COMPOSITE MULTISTAGE DRY VACUUM PUMP HAVING ROOTS ROTORS AND SCREW ROTOR

摘要

mainly caused Semiconductor manufacturing equipment in the process chamber or the process chamber for evacuation gaseous as the materials and / or dry vacuum pump for discharging the process by-product to the outside, so the number of roots-type rotors are required decreases and the screw-type rotor and a roots-type dry vacuum pump having an improved structure that eliminates the need for a partition wall between the rotor is disclosed. The dry vacuum pump is provided with a space capable of remaining substance may be sucked in any one of the roots of the lower rotor, and the other one of the roots of the lower rotor, screw-type connection of the Roots-type rotor and the lower portion of the rotor The substance to which suction can be provided with the remaining space, the upper part of the space and the Roots type rotor provided in the lower portion of the Roots-type rotor includes a structure that is in communication with a predetermined fluid passage.