Patent ID: 8164754

Claim:
An immersion exposure apparatus configured to expose a substrate via liquid between a projection optical system and the substrate, the immersion exposure apparatus comprising: an optical element constituting a part of the projection optical system; a reflective member configured to reflect light to the projection optical system; a water repellent member in which one or more openings are formed; a light intensity detecting unit configured to detect a light intensity of a first light and a second light; and an arithmetic processing unit configured to calculate a reflectance of the optical element based on the light intensity of the first light and the second light, wherein the first light is light which enters the projection optical system, passes through one of the one or more openings of the water repellent member to be reflected by the reflective member, is reflected on a surface of the optical element, and passes through one of the one or more openings to be received by the light intensity detecting unit, and wherein the second light is light which enters the projection optical system and passes through one of the one or more openings of the water repellent member to be received by the light intensity detecting unit without being reflected on the reflective member and the surface of the optical element.