Nonvolatile semiconductor memory with a programming operation and the method thereof

A nonvolatile semiconductor memory comprising:

• a memory cell array formed of a plurality of memory cell strings each connected to a plurality of bitlines;
• a plurality of page buffers each connected to a corresponding one of the bitlines;
• a plurality of transistors connected between the bitlines and the page buffers, each of the plurality of transistors operative when turned off to electrically isolate each of the plurality of page buffers from the corresponding one of the plurality of bitlines;
• and
• a bitline voltage controller applying a bitline control voltage to gates of the transistors selectively to turn the transistors off thus to effect electrical isolation between each of the plurality of page buffers and the corresponding one of the plurality of bitlines,
• wherein the bitline control voltage is charged to a first voltage during a part of a first bitline setup period, a second voltage during the remaining of the first bit line period, and a third voltage during a second bitline setup period.