Patent ID: 7633597

Claim:
An exposure apparatus configured to illuminate a reticle with extreme ultraviolet light and expose a substrate to extreme ultraviolet light via the reticle in a vacuum, said exposure apparatus comprising: a projection optical system configured to project a pattern of the reticle onto the substrate with extreme ultraviolet light reflected at the reticle; a diaphragm that defines a first space that accommodates the projection optical system; a pump configured to exhaust the first space; a first gas supplier configured to supply an inert gas to the first space so as to maintain a pressure of the first space higher than a pressure of a second space outside the first space; and a first cooling unit configured to cool the inert gas so that the inert gas to be supplied to the first space has a first temperature, wherein the first temperature is previously determined based on a temperature rise amount of the inert gas supplied to first space from the first gas supplier, the first temperature being lower than a reference temperature at which a temperature of the first space is to be maintained.