• 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.

Simulations of the Performance Factors on Vacuum System

  • Kim, Hyung-Taek
    • International journal of advanced smart convergence
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    • v.6 no.4
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    • pp.1-8
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    • 2017
  • In this work, the effects of fairly influential factors on performance of vacuum system, such as constant pressure and outgassing effect were simulated to propose the optimum design factors. Outgassing effects of selected vacuum materials on the vacuum characteristics were simulated by the $VacSim^{Multi}$ simulation tool. This investigation examined the feasibility of reliably simulating the outgassing characteristics of common vacuum chamber materials (aluminum, copper, stainless steel, nickel plated steel, Viton A). The optimum design factors for vacuum systems were suggested based on the simulation results. And, the effects of throttle valve applications on vacuum characteristics were also simulated to obtain the optimum design model of variable conductance on high vacuum system. Simulated vacuum characteristics of the proposed modelling were agreed with the observed experimental behaviour of real systems. Pressure limit valve and normally on-off control valve were schematized as the modelling of throttle valve for the constant process-pressure. Simulation results were plotted as pump-down curve of chamber and variable conductance of throttle valve. Simulated behaviors showed the applications of throttle valve sustained the process-pressure constantly, stably, and reliably.

Development of a Housing Component for an Auto-compressor Using Vacuum Ladling Die Casting (진공급탕식 다이캐스팅법을 이용한 자동차 콤프레서용 하우징 부품 개발)

  • Lee, H.S.;Park, J.S.
    • Transactions of Materials Processing
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    • v.21 no.3
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    • pp.195-201
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    • 2012
  • A vacuum ladling die casting system is suggested as a means to obtain a high vacuum level. A high vacuum of 17.8 mmHg is obtained by sealing the inner space of the mould. The sample product is a rear-head housing for an auto-compressor, and the die-casting with 6-cavities was conducted. The flow analysis shows that the filling speed during vacuum ladling is faster than for a non-vacuum system. The air holes in the sample product were too small to be seen with the naked eye in X-ray films. Density tests show that the high vacuum ladling system reduces the internal porosity as much as 57.8% when compared to the non-vacuum system. A defective rate of only 0.17% was found from leak testing. The results of this research prove that the high vacuum die-casting process is useful for manufacturing of aluminium components under high internal pressure.

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 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.

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.