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:
Oct. 06, 1998
Filed:
Jan. 17, 1997
Katsuo Honda, Mitaka, JP;
Tokyo Seimitsu Co., Ltd., Tokyo, JP;
Abstract
A semiconductor wafer is placed on a table, and a grinding wheel grinds the surface of the semiconductor wafer. Non-contact sensors are arranged above the semiconductor wafer to detect the thickness of the semiconductor wafer during grinding. Each piece of information relating to the thickness is output to a CPU. Piezoelectric devices are arranged at regular intervals between a flange, which is secured to a grinding wheel spindle, and a frame 40. Voltages applied to the piezoelectric devices are controlled by a piezoelectric device controller which is controlled by the CPU. When the piezoelectric devices are driven, the attitude of the grinding wheel spindle is controlled in such a manner as to be rocked with regard to the table. If the CPU calculates the detected values of the sensors during the grinding, the direction and magnitude of inclination of the table and the grinding wheel spindle can be found. Then, the attitude of the grinding wheel spindle is controlled, so that the surface of the semiconductor wafer can be ground to be flat.