Method and system to determine quick pass write operation in increment step pulse programming operation

摘要

A method for determining quick-pass-write (QPW) operation in increment-step-program-pulse (ISPP) operation is provided. The QPW operation is simultaneously applying a bit line voltage during the ISPP operation. The method includes, according to bit line voltages varying in a first range and voltage difference values varying in a second range with respect to a verified voltage, estimating a shrinkage quantity of threshold voltage distribution width at each bit line voltage and each voltage difference value, so as to obtain a shrinkage-quantity topographic contour. According to the bit line voltages and the voltage difference values, a program shot number as needed to achieve the verified voltage is estimated, so as to obtain a program-shot-number topographic contour. The shrinkage-quantity topographic contour and the program-shot-number topographic contour are overlapped to determine an operation region formed from an application range of the bit line voltage and an application range of the voltage difference value.