The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 24, 2009
Filed:
Oct. 18, 2004
Mitsuo Tada, Tokyo, JP;
Yasunari Suto, Tokyo, JP;
Mitsuo Tada, Tokyo, JP;
Yasunari Suto, Tokyo, JP;
Ebara Corporation, Tokyo, JP;
Abstract
An eddy current sensor () has a sensor coil () disposed near a conductive film () formed on a semiconductor wafer (W) and a signal source () configured to supply an AC signal to the sensor coil () to produce an eddy current in the conductive film (). The eddy current sensor () includes a detection circuit operable to detect the eddy current produced in the conductive film (). The detection circuit is connected to the sensor coil (). The eddy current sensor () also includes a housing () made of a material having a high magnetic permeability. The housing () accommodates the sensor coil () therein. The housing () is configured so that the sensor coil () forms a path of a magnetic flux (MF) so as to effectively produce an eddy current in the conductive film ().