Exposure apparatus and air-conditioning apparatus for use with exposure apparatus

Abstract

Air-conditioning is effected in a chamber of an exposure apparatus for transferring a pattern formed on a mask onto a photosensitized substrate by exposure. The chamber houses at least a part of the exposure apparatus. An impurity-removing filter is provided for removing gaseous impurities from a stream of ambient air being introduced into the chamber and/or from a gas stream recirculating in the chamber. A pair of impurity-concentration-measuring devices are disposed upstream and downstream, respectively, of the filter. End-of-life of the filter is determined based on measurements from the impurity-concentration-measuring devices. Introducing the ambient air into the chamber is stopped when the impurity-concentration-measuring device disposed upstream of the filter has indicated a gaseous impurity concentration above a predetermined level. The integrity of the airtightness of the chamber around a negative pressure area in the chamber is sensed. When a failure in airtightness is detected, the failure is indicated and/or the recirculation of a gas stream in the chamber is stopped to prevent the ambient air containing impurities from leaking into the chamber under the influence of the negative pressure. In the exposure apparatus, among others the photosensitized substrate and the illumination optical system are quite sensitive to impurities, so that dehumidified gas is supplied to the areas around them. An air-conditioning apparatus for effecting air-conditioning to the chamber is separated from the chamber, and an impurity-removing filter element is disposed in a gas supply duct in the air-conditioning apparatus.