US 2026/0293105 A1Published application

Semiconductor storage device and manufacturing method of semiconductor storage device

OwnerDaisuke WATANABE, Akifumi GAWASE +1inventors

InventorsDaisuke WATANABE, Akifumi GAWASE, Takuya KIKUCHI

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Abstract

A semiconductor storage device includes a capacitor including a first electrode, a second electrode, and a capacitor insulating film between the first electrode and the second electrode, and a transistor including a third electrode, a fourth electrode, an oxide semiconductor layer between the third electrode and the fourth electrode, and a gate electrode. The first electrode includes a first portion, a second portion, and a third portion. A chemical composition of the first portion is different from a chemical composition of the third portion, and a chemical composition of the second portion is different from the chemical composition of the third portion. The first portion is provided between the third portion and the third electrode in a first direction, and the second electrode includes a fourth portion. The second portion surrounds the fourth portion, and the fourth portion surrounds the first portion in a cross-section perpendicular to the first direction.

Claims22

Dependent claims

A semiconductor storage device comprising:

a first capacitor that includes a first electrode, a second electrode, and a first capacitor insulating film provided between the first electrode and the second electrode;
and
a first transistor that includes a third electrode in contact with the second electrode, a fourth electrode, a first oxide semiconductor layer provided between the third electrode and the fourth electrode, a first gate electrode facing the first oxide semiconductor layer, and a first gate insulating film provided between the first gate electrode and the first oxide semiconductor layer, wherein
the first transistor and the first capacitor are arranged in a first direction,
the first electrode includes a first portion having a first chemical composition, a second portion having a second chemical composition, and a third portion having a third chemical composition,
the first chemical composition of the first portion is different from the third chemical composition of the third portion,
the second chemical composition of the second portion is different from the third chemical composition of the third portion,
the first portion is provided between the third portion and the third electrode in the first direction,
the second electrode includes a fourth portion, and
in a first cross-section perpendicular to the first direction, the second portion surrounds the fourth portion and the fourth portion surrounds the first portion.

7 more elements

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

forming an opening in a first insulating layer;
forming a first conductive film in the opening;
forming a second conductive film having a chemical composition different from a chemical composition of the first conductive film on the first conductive film in the opening;
forming a third conductive film having a chemical composition different from a chemical composition of the second conductive film on the second conductive film in the opening to fill the opening;
removing the third conductive film, the second conductive film, and the first conductive film on a surface of the first insulating layer;
selectively removing an upper portion of the first conductive film and an upper portion of the third conductive film in the opening without removing an upper portion of the second conductive film;
selectively removing a part of the second conductive film in the opening without removing a part of the first conductive film or a part of the third conductive film, to form a pillar structure of the third conductive film;
forming an insulating film on the first conductive film, the second conductive film, and the third conductive film in the opening;
and
forming a fourth conductive film on the insulating film in the opening to fill a space between the first conductive film and the pillar structure.

7 more elements

Dependencies are inferred from the claim text.