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:
Jul. 13, 2010
Filed:
Sep. 28, 2006
Wolfgang Hensel, Burghausen, DE;
Rudolf Lehner, Trostberg, DE;
Helmut Schwenk, Burghausen, DE;
Siltronic AG, Munich, DE;
Abstract
Unpolished semiconductor wafers are produced by: (a) pulling a single crystal of a semiconductor material, (b) grinding the single crystal round, (c) separating a semiconductor wafer from this crystal, (d) rounding the edge of the semiconductor wafer, (e) surface-grinding at least one side of the semiconductor wafer, (f) treating the semiconductor wafer with an etchant, and (g) cleaning the semiconductor wafer. The unpolished semiconductor wafers have, on at least the front side, a reflectivity of 95% or more, a surface roughness of 3 nm or less, have a thickness of 80-2500 μm, an overall planarity value GBIR of 5 μm or less with an edge exclusion of 3 mm and a photolithographic resolution of at least 0.8 μm, and which furthermore contain a native oxide layer with a thickness of 0.5-3 nm on both sides.