| 摘要 |
PURPOSE:To enable to enter all picture images to be exposed into specified focal depth by a method wherein the surface shape of wafer is preliminarily detected before exposure to autofocus comforming to the surface shape. CONSTITUTION:A wafer chuck 7 with a wafer 6 preliminarily attracted thereto is arranged below a laser interferometer 1. The interferostripes are produced by an autofocus detecting mechanisms 3a and a laser interferometer 1 while the reference plane 33 of surface 30 is decided so that the surface 30 may enter into the specified focal depth of a projection optical system 9 in terms of the calculated results of wafer surface 30 shape by an inteferostripe processor 4 and the wafer chuck focus reference plane 31 as well as the measured results of surface shape of wafer 6. Finally the excellent resolving power of projection optical system 9 may be displayed by means of focussing the reference plane on the specified focal plane of projection optical system 9 by controlling an autofocus driving mechanism 8b conforming to the output from an autofocus driving control mechanism 5 memorizing the relation between the measured results of reference plane 31 and the reference planes 33, 31 of wafer surface 30. |
