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:
Sep. 07, 1999
Filed:
Dec. 17, 1997
Takao Inaba, Mitaka, JP;
Minoru Numoto, Mitaka, JP;
Tokyo Seimitsu Co., Ltd., Tokyo, JP;
Abstract
The differential transformer is secured to the wafer holding table provided in the head, and the core of the differential transformer is secured to the rod member, which is provided to the head and freely projects and retracts from the face of the wafer. Then, the tip of the rod member is in contact with the polishing pad and keeps the core at a constant height from the polishing pad during polishing. When the head is displaced as polishing progresses with respect to the polishing pad, the differential transformer is displaced in connection with the displacement of the head. Therefore, the removed amount of the wafer can be determined by measuring the displacement amount of the differential transformer with respect to the core.