Method and apparatus for visual inspection
US8472697B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 19, 2012 |
| Grant date | Jun 25, 2013 |
| Priority date | — |
| Expiry date | Jan 19, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In the case of die-to-die comparison, threshold processing units process the differential image between the image of a sample chip and the images of left and right adjacent chips using a second threshold value lower than a first threshold value thereby to determine a defect candidate for the sample chip. Further, threshold processing units process the differential image using the first threshold value. The defect candidates which develops a signal not smaller than the first threshold is detected as a defect. Also in the cell-to-cell comparison, the differential image is first processed by the second threshold value to determine a defect candidate, and the differential image is further processed by the first threshold value. The defect candidates which develops a signal not smaller than the first threshold value is detected as a defect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.