| 摘要 |
PROBLEM TO BE SOLVED: To provide a satisfactorily large aperture, while using fewest optical means possible in a projection object lens device which is proper for lithography having advantageously a short wavelength, a wavelength of 100 nm or less. SOLUTION: In a microlithography projection object lens for a short wavelength of 100 nm or less which has a first mirror (S1), a second mirror (S2), a third mirror (S3), a fourth mirror (S4) and a fifth mirror (S5), a mirror closest to an object to be exposed whose numerical aperture (NA) at an image side is larger than 0.10 has an optically free operation distance at an image side, which coincides with a diameter D of the mirror to be used and is arranged, so that the operation distance is the sum of one third of the diameter D of a mirror used and a length between 20 mm and 30 mm, and the operation clearance is at least 50 mm.
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