| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor storage device and its manufacturing method which can enhance reliability. <P>SOLUTION: In a flash EEPROM 20, read voltage Vread applied to a control gate of a memory cell is generated by a read voltage generating part 30 which can be externally set by the Vread setting data in reading the data stored in a memory cell of a memory cell array 21, thereby the optimal read voltage Vread in accordance with the characteristics for each of the flash EEPROMs 20 can be set even when there is variation in semiconductor characteristics of the memory cell or the variation in depth of rewriting between the multiple flash EEPROMs 20. The reliability of the flash EEPROM 20 can be enhanced because garble of the read data is prevented by suppressing incompatibility between the characteristics of the flash EEPROM 20 and the read voltage Vread. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
