Patent ID: 8052376

Claim:
A turbo-molecular pump configured to discharge a deposition-causing gas from a processing chamber for performing processing on a substrate, said turbo-molecular pump comprising: a rotor having a rotor shaft aligned with an exhaust stream; a cylindrical casing housing said rotor therein; a plurality of blade-form rotor blades projecting from said rotor orthogonally with respect to the rotor shaft, said plurality of rotor blades being divided into a plurality of rotor blade groups; a plurality of blade-form stator blades projecting orthogonally with respect to the rotor shaft from a rotor-facing surface in said cylindrical casing, said plurality of stator blades being divided into a plurality of stator blade groups; and a gas supply port included in said rotor, the gas supply port being located on an upstream side of the rotor blade group that is located furthest downstream in the exhaust stream, wherein the rotor blade groups and the stator blade groups are disposed alternately along the rotor shaft, and wherein said gas supply port supplies a deposition-suppressing gas which includes gas molecules having a molecular weight not less than an atomic weight of argon.