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.

Date of Patent:
Feb. 27, 2007

Filed:

Dec. 03, 2004
Applicants:

Shinichi Yamada, Kawasaki, JP;

Waichiro Fujieda, Kawasaki, JP;

Shinichiroh Ikemasu, Kawasaki, JP;

Inventors:

Shinichi Yamada, Kawasaki, JP;

Waichiro Fujieda, Kawasaki, JP;

Shinichiroh Ikemasu, Kawasaki, JP;

Assignee:

Fujitsu Limited, Kawasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C 7/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

First dummy memory cells connected to a first dummy signal line have the same shape and characteristics as those of a real memory cell. The first dummy memory cells are arranged to be adjacent to outermost real memory cells. A voltage setting circuit changes the voltage of the first dummy signal line from a first voltage to a second voltage in order to write test data onto the first dummy memory cell during a test mode. By writing data of a logic opposite to that of the test data onto the real memory cell adjacent to the first dummy memory cell by means of an operation control circuit, a leak failure that may occur between the first dummy memory cell and the real memory cell adjacent thereto can be checked.


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