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. 21, 2004
Filed:
Jun. 18, 2002
Guido Wenski, Burghausen, DE;
Thomas Altmann, Haiming, DE;
Gerhard Heier, Burghausen, DE;
Wolfgang Winkler, Tittmoning, DE;
Gunther Kann, Griesstätt, DE;
Siltronic AG, Munich, DE;
Abstract
A process is for material-removing machining, on both sides simultaneously, of semiconductor wafers having a front surface and a back surface, the semiconductor wafers resting in carriers which are set in rotation by means of an annular outer drive ring and an annular inner drive ring and being moved between two oppositely rotating working disks in a manner which can be described by means of in each case one path curve relative to the upper working disk and one path curve relative to the lower working disk, wherein the two path curves after six loops around the center have the appearance of still being open, and at each point have a radius of curvature which is at least as great as the radius of the inner drive ring.