Image splitting in optical inspection systems
US7719674B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 2007 |
| Grant date | May 18, 2010 |
| Priority date | — |
| Expiry date | Nov 26, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/95615
- 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 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 mirrors or other suitable reflecting elements positioned tangent to the focal plane and/or with at least some portion at the focal plane with additional portions past the focal plane so that the focal plane lies between the imaging optics and the splitting apparatus. In some embodiments, reflective planes may be arranged to direct different portions to different detectors. Some reflective planes may be separated by a gap so that some portions of the light are directed while some portions pass through the gap. Other splitting elements may comprise a group of transmissive and reflective areas interspersed in an element positioned at or in the focal plane, with some portions of the light are reflected to detectors while other portions pass through the element(s) to other detectors. Splitting apparatuses and elements may be cas…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.