| 摘要 |
PURPOSE:To align a reticle and a wafer with a high precision even if the reticle size is changed, by providing a rectangular aperture in a light source means and making the lengthwise direction of the rectangular aperture coincident with the direction in which the reticle-side focus of a reticle-side positive lens group can be moved on the reticle. CONSTITUTION:A rectangular aperture 70a formed with a slit-shaped rectangular diaphragm 70 provided in a light source part is so arranged that its lengthwise direction corresponds to the direction of movement of the focus position of the first positive lens group L10, namely, the radial direction of a reticle R; and when an object lens barrel 10 and a focus barrel 20 in an alignment system are moved in accordance with the change of the reticle size, a rectangular aperture image 70a' of the light source part is moved in the lengthwise direction to an entrance pupil IE on the entrance pupil plane of a projection object lens L50, and an entrance pupil image IE' of the projection object lens L50 is moved in the lengthwise direction of the rectangular aperture 70a on the rectangular aperture 70a on the aperture plane of the light source part. Therefore, the state where an alignment mark Wm on a wafer W is illuminated through the projection object lens L50 is hardly changed. |
