Patent attributes
There are provided a memory device and an operating method thereof. The memory device includes: sub-blocks divided with respect to a buffer page in which buffer cells are included; a voltage generator for, in a program operation of a selected sub-block among the sub-blocks, applying a first pass voltage to unselected word lines connected to the selected sub-block, and applying a second pass voltage lower than the first pass voltage to unselected word lines connected to an unselected sub-block; and a buffer line circuit for selectively turning on or turning off the buffer cells by selectively applying a turn-on voltage or a turn-off voltage to buffer lines connected to the buffer cells. A position of the buffer page is set as a default according to a physical structure of memory cells included in the sub-blocks, and is reset according to an electrical characteristic of the memory cells.