Patent ID: 8760618
Filing Date: 2014-06-24
Classification: G02B,G03B,G03F

Abstract:
1. A projection optical system for projecting a pattern of a mask onto a substrate, the projection optical system comprising: a pair of optical elements that includes a first optical element having a first aspheric surface and a second optical element having a second aspheric surface, wherein the first aspheric surface and the second aspheric surface have a complementary relationship with each other and are arranged facing each other, wherein the first aspheric surface and the second aspheric surface are curved in a first direction and a second direction orthogonal to the first direction, wherein the first direction and the second direction each are orthogonal to an optical axis of the projection optical system, wherein a first distortion of the projection optical system generated by changing a relative position between the first aspheric surface and the second aspheric surface in the first direction is a different type from a second distortion of the projection optical system generated by changing a relative position between the first aspheric surface and the second aspheric surface in the second direction, and wherein the first distortion of the projection optical system is anisotropic between the first direction and the second direction.