High speed laser scanning inspection system
US7589835B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 8, 2008 |
| Grant date | Sep 15, 2009 |
| Priority date | — |
| Expiry date | Apr 8, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/104
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical inspection system rapidly evaluates a substrate by illumination of an area of a substrate larger than a diffraction-limited spot using a coherent laser beam by breaking temporal or spatial coherence. Picosecond or femtosecond pulses from a modelocked laser source are split into a plurality of spatially separated beamlets that are temporally and/or frequency dispersed, and then focused onto a plurality of spots on the substrate. Adjacent spots, which can overlap by up to about 60-70 percent, are illuminated at different times, or at different frequencies, and do not produce mutually interfering coherence effects. Bright-field and dark-field detection schemes are used in various combinations in different embodiments of the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.