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:
Nov. 27, 2012
Filed:
Oct. 04, 2011
Shuichi Inami, Tokyo, JP;
Shuichi Inami, Tokyo, JP;
Sumco Corporation, Tokyo, JP;
Abstract
A whole determination area of a targeted wafer is concentrically divided in a radial direction, COP density is obtained in each divided determination segment, a maximum value of the COP density is set as COP density, a minimum value of the COP density is set as COP density, a value computed by '(COP density−COP density)/COP density' is compared to a predetermined set value, and a non-crystal-induced COP and a crystal-induced COP are distinguished from each other based on a clear criterion, thereby determining the COP generation factor. Therefore, a rejected wafer in which a determination of the crystal-induced COP is made despite being the non-crystal-induced COP can be relieved, so that a wafer production yield can be enhanced.