Patent ID: 7619748

Claim:
An exposure apparatus for exposing a pattern of a mask onto an object using light from a light source, said exposure apparatus comprising: a projection optical system configured to project the pattern of the mask onto the object; and a measuring apparatus configured to measure optical performance of said projection optical system, wherein said measuring apparatus is a line diffraction interferometer that uses a transparent substrate, wherein said measuring apparatus includes: an illumination optical system; a second measurement mask having a pair of a 0° orienting slit and a window, and a pair of a 90° orienting slit and a window; and an image pickup device, wherein the transparent substrate includes: a first measurement mask having a pair of a 0° orienting slit and a window, and a pair of a 90° orienting slit and a window; and a light splitter for splitting light, wherein the light splitter is formed at one side of the transparent substrate and the first measurement mask is formed at the other side of the transparent substrate, so that the light splitter is arranged on the transparent substrate on the side of the illumination optical system and the first measurement mask is arranged on the transparent substrate on the side of said projection optical system, wherein said measuring apparatus is arranged such that the split light from the light splitter is directed to the first measurement mask, the light passed by the first measurement mask is imaged on the second measurement mask by said projection optical system, the light that pass the second measurement mask interfere with each other, and the image pickup device observes the interference fringe, and wherein the light splitter includes a first diffraction grating that has lines arranged in a 0° direction and a second diffraction grating that has lines arranged in a 90° direction, and is arranged so that lights split by the first diffraction grating is introduced to the pair of the 0° orienting slit and the window in the first measurement mask and so that light split by the second diffraction grating is introduced to the 90° orienting slit and the window in the first measurement mask.