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. 16, 2008
Filed:
Oct. 14, 2003
Yasuyo Muto, Tochigi, JP;
Yukio Takabayashi, Saitama, JP;
Yasuyo Muto, Tochigi, JP;
Yukio Takabayashi, Saitama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is a wafer chuck, which has protrusions for supporting a substrate, for attracting and holding the substrate by negative pressure while the substrate is being supported by the protrusions. The wafer chuck includes pin-shaped protrusions dispersed on a suction side of the chuck, and circular peripheral wall portions disposed in the vicinity of the rim of the supported substrate and in the vicinity of the outer peripheral portion of a lifting hole, respectively. The suction side of the wafer chuck is provided with a first area in which the pin-shaped protrusions are arrayed in a grid-line manner, and a second area in which the pin-shaped protrusions are arrayed in circumferential form. The second area is provided in the vicinity of the peripheral wall portion and peripheral wall portion, and the first area is provided elsewhere.