Projection exposure system
US6593998B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 2001 |
| Grant date | Jul 15, 2003 |
| Priority date | — |
| Expiry date | Aug 21, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70958
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection exposure system for microlithography that has a catadioptric projection objective and a light source is claimed. The projection objective has at least one mirror and at least one lens that are composed of specified materials. Also the positions of the mirror and of the lens within the projection objective are also specified. The material and position are specified in such a way that imaging changes in the projection objective that are due to illumination-induced change in the reflecting surface of the mirror counteract illumination-induced imaging changes in the lens. Illumination-induced imaging changes in the entire projection objective are reduced in this way.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.