Semiconductor memory device and manufacturing method of semiconductor memory device

The semiconductor memory device of claim further comprising:

• a first interlayer insulating layer surrounding the channel structure between the first gate conductive pattern and the second gate conductive pattern;
• a second interlayer insulating layer overlapping with the first interlayer insulating layer with the first gate conductive pattern interposed between the second interlayer insulating layer and the first interlayer insulating layer, wherein the second interlayer insulating layer surrounds the channel structure;
• a first gate spacer insulating layer surrounding a sidewall of the first vertical part, wherein the first gate spacer insulating layer is penetrated by the first horizontal part;
• and
• a second gate spacer insulating layer surrounding a sidewall of the second vertical part, wherein the second gate spacer insulating layer is penetrated by the second horizontal part.

A semiconductor memory device comprising:

• a peripheral circuit layer including a first region and a second region;
• a bonding structure disposed on the peripheral circuit layer;
• a cell stack structure overlapping with the first region, the cell stack structure including gate conductive patterns and interlayer insulating layers, which are alternately stacked on the bonding structure;
• a channel structure penetrating the cell stack structure;
• a dummy stack structure overlapping with the second region, wherein the dummy stack structure includes first material layers and second material layers, which are alternately stacked on the bonding structure;
• a vertical contact structure penetrating the dummy stack structure and the bonding structure to be connected to the peripheral circuit layer;
• and
• a dummy spacer insulating layer surrounding a sidewall of the vertical contact structure,
• wherein the dummy spacer insulating layer includes a pillar part extending along the sidewall of the vertical contact structure and protrusion parts protruding toward the second material layers from the pillar part to fill spaces between the first material layers.