| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure that achieves a full effect of a layered structure of word and common I/O. SOLUTION: A plurality of first (and second) sub-word lines are provided so as to correspond to main word lines. A plurality of first (and second) memory cells are provided at intersecting points of these sub-word lines and a plurality of first (and second) bit lines to configure first (and second) memory arrays. A sub-common I/O line is connected to the plurality of first (and second) bit lines and extends in a first direction. A main I/O line is connected to the sub-common line and extends in a second direction that intersects with the first direction. A plurality of first (and second) switch circuits are provided between each of the plurality of first (and second) bit lines and the sub-common I/O line. An amplifier circuit is provided between the sub-common I/O line and the main I/O line and amplifies a signal transmitted through the sub-common I/O line. The length of the sub-common I/O line is shorter than that of the main I/O line. COPYRIGHT: (C)2008,JPO&INPIT
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