| 摘要 |
PURPOSE: A method for screening a high speed erase bit of a flash memory is provided to detect the high speed erase bit, to correct the bit without further circuit variation, to prevent recovery failure and to increase the yield. CONSTITUTION: The screening method includes following steps. At first, a manual programming is performed at a pre-program step(S10). At second, the manual programming operation is verified(S20). At an erase step(S30), manual erase operation is perform after the second step. At a screen verification step(S40), high erase screening is verified for detecting the high speed bit after the erase step. At a cell state determining step(S50), whether the cell is a failed one or is to be recovered is determined according to the result of the screen verification step. At a recovery verification step(S90), the manual recovery is verified. At the last step(S100), the manual recovery is performed after the recovery verification step.
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