| 摘要 |
PROBLEM TO BE SOLVED: To surely read data even when the reading margin of data written in a manufacturing process is lowered in a subsequent heat process. SOLUTION: A second reading operation is executed to read data from a dummy memory cell before a first reading operation for reading data from a real memory cell by using a reference memory cell. By the second reading operation, the residual polarized value of the ferroelectric capacitor of the reference memory cell reduced by the heat treatment or the like of the manufacturing process is returned to an original value before reading access to the real memory cell. Thus, in the subsequent first reading operation, the data of the real memory cell are correctly read. As a result, for example, data stored in a ROM area are surely read from the ferroelectric memory having the ROM area in which the data are written beforehand in the testing step or the like of the manufacturing process. COPYRIGHT: (C)2004,JPO
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