| 摘要 |
PURPOSE:To obtain good alignment accuracy with a high contrast marking image realized and obtain high projection resolution by appropriately setting either the number of openings on a lighting system mark side or those on an observation system mark side according to difference in mark levels. CONSTITUTION:A lighting system 101 makes a beam emitted from a fiber 1 incident to an alignment mark on a reticle 8 surface and illuminates a mark on a wafer 12 surface with the passed beam while an observation system 102 leads a reflected beam from a mark and its vicinity onto an image picking element 16 to permit both mark images to be observed. An iris aperture 6 which is variable in an opening size is placed on an iris of an objective lens 7 of the observation system 102, while an iris aperture 2 which is variable in an opening size is placed on an iris surface of a condenser lens 103 of the lighting system 101 so that the degree of coherence of the lighting system is made variable or one of the openings is changed in size. With respective images of alignment marks on the reticle 8 and the wafer 12 picked, a mutual positional relation is detected whereby alignment exposure according to the detection result is performed. |
