| 摘要 |
PURPOSE:To make a light flux incident on a measuring region in such a way that reflection conditions form the measuring region are individually nearly equal and to position a wafer at high speed by a method wherein one measuring region out of a plurality of measuring regions on the face of a second object is irradiated, from the oblique direction, with the light flux from a light source and a change in the light path of a reflected light flux from the measuring region is detected. CONSTITUTION:An opening shape 14a in a field disphragm 14 used to irradiate a wafer 5 is set in such a way that it is situated as a measuring region IF inside a scribing line SL when an alignment mark AM is moved to the observation position of an alignment scope 1. When the opening shape 14a in the irradiating field diaphragmg 14 is set in this manner, conditions such as the pattern shape of an irradiation position and the like can be kept nearly the same when the wafer is aligned by driving an X-Y stage 6a and by detecting an alignment mark for another shot. That is to say, reflection conditions from a plurality of measuring regions on the face of the wafer 5 become individually nearly equal. Thereby, a focus can be detected at high speed. |
