Method and apparatus for particle inspection
US5748305A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 1996 |
| Grant date | May 5, 1998 |
| Priority date | — |
| Expiry date | Jun 28, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/94
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for foreign particles inspection includes illuminating an inspection surface of an inspection object with a beam which is, one of s-polarized and p-polarized relative to the inspection surface of the inspection object. The illumination utilizes an optical axis which is generally parallel to the inspection surface or which intersects the inspection surface at an angle that is greater than or equal to 1.degree. and less than 5.degree.. Reflected and scattered light is detected utilizing an optical axis which makes an acute angle with the inspection surface and which makes a differential angle of 30.degree. or less with the optical axis of the illumination beam. The detection of foreign particles is accomplished by detecting the component of the reflected and scattered light which is the other of s-polarized and p-polarized relative to the inspection surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.