Semiconductor device

1 . A semiconductor device comprising:

a lower structure;

a first contact structure connected to the lower structure;

a first conductive wiring connected to the first contact structure;

a first etch-stop layer and an interlayer insulating layer sequentially provided on the first conductive wiring;

a second contact structure passing through the first etch-stop layer, provided in the interlayer insulating layer, and connected to the first conductive wiring;

a second conductive wiring provided on the second contact structure and provided in the interlayer insulating layer;

a barrier layer comprising a first barrier portion provided on a bottom surface of the second contact structure;

a second etch-stop layer on a top surface of the second conductive wiring and a top surface of the interlayer insulating layer, the second etch-stop layer comprising an extension portion extending toward the barrier layer and extending between the second conductive wiring and the interlayer insulating layer such that the extension portion is provided on an upper portion of a side surface of the second conductive wiring; and

an air gap between the barrier layer and the extension portion.

2 . The semiconductor device of claim 1 , wherein the barrier layer extends such that the barrier layer is provided on at least a portion of a side surface of the second contact structure.

3 . The semiconductor device of claim 1 , wherein the second contact structure and the second conductive wiring form a conductive structure, and

wherein the air gap is defined by the conductive structure, the interlayer insulating layer, the extension portion, and the barrier layer.

4 . The semiconductor device of claim 1 , wherein the barrier layer further comprises:

a second barrier portion covering a side surface of the second contact structure,

a third barrier portion covering a bottom surface of the second conductive wiring, and

a fourth barrier portion covering a portion of the side surface of the second conductive wiring.

5 . The semiconductor device of claim 1 , wherein the air gap comprises:

a first gap portion covering a side surface of the second contact structure,

a second gap portion covering a bottom surface of the second conductive wiring, and

a third gap portion covering a portion of the side surface of the second conductive wiring.

6 . The semiconductor device of claim 1 , wherein at least a portion of a bottom surface of the barrier layer contacts a top surface of the first conductive wiring.

7 . The semiconductor device of claim 1 , wherein the second contact structure and the second conductive wiring have an integrated structure.

8 . The semiconductor device of claim 1 , wherein the top surface of the second conductive wiring and the top surface of the interlayer insulating layer are substantially coplanar.

9 . The semiconductor device of claim 1 , wherein the second contact structure and the second conductive wiring comprise at least one of ruthenium (Ru) and molybdenum (Mo).

10 . The semiconductor device of claim 1 , wherein the lower structure comprises a cell switching device, a bit line, and a cell capacitor, and

wherein the first conductive wiring, the second contact structure, and the second conductive wiring are at a level higher than a level than the cell capacitor.

11 . The semiconductor device of claim 1 , wherein the first contact structure and the first conductive wiring have an integrated structure.

12 . The semiconductor device of claim 11 , wherein the integrated structure of the first contact structure and the first conductive wiring comprises at least one of ruthenium (Ru) or molybdenum (Mo).

13 . A semiconductor device comprising:

a first conductive wiring;

a contact structure connected to the first conductive wiring, the contact structure comprising at least one of ruthenium (Ru) or molybdenum (Mo);

a second conductive wiring connected to the contact structure, the second conductive wiring comprising at least one of ruthenium (Ru) or molybdenum (Mo);

an interlayer insulating layer surrounding a side surface of the contact structure and a side surface of the second conductive wiring;

a barrier layer comprising:

a first barrier portion provided between a bottom surface of the contact structure and a top surface of the first conductive wiring, and

a second barrier portion provided between a side surface of the contact structure and the interlayer insulating layer;

an etch-stop layer provided on a top surface of the interlayer insulating layer and a top surface of the second conductive wiring, the etch-stop layer comprising an extension portion extending toward the barrier layer and provided between the side surface of the second conductive wiring and the interlayer insulating layer; and

an air gap between the second barrier portion of the barrier layer and the extension portion of the etch-stop layer.

14 . The semiconductor device of claim 13 , wherein the second barrier portion of the barrier layer entirely covers the side surface of the contact structure, and

wherein the barrier layer further comprises:

a third barrier portion extending from the second barrier portion such that the third barrier portion is provided on a bottom surface of the second conductive wiring, and

a fourth barrier portion extending from the third barrier portion such that the fourth barrier portion is provided on a first portion of the side surface of the second conductive wiring.

15 . The semiconductor device of claim 14 , wherein the air gap covers a second portion of the side surface of the second conductive wiring.

16 . The semiconductor device of claim 13 , wherein the second barrier portion of the barrier layer is provided on a first portion of the side surface of the contact structure.

17 . The semiconductor device of claim 16 , wherein the air gap comprises:

a first gap portion covering a second portion of the side surface of the contact structure,

a second gap portion covering a bottom surface of the second conductive wiring, and

a third gap portion covering a portion of the side surface of the second conductive wiring.

18 . A semiconductor device comprising:

a lower structure;

a contact structure connected to the lower structure, the contact structure comprising:

a lower portion comprising a first side surface having a first inclination, and

an upper portion comprising a second side surface having a second inclination different from the first inclination;

a conductive wiring provided on the contact structure and having a structure integrated with the contact structure, the conductive wiring comprising a third side surface aligned with the second side surface of the contact structure and having a third inclination that is the same as the second inclination; and

a barrier layer provided on at least the first side surface of the lower portion of the contact structure,

wherein the first side surface of the lower portion contacts the second side surface of the upper portion.

19 . The semiconductor device of claim 18 , wherein the lower portion of the contact structure has a gradually decreasing width in a downward direction, and

wherein the upper portion of the contact structure and the conductive wiring have a gradually decreasing width in an upward direction.

20 . The semiconductor device of claim 18 , wherein the contact structure and the conductive wiring are formed of a same first material, and

wherein the first material comprises at least one of ruthenium (Ru) or molybdenum (Mo).