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:
Aug. 17, 1999
Filed:
Dec. 16, 1997
Tokio Takei, Nagano, JP;
Susumu Nakamura, Nagano, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
There is disclosed a wafer holding jig having a porous holding surface for vacuum-holding a semiconductor wafer while the wafer is ground or polished. The porosity of a center region of the holding surface is made larger than that of an outside region formed to surround the center region. The outer diameter of the center region is made less than that of the wafer, while the outer diameter of the outside region is made greater than that of the wafer. It is possible to prevent deterioration in machining accuracy, which deterioration would otherwise occur due to deformation of a wafer stemming from catch of dust or the like, or application of machining pressure to the wafer.