FLASH MEMORY DEVICE AND PROGRAM METHOD THEREOF

摘要

PURPOSE: A flash memory device and a program method thereof are provided to improve program speed by removing a program verification operation of a small memory cell which has a little threshold voltage change. CONSTITUTION: In a flash memory device and a program method thereof, a program of 1 -th bit of a 4- bit MLC is performed. The program of an upper 3 bit excluding a least significant bit(LSB) is performed through a plurality of program steps. Each program step is composed of a plurality of program loops. The level of change of a threshold voltage is highest at sT7 and lowest at ST4. A program verification operation of ST5 and ST6 program is removed. The program verification operation of ST7 program is performed. The program verification operation of ST4 program is performed.