• Title, Summary, Keyword: microcolumn

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A New Miniaturized Electron-Beam deflector for Microcolumn (Microcolumn 을 위한 새로운 개념의 초소형 전자빔 deflector)

  • Han, Chang-Ho;Kim, Hak;Chun, Kuk-Jin
    • Proceedings of the IEEK Conference
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    • pp.1037-1040
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    • 2003
  • 본 논문에서는 microcolumn 을 위한 초소형 전자빔 deflector 의 제작방법과 microcolumn array 에서 deflector 의 외부 패드를 최소화 할 수 있는 새로운 배선방법을 기술하였다. 배선의 통로 및 절연체 역할을 하는 Pyrex glass 의 양쪽에 각각 실리콘 웨이퍼의 양극접합 및 deep reactive ion etching(DRIE)과 금속 전기 도금을 이용하여 다층배선을 하였다. 이 배선방법을 이용하면 microcolumn array 가 수백개가 되더라도 deflector 의 외부 패드는 항상 8개를 유지할 수 있다.

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Fabrication and Test of Micro Direct Methanol Fuels using Platinum Sputtered Microcolumn Electrodes with a Limited Fuel Source (백금 촉매가 증착된 미소돌기 전극과 유한 연료를 가지는 극소형 직접메탄을 연료전지의 제작 및 성능 평가)

  • 서영호;조영호
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.4
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    • pp.218-224
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    • 2004
  • We present a miniature Direct Methanol Fuel Cell (micro-DMFC) using platinum sputtered microcolumn electrodes with a limited amount of fuel. We use the microcolumn electrode in order to improve the power density of the micro-DMFC that consists of two electrodes and polymer electrolyte. We also design the built-in fuel chamber in the anode for the portable electronics applications. We design and fabricate both microcolumn and planar electrodes, having an identical projective area of 5mm${\times}$5mm. The diffusion current density of the microcolumn electrode is 1.73 times higher than that of the planar electrode at electrode potential of 1.1V in the half-cell test. The micro-DMFC based on the microcolumn electrodes shows the maximum power of 10.8$\pm$7.54㎼(43.23$\pm$0.16㎼/$\textrm{cm}^2$) at the projective area of 5mm${\times}$5mm, while the planar electrode micro-DMFC shows the maximum power of 0.81$\pm$0.42㎼(3.24$\pm$1.68㎼/$\textrm{cm}^2$) at the same projective area. The micro-DMFC based on the microcolumn electrodes shows 13 times higher power density that the micro-DMFC based on the planar electrodes does.

Laser Micromachining of Submicron Aperture for Electronbeam Microcolumn Application using Piezo Q-Switched Nd:YAG Laser

  • S.J. Ahn;Kim, D.W.;Park, S.S.
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.78-78
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    • 1999
  • Experimental studies of laser micromachining on Mo metal using piezo Q-switched Nd:YAG laser have been performed. Miniaturized microcolumn electron gun arrays as a potential electron beam lithography or portable mini-scanning electron microscope application have recently extensively examined. For these purpose, the electro-static electron lens and deflector system called microcolumn has to be assembled. The conventional microcolumn fabrication technique would gave a limitation on the minimization of aberration. The current technique of a 1 $\mu$m misalignment would lead to ~1.3 nm coma. In order to reduce aberration, assembling the microcolumn component followed by laser drilling should be very beneficial. In this report, we will address the preliminary report of laser micromachining on Mo substrate using piezo Q-switched Nd:YAG laser. The geometrical figures, such as the diameter and the depth of the frilled aperture are dependent upon the total energy of the laser pulse train, laser pulsewidth, and the diameter of laser beam in addition to the materials-dependent parameters.

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Experimental Study on the Operation of a Keyhole-Shaped Lens in a Microcolumn

  • Oh, Tae-Sik;Jin, Sang-Won;Choi, Sang-Kuk;Kim, Young-Chul;Kim, Dae-Wook;Ahn, Seung-Joon;Lee, Young-Bok;Kim, Ho-Seob
    • Journal of the Optical Society of Korea
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    • v.15 no.4
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    • pp.368-372
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    • 2011
  • An advanced microcolumn is proposed which adopts a modified einzel lens structure. The newly designed einzel lens is composed of four electrodes. The two center electrodes are specially designed electrostatic quadrupole (EQ) einzel lenses having keyhole instead of circular apertures. We constructed the advanced microcolumn with the EQ-einzel lenses, and operated the newly designed microcolumn in single lens mode and double-lens mode. The preliminary results show that the EQ-einzel lens can improve the performance of the micro-column for large sample applications.

New Fabrication Method of the Electron Beam Microcolumn and Its Performance Evaluation (초소형 전자칼럼의 제작 및 특성 연구)

  • Ahn S;Kim D. W;Kim Y. C;Ahn S. J;Kim Y. J;Kim H. S
    • Korean Journal of Materials Research
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    • v.14 no.3
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    • pp.186-190
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    • 2004
  • An electron beam microcolumn composed of an electron emitter, micro lenses, scan deflector, and focus lenses have been fabricated and tested in the STEM mode. In this paper, we report a technique of precisely aligning the electron lenses by the laser diffraction patterns instead of the conventional alignment method based on aligner and STM. STEM images of a standard Cu-grid were observed using a fabricated microcolumn under both the retarding and accelerating modes.

Electron Beam Properties of Microcolumn Based on the Structure of Electrostatic Lens Apertures (전자 렌즈 Aperture 구조에 따른 마이크로칼럼의 전자빔 특성)

  • Choi, Sang-Kuk;Yi, Cheon-Hee
    • Korean Journal of Optics and Photonics
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    • v.16 no.5
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    • pp.428-432
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    • 2005
  • Microlens precisely fabricated by MEMS process, is a key component of the Microcolumn, Since, miniaturization can reduces aberrations, microcolumn is expected to have better performance than conventional columns. Depending on the fabrication techniques, the sectional view of micro lens has different shape. In the paper, the effect of the sectional shape of extractor lens and limiting aperture on the focusing property of microcolumns have been studied.

Development of microcolumn control unit to detect of via-hole defects on wafer (반도체소자의 Via hole 결함 측정을 위한 전자컬럼 제어기술 개발)

  • Roh, Young-Sup;Kim, Heung-Tae;Kim, H.S.;Kim, D.W.;Ahn, S.J.;Kim, Y.C.;Jin, S.W.;Whang, N.W.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.528-529
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    • 2008
  • A new concept based on sample current measurements for detecting of via-hole defects on wafer has been performed by low energy electron beam microcolumn. The microcolumn has been operated at a low voltage of 290 eV with total emission current of 400 nA, and a sample current of 6 nA. The test sample was fabricated with SiO2 layer of 300 nm thickness on a piece of a silicon substrate. Preliminary results of both sample current method and secondary electron method show microcolumn and its control can be useful technology for detecting of via-hole defects on wafer.

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Study on Determination of Seven Transition Metal Ions in Water and Food by Microcolumn High-Performance Liquid Chromatography

  • Hu, Qiufen;Yang, Guangyu;Li, Haitao;Tai, Xi;Yin, Jiayuan
    • Bulletin of the Korean Chemical Society
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    • v.25 no.5
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    • pp.694-698
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    • 2004
  • A new method for the simultaneous determination of seven transition metal ions in water and food by microcolumn high-performance liquid chromatography has been developed. The lead, cadmium, mercury, nickel, cobalt, silver and tin ions were pre-column derivatized with tetra-(4-aminophenyl)-porphyrin ($T_4$-APP) to form the colored chelates which were then enriched by solid phase extraction with $C_{18}$ cartridge. The enrichment factor of 50 was achieved by eluted the retained chelates from the cartridge with tetrahydrofuran (THF). The chelates were separated on a ZORBAX Stable Bound microcolumn ($2.0{\times}50\;mm,\;1.8\;{\mu}m$)with methanol-tetrahydrofuran (95 : 5, v/v, containing 0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0) as mobile phase at a flow rate of 0.5 mL/min and detected with a photodiode array detector from 350-600 nm. The seven chelates were separated completely within 2.0 min. The detection limits of lead, cadmium, mercury, nickel, cobalt, silver and tin are 4 ng/L, 3 ng/L, 6 ng/L, 5 ng/L, 5 ng/L, 6 ng/L, 4 ng/L respectively in the original samples. This method was applied to the determination of the seven transition metal in water and food samples with good results.

Construction of a Gradient ${\mu}LC/MS$ system and Its Application

  • Cheong, Won-Jo
    • 한국생물공학회:학술대회논문집
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    • pp.103-106
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    • 2002
  • A gradient LC/MS system was constructed and applied for separation of biological samples. For example, a rapid and simple analytical method without pretreatment based on gradient ${\mu}LC/MS$ with a disposable microcolumn has been developed to determine B group vitamins in urine. Urine samples were directly injected to the disposable home-made microcolumn. The microcolumn can be emptied after being used for a series of urine samples, and repacked with fresh stationary phase. An overdose of vitamin pills were swallowed by healthy volunteers and the urine samples were taken 1,2,3,5, and 8 hours after swallowing. Vitamins immediately showed up in urine, hit the maximum, and disappeared swiftly. This technique is expected to have some application for clinical purposes.

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Development and Evaluation of an Electron Beam Source for Microscopy and Its Applications

  • Ahn, Seung-Joon;Oh, Tae-Sik;Kim, Ho-Seob;Ahn, Seong-Joon
    • Journal of the Optical Society of Korea
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    • v.14 no.2
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    • pp.127-130
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    • 2010
  • We have developed an efficient electron beam (e-beam) source, a microcolumn, that can be used as a source module for of microscopy and its applications. To obtain a low operating voltage, a very sharp cold field electron emitter was developed by electrochemically etching a tungsten wire. Laser diffraction was used for the fabrication of high-quality electron lenses and for their precise alignment. The measurement of the e-beam currents, and SEM images captured by the microcolumn confirmed the potential of the device as a very good e-beam source.