Polishing device using eddy current sensor
US7078894B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 2003 |
| Grant date | Jul 18, 2006 |
| Priority date | — |
| Expiry date | Apr 17, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R23/10
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
An eddy current sensor and a method for detecting the thickness of a film formed on a substrate. The eddy current sensor, which is capable of stable operation, is operable to accurately detect a polishing endpoint. The eddy current sensor detects the thickness of a conductive film from a change in an eddy current loss generated in the conductive film. The eddy current sensor comprises a sensor coil for generating an eddy current in the conductive film, and an active element unit connected to the sensor coil for oscillating a variable frequency corresponding to the eddy current loss. The sensor coil and active element unit are integrated to form the eddy current sensor. Alternatively, the eddy current sensor comprises a sensor coil for generating an eddy current in the conductive film, and a detector for detecting a change in the thickness of the conductive film from a change in a resistance component in an impedance formed by the sensor coil and conductive film.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.