Mapping variations of a surface
US8724882B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 2009 |
| Grant date | May 13, 2014 |
| Priority date | — |
| Expiry date | Aug 4, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8848
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for characterizing a surface, consisting of dividing the surface into pixels which are characterized by a parameter variation and defining blocks of the surface as respective groups of the pixels. The pixels are irradiated in multiple scans over the surface with radiation having different first polarization states. At least part of the radiation returning from the pixels is analyzed using second polarization states, to generate processed returning radiation. For each scan, block signatures of the blocks are constructed using the processed returning radiation from the group of pixels in each block. Also for each scan, a block signature variation is determined using the respective block signatures of the blocks, and, in response to the block signature variation, one of the first polarization states and at least one of the second polarization states are selected for use in subsequent examination of a test object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.