Abstract: A semiconductor memory device including a substrate; a mold structure including gate electrodes and mold insulating layers stacked in a stair shape, channel structures on the substrate, intersecting the gate electrodes, and passing through the mold structure; cell contacts connected to the gate electrodes; a first interlayer insulating layer on the mold structure and covering the channel structures and cell contacts; first metal patterns connected to the channel structures, an upper surface of the first metal patterns being coplanar with an upper surface of the first interlayer insulating layer; second metal patterns connected to the cell contacts, an upper surface of the second metal patterns being coplanar with the upper surface of the first metal patterns; a first blocking layer along the upper surface of the first interlayer insulating layer, the first metal patterns, and the second metal patterns; and a first dummy vias passing through the first blocking layer.

Abstract: A semiconductor memory device comprising a substrate including a cell array area and an extension area, a mold structure including, a plurality of gate electrodes sequentially stacked on the cell array area of the substrate and stacked in a stair shape on the extension area of the substrate, and a plurality of mold insulating films stacked alternately with the plurality of gate electrodes, a plurality of channel structures on the cell array area of the substrate, wherein each of the plurality of channel structures extends through the mold structure and intersects the plurality of gate electrodes, a plurality of cell contacts on the extension area of the substrate and respectively connected to the plurality of gate electrodes, a first interlayer insulating film on the mold structure so as to cover the plurality of channel structures and the plurality of cell contacts.