Apparatus and Method for Adaptive Incremental Step Pulse Programming in Flash Memory Device

An apparatus and a method for adaptive ISPP(Incremental Step Pulse Programming) in a flash memory device are provided to improve threshold voltage dispersion of a cell without much loss of program time during a program operation of the flash memory, by comprising a voltage generator supplying a first or a second program voltage to a word line. A flash memory device includes a plurality of memory cells. A voltage generator(10) supplies a first or a second program voltage to word lines of the memory cells. Sense amplifiers are connected to each of bit lines of the memory cells to sense a first or a second verify time, and output the results as pass signals, respectively. A program control part(60) controls to convert the verify time of the sense amplifier and the program voltage of the voltage generator by detecting that at least more than one cells passes, referring to the pass signals. The program control part controls to perform one or more verify operation to the cells with the converted verify time.