| 摘要 |
PURPOSE:To easily measure the optical characteristics of an image forming optical system, by performing operation treatment on the basis of the positional information of the mark projection image of a mask provided with a plurality of marks and the positional information of the mark on the mask. CONSTITUTION:Light emitted from an illumination light source 1 irradiates reticle 5 through condenser lenses 2, 3 and light permeated through light pervious marks M11-M66 are converted to converged light flux l2 by a projection lens 6 to form an image on a fine opening 8. The lights passing slit openings 8a, 8b crossing at right angles to each other are detected by a photoelectric detector 9. A stage 7 is two-dimensionally moved to directions x, y along with a wafer 10 and the position thereof is calculated through a laser interferometer 13 and the reflective mirror 14 fixed to the stage 7 and the position of the projection image of a cross mark Mij in the directions x, y is detected. From this data and the preliminarily measured position data of the mark on the reticle 5, the optical characteristics of an image forming optical system are calculated. |
