Standalone eddy current measuring system for thickness estimation of conductive films
US6762604B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Apr 14, 2003 |
| Grant date | Jul 13, 2004 |
| Priority date | — |
| Expiry date | Apr 14, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A standalone eddy current monitoring system provides a thickness profile of a substrate sample by obtaining initial and terminating resistance and reactance measurements from the sample. Initial eddy current measurement values are obtained while an eddy current probe is positioned at an initial distance relative to the substrate sample, and terminating values are obtained while the eddy current probe is positioned at a modified distance relative to the sample. An intersecting line can be calculated using the initial and terminating resistance and reactance measurements. An intersecting point between a previously defined natural intercepting curve and the intersecting line may also be determined. A reactance voltage of the intersecting point may be located along a digital calibration curve to identify a closest-two of a plurality of calibration samples. The conductive top layer thickness of the substrate sample can then be determined by approximating a location, using linear or non-linear calculations, of the reactance voltage relative to the closest-two of the plurality of calibration samples.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.