Patent ID: 6898025

Claim:
A scanning type projection aligner that projects a pattern formed on a mask onto an image plane at substantially equi-magnification using a plurality of projection optical systems, said image plane being substantially parallel with the mask, the mask and the image plane being movable relative to said plurality of projection optical systems, systems, wherein each of said projection optical system comprises: a first condenser lens; a second condenser lens, said first and second condenser lenses having a first optical axis which is common between said first and second condenser lens and perpendicular to the pattern and the image plane; an imaging lens having a second optical axis that intersects with the first optical axis at an intermediate position between said first and second condenser lenses; a first mirror that reflects a beam emerged from said pattern and passed through said first condenser lens toward said imaging lens; a second mirror that is provided in the vicinity of a pupil of said imaging lens and reflects the beam passed through said imaging lens toward said imaging lens; and a third mirror that reflects the beam reciprocally passed through said imaging lens toward said second condenser lens, wherein said imaging lenses included in said plurality of projection optical systems are arranged such that the optical axes thereof are parallel with each other and aligned along a line perpendicular to the first optical axis and the second optical axis, wherein said first condenser lens, said second condenser lens, said first mirror, said second mirror and said third mirror included in one of said plurality of projection optical systems and those included in another one of said plurality of projection optical systems next to said one of said plurality of projection optical systems are arranged at opposite positions with respect to the imaging lenses included therein.