Method and apparatus for measuring a thickness of a layer of a wafer
US7777483B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 2008 |
| Grant date | Aug 17, 2010 |
| Priority date | — |
| Expiry date | Apr 8, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus are provided for measuring the thickness of a test object. The apparatus includes an eddy current sensor having first and second sensor heads. The sensor heads are positioned to have a predetermined gap therebetween for passage by at least a portion of the test object through the gap. The sensor heads make measurements at given sampling locations on the test object as the test object is moved through the gap. The apparatus also includes a position sensing mechanism to determine positions of the sampling locations on the test object. The apparatus also includes an evaluation circuit in communication with the eddy current sensor and to the position sensing mechanism for determining the thickness of the test object at the sampling locations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.