Electrostatic capacitance sensor
US11688617B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 2019 |
| Grant date | Jun 27, 2023 |
| Priority date | — |
| Expiry date | May 19, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/6838
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Provided is an electrostatic capacitance sensor which can remove an influence of a noise occurring from a static eliminator or a driving source and accurately perform measurement even on electrostatic capacitance detected by a thin-type detection unit which can be passed to a finger surface of a wafer transfer robot. The present invention is provided with an AC supply source which supplies an AC voltage to a detection unit, a parasitic capacitance compensation circuit, an operational amplifier, a differential amplifier, a phase detection means, and a low pass filter. An operational amplification output terminal is connected to an inversion input terminal of the differential amplifier through a first band pass filter, the AC supply source is connected to a non-inversion input terminal of the differential amplifier through a second band pass filter, an output terminal of the differential amplifier is connected to an input terminal of the phase detection means, and the phase detection means takes, as a reference signal, an AC signal output from the AC supply source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.