| 摘要 |
PURPOSE:To realize accurate automatic focusing without lowering the scanning speed at the time of exposure by the scanning exposing system and improve total tracking accuracy in the automatic focusing even when height of wafer surface is changed to a large extent. CONSTITUTION:Automatic focusing is performed to a wafer 5 via a Z leveling stage 4 based on a measuring region 25C in the exposing field 24 and focusing position measured in the pre-reading region 25D at the front side of the measuring direction. In this case, when an absolute value of the difference DELTAZ between the pre-read focusing position and focusing position of the focusing surface 39 exceeds the allowable value, height of wafer 5 is fixed to the preset height, neglecting the pre-read data. |
