Patent ID: 8724076

Claim:
A liquid immersion type projection exposure apparatus in which a space under an optical element is filled with a liquid, the liquid immersion type projection exposure apparatus comprising: a liquid supply system connected to a supply flow path, which supplies the liquid to the space via the supply flow path; a liquid recovery system connected into a recovery flow path, which removes the liquid from the space to the recovery flow path; and a cleaning system which performs a cleaning operation, the cleaning system having a flow meter which ascertains a liquid supply flow volume per unit time and a controller which controls the liquid supply system and the liquid recovery system such that (i) the liquid supply flow volume per unit time fluctuates, and (ii) the liquid in the space under the optical element covers only a portion of a surface of an object located under the optical element by supplying the liquid to the space via the liquid supply path and recovering the liquid from the space into the recovery flow path.