Nonvolatile semiconductor memory and method of operating the same

A nonvolatile semiconductor memory comprising:

• a plurality of memory cells arranged in a memory cell array in the form of a matrix, the memory cells storing data having two or more levels associated with two or more threshold levels, respectively;
• and
• a control circuit configured to control operations of the memory cells, the control circuit executing data reading by using a selected potential applied to a selected word line and a non-selected potential applied to a non-selected word line in a read sequence, the non-selected potential being larger than the selected potential, and the control circuit executing data writing with respect to the memory cells and verification using a judgment level that is not lower than the non-selected potential in a write sequence.

A method of operating a nonvolatile semiconductor memory, comprising:

• writing data having two or more levels from the outside into each of memory cells by the control circuit, the data being associated with two or more threshold levels of the memory cell, respectively;
• and
• executing first verification using judgment information with respect to the memory cells by the control circuit, the judgment information being assigned to the two or more threshold levels, which are not adjacent to each other, in common.