• Title, Summary, Keyword: vacuum

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Design and Performance Test of Vacuum Control Valve for Electron Beam Lithography (전자빔 가공기의 진공제어 밸브설계 및 특성평가)

  • Lee Chan-Hong;Lee Hu-Sang
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.777-780
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    • 2005
  • The high vacuum in a electron beam lithography is basic condition, because electron beam vanish by collision with air molecules in generally atmosphere. To make high vacuum state, the vacuum control valve is essential. Most vacuum control valve are manual units. So, user of manual vacuum valve must have understanding vacuum process to change from low vacuum to high vacuum state. The user of electron beam lithography are troubled with operation of manual vacuum valve, in case the vacuum chamber is frequently open. In this paper, the design and performance test of auto vacuum control valve for electron beam lithography are described. With the auto vacuum control valve, the high vacuum level can reach 2.8E-5 Torr.

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Vacuum Test of Cavity with Liquid Nitrogen

  • Choi, Suk;Park, Gunn-Tae;Kim, Heetae
    • Applied Science and Convergence Technology
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    • v.24 no.5
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    • pp.132-135
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    • 2015
  • Schematic of RAON vacuum system is introduced. Vacuum test for superconducting cavity with liquid nitrogen is performed. Schematic plan for RAON vacuum system is introduced and vacuum control system for superconducting cavity test is constructed. Vacuum pressure of cavity is shown as a function of pumping time. The temperature of cavity is shown as a function of cooling time. Outgassing species from cavity is also detected. Detailed experimental procedure is presented to test the cavity vacuum with liquid nitrogen.

Vacuum distribution with depth in vertical drains and soil during preloading

  • Khan, Abdul Qudoos;Mesri, G.
    • Geomechanics and Engineering
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    • v.6 no.4
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    • pp.377-389
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    • 2014
  • The vacuum consolidation method which was proposed by Kjellman in 1952 has been studied extensively and used successfully since early 1980 throughout the world, especially in East and Southeast Asia. Despite the increased successful use, different opinions still exist, especially in connection to distribution of vacuum with depth and time in vertical drains and in soil during preloading of soft ground. Porewater pressure measurements from actual cases of field vacuum and vacuum-fill preloading as well as laboratory studies have been examined. It is concluded that (a) a vacuum magnitude equal to that in the drainage blanket remains constant with depth and time within the vertical drains, (b) as expected, vacuum does not develop at the same rate within the soil at different depths; however, under ideal conditions vacuum is expected to become constant with depth in soil after the end of primary consolidation, and (c) there exists a possibility of internal leakage in vacuum intensity at some sublayers of a soft clay and silt deposit. A case history of vacuum loading with sufficient subsurface information is analyzed using the ILLICON procedure.

Simulation of Vacuum Characteristics in Semiconductor Processing Vacuum System by the Combination of Vacuum Pumps (진공펌프 조합에 의한 반도체공정 진공시스템 진공특성 전산모사)

  • Kim, Hyung-Taek;Kim, Dae-Yeon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.6
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    • pp.449-457
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    • 2011
  • Effect of pump combinations on the vacuum characteristics of vacuum system was simulated for optimum design of system. In this investigation, the feasibility of modelling mechanism for VacSimMulti simulator was proposed. Simulation results of various pumping combinations showed the possibilities and reliabilities of simulation for the performance of vacuum system in specific semiconductor processing. Simulation of roughing pump presented the expected pumping behaviors based on commercial specifications of employed pumps. Application of booster pump exhibited the high pumping efficiency for middle vacuum range. Combinations of optimum backing pump for diffusion and turbo vacuum system were obtained. And, the predictable characteristics of process application of both simulated systems were also acquired.

Development of Dry-Vacuum-Pump for Semiconductor/Display Process (반도체/디스플레이 공정급 건식진공펌프 개발 개요)

  • Lee, S.Y.;Noh, M.;Kim, B.O.;Lee, A.S.
    • Journal of the Korean Vacuum Society
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    • v.19 no.4
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    • pp.265-274
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    • 2010
  • The excellent performance and stability of dry-vacuum-pump is essential to create and maintain high quality vacuum condition in semiconductor and display process. The development of dry-vacuum-pump needs systematic consideration for target application as well as delicate mechanical issues. Here, we introduce a development procedures of dry-vacuum-pump for semiconductor-process-class.

Simulation of Conductance Effects on Vacuum Characteristics of High Vacuum System for Semiconductor Processing (반도체공정 고진공시스템 진공특성에 대한 배기도관 컨덕턴스 영향 전산모사)

  • Kim, Hyung-Taek;Seo, Man-Jae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.4
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    • pp.287-292
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    • 2010
  • Effect of conductance factors on performance of vacuum system was simulated for optimum design of vacuum system. In this investigation, the feasibility of modeling mechanism for VacSim$^{Multi}$ simulator was proposed. Application specific design of vacuum system is required to meet the particular process conditions for various industrial implementations of vacuum equipments. Geometry and length, diameter of exhaust pipeline were modeled as simulation modeling variables for conductance effects. Series vacuum system was modeled and simulated with varied dimensions and structures of exhaust pipeline. Variation of pipeline diameter showed the more significant effects on vacuum characteristics than that of pipeline length variations. It was also observed that the aperture structure of pipeline had the superior vacuum characteristics among the modeled systems.