Prealigner probe
US4958129A · kind A · utility
34Cited by
19References
19Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1989 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Mar 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/023
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An edge detection system for measuring lateral position in the presence of height variations such as found in gauging the edge position of a wafer uses first and second capacitive probes formed of passive elements with the active components kept outside the probe and at a distance that permits a smaller, stabler and more economical probe to be located at the location of the wafer. The probes are instrumented in an electronic circuit having plural operational amplifiers that drive the probes to compensate the edge detection for wafer height effects.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.