Apodization measurement for lithographic apparatus
US7315353B2 · kind B2 · utility
6Cited by
0References
19Claims
0Family size
Assignee
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Key dates
| Filing date | Sep 8, 2004 |
| Grant date | Jan 1, 2008 |
| Priority date | — |
| Expiry date | Oct 2, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70591
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus are provided for measuring the apodization of projection optics for use in a lithographic apparatus, the projection optics having an object plane where, in use, a reticle is placed, a pupil plane, and an image plane where, in use, a wafer is placed. The method includes placing one or more appropriate apertures in said object plane for creating a substantially uniform light distribution, illuminating the or each aperture and measuring the intensity distribution at a plane which is conjugate to the pupil plane in order to calculate the apodization of the projection optics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.