Illumination optical unit for EUV projection lithography
US9280061B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 21, 2014 |
| Grant date | Mar 8, 2016 |
| Priority date | — |
| Expiry date | Aug 21, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B26/0825
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An illumination optical unit for EUV projection lithography serves for guiding illumination light towards an illumination field, in which a lithography mask can be arranged. The illumination optical unit has a first facet mirror having a plurality of individual mirrors. The latter predefine illumination channels for guiding illumination light partial beams towards the illumination field. A second facet mirror of the illumination optical unit is disposed downstream of the first facet mirror and has a plurality of facets. The latter respectively contribute to the imaging of a group of the individual mirrors of the first facet mirror into the object field via a group-mirror illumination channel. The latter comprises the individual-mirror illumination channels of the individual-mirror group. Images of the different individual-mirror groups are superimposed on one another in the object field via the assigned group-mirror illumination channels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.