Nonvolatile memory device and programming method of the same

A programming method of a multi-level cell flash memory device, the programming method comprising:

• programming a plurality of first memory cells to a first program state by applying a first program pulse to the plurality of first memory cells via a word line in a first type programming operation;
• and
• programming a plurality of second memory cells to one of a second memory state or a third memory state by applying a second program pulse to the plurality of second memory cells via the word line in a second type programming operation,
• wherein a width of distribution of the first program state varies from at least one of widths of distribution of the second and third program states, according to the first and second type programming operations.

A semiconductor memory system, comprising:

• a flash memory device comprising a plurality of multi-level memory cells connected to a word line;
• and
• a memory controller, configured to control storage of data in the plurality of multi-level memory cells by applying a first program pulse to at least one first memory cell of the plurality of multi-level memory cells in a first type programming operation for programming the at least one first memory cell to a first program state, and by applying a second program pulse to at least one second memory cell of the plurality of multi-level memory cells in a second type programming operation for programming the at least one second memory cell to one of a second program state or a third program state,
• wherein at least one of a second step voltage, a second bit-line forcing voltage and a second verification operation of the second type programming operation is different from a first step voltage, a first bit-line forcing voltage, and a first verification operation of the first type programming operation, respectively.