Non volatile memory device and program method thereof

The present invention is coupled to the non-volatile memory devices, and relates to its application method, a plurality of the pair of cell string of a plurality of memory cell array including a bit line, the plurality of bit lines connected respectively, selected for the program memory, and storing the data to program the cell, it is connected to a plurality of page buffer, and each of the plurality of page buffers for sensing a potential of the bit line by one of the plurality of sensing signals when the program verify operation, the program verify the non-volatile memory device which comprises a voltage sensing signal generating circuit for generating a plurality of different sensing signal for the operation. And a sensing signal generation circuit that generates a sensing signal for controlling the sensing operation.