Method and apparatus for inspecting reticles
US4875780A · kind A · utility
23Cited by
8References
46Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 25, 1988 |
| Grant date | Oct 24, 1989 |
| Priority date | — |
| Expiry date | Feb 25, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/95676
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A laser light inspection device for inspecting opposite surfaces of a workpiece with a low angle laser light beam. The laser light beam is directed in successive scans of a first and second sides in a repetitive manner using a pair of dividing mirrors and a pair of low angle mirrors. Light reflected by any debris back toward the direction of origin of the light beam is collected and analyzed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.