Projection objective for microlithography
US8212988B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 3, 2005 |
| Grant date | Jul 3, 2012 |
| Priority date | — |
| Expiry date | Mar 2, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70783
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection objective for imaging a pattern arranged in an object surface of the projection objective into an image surface of the projection objective with a demagnified imaging scale has a plurality of optical elements which are arranged along an optical axis of the projection objective and are configured in such a way that a defined image field curvature of the projection objective is set in such a way that an object surface that is curved convexly with respect to the projection objective can be imaged into a planar image surface. What can be achieved given a suitable setting of the object surface curvature is that a gravitation-dictated bending of a mask does not have a disturbing effect on the imaging quality.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.