Semiconductor memory device

A semiconductor memory device comprising:

• a substrate comprising a stack region and a pad region arranged in a first horizontal direction;
• a first word line stack comprising a plurality of first word lines each extending in the first horizontal direction in the stack region and the pad region and stacked in a vertical direction;
• a second word line stack spaced apart from the first word line stack in a second horizontal direction intersecting the first horizontal direction and comprising a plurality of second word lines each extending in the first horizontal direction in the stack region and the pad region and stacked in the vertical direction;
• a plurality of bit lines extending in the vertical direction in the stack region and spaced apart in the first horizontal direction;
• and
• a plurality of word line pads between the first word line stack and the second word line stack in the pad region and spaced apart in the vertical direction and the first horizontal direction.

A semiconductor memory device comprising:

• a substrate comprising a stack region and a pad region arranged in a first horizontal direction;
• a first word line stack comprising a plurality of first word lines each extending in the first horizontal direction in the stack region and the pad region and stacked in a vertical direction;
• a second word line stack spaced apart from the first word line stack in a second horizontal direction intersecting the first horizontal direction and comprising a plurality of second word lines each extending in the first horizontal direction in the stack region and the pad region and stacked in the vertical direction;
• a plurality of bit lines extending in the vertical direction in the stack region and spaced apart in the first horizontal direction;
• a plurality of memory cells in the stack region and comprising a cell transistor and an information storage element;
• a plurality of word line pads arranged in the first horizontal direction at different vertical levels, between the first word line stack and the second word line stack in the pad region;
• and
• a plurality of word line contacts extending in the vertical direction on the plurality of word line pads, each word line contact comprising a plurality of contact portions spaced apart from each other in the second horizontal direction,
• wherein a width of each of the plurality of word line pads in the first horizontal direction is less than a width of each word line pad in the second horizontal direction.