| 摘要 |
<p>PURPOSE:To obtain high resolution by providing a reducing optical system with a schwerzshild's optical system having a concave mirror having an opening on the central part and a convex mirror arranged opposite to the opening, and placing an object to be exposed inside the opening of the concave mirror. CONSTITUTION:The reducing optical system is provided with the schwerzshild's optical system having the concave mirror M1 having the opening on the central part and the convex mirror M2 arranged opposite to the opening, and simultaneously, the object to be exposed (mask) is placed inside the opening of the concave mirror M1. In other words, a curved mask buries the central opening of the concave mirror M1, so that the peak position of the concave mirror M1 is accurately and easily obtained. On the other hand, the mask is curved, so that the correction of the curvature of an image surface is easily carried out, and the load of the correction of aberration with respect to an optical system is reduced. Thus, the high resolution can be obtained.</p> |
