| 摘要 |
PURPOSE:To improve S/N by a method wherein laser lights having different wavelengths are used as projection laser lights and diffracted lights having the wavelengths corresponding thereto are detected in the alignment for which a mask provided with Fresnel zone plates (LFZP), a diffraction grating, etc. are employed. CONSTITUTION:A projection laser light is diffracted by LFZP 3 provided in a plurality, e.g. three, in a mask, and is condensed into a slender base-line light. This light is diffracted by a diffraction grating 5 of a substrate 4 to be processed, and a diffracted light thus obtained is received and detected for alignment of the mask with the substrate 4. Laser lights having different wavelengths are used as this laser light, and diffracted lights obtained from the laser lights and having wavelengths corresponding thereto are received and detected by a photodetector provided with a filter. Then the lowering of S/N due to the incidence of scattered lights from the mask and the substrate 4 can be prevented, and thus the excellent alignment with high S/N is conducted. |
