Patent ID: 9140993
Filing Date: 2015-09-22
Classification: G02B,G03F

Abstract:
1. An illumination optical apparatus which illuminates a mask having a pattern with illumination light, the apparatus comprising: a plurality of birefringent members arranged in an optical path of the illumination light on an incidence side of a pupil plane of the illumination optical apparatus along an optical axis of the illumination optical apparatus, which change a polarization direction of the illumination light, being incident on a first birefringent member of the plurality of birefringent members in a linearly polarized state, so that the polarization direction of the illumination light on the pupil plane is substantially coincident with a circumferential direction about the optical axis, the first birefringent member being arranged on an incidence side relative to the rest of the plurality of birefringent members, wherein the first birefringent member of the plurality of birefringent members has a fast axis of which direction is different from a direction of a fast axis of a second birefringent member, different from the first birefringent member, of the plurality of birefringent members.