US Patent 7983079 Nonvolatile semiconductor memory device and programming method thereof

Provided is a program method of a multi-bit flash memory device. The program method includes correspondingly programming multi-bit data into selected memory cells through pluralities of programming loops. In each programming loop, an increment of a programming voltage applied to the selected memory cells is variable in accordance with a result of program-verification to each of data states with the multi-bit data and the program-verification for the data state corresponding to program-pass is skipped if the result of the program-verification to the data state is passed.