| 摘要 |
PURPOSE:To contrive improvement in alignment accuracy by a method wherein an independent alignment optical system is provided at an adjacent and the nearest position of a projection optical system. CONSTITUTION:Four alignment optical system 4A are provided at an adjacent and the nearest position to a projection optical system 3. The laser beam sent from a light detector 6A containing a light source is formed into a plurality of luminous flux by reflection mirror 6A, and they pass the alignment marks 2a of a mask 2 respectively, reach the optical system 4A, pass reflection mirror 7B while the laser beam is focussed thereon, and are projected on the target 1a of a wafer 1. This reflected light passes the reverse optical path, detected by a detector 6A, a stage 5 is shifted based on the detected data, and the wafer 1 is positioned. As the optical system 4A for long wavelength light to be used for alignment is projected, the relative position of the mark and the target can be detected in a highly precise manner. As an optical axis is provided in such a manner that is perpendiculary faces the target 1a provided out side the pattern exposure region, the alignment position in a state as it is can be used as a position of exposure. |
