Patent ID: 6954009

Claim:
A positioning apparatus, comprising: a process chamber exposed under reduced pressure; a first casing having a first guide face that has a first opening communicating with inside of the process chamber; a moving block movable in at least one direction and opposed to said first guide face through a predetermined gap; a second casing including: a second guide face being on the other side of the moving block via the moving block, and guiding in a state that the second guide face is opposed to the moving block through a predetermined gap; and a decompression chamber whose internal pressure is lower than a pressure of an outside of the process chamber; a first differential pumping seal including a plurality of stages, provided between the first casing and the moving block to surround the first opening and sealing between an inside of the process chamber and an outside of said process chamber, wherein a pressure of the outside of the process chamber is higher than that of the inside of the process chamber; and a seal mechanism for maintaining an inside of the decompression chamber at a pressure that is lower than that of an outside of the decompression chamber, wherein a stage of the first differential pumping seal, which is most far from said process chamber, and the inside of the decompression chamber are connected to a same exhaust source.