Method for improving an optical imaging property of a projection objective of a microlithographic projection exposure apparatus
US8237915B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 3, 2008 |
| Grant date | Aug 7, 2012 |
| Priority date | — |
| Expiry date | Apr 25, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70891
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method is disclosed for improving an optical imaging property, for example spherical aberration or the focal length, of a projection objective of a microlithographic projection exposure apparatus. First, an immersion liquid is introduced into an interspace between a photosensitive surface and an end face of the projection objective. Then an imaging property of the projection objective is determined, for example using an interferometer or a CCD sensor arranged in an image plane of the projection objective. This imaging property is compared with a target imaging property. Finally, the temperature of the immersion liquid is changed until the determined imaging property is as close as possible to the target imaging property.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.