Foreign particle detecting method and apparatus
US4669875A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1983 |
| Grant date | Jun 2, 1987 |
| Priority date | — |
| Expiry date | Nov 3, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/1053
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The foreign particle detecting method and apparatus are disclosed wherein a polarized laser beam emitted by a laser beam irradiating system from a direction inclined with respect to the direction perpendicular to the surface of a substrate is used by a scanning means to linearly scan the substrate surface from a direction approximately 90.degree. with respect to the laser light irradiating direction; and the laser light reflected from a foreign particle on the substrate surface is detected by a polarized light analyzer and a photoelectric conversion device from a direction set approximately equal to said scanning direction and inclined with respect to the direction perpendicular to the substrate surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.