Semiconductor memory device and method for manufacturing same

A semiconductor memory device, comprising:

• a semiconductor pillar extending in a first direction;
• a first electrode extending in a second direction crossing the first direction;
• a second electrode provided between the semiconductor pillar and the first electrode;
• a first insulating film provided between the semiconductor pillar and the second electrode;
• and
• a second insulating film provided between the first electrode and the second electrode,
• the second insulating film including
• a first layer disposed on the first electrode side of the second electrode and on two first-direction sides of the second electrode,
• a second layer disposed between the first layer and the first electrode and on two first-direction sides of the first electrode, and
• a third layer disposed between the first electrode and the second layer,
• a portion of the second layer being disposed on two first-direction sides of the first layer.

A semiconductor memory device, comprising:

• a semiconductor pillar extending in a first direction;
• a first electrode extending in a second direction crossing the first direction;
• a second electrode provided between the semiconductor pillar and the first electrode;
• a first insulating film provided between the semiconductor pillar and the second electrode;
• and
• a second insulating film provided between the first electrode and the second electrode,
• the second insulating film including
• a first layer contacting the second electrode, the first layer not being disposed on two first-direction sides of the second electrode,
• a second layer contacting the first layer and being disposed between the first layer and the first electrode, and
• a third layer contacting the second layer and the first electrode and being disposed between the second layer and the first electrode, the third layer not being disposed on two first-direction sides of the first electrode.

A method for manufacturing a semiconductor memory device, comprising:

• stacking an inter-layer insulating film and a first film alternately along a first direction;
• forming a trench extending in a second direction and piercing the inter-layer insulating film and the first film, the second direction crossing the first direction;
• forming a first recess in a side surface of the trench by removing a portion of the first film via the trench;
• forming a first insulating layer on the side surface of the trench and on an inner surface of the first recess;
• forming a first conductive film on the first insulating layer inside the first recess;
• performing etch-back of the first insulating layer to remove a portion of the first insulating layer disposed on the side surface of the trench, remove a portion of the first insulating layer disposed on the trench side of the first recess, and cause a portion of the first insulating layer disposed on an inner portion of the first recess to remain;
• forming a second conductive film inside the first recess;
• forming a first insulating film on the side surface of the trench;
• forming a semiconductor film on a side surface of the first insulating film;
• forming a slit extending in the second direction and piercing the inter-layer insulating film and the first film;
• forming a second recess in a side surface of the slit by removing the first film via the slit;
• forming a second insulating layer on an inner surface of the second recess;
• forming a first electrode inside the second recess;
• and
• dividing the semiconductor film, the first insulating film, the second conductive film, and the first conductive film along the second direction.

A method for manufacturing a semiconductor memory device, comprising:

• stacking an inter-layer insulating film and a first film alternately along a first direction;
• forming a trench extending in a second direction and piercing the inter-layer insulating film and the first film, the second direction crossing the first direction;
• forming a first recess in a side surface of the trench by removing a portion of the first film via the trench;
• forming a first insulating layer on an inner surface of the first recess;
• forming a first conductive film on the first insulating layer;
• forming a first insulating film on the side surface of the trench;
• forming a semiconductor film on a side surface of the first insulating film;
• forming a slit extending in the second direction and piercing the inter-layer insulating film and the first film;
• forming a second recess in a side surface of the slit by removing the first film via the slit;
• enlarging the second recess to two first-direction sides of the first insulating layer by etching the inter-layer insulating film;
• forming a second insulating layer on an inner surface of the second recess;
• forming a first electrode inside the second recess;
• and
• dividing the semiconductor film, the first insulating film, and the first conductive film along the second direction.

A method for manufacturing a semiconductor memory device, comprising:

• stacking an inter-layer insulating film and a first film alternately along a first direction;
• forming a trench extending in a second direction and piercing the inter-layer insulating film and the first film, the second direction crossing the first direction;
• forming a first recess in a side surface of the trench by removing a portion of the first film via the trench;
• forming a first insulating layer on the side surface of the trench to fill an interior of the first recess;
• recessing the first insulating layer to expose the inter-layer insulating film at a portion of an upper surface of the first recess and a portion of a lower surface of the first recess, and to cause the first insulating layer to remain on a back surface of the first recess;
• forming a first conductive film inside the first recess;
• forming a first insulating film on the side surface of the trench;
• forming a semiconductor film on a side surface of the first insulating film;
• forming a slit extending in the second direction and piercing the inter-layer insulating film and the first film;
• forming a second recess in a side surface of the slit by removing the first film via the slit;
• forming a second insulating layer on an inner surface of the second recess;
• forming a first electrode inside the second recess;
• and
• dividing the semiconductor film, the first insulating film, and the first conductive film along the second direction.

A method for manufacturing a semiconductor memory device, comprising:

• stacking an inter-layer insulating film and a first film alternately along a first direction;
• forming a trench extending in a second direction and piercing the inter-layer insulating film and the first film, the second direction crossing the first direction;
• forming a first recess in a side surface of the trench by removing a portion of the first film via the trench;
• forming a first insulating layer on an inner surface of the first recess;
• forming a first conductive film on the first insulating layer;
• forming a first insulating film on the side surface of the trench;
• forming a semiconductor film on a side surface of the first insulating film;
• forming a slit extending in the second direction and piercing the inter-layer insulating film and the first film;
• forming a second recess in a side surface of the slit by removing the first film via the slit;
• forming a second insulating layer on the side surface of the trench to fill an interior of the second recess;
• recessing the second insulating layer to expose the inter-layer insulating film at a portion of an upper surface of the second recess and a portion of a lower surface of the second recess, and to cause the second insulating layer to remain on a back surface of the second recess;
• forming a first electrode inside the second recess;
• and
• dividing the semiconductor film, the first insulating film, and the first conductive film along the second direction.