• Laser Solutions
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• v.15 no.3
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• pp.7-10
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• 2012

Dimensions (line/space) of circuits in IC substrates for high-end chips (e.g. CPU, etc.) are anticipated to decrease as small as $10{\mu}m/10{\mu}m$ in 2014. Since current etch-based circuit-patterning processes are not able to address the urgent requirement from industry, laser-based circuit patterning processes are under active research in which UV laser is used to engrave embedded circuits patterns into IC substrates. In this paper, we used a nanosecond UV laser to directly fabricate embedded circuit patterns into IC substrates with/without ceramic powders. In experiments, we engraved embedded circuit patterns with dimensions (width/depth) of abut $10{\mu}m/10{\mu}m$ and $6{\mu}m/6{\mu}m$ into the IC substrates. Due to the recoil pressure occurring during ablation, the circuit patterning of the IC substrates with ceramic powders showed the higher ablation rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.767-768
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• 2013

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.497-497
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• 2012

산업의 발전함에 따라 고기능성 박막의 수요가 증가하고 있으며, magnetron sputtering, e-beam evaporation, ion beam 등을 이용한 박막 증착에 대한 연구가 많이 진행되고 있다. 그러나 기존 방법만으로는 박막 접착계면의 불균일로 인해 고기능성 박막 성장이 어렵다는 단점을 가지고 있다. 이러한 문제를 해결하기 위하여 박막 공정 중 고밀도 플라즈마 소스(high density plasma source)를 통해 추가적인 에너지를 인가하여 박막의 밀도를 bulk 수준으로 증가시키고 내부 응력을 조절하는 연구에 대한 관심이 커지고 있다. 특히 grid를 이용하여 플라즈마 내 이온의 입사에너지를 증가시킴으로써, 기존 공정보다 고기능성 박막을 구현할 수 있다. 본 연구에서는 RF power를 이용한 inductively coupled plasma를 통해 플라즈마를 생성시킨 후 grid에 DC power를 인가하는 플라즈마 소스를 개발하였으며, 시뮬레이션을 통해 plasma density와 ion current density, ion energy 분석 및 grid 디자인을 하였다. 개발된 플라즈마 소스는 ion energy analyzer를 통해 RF power 및 grid에 인가하는 power의 세기에 따라 이온화 정도 및 이온의 입사에너지를 측정하였다.

• Bulletin of the Society of Naval Architects of Korea
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• v.20 no.2
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• pp.51-59
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• 1983

The versatile practical use of electron beam welding which is very high energy density is still in early stage, but in the special welding field, the welding process is used in manufactured goods. The investigation for electron beam welding up to the present was almost achieved not for the mechanical properties of welded joint but for the process itself. On this investigation, the fatigue strength, crack propergation phenomena and hardness of weld metal and heat affected zone of partially penetrated welded joint of HT80 steel by electron beam welding was accomplished. The tensile fatigue strength in weld line direction of the joint was about $25kg/mm^2$. There still appeared spikes on the tips of penetration, and the crack initiated at the tips of spikes not from the roots. The hardness of the weld metal was higher than it of base metal because of production of martensite by rapid cooling.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.35-35
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• 2001

agnesium Oxide (MgO) with a NaCI structure is well known to exhibit high secondary electron emission, excellent high temperature chemical stability, high thermal conductance and electrical insulating properties. For these reason MgO films have been widely used for a buffer layer of high $T_c$ superconducting and a protective layer for AC-plasma display panels to improve discharge characteristics and panel lifetime. Up to now MgO films have been synthesized by lE-beam evaporation, Molecular Beam Epitaxy (MBE) and Metalorganic Chemical Vapor Deposition (MOCVD), however there have been some limitations such as low film density and micro-cracks in films. Therefore magnetron sputtering process were emerged as predominant method to synthesis high density MgO films. In previous works, we designed and manufactured unbalanced magnetron source with high power density for the deposition of high quality MgO films. The magnetron discharges were sustained at the pressure of O.lmtorr with power density of $110W/\textrm{cm}^2$ and the maximum deposition rate was measured at $2.8\mu\textrm{m}/min$ for Cu films. In this study, the syntheses of MgO films were carried out by unbalanced magnetron sputtering with various $O_2$ partial pressure and specially target power densities, duty cycles and frequency using pulsed DC power supply. And also we investigated the plasma states with various $O_2$ partial pressure and pulsed DC conditions by Optical Emission Spectroscopy (OES). In order to confirm the relationships between plasma states and film properties such as microstructure and secondary electron emission coefficient were analyzed by X-Ray Diffraction(XRD), Transmission Electron Microscopy(TEM) and ${\gamma}-Focused$ Ion Beam (${\gamma}-FIB$).

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.743-747
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• 2003

The improvement of luminance and luminous efficiency is the one of the most important part in AC-PDPs. To achieve high luminance and luminous efficiency, high VUV emission efficiency is needed. We measured the emission spectra of vacuum ultraviolet(VUV) and infrared(IR) rays in surface discharge AC-PDP with Ne-Xe mixture gas. The influence of Ne-Xe gas-mixture ratio on resonance state $Xe^{\ast}(3P_{1})$ and exited state $Xe^{\ast}(3P_{2})$ has been investigated. It is found that the intensity of VUV 147nm emission is proportional to that of the IR 828 nm emission, and the VUV 173nm emission is roughly proportional to that of the IR 823nm emission. The electron temperature and plasma density have been experimentally measured from the center of sustaining electrode gap by a micro Langmuir probe in AC-PDPs. The plasma density from the center of sustaining electrode gap are shown to be maximum value of $9{\times}10^{11}cm^{-3}$, where the electron temperature is about 1.6 eV in this experiment

• Journal of the Korean institute of surface engineering
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• v.37 no.4
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• pp.220-225
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• 2004

A new ion beam extraction system is designed using a simple ion mass filter and a micro mass balance and a QMS based detecting system. A quadrupole Mass Filter is used for selective ion beam formation from inductively coupled high density plasma sources with appropriate electrostatic lens and final analyzing QMS. Also a quartz crystal microbalance is set between a QMF and a QMS to measure the etching and polymerization rate of the mass selected ion beam. An inductively coupled plasma was used as a ion/radical source which had an electron temperature of 4-8 eV and electron density of $4${\times}$10^{11}$＃/㎤. A computer interfaced system through 12bit AD-DA board can control the pass ion mass of the qmf by setting RF/DC voltage ratio applied to the quadrupoles so that time modulation of pass ion's mass is possible. So the direct measurements of ion - surface chemistry can be possible in a resolution of $1\AA$/sec based on the qcm's sensitivity. A full set of driving software and hardware setting is successfully carried out to get fundamental plasma information of the ICP source and analysed $Ar^{+}$ beam was detected at the $2^{nd}$ QMS.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.161-166
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• 2005

The plasma ion density in AC-PDP has shown to be increased from $5.6{\times}10^{11}cm^{-3}$ to $9.0{\times}10^{11)cm^{-3}$ as the Xe mixture ratio to neon increase from 1 % to 10 %, respectively, at fixed pressure of 400 Torr, by using the micro-Langmuir probe. It is noted that the plasma ion density is density increases as the gas pressure increases in this experiment. The electron temperature decreases from 2.3 to 1.2 eV as the Xe mole fraction increases from 1 % to 10 % at fixed pressure of 400 Torr, which is measured by the micro Langmuir probe and high-speed ICCD camera in this experiment. It is noted that the electron temperature decreases as the gas pressure increases from 150 to 400 Torr in this experiment. It is also observed that the exited Xe atom density and the plasma ion density are in strong correlation sharp between each other in this experiment. It is noted that $5.2{\times}10^{12}cm^{-3}$ in the $1s_5$ metastable state and $1.2{\times}10^{12}cm^{-3}$ in the $1s_4$ resonance state for the PDP cell with gap of 50 um distances under the fixed gas pressure of 400 Torr and Xe content ratio of 10 %.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1051-1055
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• 2008

If ZnS receive electric energy, it can generate light. Thin film ELD has merits of excellent sight effect, solid state and easy fabrication but has problems of low emission density, high power loss and high operating voltage. Thin film deposited by electron beam evaporator has good uniformity of 6%. We fabricate excellent thin film ELD for solution of this problems. The thin film ELD made in this study has brightness of 650fL at yellow light and 350fL at green light.

• Proceedings of the Korean Vacuum Society Conference
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• 1996.02a
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• pp.102-102
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• 1996

This paper represents a new type low power High Frequency technological ion source (HF TIS) for ion - beam processing: the surface modification of materials, cleaning of surface, sputtering, coating of thin films, and polishing. The operational principle of HF TIS is based on the excitation of electrostatic waves in plasma located in the external magnetic field. Low power HF TIS with diameter 92 rom gives the opportunity to obtain beams of inert and chemically reactive gases with currents range from 5 to 150 mA (current density $0.015\;~\;3.5\;mA/\textrm{m}^2$) and ion beam energy 100 ~ 2500 eV at a HF power level 10 ~ 150 W. Three grid concave type ion optical system (IOS) is used for extraction and formation ofion beam.n beam.