Non-volatile memory device including a verify circuit to control word and bit line voltages and method of operating the same

A nonvolatile memory system comprising a memory controller and a nonvolatile memory device, the nonvolatile memory system comprising:

• the memory controller outputting a command and an address to the nonvolatile memory device to access data from the nonvolatile memory device;
• and
• the nonvolatile memory device storing the data based on control of the memory controller,
• the nonvolatile memory device comprising:
• a memory cell region including a first metal pad;
• a peripheral circuit region including a second metal pad and vertically connected to the memory cell region by the first metal pad and the second metal pad;
• a memory cell array, in the memory cell region, comprising a plurality of memory cells, a plurality of word lines and a bit line connected to the memory cells, wherein each memory cell is connected to one of the word lines;
• a voltage generator, in the peripheral circuit region, supplying a plurality of voltages to the memory cell array;
• a control logic circuit, in the peripheral circuit region, programming a selected one of the memory cells into a first program state by controlling the voltage generator in response to a program command of the memory controller;
• and
• a verify circuit, in the peripheral circuit region, controlling performance of a verify operation on the memory cell array by controlling the voltage generator in response to the program command,
• wherein the verify circuit controls a word line voltage applied to at least one unselected word line not to be programmed among the plurality of word lines in the verify operation to be different from a read voltage level of a read voltage applied in a read operation of the nonvolatile memory and controls a bit line voltage applied to the bit line in the read operation,
• wherein the at least one unselected word line comprises a first word line located directly above a selected word line to be programmed and a second word line located directly below the selected word line, the verify circuit controls the voltage generator to apply a word line voltage among the supply voltages to the first word line and apply the same word line voltage to the second word line in the verify operation, and the word line voltage has a different voltage level than a read voltage applied to the first word line and the second word line in a read operation.

A method of operating a nonvolatile memory device comprising a plurality of memory cells connected to a bit line, where each memory cell is connected to one of a plurality of word lines, the method comprising:

• performing a first program operation by applying a first program voltage to a selected one of the word lines connected to a selected one of the memory cells to be programmed;
• and
• performing a first verify operation by sequentially applying a plurality of different and decreasing first verify voltages to the selected word line and applying a first bit line voltage to the bit line,
• wherein the first bit line voltage has a higher voltage level than a read voltage applied to the bit line in a read operation of the nonvolatile memory device.