Semiconductor device and manufacturing method thereof

1. A semiconductor device comprising:

a substrate;

an insulating film that is provided on the substrate; and

a contact plug that includes a first barrier metal layer and a second barrier metal layer provided in the insulating film, and a plug material layer provided in the insulating film, the second barrier metal layer disposed between the plug material layer and the first barrier metal layer, and the first barrier metal layer disposed between the second barrier metal layer and the insulating film,

wherein the first barrier metal layer includes a first metal element, and the second barrier metal layer includes:

a plurality of first layers including the first metal element and nitrogen, and

a second layer disposed between the plurality of first layers, the second layer including nitrogen and a second metal element different from the first metal element.

2. The semiconductor device according to claim 1 , wherein the first metal element is titanium and the second metal element is a metal element having a free energy of nitride formation smaller than that of titanium.

3. The semiconductor device according to claim 2 , wherein at least one first layer of the plurality of first layers further includes a third element having a free energy of nitride formation smaller than that of titanium.

4. The semiconductor device according to claim 3 , wherein at least one first layer of the plurality of first layers further includes a fourth element that is positioned along a boundary of crystal grains in the first layer.

5. The semiconductor device according to claim 1 , wherein the second barrier metal layer includes a plurality of the second layers disposed in alternating fashion.

6. The semiconductor device according to claim 5 , wherein at least one of the second layers includes a lower layer including the second metal element and nitrogen, and an upper layer including the second metal element, nitrogen, and oxygen.

7. The semiconductor device according to claim 1 , wherein the second layer includes a lower layer including the second metal element and nitrogen, and an upper layer including the second metal element, nitrogen, and oxygen.

8. A semiconductor device comprising:

a substrate;

an insulating film that is provided on the substrate; and

a contact plug that includes a first barrier metal layer and a second barrier metal layer provided in the insulating film, and a plug material layer provided in the insulating film, the second barrier metal layer disposed between the plug material layer and the first barrier metal layer, and the first barrier metal layer disposed between the second barrier metal layer and the insulating film,

wherein the first barrier metal layer includes a first metal element, and the second barrier metal layer includes:

a first layer including the first metal element and nitrogen, and

a second layer including the first metal element, nitrogen, and oxygen, and

wherein the first layer of the second barrier metal layer is disposed between the first barrier metal layer and the second layer of the second barrier metal layer.

9. The semiconductor device according to claim 8 , wherein the second barrier metal layer includes a plurality of the first layers and a plurality of the second layers disposed in alternating fashion.

10. A manufacturing method of a semiconductor device, comprising:

forming an insulating film on a substrate;

forming a contact hole in the insulating film;

forming a first barrier metal layer in the contact hole, the first barrier metal layer including a first metal element;

forming a second barrier metal layer on the first barrier metal layer, the second barrier metal layer including:

a first layer including the first metal element and nitrogen, and

a second layer including the first metal element or a second metal element different from the first metal element;

forming a plug material layer in the contact hole, at least one of the first barrier metal layer and the second barrier metal layer disposed between the plug material layer and the insulating film; and

performing a heating treatment to diffuse nitrogen atoms from the first layer to the second layer.

11. The manufacturing method of the semiconductor device according to claim 10 ,

wherein the first layer is formed using a first gas including the first metal element and a second gas including nitrogen, and

the second layer is formed using the first gas.

12. The manufacturing method of the semiconductor device according to claim 10 , wherein the second layer is formed by oxidizing a surface of the first layer.

13. The manufacturing method of claim 10 , wherein the first metal element is titanium and the second metal element is a metal element having a free energy of nitride formation smaller than that of titanium.

14. The manufacturing method of claim 10 , wherein the first layer further includes a third element having a free energy of nitride formation smaller than that of titanium.

15. The manufacturing method of claim 14 , wherein the first layer further includes a fourth element that is positioned along a boundary of crystal grains in the first layer.

16. The manufacturing method of claim 10 , wherein the second barrier metal layer includes a plurality of the first layers, and the second layer is disposed between the plurality of the first layers.

17. The manufacturing method of claim 16 , wherein the second layer includes a lower layer including the second metal element and nitrogen, and an upper layer including the second metal element, nitrogen, and oxygen.

18. The manufacturing method of claim 10 , wherein the second layer includes a lower layer including the second metal element and nitrogen, and an upper layer including the second metal element, nitrogen, and oxygen.