| 摘要 |
PURPOSE:To enable the yield of detection signals for alignment patterns of high contrast suitable for detecting the positions of alignment patterns,m by a method wherein a space filter is provided between an image of alignment pattern and a detecting element at a position unrelated to image formation with the alignment pattern. CONSTITUTION:A position 8 of Fourier transformation of an image of alignment pattern or a position 9 of image formation of the incidence iris 4 of a reducing projection lens 3 is preferable as the position of inserting the space filter. However, providing this filter within approx. 30% of the distance of an object lens 6 between the object image can produce almost the same effect as in the above case. As the space filter, a material resulting from evaporation of a non- transparent film such as the Cr film onto a glass substrate can be used, or a material such as the liquid crystal that can be locally controlled in permeability from outside can be used. On the other hand, as the illuminating light used for detection, a wide range of base color light can be utilized, and e.g. g-light or a laser light of similar wavelength can be also used. |
