Characterization of a Newly Designed Vacuum Valve Having a Variable Conductance Function
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ORIGINAL PAPER
Characterization of a Newly Designed Vacuum Valve Having a Variable Conductance Function H. W. Song*
and S. Y. Woo
Center for Mass and Related Quantities, Division of Physical Metrology, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong Gu, Daejeon 34113, Republic of Korea Received: 09 September 2019 / Accepted: 10 August 2020 Ó Metrology Society of India 2020
Abstract: A valve has a function of controlling the flow of a fluid by opening or closing a passage. A valve can thus be used to create different pressures for the two areas on either side of the valve. However, the conventional vacuum valve has a problem that the flow rate of the gas cannot be controlled. In this light, it is necessary to develop a vacuum valve that is capable of precisely controlling the flow rate of the gas without leakage of the gas. Recently, we developed a variable conductance vacuum valve to control the inlet pressure for the vacuum chamber. The variable conductance valve developed in this study uses a similar iris structure to that of conventional control valves employed in normal water and sewage pipes, but the valve has no outer mounting hole or fastening holes for coupling the driving parts because the iris structure is changed in a non-contact manner by a magnetic field. Therefore, the valve in this study has the advantage that the fluid leakage of the valve can be completely blocked without a separate device such as packing or sealing components or an O-ring, and therefore, the internal vacuum state can be maintained. The fabricated valve showed a relative repeatability error within 0.5% and a relative reproducibility error within 5%. These results demonstrate that the conductance variable valve developed in this study is suitable for easily changing the pressure inside a vacuum chamber by adjusting the conductance. Keywords: Variable; Conductance; Valve; Iris; Magnetic 1. Introduction Manufacturing a semiconductor device requires high precision, a high degree of cleanliness, and a special manufacturing technique. For this reason, the semiconductor devices are manufactured in a state in which contact with foreign substances contained in the air is completely blocked, that is, in a vacuum state, thereby making it possible to produce a product with high reliability and a high degree of completion. A valve has a function of controlling the flow of a fluid by opening or closing a passage. A valve can thus be used to create different pressures for the two areas on either side of the valve [1, 2]. For example, when a vacuum valve installed between a vacuum chamber and a suction pump is used to discharge gas in the vacuum chamber to the outside, the vacuum valve is opened. On the other hand, when it is necessary to maintain a vacuum state inside the
*Corresponding author, E-mail: [email protected]
vacuum chamber, the vacuum valve should be closed to maintain the vacuum chamber state. However, the conventional vacuum valve has a problem that the flow rate of the gas cannot be freely contro
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