Illumination system particularly for microlithography
US7186983B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 2004 |
| Grant date | Mar 6, 2007 |
| Priority date | — |
| Expiry date | Aug 17, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG21K2201/061
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
There is provided a projection objective for a projection exposure apparatus that has a primary light source for emitting electromagnetic radiation having a chief ray with a wavelength ≦193 nm. The projection objective includes an object plane, a first mirror, a second mirror, a third mirror, a fourth mirror; and an image plane. The object plane, the first mirror, the second mirror, the third mirror, the fourth mirror and the image plane are arranged in a centered arrangement around a common optical axis. The first mirror, the second mirror, the third mirror, and the fourth mirror are situated between the object plane and the image plane. The chief ray, when incident on an object situated in the object plane, in a direction from the primary light source, is inclined away from the common optical axis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.