| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a write-in method for a semiconductor memory in which a write-in time can be shortened controlling memory threshold voltage at the time of write-in highly accurately. SOLUTION: In write-in processing of a 256 Mb multi-value flash EEPROM, for example, in write-in processing of '01', after all bits of bits to be written are decided as pass by data latch processing (221), write-in processing (222), and write-in verifying processing (223), data latch processing selecting an object bit line after write-in is performed (224), and write-in verifying processing is performed for the initial value (225). Thereby, in the process of '01' write-in processing and write-in verifying processing, for even a bit which is discriminated as verify-pass due to any cause, when it is decided as fail by this operation, write-in voltage is applied again, and the prescribed threshold voltage can be obtained.</p> |
