Semiconductor memory device and method of manufacturing the same

A semiconductor memory device comprising:

• a substrate;
• a plurality of first control gate electrodes stacked in a first direction crossing the substrate;
• a plurality of second control gate electrodes stacked in the first direction and aligned with the plurality of first control gate electrodes in a second direction crossing the first direction;
• a first semiconductor layer extending in the first direction;
• a charge accumulation layer disposed between one of the plurality of first control gate electrodes and the first semiconductor layer;
• a plate-like shape layer extending in the first direction and a third direction crossing the first direction and the second direction, the plate-like shape layer being provided between the plurality of first control gate electrodes and the plurality of second control gate electrodes in the second direction;
• a first spacer insulating layer disposed between the plurality of first control gate electrodes and the plate-like shape layer and including a first material;
• and
• a second spacer insulating layer disposed between the plate-like shape layer and the first spacer insulating layer and including a second material different from the first material, wherein
• the second spacer insulating layer includes:
• a first portion disposed between the plate-like shape layer and the plurality of first control gate electrodes;
• and
• a second portion further from the substrate than the plurality of first control gate electrodes, the second portion including an end in the first direction of the second spacer insulating layer, and
• a width of the second portion in the second direction decreases towards the end in the first direction of the second spacer insulating layer.