| 摘要 |
PURPOSE:To make alignment with a high accuracy by a method wherein a wafer signal detecting system is arranged between a projection lens and a wafer to detect any surface reflected light from the wafer surface and any diffractedlight outside a multiple reflection angle. CONSTITUTION:Within a wafer detecting system, the slope angle D of resist is 5 deg., the angle B of surface reflected light 18 is 10 deg. assuming the luminous flux expanding angle of illumination light 17 as A while the multiple reflected light 19, if reflected on a substrate twice, is around 25 deg.. When said light 19 is reflected two times on more times, the angle E to detect an edge diffraction 20 of an alignment mark 6 is specified to be E>=C + A since the reflection intensity is actually very low. Through these procedures, both the illumination reflected light on the resist surface and the multiple reflected light do not enter into a wafer signal detection system. On the other hand, a reticle signal detec tion system scans a reticle mark 15 on the reticle 1 by scanning the beams of a light source g using a rotary polyhedral mirror 8 to detect any reflected light from the mark 15 by a detecting element 10. Thus, the beams transmitting the reticle 1 illuminate the wafer mark 6 through the intermediary of a projec tion system. |
