Hitachi, Ltd.

Yoichiro Aihara

Keiichi Higeta

Shigeru Nakahara

Masahiko Nishiyama

Daisuke Sasaki

Satoshi Iwahashi

In relation to the built-in self-test circuit (BIST circuit) for testing CAM macros, the present invention is intended to provide a means to enable reduction in amount of materials as required for wiring channel region for signal distribution, buffer, FF, etc., and in number of LSI pins, and further, to facilitate mounting on chips. The data generators for CAM testing, inserted between the APG for RAMs and CAM macros, create data to write to the CAM macros by obtaining the address signals directly or by decoding the same signals. The APG is common to all the memory macros, and testing proper to each CAM can be carried out by changing over the operation of the inserted data generators by means of the control signal. The data generators are arranged in the proximity of the CAM macros, the circuits to be tested.

Semiconductor memory device

Data lines (D, D) are shared by a first storage portion (MA) and a second storage portion (MB), and furthermore, a first transistor (MC) coupled to a first comparison data portion (CD) and a second transistor (MCA) coupled to the storage node of a first storage portion are connected in series to form a first comparing circuit (), and a third transistor (MC) coupled to a second comparison data line (CD) and a fourth transistor (MCB) coupled to the storage node of the second storage portion are connected in series to form a second comparing circuit (). Consequently, it is possible to enhance a symmetry in the layout of a diffusion layer and a wiring layer and to achieve the easiness of a layout in which a memory cell is line symmetrical with respect to a center line passing through a center thereof. Thus, a manufacturing process condition can easily be optimized and a variation in a manufacturing process can be reduced so that the microfabrication of the memory cell can be achieved.

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Ome, Japan

Yoichiro Aihara