Light condenser
US6801298B2 · kind B2 · utility
2Cited by
4References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 25, 2002 |
| Grant date | Oct 5, 2004 |
| Priority date | — |
| Expiry date | Oct 11, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B27/42
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A light condenser suitable for EUV lithography that includes reflective rings concentric to an optical axis. Each ring has a reflective surface to reflect light rays emanating from a light source so that the light rays converge towards a mask to produce Köhler illumination on the mask. The reflective surface has a curve segment that includes a section of a parabolic curve that is rotated relative to an optical axis and has a focal point at the light source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.