Particle detection method and apparatus
US4895446A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 1988 |
| Grant date | Jan 23, 1990 |
| Priority date | — |
| Expiry date | Sep 19, 2008 |
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 collimated beam of light is directed onto an area on the surface of the object at a grazing angle of incidence. A detector positioned above the surface detects light scattered from any particles which may be present on the surface, but not specularly reflected light. The output of the detector is fed into a computer where the information is processed and then displayed on a display. The surface is prepositioned relative to the incident light beam so that the diffracted light from the surface and the pattern 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.