Dark field inspection apparatus and methods
US7436503B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 2004 |
| Grant date | Oct 14, 2008 |
| Priority date | — |
| Expiry date | Mar 25, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/9563
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Accordingly, the present invention provides methods and apparatus for performing a darkfield inspection on a specimen having periodic structures thereon while substantially reducing or eliminating the long range ringing response, which is typically produced by a traditional Fourier filter mask used to eliminate the diffraction caused by the periodic structures. In one embodiment, an apparatus for inspecting a specimen by detecting optical beams scattered from the specimen. The apparatus includes a beam generator for providing and directing an incident beam towards a specimen and an array subtraction device for substantially subtracting a periodic component from an output beam scattered from the specimen in response to the incident beam. The periodic component corresponds to at least one periodic structure on the specimen, and the subtraction is performed so as to substantially reduce or eliminate a ringing response from the output beam. The subtraction is also performed so as to substantially prevent subtracting any actual defect components from the output beam. The apparatus further includes a detector for receiving the output beam and generating an output image or signal based on…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.