| 摘要 |
In an alignment device, irradiation means irradiates two coherent beams, having a predetermined wavelength, to a first diffraction grating formed on a mask and a second diffraction grating formed on a photosensitive substrate via an object optical system in such a manner as to cross with each other at a predetermined angle on one of the first and second diffraction gratings. First light receiving means photoelectrically detects interference light of diffracted rays produced substantially in the same direction from the one diffraction grating. A third diffraction grating is disposed in a plane substantially conjugate to the one diffraction grating, and second light receiving means photoelectrically detects interference light of diffracted rays produced by the third diffraction grating from diffracted rays of the two beams which are diffracted by the other of the first and second diffraction gratings and impinged upon the third diffraction grating at a predetermined incident angle via the object optical system. Detection means compares respective signals from the first and second light receiving means to output a detection signal depending on a shift in relative position between the mask and the photosensitive substrate, and movement means moves the mask and the photosensitive substrate based on the detection signal for changing the relative position therebetween.
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