Scanning focal length metrology
US8259296B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 2010 |
| Grant date | Sep 4, 2012 |
| Priority date | — |
| Expiry date | Mar 30, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J3/0278
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical metrology system collects spectral data while scanning over the focal range. The spectral data is evaluated to determine a plurality of peak intensity values for wavelengths in the spectra. The peak intensities are then combined to form the measured spectrum for the sample, which can then be used to determine the sample properties of interest. In one embodiment, the peak intensity is determined based on the measured maximum intensity and a number n of intensity values around the measured maximum intensity, e.g., using curve fitting. If desired, the number n may be varied as a function of wavelength to vary the effective spot size of the metrology system while optimizing noise performance. The peak intensity may also be derived as the measured maximum intensity or through a statistical analysis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.