Patent Number: 
Section: abstract

X-ray projection-exposure apparatus are disclosed that achieve a higher accuracy of pattern overlay than conventionally. An embodiment of such an apparatus includes an X-ray source, an illumination-optical system for irradiating an X-ray beam from the X-ray source onto a mask defining a pattern, a mask stage for holding the mask, a projection-optical system for directing the patterned beam from the mask to project an image of the pattern onto a resist-coated wafer, a wafer stage for holding the wafer, and a mark-position-detection system for detecting the position of a mark formed on the wafer. The center of an exposure-image field of the projection-optical system is located at a position displaced from the center axis of the projection-optical system, and the center axis of the mark-position-detection system is located laterally adjacent the exposure-image field with respect to the center axis of the projection-optical system.