System and method for conducting adaptive fourier filtering to detect defects in dense logic areas of an inspection surface
US7505619B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2005 |
| Grant date | Mar 17, 2009 |
| Priority date | — |
| Expiry date | Feb 10, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8822
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A dark field surface inspection tool and system are disclosed herein. The tool includes an illumination source capable of scanning a light beam onto an inspection surface. Light scattered by each inspection point is captured as image data by a photo detector array arranged at a fourier plane. The images captured are adaptively filtered to remove a portion of the bright pixels from the images to generate filtered images. The filtered images are then analyzed to detect defects in the inspection surface. Methods of the invention include using die-to-die comparison to identify bright portions of scattering patterns and generate unique image filters associated with those patterns. The associated images are then filtered to generate filtered images which are then used to detect defects. Also, data models of light scattering behavior can be used to generate filters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.