Methods and apparatus for wavefront manipulations and improved 3-D measurements
US8319975B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 2005 |
| Grant date | Nov 27, 2012 |
| Priority date | — |
| Expiry date | May 26, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and apparatus to perform wavefront analysis, including phase and amplitude information, and 3D measurements in optical systems, and in particular those based on analyzing the output of an intermediate plane, such as an image plane, of an optical system. Measurement of surface topography in the presence of thin film coatings, or of the individual layers of a multilayered structure is described. Multi-wavelength analysis in combination with phase and amplitude mapping is utilized. Methods of improving phase and surface topography measurements by wavefront propagation and refocusing, using virtual wavefront propagation based on solutions of Maxwell's equations are described. Reduction of coherence noise in optical imaging systems is achieved by such phase manipulation methods, or by methods utilizing a combination of wideband and coherent sources. The methods are applied to Integrated Circuit inspection, to improve overlay measurement techniques, by improving contrast or by 3-D imaging, in single shot imaging.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.