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, 1978
Filed:
Jun. 02, 1978
Takatoshi Ono, Tokyo, JP;
Michio Ikeda, Tokyo, JP;
Disco Kabushiki Kaisha, Tokyo, JP;
Abstract
Suction apparatus for holding workpieces such as semiconductor substrates or wafers having different diameters comprises a table having an upper surface with a plurality of concentric circular air grooves having different diameters and a plurality of sleeves in radial arcuately spaced bores, respectively, for selectively switching a vacuum source to all or less than all of the grooves. In a preferred embodiment, each sleeve is rotatable about its axis and has a plurality of axially spaced holes which communicate with the vacuum source through the central axial passage in the sleeve. Correspondingly axially spaced holes in the table connect the respective grooves with the bore and are registerable with the sleeve holes through selective rotation of the sleeve to connect the vacuum source and the grooves. The respective sleeves control different numbers of grooves as each is rotated between operating and non-operating positions so as to hold wafers of correspondingly different diameters to the table without necessitating costly and time consuming replacement of major structural components.