Pumping of corrosive or hazardous gases with turbomolecular and oil-filled rotary vane backing pumps

Abstract

Since at high-vacuum pressure the gas density is low, no real problems occur while pumping, e.g., corrosive or even explosive media by means of turbomolecular pumps. New problems arise from pumping radioactive gases like tritium. Here the turbomolecular pumps have to be adapted to the fact that the leakage from the pump’s interior to the ambient has to be kept as low as possible. Backing pumps have to pump higher gas densities. Some corrosive or hazardous gases can be pumped with standard pumps using special pump fluids. Many other applications, however, require protective measures to guarantee acceptable lifetimes of the vacuum equipment. The paper describes the necessary pumps and accessories to meet the requirements of safely pumping vapors and gases in the processes of plasma etching, plasma deposition, low pressure CVD, and explosive gas mixtures.