Process and device for checking substrate wafers
US4194127A · kind A · utility
12Cited by
4References
21Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 17, 1978 |
| Grant date | Mar 18, 1980 |
| Priority date | — |
| Expiry date | Mar 17, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9501
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Polished single crystal wafers are checked for defects by means of a method employing a optical microscope. The image is blurred by a translucent material and the transmitted light is then sensed by a light sensitive instrument which records the increased light intensity caused by a defect passing through the field of view. The position of the defects are then plotted automatically.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.