Apparatus and method for inspection of a patterned object by comparison thereof to a reference
US5586058A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1992 |
| Grant date | Dec 17, 1996 |
| Priority date | — |
| Expiry date | Apr 21, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention seeks to provide an improved system for inspection of and detection of defects in objects such as reticles, photomasks, semiconductor wafers, flat panel displays and other patterned objects. Preferably, the system has two or more stages, whereby the object is examined separately for fine defects, preferably by inspecting a binary level representation of the object, and for ultra fine defects, preferably by inspecting a gray level representation of the object. The system also preferably includes reinspection apparatus for reinspection of detected defects, thereby to reduce the false alarm rate, and for classifying the remaining defects by size, area and type.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.