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:
Feb. 27, 2007
Filed:
May. 26, 2005
Kenichi Tajima, Akishima, JP;
Hiroshi Akasaki, Ome, JP;
Masatoshi Hasegawa, Hamura, JP;
Yousuke Tanaka, Ome, JP;
Kenichi Tajima, Akishima, JP;
Hiroshi Akasaki, Ome, JP;
Masatoshi Hasegawa, Hamura, JP;
Yousuke Tanaka, Ome, JP;
Hitachi, Ltd, Tokyo, JP;
Hitachi ULSI Systems Co., Ltd., Tokyo, JP;
Abstract
A semiconductor memory device capable of improving the reliability when driving a word line and capable of reducing the access delay due to the defect relief is provided. In order to prevent the multiple selection of a sub-word line of a normal memory mat and a sub-word line of a redundant memory mat, the start of the redundant memory mat is delayed from that of the normal memory mat, and in order to compensate the start delay, the shared circuit is eliminated and the bit line length is reduced in the redundant memory mat. By doing so, the read time of the bit lines is reduced and the signal amount is increased. Consequently, the same activation timing of the sense amplifier as that of the normal memory mat can be used also in the redundant memory mat.