VALVE

PROBLEM TO BE SOLVED: To provide a plasma processing device stable in sealability and high in reliability. SOLUTION: A vacuum processing device includes a vacuum container 509 the inside of which is pressure-reduced, an opening 1201 which is disposed in a wall of the vacuum container and through which the inside of the container communicates with the outside to give and take a sample to be processed, a valve 1001 disposed on the outer side of the wall to air-tightly close and open the opening 1201, a seal member 1002 disposed on the valve on a side which is in contact with the wall around the opening and coming into contact with the wall and the valve 1001 to seal the inside of the opening in a state that the valve closes the opening 120, a first protruded part having a protruded curved surface which is in contact with the wall constituting the seal member and an overhanging part extending from the protruded part to engage with the valve 1001 to be attached into the valve, and a cover 1003 attached to the valve on a side in contact with the wall and pressing at least a portion of the overhanging part against the valve to position it. COPYRIGHT: (C)2010,JPO&INPIT