Sensor for measuring degree of flatness
US6255664A · kind A · utility
3Cited by
5References
6Claims
0Family size
Assignees
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Key dates
| Filing date | Apr 5, 1999 |
| Grant date | Jul 3, 2001 |
| Priority date | — |
| Expiry date | Apr 5, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/345
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A sub sensor for measuring a small area is integrally incorporated in a main sensor for measuring a large area and a part in the vicinity of the edge of a wafer is measured by the sub sensor, while a center of a wafer is measured by the main sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.