Abstract: A throttle valve connects with a chamber for adjusting air pressure in the chamber. The throttle valve has a housing having a channel in it, a piston ring positioned at an end of the channel, a stopper positioned in the channel, and a driver for rotating the stopper. The piston ring has a plane surface contacting with the housing, a first cambered surface contacting with the housing and vertically connecting with the plane surface, and a second cambered surface connecting with the first cambered surface. The second cambered surface of the piston ring contacts with a third cambered surface of the stopper.

Abstract: A lift pin mechanism is applied to a process chamber for carrying a substrate and moving the substrate upward or downward. The mechanism includes a plurality of lift pins positioned in a plurality of through holes of a pedestal and a lift ring positioned below the lift pins. The lift pins are fixed on the lift ring perpendicularly and are smaller than the through holes so that the lift pins can move upward or downward in the through holes.

Abstract: A throttle valve connects with a chamber for adjusting air pressure in the chamber. The throttle valve has a housing having a channel in it, a piston ring positioned at an end of the channel, a stopper positioned in the channel, and a driver for rotating the stopper. The piston ring has a plane surface contacting with the housing, a first cambered surface contacting with the housing and vertically connecting with the plane surface, and a second cambered surface connecting with the first cambered surface. The second cambered surface of the piston ring contacts with a third cambered surface of the stopper.