Patent ID: 8472245

Claim:
A method of operating a nonvolatile memory device, comprising: executing an i-th programming interval of a programming operation directed to a memory cell by applying an i-th programming voltage to a word line connected to the memory cell and applying either (1) a bit line forcing voltage to a bit line connected to the memory cell if the memory cell is a fast memory cell having a threshold voltage that resides in a proximate threshold voltage range less than a target threshold voltage distribution, or (2) a bit line program voltage less than the bit line forcing voltage to the bit line if the memory cell is a slow memory cell having a threshold voltage that resides in a distant threshold voltage range less than the proximate threshold voltage range; evaluating a programming condition; selecting a verification mode from a group of verification modes on the basis of the evaluated programming condition; and executing a verification operation using the selected verification mode in relation to the memory cell.