Defect inspection method
US7181060B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 2002 |
| Grant date | Feb 20, 2007 |
| Priority date | — |
| Expiry date | Oct 31, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N23/225
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An image picked up by a detection system capable of actualizing a three-dimensional inclination is usually poor in the signal-to-noise ratio, and it is difficult to stably detect minute defects. Images that actualize a three-dimensional inclination are picked up from opposed directions. The images are subject to subtraction and addition. The images improved in signal-to-noise ratio as compared with original images are calculated. The images calculated and improved in signal-to-noise ratio respectively of a defect portion and a reference portion are compared with each other. Regions differing in comparison results are detected as defects. As a result, minute defects can be inspected stably.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.