| 摘要 |
PURPOSE:To extend the focal depth of an optical system by providing a multiple image forming and exposure control means in a device which projects a mask pattern on a substrate and exposing the pattern at two or more image forming points on the same optical axis in the same position of the substrate. CONSTITUTION:A reticle 1 is projected and exposed on the substrate, which is arranged on an XY stage 3 and a Z stage 4, through a lens 2 of a projection optical system. Positions of stages 3 and 4 are detected by sensors 5 and 6 and are controlled by an XY control system 9 and a Z control system 10. By the control of a multiple image forming and exposure control system 11, the Z stage 4 is driven in the same position of the XY stage 3 to set two or more preliminarily designated image forming points on the same optical axis. Exposure is performed no respective positions of image forming points by an exposure shutter control system 8. Since two or more image forming points are set on the same optical axis to perform exposure, the effective focal depth is extended to cope with the increase of numerical aperture of the projection lens, the distortion of image surface, and the increase of ruggedness of the substrate surface. |
