Method of measuring focus of a lithographic projection apparatus
US8436998B2 · kind B2 · utility
1Cited by
8References
9Claims
0Family size
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Key dates
| Filing date | Sep 4, 2012 |
| Grant date | May 7, 2013 |
| Priority date | — |
| Expiry date | Sep 4, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70683
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of measuring focus of a lithographic projection apparatus includes exposure of a photoresist covered test substrate with a plurality of verification fields. Each of the verification fields includes a plurality of verification markers, and the verification fields are exposed using a predetermined focus offset. After developing, an alignment offset for each of the verification markers is measured and translated into defocus data using a transposed focal curve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.