Semiconductor memory device and method for manufacturing semiconductor memory device

A method for manufacturing a semiconductor memory device,

• the semiconductor memory device comprising:
• a first stacked body stacked a plurality of conductive layers via a first insulating layer above a substrate;
• a second stacked body disposed in a region in the first stacked body and stacked a plurality of second insulating layers via the first insulating layer;
• and
• a first pillar extending in the first stacked body in a stacking direction of the first stacked body and forming a memory cell at an intersection with at least a part of the conductive layers, and
• the method comprising:
• forming a plurality of first through holes extending in a boundary portion between a first region and a second region of a third stacked body in the stacking direction and arranged in two rows in a first direction along the substrate, the third stacked body being stacked the second insulating layers via the first insulating layer, and the first stacked body being to be formed in the first region of the third stacked body by replacing the second insulating layers of the first region with the conductive layers and the second stacked body being to be formed in the second region of the third stacked body by inhibiting replacement of the second insulating layers of the second region with the conductive layers;
• receding the second insulating layers from inner wall surfaces of the first through holes to remove the second insulating layers between the first through holes adjacent in the same row;
• covering the inner wall surfaces of the first through holes with a third insulating layer and filling, with the third insulating layer, a gap from which the second insulating layers have been removed to form a plurality of second pillars connected to each other in the same row by the third insulating layer;
• forming, outside an arrangement of the second pillars in two rows, a groove extending in the third stacked body in the stacking direction and facing the arrangement of the second pillars;
• and
• replacing, with the conductive layers, the second insulating layers between the second pillars and the groove without replacing the second insulating layers inside the arrangement of the second pillars in two rows.