Optical diffraction method and apparatus for integrated circuit lead inspection
US5663799A · kind A · utility
3Cited by
7References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 24, 1996 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | Jan 24, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95684
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A technique for detecting damage of leads arranged in a generally parallel periodic pattern, includes the following steps: directing a coherent light beam at a plurality of adjacent leads; detecting an image at a distance from the leads at which the light beam would form a diffraction image having substantially uniform intensity when the leads form a substantially uniform pattern; moving the pattern of leads and the light beam with respect to each other; and detecting damage of leads from variation in intensity of the detected image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.