Method and apparatus for angular-resolved spectroscopic lithography characterization
US8724109B2 · kind B2 · utility
3Cited by
7References
16Claims
0Family size
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Key dates
| Filing date | Feb 9, 2009 |
| Grant date | May 13, 2014 |
| Priority date | — |
| Expiry date | Jun 15, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apparatus and method to determine overlay of a target on a substrate (6) by measuring, in the pupil plane (40) of a high numerical aperture len (L1), an angle-resolved spectrum as a result of radiation being reflected off the substrate. The overlay is determined from the anti-symmetric component of the spectrum, which is formed by subtracting the measured spectrum and a mirror image of the measured spectrum. The measured spectrum may contain only zeroth order reflected radiation from the target.
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