Symmetric target design in scatterometry overlay metrology
US9739702B2 · kind B2 · utility
22Cited by
7References
46Claims
0Family size
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Key dates
| Filing date | Jan 22, 2014 |
| Grant date | Aug 22, 2017 |
| Priority date | — |
| Expiry date | Apr 25, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/068
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Metrology methods, systems and targets are provided, which implement a side by side paradigm. Adjacent cells with periodic structures are used to extract the overlay error, e.g., by introducing controllable phase shifts or image shifts which enable algorithmic computation of the overlay. The periodic structures are designed to exhibit a rotational symmetry to support the computation and reduce errors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.