| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a semiconductor storage device of high reliability which allows no uselessness, by arranging a first storage region and a second storage region different in read/write characteristics, and accessing the storage region in response to the reliability of read/write required for the data as the access object. SOLUTION: A memory cell array is divided into a first part connected with word lines WL1-WLk and a second part connected with word lines WL(k+1)-WLm. A first row decoder 32-1 for selecting the word lines WL1-WLk and a second row decoder 32-2 for selecting the word lines WL(k+1)-WLm are individually installed. The first part is a storage region of high reliability wherein a one-bit data storage device is constituted of two cells. The second part is a usual storage region wherein a one-bit storage device is constituted of a cell. Therefore, reliability is improved and increase of the chip area can be restrained to a minimum.</p> |
