Projection objective for microlithography
US9217932B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 29, 2012 |
| Grant date | Dec 22, 2015 |
| Priority date | — |
| Expiry date | Mar 20, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/703
- 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 so that a defined image field curvature of the projection objective is set such that an object surface that is curved convexly with respect to the projection objective is imaged into a planar image surface. Such projection objective, with a suitable setting of the object surface curvature, avoids the disturbing effect on the image quality that would otherwise result from gravitation-dictated bending of a mask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.