IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Vacuum Science & Technology Monday Sessions
       Session VST-MoP

Paper VST-MoP14
Surface Cleaning on Aluminum for Ultra-high Vacuum using Supercritical Fluid CO@sub 2@ with O@sub 2@

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Developments in Vacuum Technology Poster Session
Presenter: T. Momose, Miyagi National College of Technology, Japan
Authors: T. Momose, Miyagi National College of Technology, Japan
H. Iki, Miyagi National College of Technology, Japan
Correspondent: Click to Email
Contamination on metals used in ultra-high vacuum equipments causes the degradation of function of the equipments. Therefore, cleaning of metal surface is necessary. Supercritical fluid (SCF) carbon dioxide (CO@sub2@) with high solubility for organic compounds was employed for the cleaning.@footnote 1@ However, the cleaning rate using SCFCO@sub2@ alone was low.@footnote 2@ Therefore, oxygen gas (O@sub2@) was added to SCFCO@sub2@. Aluminum (Al) sample is @phi@5 x t1 mm. Sample was analyzed using x-ray photoelectron spectroscopy (XPS). It is defined that carbon (C) 1s peak in XPS spectra represents contamination. It is also defined that contamination rate is the ratio of area of C1s peak and summation of the area of C1s, O1s, and Al2p peaks. The cleaning rate at 55 °C for 30 minute cleaning was 2 % at 25 mega-Pascal (MPa) in SCFCO@sub2@ without O@sub2@, and 25 % at 20-30 MPa in SCFCO@sub2@ with O@sub2@ of 1.5 MPa. The addition of O@sub2@ is effective on the cleaning using SCFCO@sub2@. Cleaning at the constant ratio of O@sub2@ in SCFCO@sub2@ showed that cleaning rate is approximately proportional to the oxygen molecule number. @FootnoteText@@footnote 1@ H. Mishina, and T. Momose, et.al., J. Vacuum Soc. Japan, 43,No3, 2000, 341. @footnote 2@ T.Momose et.al, JVST, A17(4), Jul/Aug, 1999, 1391.