Automatic photomask inspection method and system
US4448532A · kind A · utility
99Cited by
3References
10Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1981 |
| Grant date | May 15, 1984 |
| Priority date | — |
| Expiry date | Mar 31, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/84
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus for receiving two sets of digitized scan data from two optical detectors which simultaneously scan two supposedly identical portions of a photomask for comparing the two sets of scan data to detect defects, and for evaluating the defect data to determine whether or not it represents real defect information or false defect information. Scan lines containing defect data are scanned twice to produce two sets of defect data and the two sets are then compared to produce a real defect data set including only defects detected in both scans. False defects are thus eliminated from the final data set.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.