Image splitting in optical inspection systems
US7714998B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 2007 |
| Grant date | May 11, 2010 |
| Priority date | — |
| Expiry date | Nov 26, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/068
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an optical inspection tool, an image of an object under inspection, such as a semiconductor wafer, may be obtained using imaging optics defining a focal plane. Light comprising the image can be split into portions that are detected using multiple detectors which each register a portion of the image. The image of the object at the focal plane can be split into two, three, or more parts by polarization-based beam splitters and/or lenses positioned tangent to the focal plane. The splitting apparatus may comprise a pair of arrays of half-cylinder lenses comprising a convex side and a flat side. The arrays can be positioned with the cylinder axes perpendicular to one another and the flat sides facing each other. Thus, the pair of arrays can divide incoming light into a plurality of rectangular portions without introducing non-uniformities which would occur if several spherical lenses are configured for use in a rectangular array.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.