Non-volatile memory devices, operating methods thereof and memory systems including the same

A method of programming a nonvolatile memory device including a plurality of memory cells stacked on a substrate in a direction vertical to the substrate, each of the plurality of memory cells coupled to corresponding word line among a plurality of word lines stacked along the plurality of memory cells, and the plurality of memory cells being divided into a first portion and a second portion, the second portion being stacked over the first portion, the method comprising:

• applying a first program voltage on a first word line located in the first portion;
• applying a first pass voltage on a third word line located in the first portion while applying the first program voltage on the first word line;
• applying a second program voltage on a second word line located in the first portion;
• and
• applying a second pass voltage on the third word line located in the first portion while applying the second program voltage on the first word line,
• wherein the second word line being located farther from the substrate than the first word line and adjacent to the first word line, the third word line being located farther from the substrate than the second word line and adjacent to the second word line, and the level of the second pass voltage is higher than the level of the first pass voltage.

A method of programming a nonvolatile memory device including a plurality of memory cells stacked on a substrate in a direction vertical to the substrate, each of the plurality of memory cells coupled to corresponding word line among a plurality of word lines stacked along the plurality of memory cells, and the plurality of memory cells being divided into a first portion and a second portion, the second portion being stacked over the first portion, the method comprising:

• applying a first program voltage on a first word line located in the first portion;
• and
• applying a first pass voltage on a second word line and applying a second pass voltage on a third word line respectively, the second word line being located farther from the substrate than the first word line and adjacent to the first word line, the third word line being located farther from the substrate than the second word line and adjacent to the second word line,
• wherein the level of the second pass voltage is lower than the level of the first pass voltage.