Patent ID: 8536550

Claim:
A cleaning apparatus for cleaning collector mirrors in an EUV light generator in which a target is made into a plasma state and EUV light generated is collected and output by a collector mirror, the apparatus being applied to the EUV light generator for cleaning debris adhering to the collector mirror, the apparatus comprising: a first chamber within which plasma is generated, the collector mirrors which collect the EUV light radiated from the plasma, a second chamber arranged adjacent to the first chamber, a conveyor device which moves the collector mirror between the first chamber and the second chamber, a positioning mechanism which positions the collecting mirrors at an EUV light condensing position inside the first chamber, a gas supplying device which supplies a gas to the second chamber, a gas discharging device which discharges the gas out of the second chamber, a first gate valve provided between the first chamber and the second chamber, a second gate valve arranged at an EUV light outputting portion of the first chamber, and a controller connected to the first gate valve and the second gate valve, wherein: the controller is configured to close the first gate valve and open the second gate valve at least while the EUV light is being generated.