| 摘要 |
PURPOSE: To accurately detect the position of a reticle on which an alignment mark having low reflectivity is formed when the reticle is used by controlling a moving means so that a conjugate relation can be established between the high-reflectivity part of a reference reflecting surface and the alignment mark through a projecting optical system. CONSTITUTION: A reticle mark 9 is composed of a transmitting section and reflecting section and a reference surface 10 is composed of a high-reflectivity part 10a and low-reflectivity part 10b. Each part of the surface 10 is set in a conjugate relation with a reticle 1 through a projecting lens 3. When the reflectivity of the reflecting part of the mark 9 becomes lower, the reflecting part of the reflecting surface 10 is changed to the high-reflectivity part 10a from the low-reflectivity part 10b by moving a wafer stage 5. When the high- reflectivity part 10a is used as the reflecting surface, the leading and trailing edges of a peak waveform can be surely detected from the output waveform detected by means of a one-dimensional image sensor 25. |
