Method of inspecting the surface of an object and apparatus therefor
US4342515A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 1979 |
| Grant date | Aug 3, 1982 |
| Priority date | — |
| Expiry date | Jan 23, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9503
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This invention discloses inspection apparatus for detecting unfavorable foreign matters existent on the surface of an object such as semiconductor wafer. The apparatus includes a collimated beam generator portion which projects a collimated beam towards the object to-be-inspected from a side thereof, and a mechanism which senses light reflected from the surface of the object, through a polarizer plate. In accordance with this invention, the signal-to-noise ratio between a detection signal generated by a pattern of the foreign matter to-be-detected and a signal generated by a normal pattern of the object surface and sensed as a noise component can be enhanced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.