Patent ID: 7428165

Claim:
A method for programming a memory system, said system comprising strings of charge storage transistors for storing different charge states, said strings including a first and a second string each connected between one of a plurality of bit lines and a source line and controlled by common word lines, said method comprising: programming the system by applying a program voltage to the word lines, one selected word line at a time, to program all of the transistors in the first string; coupling, during the programming, first boosting voltage level(s) to at least some of the transistors in the second string between said selected word line and said one bit line connected to the second string to boost electrical potential(s) of channel regions of transistors in the second string to a value or values closer to the program voltage to reduce program disturb; and coupling, during the programming, a second voltage level that is less than the first voltage level(s) to at least one isolation charge storage transistor having a source and drain in the second string between the selected word line and the source line, said second voltage level being such that a first channel area of the second string on the source side of the at least one isolation transistor is electrically isolated from a second channel area of the second string on the drain side of the at least one isolation transistor, so that the at least one isolation transistor is at a plurality of positions separated from the selected word line at different times during the programming; wherein when the selected word line is at a first position at a first distance from said one bit line and at a second position at a second distance smaller than the first distance from said one bit line at two different times, the coupling is such that the position or positions of the at least one isolation transistor is separated from the second position by a larger number of word lines than from the first position, to reduce program disturb, and such that the position or positions of the at least one isolation is separated from the first and second positions by at least one word line.