Pupil plane calibration for scatterometry overlay measurement
US9909982B2 · kind B2 · utility
1Cited by
0References
18Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 3, 2014 |
| Grant date | Mar 6, 2018 |
| Priority date | — |
| Expiry date | Feb 21, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and calibrations modules are provided, for calibrating a pupil center in scatterometry overlay measurements. The calibration comprises calculating fluctuations from a first statistical figure of merit such as an average of an overlay signal per pixel at the pupil and significantly reducing, for example minimizing, the fluctuations with respect to a second statistical figure of merit thereof, such as a pupil weighted variance of the fluctuations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.