Camera-aided focusing in optical metrology
US9215425B1 · kind B1 · utility
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20Claims
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Key dates
| Filing date | Feb 4, 2013 |
| Grant date | Dec 15, 2015 |
| Priority date | — |
| Expiry date | May 3, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/12
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A side camera is combined with a conventional optical metrology system to image the object during the focusing scan performed in normal focusing procedures. The camera is positioned in fixed spatial relation to the objective and with its focal plane in substantial alignment with the optical axis of the objective so as to image the object during the scan. The camera is used to monitor the illumination spot formed on the object by the beam projected through the system's objective. The in-focus position is found by moving the object such that the illumination spot coincides with the objective's focus seen through the camera.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.