을 보면 이들 표면의 전위는 양전하 플럭스와 음전하 플럭스가 같아서 순전류가 0이 되는 부유 전위를 갖는다. 금속과 같은 전도체의 표면은 모두 같은 전위를 가져야 한다. 일반적인 플라즈마 시뮬레이션 소프트웨어에는 이런 경계 조건이 선택 가능하지 않다. ESI사의 CFD-ACE+의 사용자 루틴 개발 기능을 이용하여 Fortran90문법으로 경계면 최인접 셀의 중심에서 구한 전자 온도와 경계면의 이온 입사 플럭스로 가중평균을 구한 이온 질량을 맥스웰분포를 가정한 부유 전위식에 대입하여 시뮬레이션을 CCP에서 구현하였다. 원형 챔버의 가장자리에 떠 있는 사각 링 전극을 가정하고 이 전극 표면이 접지 전위일때, 유전체 일때, 본 연구에서 개발한 루틴을 적용한 결과를 Ar CCP에 대해서 비교 분석하였다.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.11
• /
• pp.211-220
• /
• 2002

Optical disk drives read information by replacing a laser beam on the disk track. As information has become larger, the more accurate position control of a laser beam is necessary. In this paper, we report the analysis and fabrication of the micro mirror for optical disk drivers. A coupled simulation of gas flow and structural displacement of the micro mirror using the Finite-Element-Method is applied to this. The mirror was fabricated by using MEMS technology. Especially, the process using the lapping and polishing step after the bonding of the mirror and electrode plates was employed for the Process reliability. The mirror size was 2.5mm${\times}$3mm and it needed about 35V for displacement of 3.2 ${\mu}$.

• Smart Structures and Systems
• /
• v.4 no.5
• /
• pp.549-563
• /
• 2008

The ability of an electroactive polymer, IPMC (Ionic Polymer Metal Composites,) to produce electric charge under mechanical deformations may be exploited for the development of next generation of energy harvesters. Two different electrode types (gold and platinum) were employed for the experiments. The sample was tested under dynamic conditions, produced through programmed shaking. In order to evaluate the potential of IPMC for dry condition, these samples were treated with ionic liquid. Three modes of mechanical deformations (bending, tension and shear) were analyzed. Experimental results clearly indicate that IPMCs are attractive applicants for energy harvesting, with inherent advantages like flexibility, low cost, negligible maintenance and virtually infinite longevity. Besides, preliminary energy harvesting model of IPMC has been formulated based upon the work of previous investigators (Newbury 2002, Newbury and Leo 2002, Lee, et al. 2005, Konyo, et al. 2004) and the simulation results reciprocate experimental results within acceptable error.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.04a
• /
• pp.261-264
• /
• 1997

Polyphenylenediamine(PPD)film was prepared with organo sulfur compond (2-aminothiophenol, 1,2-ethanedithiol, and 2-aminoethaneethiol etc.) adding lithium salt to increase the electrical conductivity of the polymer surface. The molecular structure of conductive polymer synthesized were examined and discussed by using SEM, FT-IR, NMR etc. The elecrical conductivity messurement were carried out with four-probe method at dry box of He and $N_2$atmosphere. The typical value of successful electrical conductivity was 1.2$\times$10$^1$S/cm at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.04a
• /
• pp.269-272
• /
• 1997

The Lithium ion secondary battery has been developed for high energy density of portable electrical device and electronics. Among the many conductive polymer materials, the positive active film for Li polymer battery system was synthesized successfully from polyphenylene diamine(PPD) by chemical polymerization in our lab. And PPD-DMcT(2, 5-dimercapto-1, 3, 4-thi-adiazole) composite flim conductive material, at high temperature was also prerared with the addition of dimethylsulfoxide(DMSO). The surface morphology and thermal stability of prepared composite flim was carried out by using SEM and TGA, respectively. Electrochemical and electrical conductivity of composite flim were also discussed by cyclic voltammetry and four-probe method in dry box(<27pm). And the electrode reaction mechanism was detected and analyzed from the half cell unit battery system.

• Proceedings of the KIEE Conference
• /
• 1998.07d
• /
• pp.1343-1345
• /
• 1998

This work was carried out to develop a pattern on the nanometer scale using plasma polymerization and plasma etching. This study is also aimed at developing a resist for the nano process and a vacuum lithography process. The thin films of plasma polymerization were fabricated by the plasma polymerization of inter-electrode capacitively coupled gas flow system. After delineating the pattern at accelerating voltage of 30[kV], ranging the dose of $1-500[{\mu}C/cm^2$], the pattern was developed with dry type and formed by plasma etching.