OPTICAL MEMBER, INTERFEROMETER SYSTEM, STAGE APPARATUS, EXPOSURE APPARATUS AND DEVICE MANUFACTURING METHOD

摘要

An optical member is irradiated with light for measuring positional information relating to a first direction. The optical member is provided with a first reflection surface where light traveling in a second direction intersecting the first direction enters, and a second reflection surface where light traveling in the second direction enters. The first reflection surface and the second reflection surface are optically connected, and light reflected by one of the first reflection surface and the second reflection surface enters the other reflection surface.