FLASH MEMORY DEVICE HAVING FUNCTION FOR CHANGING SELECTIVELY SIZE OF MEMORY CELL BLOCK IN ERASING OPERATION, AND ITS ERASING METHOD

摘要

PROBLEM TO BE SOLVED: To select size of a memory cell block to be erased in erasing operation of a flash memory.;SOLUTION: A flash memory device is provided with a plurality of memory cell blocks, an X decoder, and a plurality of block selecting part. The X decoder decodes a block address signal, a page address signal, and a block size changing signal in response to an erasing instruction, and output word line bias voltage so that a part or a whole of a plurality of pages included in at least one memory cell block out of a plurality of memory cell blocks are erased in accordance with the decoded result. Size of the memory cell block erased in accordance with word line bias voltage is decided. During erasing operation, at least one of a plurality of block selecting parts selects at least one of a plurality of memory cell blocks. A size of a memory cell block to be erased can be changed without changing physical structure.;COPYRIGHT: (C)2008,JPO&INPIT