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:
Oct. 13, 2009
Filed:
May. 27, 2004
Sakae Koyata, Tokyo, JP;
Kazushige Takaishi, Tokyo, JP;
Sakae Koyata, Tokyo, JP;
Kazushige Takaishi, Tokyo, JP;
Sumco Corporation, Tokyo, JP;
Abstract
The inventive method for processing a silicon wafer is a method comprising stepin which a single crystal ingot is sliced into thin disc-like wafers; stepin which the surface of each wafer is lapped to be planar; stepin which the wafer is subjected to alkaline cleaning to be removed of contaminants resulting from preceding machining; and stepin which the wafer is alternately transferred between two groups of etching tanks one of which contain acidic etching solutions and the other alkaline etching solutions, wherein an additional stepis introduced between stepand stepin which a wafer is immersed in an acidic solution containing hydrofluoric acid (HF) and nitric acid (HNO) at a volume ratio of ⅛ to ½ (HF/HNO) so that degraded superficial layers occurring on the front and rear surfaces of the wafer as a result of machining can be removed and the edge surface of the wafer can be beveled. The inventive method simplifies the steps involved in the processing of a wafer, and reduces the intervention of alkaline cleaning accompanied with mechanical beveling, thereby reducing the risk of contamination due to metal impurities which may result from alkaline cleaning.