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:
May. 07, 2002
Filed:
Dec. 15, 1998
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Two wafers are properly brought into contact with each other. The first wafer is supported by a wafer support table ( ) having an annular peripheral portion ( ). The substrate support table ( ) is in contact with only the peripheral portion ( ) of the first wafer. While the second wafer opposing the first wafer is supported, the lower surface of the second wafer is pressed near its central portion, so the first and second wafers come into contact with each other outward from the central portion. The central portion ( ) of the wafer support table ( ) is not in contact with the first wafer. Even when particles adhere to the central portion, unevenness on the supported first wafer can be prevented. Therefore, no gas is left between the wafers. This invention also provides a wafer support table formed by fabricating a silicon wafer. A commercially available silicon wafer is fabricated by lithography to prepare a wafer support table ( ). The wafer support table ( ) has sealing portions ( ) and deflection prevention portions ( ). The wafer to be supported is chucked by reducing the pressure between the sealing portions ( ). The wafer to be supported is in contact only with the sealing portions ( ) and the deflection prevention portions ( )