Projection optical system and exposure apparatus having the projection optical system
US6633365B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 10, 2001 |
| Grant date | Oct 14, 2003 |
| Priority date | — |
| Expiry date | Dec 10, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70341
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection optical system according to the present invention whose image side numerical aperture is greater than or equal to 0.75, and which forms an image of a first object upon a second object using light of a predetermined wavelength less than or equal to 300 nm, comprises: a first lens group G1 of positive refractive power; a second lens group G2 of negative refractive power; a third lens group G3 of positive refractive power; and a fourth lens group G4 of positive refractive power, and: the first lens group G1, the second lens group G2, the third lens group G3 and the fourth lens group G4 are arranged in order from a side of the first object; and a distance D in mm along an optical axis between an optical surface of the fourth lens group G4 closest to the second object, and the second object, satisfies a condition of 0.1<D<5.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.