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:
Dec. 26, 2000
Filed:
Mar. 02, 1998
Applicant:
Inventors:
Masashi Ohno, Nagoya, JP;
Naohito Yamada, Kasugai, JP;
Takahiro Inoue, Gifu, JP;
Kouji Kato, Nagoya, JP;
Assignee:
NGK Insulators, Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ; H01L / ;
U.S. Cl.
CPC ...
257701 ; 361234 ; 279128 ;
Abstract
A wafer attracting apparatus includes a substrate made of a ceramic material and adapted to attract and hold a wafer onto an attracting surface thereof, wherein the attracting surface is constituted by a ductile worked surface, the ductile worked surface has concave portions, a diameter of each of the concave portions is 0.1 .mu.m or less, and when the wafer is attracted onto the attracting surface of the substrate and released therefrom, the number of particles attaching to that wafer is 9.3 or less per 1 cm.sup.2.