Noise correction for alignment signal
US11493852B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 2019 |
| Grant date | Nov 8, 2022 |
| Priority date | — |
| Expiry date | Dec 12, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7092
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of applying a measurement correction includes determining an orthogonal subspace used to characterize the measurement as a plot of data. A first axis of the orthogonal subspace corresponds to constructive interference output from an interferometer of the metrology system plus a first error variable and a second axis of the orthogonal subspace corresponds to destructive interference output from the interferometer of the metrology system plus a second error variable. The method also includes determining a slope of the plot of data and determining a fitted line to the plot of data in the orthogonal subspace based on the slope.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.