Eddy current measuring system for monitoring and controlling a CMP process
US6741076B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Apr 14, 2003 |
| Grant date | May 25, 2004 |
| Priority date | — |
| Expiry date | Apr 14, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for estimating a thickness profile of a substrate sample that has undergone a chemical-mechanical polishing (CMP) process includes 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.