Semiconductor memory device and manufacturing method thereof

A manufacturing method of a semiconductor memory device, the method comprising:

• forming a hole penetrating through a stacked body in a first direction, the stacked body including sacrifice layers and insulating layers alternately stacked on top of one another;
• forming a first insulating film along an inner surface of the hole;
• filling the hole with a sacrificial member;
• forming a staircase portion over the hole filled with the sacrificial member;
• forming a second insulating film on the sacrificial member, the second insulating film formed on a step surface of the staircase portion;
• replacing the sacrifice layer with a conductive layer;
• removing the sacrificial member to again expose the hole;
• removing, through the hole, a portion of the second insulating film;
• and
• forming a contact plug in the re-exposed hole, the contact plug being electrically connected to the conductive layer.

A semiconductor memory device comprising:

• a first stacked body including a plurality of first conductive layers and a plurality of first insulating layers alternately stacked in a first direction, the first stacked body further including a first staircase portion;
• and
• a second stacked body including a plurality of second conductive layers and a plurality of second insulating layers alternately stacked in the first direction, the second stacked body further including a second staircase portion, the first staircase portion and the second staircase portion facing each other;
• a first contact plug electrically connected to a corresponding one of the first conductive layers and extending from a first step surface of the corresponding first conductive layer in the first direction to penetrate through a corresponding portion of the first stacked body;
• and
• a second contact plug electrically connected to corresponding one of the second conductive layers and extending from a second step surface of the corresponding second conductive layer in the first direction to penetrate through a corresponding portion of the second stacked body, wherein
• the first contact plug extends to penetrate the first stacked body on a side on which the first step surface is provided and is electrically connected to a switch circuit, and
• the first contact plug extends to penetrate the first stacked body on a side opposite to the side on which the first step surface is provided and is electrically connected to the second contact plug.

A manufacturing method of a semiconductor memory device, the method comprising:

• forming a first stacked body and a second stacked body each including sacrifice layers and insulating layers alternately stacked in a first direction;
• forming a first staircase portion at an end portion of the first stacked body and a second staircase portion at an end portion of the second stacked body, the first staircase portion and the second staircase portion facing each other;
• forming a first hole passing through a first step surface of the first staircase portion and penetrating the first stacked body in the first direction and a second hole passing through a second step surface of the second staircase portion and penetrating the second stacked body in the first direction;
• replacing the sacrifice layer with a conductive layer;
• forming a first contact plug electrically connected to the conductive layer at the first step surface and a second contact plug electrically connected to the conductive layer at the second step surface in the first hole and the second hole, respectively;
• and
• forming a second wiring electrically connecting the first contact plug to the second contact plug at a position on a side opposite to a side on which the first step surface and the second step surface are provided relative to the first stacked body and the second stacked body.