METHOD FOR REPAIRING OVER ERASE IN NON-VOLATILE SEMICONDUCTOR MEMORY

摘要

PURPOSE: A non-volatile semiconductor memory device is provided to reduce a time for verifying an over erase by simultaneously performing a verification of over erase for cells connected in one bit line inside a sector when the over erase of the semiconductor memory device having a NOR-formed memory cell structure is verified. CONSTITUTION: In entering a repairing operation of over erase, every row addresses are set to '0'(70). After every word lines of selected sector are enabled(71), a reading operation for verifying the over erase(72) and an existence of over erase is decided based on the read data(73). Theses operations are repeated to the next row if there is not the cell of over erase. In existing a cell of over erase, only a first row address inside a sector is enabled(74) and a counter to decide a number of soft program is reset to '0'(75). The over erase about the first line in the first row is read(76) and the soft program is performed if the over erase is performed(78). If there is not the cell of over erase, the operation is repeated to the next row. If the over erase is performed by reading the over erase after the operation(78), the process of soft program is repeated as the decided number of soft program(78.79.7-1.7-6.7-5).