Semiconductor memory device

A semiconductor memory device comprising:

• memory pillars provided above a substrate;
• conductive layers provided around the memory pillars, isolated from each other and stacked above the substrate;
• a first insulation layer provided above the memory pillars;
• and
• a second insulation layer provided on side walls of the conductive layers and a side wall of the first insulation layer, and on an upper surface of the first insulation layer.

A method of manufacturing semiconductor memory device comprising:

• forming a stacked body in which first insulation layers and second insulation layers are stacked above a substrate along a first direction crossing a surface of the substrate;
• forming memory pillars that extend through the stacked body along the first direction;
• forming a third insulation layer on the memory pillars;
• forming a trench in the stacked body and the third insulating layer along a second direction crossing the first direction;
• forming a fourth insulation layer on a side wall of the trench and on the third insulation layer;
• forming a fifth insulation layer in the trench and on the fourth insulation layer;
• and
• removing the fifth insulation layer over the trench and on the fourth insulation layer.