Multiple beam scanner for an inspection system
US6236454A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 15, 1997 |
| Grant date | May 22, 2001 |
| Priority date | — |
| Expiry date | Dec 15, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8816
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An inspection system using dark field imaging includes a multiple beam laser scanning unit and at least one multiple beam dark field imaging unit. The laser scanning unit generates multiple beams which illuminate multiple spots on a surface to be scanned. The imaging unit separately detects light scattered from the multiple spots. The spots are separated by a separation distance which ensures that scattered light from each associated spot are received only by its associated photodetector. Each imaging unit includes collection optics and multiple photodetectors, one per spot. The collection optics and photodetectors are mounted so as to separate the light scattered from the different scan lines. In one embodiment, this separation is provided by arranging the collection optics and photodetectors according to the principles of Scheimpflug imaging.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.