Position location in surface scanning using interval timing between scan marks on test wafers
US5083035A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 17, 1990 |
| Grant date | Jan 21, 1992 |
| Priority date | — |
| Expiry date | Jul 17, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/4719
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A particle imager and method for imaging particles on surfaces of substrates. A surface is raster scanned by a collimated light beam and particles on the surface are detected by the scattered light caused by the particles. During a scan path the intensity of the scattered light is measured forming intensity traces and location addresses for the detected particles. Data from each scan path is stored in memory. The imager is pre-calibrated with a test wafer having light scattering marker points spaced at known positions thereon. Scanning the test wafer, a clock measures time elapsed from a start position to each marker point. The corresponding elapsed times and known address locations are stored in memory for reference during data collection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.