| 摘要 |
PURPOSE:To shunt and reload quickly an objective lens by a simple constitution, and also to raise reliability of a device, by installing two objective lenses on two upper tables, and constituting so that two lower tables are approached and separated in the direction opposite direction by one screw lever. CONSTITUTION:When a screw lever 26 having a left screw part 26l and a right screw part 26r is rotated by a motor 27, two lower tables are approached and separated in the direction X through an arm 24a. Following said operation, a cam follower 21 is guided by a fixed circular arc-like cam 22, therefore, two upper tables 20 slide in the direction Y, and an objective lens 13 sticking to the upper cable 20 moves along the circular arc. Accodingly, a target mark provided on a prescribed circular arc on the surface of a wafer 12 is caught quickly. When the mark matching ends, a winding drum 31 is rotated, the objective lens is shunted from an exposure area, and can be reloaded to a correct position by a spring 23, therefore, the objective lens 13 can be moved repeatedly in accordance with a desired locus. |
