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    • CommentAuthorqzz10011
    • CommentTimeNov 21st 2017

    In some engineering applications, in addition to the total outgassing rate of vacuum materials, it is also necessary to know the outgassing fraction of a single gas released. In this paper, by using constant volume boosting method of three kinds of polymer samples were tested and the outgassing rate of outgassing components analysis; the discharge of quadrupole mass spectrometer and vacuum gauge calibration compared to modify the measured partial pressure, get gas water and hydrocarbon fraction change with time; put on the basis of the diffusion type model, curve fitting of the measured the data obtained, deflation has practical significance and time expression rate index. Any solid material can dissolve and adsorb some gases in the atmospheric environment. When the material is placed in the vacuum, it will be dissolved and desorbed and deflated. The study of outgassing characteristics of vacuum materials has wide application value in aerospace (satellite, spacecraft and space station) and semiconductor lithography.

    In view of the outgassing characteristics of vacuum materials, a lot of research work has been carried out at home and abroad, but more emphasis has been placed on the improvement of test methods and the test of total outgassing rate. In the field of semiconductor lithography, in addition to the vacuum material total outgassing rate, more concerned about deflation a single or a type of gas component pressure, such as water (H2O) and hydrocarbons (CXHY), because these gases will seriously pollute the optical system, thus affecting the performance of lithography.

    In 1995, the University of Germany adopted the orifice conductance method, using the mass spectrometer of two symmetry structure, ignoring the gas molecules greater than 45 mass, measuring the outgassing rate of metal materials. In 2013, based on the small hole conductance method of Lanzhou Institute of Space Technology Physics, a method was proposed to measure the outgassing rate of a single material by using a quadrupole mass spectrometer to detect the partial pressure of a single gas at both ends of a hole. Based on constant volume boost method, the gas composition pressure of three kinds of polymers was measured accurately by quadrupole mass spectrometer and vacuum gauge, and the variation law of total outgassing rate and outgassing fraction with time was obtained. According to the diffusion deflation model, the curve fitting of the measured data is carried out, and the expressions of the total outgassing rate and the outgassing fraction and the time index alpha are obtained, which can be used to predict the long time outgassing characteristics of the polymer in the vacuum system and have good practical application value.

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