Inspection apparatus for lithography
US8681312B2 · kind B2 · utility
43Cited by
3References
20Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 20, 2009 |
| Grant date | Mar 25, 2014 |
| Priority date | — |
| Expiry date | Dec 29, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/956
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The measurement of two separately polarized beams (Ix, Iy) upon diffraction from a substrate (W) in order to determine properties of the substrate is disclosed. Circularly or elliptically polarized radiation is passed via a variable phase retarder in order to change the phase of one of two orthogonally polarized radiation beams with respect to the other of the two beams. The phase change is dependent on the wavelength of the polarized beam. The relative phases of the two radiation beams and other features of the beams as measured in a detector gives rise to properties of the substrate surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.