Excavating
Patent
1996-07-19
1998-05-19
Beausoliel, Jr., Robert W.
Excavating
365201, G11C 1300
Patent
active
057545588
ABSTRACT:
According to a method for screening a nonvolatile semiconductor memory device, data is written to all memory cells. The data is slightly erased such that the memory cells have a positive distribution of threshold voltages. The threshold voltages of the memory cells are measured, and the number of memory cells whose threshold voltages are lower than a reference threshold voltage, is counted. When the counted number is not larger than the number of spare cells provided in a redundant circuit, the memory cells whose threshold voltages are lower than the reference threshold voltage are replaced with the spare cells. When the counted number is larger than the number of spare cells, the nonvolatile semiconductor memory device is determined as a defective one.
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Hayakawa Toshiyuki
Yamada Seiji
Beausoliel, Jr. Robert W.
Iqbal Nadeem
Kabushiki Kaisha Toshiba
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