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, 2010
Filed:
Feb. 25, 2008
Satoshi Murakami, Tokyo, JP;
Nobuyuki Morimoto, Tokyo, JP;
Tamio Motoyama, Tokyo, JP;
Sumco Corporation, Tokyo, JP;
Abstract
A bonded wafer formed by directly bonding a wafer for active layer and a wafer for support substrate without an insulating film and thinning the wafer for active layer is evaluated by a method comprising steps of removing native oxide from a surface of an active layer in the bonded wafer, subjecting the bonded wafer to an etching with an etching liquid having an etching rate to a material constituting the wafer faster than that to an oxide of the material to remove at least a whole of the active layer, and detecting island-shaped oxides exposed by the etching, in which the etching is carried out so as to satisfy a relation of T≦X≦T+500 nm wherein T is a thickness of the active layer (nm) and X is an etching depth (nm) to detect the number and size of the island-shaped oxides.