US Patent 7623375 Method of operating a flash memory device

In a method of operating a flash memory device including a memory cell array having a Multi-Level Cell (MLC) for storing plural bit data, a first memory block included in the MLC is selected. First to Mth word lines are selected while increasing from a first column line to an Nth column line, which are included in the first memory block. A lower page of each word line is selected in the order of the word lines. The first to Mth word lines are selected while increasing from the first column line to the Nth column line. An upper page of each word line is selected in the order of the word lines.