| 摘要 |
PURPOSE:To improve resolution by simple constitution by providing a pattern magnifying optical system with a flat-shaped objective having a high numerical aperture only in the direction perpendicular to the optical axes of reflection by the surfaces of the mask of illumination light and a wafer and parallel with the surfaces of the mask and the wafer. CONSTITUTION:A magnified image is formed by a flat objective 9 being arranged on the optical axes of regular reflection by the surfaces of the mask 4 of white light condensed by a lens 3 and a wafer 5, having a high numerical aperture only in the direction perpendicular to the optical axes and parallel with these surfaces and magnifying the images of a mask alignment mark 6 and a wafer alignment mark 7. Since these alignment marks 6, 7 are disposed on the same focal surface by the objective 9 from the oblique direction the images of these alignment marks 6, 7 can be observed simultaneously even when the objective 9 having the high numerical aperture and shallow focal depth is used. Since the objective 9 has a large numerical aperture regarding the direction of the detection of positional displacement, the objective 9 has high resolution, and has low resolution in the direction at a right angle to said direction, thus optically levelling picture data by a TV camera 11. |
