Threshold based multi-level cell programming for a non-volatile memory device

A method of programming a memory device includes programming a low bit to a memory cell included in a word line and a bit line based on a first verification condition, the low bit belonging to a group of bits including a high bit. The first verification condition is based on at least one of a first bit line current, a first develop time for verifying the programming of the low bit, and a first word line voltage. The method includes programming the high bit to the memory cell based on a second verification condition. The second verification condition is based on at least one of a second bit line current, a second develop time for verifying the programming of the high bit, and a second word line voltage.