Patent Number: 053176154
Section: summary

FIELD OF THE INVENTION AND RELATED ART This invention relates to an exposure view-angle limiting means suitably usable, for example, in a step-and-repeat type exposure apparatus wherein a mask and a wafer are disposed close to or in contact with each other and wherein exposures are made to divided zones on the wafer sequentially. The manufacture of integrated circuits or semiconductor devices includes repetition of a process of optically transferring a pattern, formed on a mask, onto a wafer coated with a photosensitive material. Particularly, in consideration of the decreasing linewidth of the pattern, exposure apparatuses of the type using X-rays as an exposure light source are used. A practical example of such X-ray exposure apparatuses is a step-and-repeat type exposure apparatus wherein the surface of one wafer is divided into plural zones so as to reduce the size of the exposure region which is an area to be exposed at once, and wherein exposures are made to the zones of the wafer while sequentially moving the wafer relative to a mask. Such a step-and-repeat method is effective in a high-precision X-ray exposure apparatus. In this method, it is necessary to use some means for limiting the exposure region so as to prevent a neighboring portion of a wafer zone from being exposed. Also, around a circuit pattern region of a mask, usually there are provided alignment marks for effecting alignment between a circuit pattern of the mask with a circuit pattern already formed on a wafer, and the exposure apparatus is equipped with detecting means for detecting any positional deviation of such alignment marks. In order to prevent exposure of these alignment marks, preferably an aperture means for limiting the exposure region is provided to cover the alignment marks against the exposure illumination. SUMMARY OF THE INVENTION The present invention, in one aspect, pertains to an exposure apparatus of the type as described above, and it is an object of the present invention to provide a structure for controlling an X-ray exposure region very precisely when the same is to be limited, without blocking path of an optical system of a positional deviation detecting system and without exposing an alignment mark on a wafer. These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.