Three-dimensional semiconductor device

A semiconductor device comprising:

• a substrate including a cell array region and a connection region;
• and
• a stack structure including a first stack and a second stack on the first stack, each of the first and second stacks including a first electrode and a second electrode on the first electrode,
• wherein the second electrode of the first stack has a first length in a first direction, the second electrode of the second stack has a second length in the first direction, and the second length is shorter than the first length,
• wherein, in each of the first and second stacks, a sidewall of the first electrode is spaced apart from a sidewall of the second electrode by a first distance in the first direction,
• wherein the first distance is less than a difference between the first length and the second length, and
• wherein each of the first and second stacks has a sloped sidewall defined by sidewalls of the first and second electrodes.

A semiconductor device comprising:

• a substrate including a cell array region and a connection region;
• and
• a stack structure including a first stack on the substrate and a second stack on the first stack, each of the first and second stacks including first, second, third, and fourth electrodes sequentially and vertically stacked;
• and
• contact plugs respectively connected to the fourth electrodes of the first and second stacks,
• wherein the first stack has a first length in a first direction, the second stack has a second length in the first direction, and the second length is shorter than the first length, and
• wherein each of the first and second stacks has a sloped sidewall defined by sidewalls of the first, second, third, and fourth electrodes.