Methods and apparatus for inspection of articles, EUV lithography reticles, lithography apparatus and method of manufacturing devices
US9488922B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 2011 |
| Grant date | Nov 8, 2016 |
| Priority date | — |
| Expiry date | Sep 18, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An EUV lithography reticle is inspected to detect contaminant particles. The inspection apparatus comprises illumination optics with primary radiation. An imaging optical system with plural branches is arranged to form and detect a plurality of images, each branch having an image sensor and forming its image with a different portion of radiation received from the illuminated article. A processor combines information from the detected images to report on the presence and location of contaminant particles. In one or more branches the primary radiation is filtered out, so that the detected image is formed using only secondary radiation emitted by contaminant material in response to the primary radiation. In a dark field imaging branch using the scattered primary radiation, a spatial filter blocks spatial frequency components associated with periodic features of the article under inspection, to allow detection of particles which cannot be detected by secondary radiation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.