Polymeric tubes are used in the semiconductor manufacturing industry to provide mechanical flexibility and electrical insulation. Since polymeric tubing has higher permeation rate compared to metal tubing, it can easily become a source of contamination in ultrapure gas distribution and delivery systems. In this study, an Atmospheric Pressure Ionization Mass Spectrometer (APIMS) is used to determine the permeation coefficients for two widely used polymeric tubing, PFA and Kel-F (PCTFE), at 25°C and 75°C. In the experiments, an ultra-high purity N2 gas flow was maintained through the test tubing. The net impurity uptake by nitrogen due to the permeation of O2, CO2, H2O, and CH4 from surrounding air into the polymeric tubing was measured by APIMS with sub-ppb sensitivities. CH4 had the highest and 02 had the lowest permeation coefficients. Results showed that Kel-F was a superior barrier material for all impurities studied. The permeation coefficients for these polymers increased with temperature but did not change significantly with the permeant partial pressure. Permeability of PFA showed a stronger temperature dependence than that of Kel-F.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Industrial and Manufacturing Engineering
- Electrical and Electronic Engineering