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

Paper VST-TuM3
Effects of Surface Roughness of Blades on the Pumping Performance of a Turbomolecular Pump

Tuesday, October 30, 2001, 9:00 am, Room 125

Session: Turbomolecular, Molecular Drag and Similar Pumps
Presenter: T. Sawada, Akita University, Japan
Authors: M. Yabuki, Akita University, Japan
T. Sawada, Akita University, Japan
W. Sugiyama, Akita University, Japan
M. Watanabe, Osaka Vacuum Ltd., Japan
Correspondent: Click to Email
Turbomolecular pumps (TMPs) are widely used in the semiconductor and other thin film industries. Some semiconductor processes form corrosive gases such as HCl or HF as byproducts. The elements of a TMP are sometimes coated with ceramic (SiO @sub2@) film for the purpose of preventing corrosion on the TMP. The blades coated with SiO@sub2@ have relatively rough surfaces and may change the pumping performance. The effects of the surface roughness of the blades on the pumping performance were studied experimentally and theoretically. First, the maximum-compression ratio was measured for the non-coated TMP that had two rotor discs and one stator disc. Next, the pump that had been tested was disassembled and the elements were coated with SiO@sub2@. Then the maximum-compression ratio was measured for the reassembled-coated pump. The compression ratio attained by the coated pump was compared with the one attained by the non-coated pump. The effects of the surface roughness were also estimated by a two dimensional calculation. Both the experimental and calculated results show that the TMP coated with SiO@sub2@ film gives about a 13% higher maximum-compression ratio than that of the non-coated TMP when the blade speed ratio is 0.47.