Nonvolatile memory device and programming method thereof

A non-volatile memory device and an operating method thereof are provided. An operating method of a non-volatile memory device, the non-volatile memory device including a plurality of cell strings each including a first stack and a second stack adjacent to the first stack, the operation method includes the steps of: performing a first program operation during a period in which a plurality of program loops are performed by applying a program voltage including a first plurality of voltage levels to a selection word line of a first stack connected to each of a plurality of cell strings; applying a second voltage including a second plurality of voltage levels to a non-selection word line of the first stack connected to each of the plurality of cell strings during the period; and during the period, maintaining a third voltage at the first level, the third voltage being applied to a non-selected word line of the second stack connected to each of the plurality of cell strings. 提供了一种非易失性存储器装置及其操作方法。非易失性存储器装置的操作方法，非易失