| 摘要 |
An exposing method in which the gas present at least along a part of the optical path of an exposing beam can be stably replaced with a gas through which the exposing beam is transmitted at low operating cost. The gas in a gas-tight unit (8) enclosing a beam matching unit, an illuminating optical system, a reticle stage system, a projection optical system, or a wafer stage system of an exposing apparatus is replaced with a low-absorption gas (GA, GB) through which the exposing beam is transmitted by a gas replacing unit (S). After a predetermined repetition of a step of reducing the pressure of the gas in the gas-tight unit (8) to a first pressure lower than the atmospheric pressure by using a gas evacuating device (7) and a step of supplying the low-absorption gas (GA, GB) in to the gas-tight unit (8) to a pressure between the first pressure and the atmospheric pressure, the low-absorption gas (GA, GB) is supplied into the gas-tight unit (8) to nearly the atmospheric pressure. |
