Process and assembly for non-destructive surface inspection
US6861660B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 2002 |
| Grant date | Mar 1, 2005 |
| Priority date | — |
| Expiry date | Sep 9, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9501
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical system for detecting defects on a wafer that includes a device for producing a beam and directing the beam onto the wafer surface, producing an illuminated spot on the wafer's surface. The system further includes a detector detecting light, and a mirrored assembly having together with the detector an axis of symmetry about a line perpendicular to the wafer surface. The assembly is configured to receive scattered light from the surface, where the scattered light including a first scattered light part being scattered from the pattern. The assembly is further configured to reflect and focus rotationally symmetrically about the axis of symmetry the scattered light to the detector. The system further includes a device operating with the detector for facilitating detection of a scattered light other than the specified scattered light due to pattern.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.