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IndiaRubberDirectory.com > Rubber Engineering > Elastromer Properties |
Vacuum Seal
Performance
In the semiconductor industry, many of the
process steps are performed in a vacuum environment. Vacuum environments, even
at levels of 10–9 Torr, often do not result in extrusion. The unique environment
demands elastomer materials that have very low gas permeability and outgassing
rates. The table shown lists a range of permeation rates for several types of
elastomers.
Gas release from vacuum components, referred to
as outgassing, is a combination of volume, surface desorption, diffusion and
permeation sources. The chart shown below is a generalized pump-down curve
illustrating the contribution of these various sources in a high-vacuum system.
Analysis of outgassing components may be
performed using a Residual Gas Analyzer (RGA). The mass spectra obtained during
heating of AEGIS perfluoroelastomer is shown in the chart below. Water vapor
(H2O), carbon monoxide (CO), and carbon dioxide (CO2) are released as the
elastomer is heated. The decomposition temperature for fluoroelastomers is about
300°C. The decomposition temperature for AEGIS perfluoroelastomer is above
350°C.
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