Particle detection method and apparatus
US4772126A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1986 |
| Grant date | Sep 20, 1988 |
| Priority date | — |
| Expiry date | Oct 23, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N15/0227
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method are disclosed for detecting the presence of particles on the surface of an object such as the front side of a patterned semiconductor wafer. A vertically expanded, horizontally scanning, beam of light is directed onto an area on the surface of the object at a grazing angle of incidence. A video camera positioned above the surface detects light scattered from any particles which may be present on the surface, but not specularly reflected light. The surface is angularly prepositioned (rotated) relative to the incident light beam so that the diffracted light from the surface and the pattern of lines on the surface is at a minimum. The object is then moved translationally to expose another area to the incident light beam so that the entire surface of the object or selected portions thereof can be examined, an area at a time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.