Focus measurement in projection exposure apparatus
US6633390B2 · kind B2 · utility
16Cited by
4References
48Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 20, 2001 |
| Grant date | Oct 14, 2003 |
| Priority date | — |
| Expiry date | Jul 3, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7026
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of detecting focus information about an image projecting optical system includes performing mark projection through the optical system, and, based on illumination lights having different chief ray incidence directions, the mark projection is carried out so that mark images formed by the illumination lights, respectively, are superposed one upon another approximately upon an imaging plane, and detecting focus information about the optical system on the basis of information related to a deviation between the mark images superposed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.