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. 01, 2011
Filed:
Oct. 27, 2008
Applicant:
Gen Koshita, Tokyo, JP;
Inventor:
Gen Koshita, Tokyo, JP;
Assignee:
Elpida Memory, Inc., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C 29/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A semiconductor memory device simultaneously selects an object cell and a counter cell which connect with a common bit line, simultaneously activates sub-word lines of the object cell and the counter cell after predetermined levels are written in the object cell and the counter cell, simultaneously read data of the object cell and the counter cell from the common bit line, and hence, determines whether the object cell is normal or defective, based on a voltage level of the common bit line. Thereby, the defective cell in the semiconductor memory device can be reliably detected.