Device inspection method and apparatus using an asymmetric marker
US7112813B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 2003 |
| Grant date | Sep 26, 2006 |
| Priority date | — |
| Expiry date | Mar 18, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7092
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of device inspection, the method comprising providing an asymmetric marker on a device to be inspected, the form of asymmetry of the marker being dependent upon the parameter to be inspected, directing light at the marker, obtaining a first measurement of the position of the marker via detection of diffracted light of a particular wavelength or diffraction angle, obtaining a second measurement of the position of the marker via detection of diffracted light of a different wavelength or diffraction angle, and comparing the first and second measured positions to determine a shift indicative of the degree of asymmetry of the marker.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.