Metrology system using optical phase
US6710876B1 · kind B1 · utility
56Cited by
12References
52Claims
0Family size
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Key dates
| Filing date | Aug 14, 2000 |
| Grant date | Mar 23, 2004 |
| Priority date | — |
| Expiry date | Aug 1, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Misalignment error between two periodic structures such as two overlay targets placed side-by-side is measured. The two structures are illuminated by coherent radiation and the positive and negative diffraction beams of the input beam by the two structures are detected to discover the optical phase difference between the positive and negative diffraction beams. The misalignment between the two structures may then be ascertained from the phase difference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.