Patent ID: 8807914

Claim:
A method for operating a substrate processing apparatus comprising: a first chamber in which a stage device is provided and a substrate loaded on said stage device is processed; and a second chamber provided separately from said first chamber, a drive element for driving said stage device being provided in said second chamber, said first chamber being maintained in a vacuum, and a non-contacting seal device being provided between said first chamber and said second chamber, said second chamber being capable of being selectively connected to a supply source of dry gas, the non-contacting seal device being a differential vacuum seal device comprising a plurality of vacuum grooves being provided between said first chamber and said second chamber, wherein a gas feed line for feeding dry gas is connected to said seal device, wherein the degree of cleanliness of said first chamber and the degree of cleanliness of said second chamber are different, said first chamber having a high degree of cleanliness and said second chamber having a low degree of cleanliness, said gas feed line is connected to said seal device at a position between said second chamber and said vacuum groove located closest to said second chamber, and a non-contacting type guide element is provided at a position adjacent to the non-contacting seal device and on a side of the drive device, the method comprising: controlling a pressure in said second chamber to be equal to or approximate to atmospheric pressure by supplying and discharging the dry gas, and making, of said plurality of vacuum grooves of said differential vacuum seal device, the vacuum groove which is located closest to said first chamber have an internal pressure lower than or equal to a pressure in said first chamber, wherein when the non-contacting seal device stops operating, the respective control valves of an evacuation line and the dry gas feed line are closed, to thereby disconnect the second chamber from the evacuation line and the dry gas feed line.