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:
Jun. 30, 2015
Filed:
Oct. 10, 2008
Taro Takahashi, Tokyo, JP;
Yoichi Kobayashi, Tokyo, JP;
Shinrou Ohta, Tokyo, JP;
Akihiko Ogawa, Tokyo, JP;
Taro Takahashi, Tokyo, JP;
Yoichi Kobayashi, Tokyo, JP;
Shinrou Ohta, Tokyo, JP;
Akihiko Ogawa, Tokyo, JP;
EBARA CORPORATION, Tokyo, JP;
Abstract
A method monitors a change in thickness of a conductive film brought into sliding contact with a polishing surface of a polishing pad using an eddy current sensor. The output signal of the eddy current sensor includes two signals corresponding to a resistance component and an inductive reactance component of an impedance of an electric circuit including a coil of the eddy current sensor. The method includes acquiring the output signal of the eddy current sensor when the eddy current sensor is facing the conductive film, defining the two signals as coordinates on a coordinate system, repeating the acquiring of the output signal and the defining of the coordinates, determining a center of curvature of an arc specified by at least three sets of coordinates on the coordinate system, determining an angle of inclination of a line connecting the center of curvature and a latest one of the at least three sets of coordinates, and monitoring a change in thickness of the conductive film by monitoring a change in the angle of inclination.