| 摘要 |
PROBLEM TO BE SOLVED: To elevate the accuracy in alignment of a wafer by continuously detecting the quantity of dislocation in the scanning direction of a primary deflection grating on a reticle and the secondary deflection grating in a chip region. SOLUTION: A one-dimensional diffraction grating 3 on a reticle is irradiated with alignment beams 1a and 1b, and the primary beam of the diffraction grating which has passed this and has the, positional information in X direction of the reticle is condensed in the two-dimensional diffraction grating 11 on a chip region 10 through a projective lens 7. The reflected diffracted light which is reflected from the grating 11 and has the positional information in X direction of a chip is entered into a light receiving element 5 through a projective lens 7 and a reflective mirror 6, and it is converted into an electric signal so as to adjust the position of the wafer. Since the beam of different wavelength from an exposure beam is usually used as an alignment beam so that the alignment beams 1a and 1b may not expose photoresist, the image pickup relation between the reticle and the wafer differs between the alignment beam and the exposure beam, and color aberration arises. To compensate it, a color aberration compensating mechanism 4 using, for example, a lens or a prism is used. |
