Semiconductor device comprising etch stop layer over dielectric layer and method of manufacture

1. A semiconductor device, comprising:

a first conductive feature;

a second conductive feature;

a first dielectric layer positioned between the first conductive feature and the second conductive feature;

an air gap defined in a portion of the first dielectric layer;

an etch stop layer over the first dielectric layer;

a cap layer over the first conductive feature, the second conductive feature, and the etch stop layer, wherein the cap layer is adjacent a first sidewall of the etch stop layer; and

a contact overlying the portion of the first dielectric layer positioned between the first conductive feature and the second conductive feature, wherein the contact is separated from the portion of the first dielectric layer by the etch stop layer.

2. The semiconductor device of claim 1 , wherein the cap layer is in contact with the first sidewall of the etch stop layer and a top surface of the first conductive feature.

3. The semiconductor device of claim 1 , comprising:

a second dielectric layer positioned over the cap layer, wherein:

the contact is positioned in the second dielectric layer, and

the contact is in contact with a top surface of the second conductive feature and a top surface of the etch stop layer.

4. The semiconductor device of claim 1 , wherein the contact is in direct contact with a sidewall of the cap layer and a second sidewall of the etch stop layer.

5. The semiconductor device of claim 1 , comprising:

an encapsulation layer adjacent a sidewall of the second conductive feature, wherein the etch stop layer is over a top surface of the encapsulation layer.

6. The semiconductor device of claim 1 , comprising:

a second dielectric layer positioned under the first dielectric layer; and

a third conductive feature positioned in the second dielectric layer and underlying the second conductive feature.

7. The semiconductor device of claim 1 , wherein:

the contact in direct contact with a top surface of the etch stop layer and electrically coupled to the second conductive feature.

8. The semiconductor device of claim 1 , wherein the cap layer comprises a first material, and the etch stop layer comprises a second material different than the first material.

9. The semiconductor device of claim 1 , wherein the etch stop layer comprises a hydrophilic material.

10. The semiconductor device of claim 1 , wherein the contact is in direct contact with a sidewall of the cap layer.

11. A method of forming a semiconductor device comprising:

forming a first conductive feature;

forming a first dielectric layer adjacent the first conductive feature;

selectively forming a blocking layer on a top surface of the first conductive feature, wherein a top surface of the first dielectric layer remains exposed after forming the blocking layer;

forming an etch stop layer on the top surface of the first dielectric layer while the blocking layer is positioned on the top surface of the first conductive feature;

removing the blocking layer;

forming a second dielectric layer over the etch stop layer and the first conductive feature after removing the blocking layer; and

forming a contact extending through at least a portion of the second dielectric layer.

12. The method of claim 11 , wherein forming the contact comprises:

forming the contact to contact a portion of the first conductive feature and a portion of the etch stop layer positioned over the first dielectric layer.

13. The method of claim 11 , comprising:

forming a cap layer over the first conductive feature and the etch stop layer, wherein the cap layer is adjacent a first sidewall of the etch stop layer.

14. The method of claim 11 , wherein forming the contact comprises:

forming a contact opening in the second dielectric layer to expose a portion of the etch stop layer and a portion of the first conductive feature; and

forming a conductive material in the contact opening.

15. The method of claim 11 , wherein forming the first dielectric layer comprises:

forming the first dielectric layer to define an air gap adjacent the first conductive feature.

16. A method of forming a semiconductor device, comprising:

forming a first conductive feature and a second conductive feature;

forming a first dielectric layer between the first conductive feature and the second conductive feature, wherein an air gap is defined in the first dielectric layer;

selectively forming a blocking layer on a top surface of the first conductive feature and a top surface of the second conductive feature;

forming an etch stop layer on a top surface of the first dielectric layer after selectively forming the blocking layer;

removing the blocking layer after forming the etch stop layer;

forming a second dielectric layer over the etch stop layer, the first conductive feature, and the second conductive feature after removing the blocking layer;

forming a contact opening in the second dielectric layer to expose the first conductive feature and a portion of the etch stop layer; and

forming a contact in the contact opening.

17. The method of claim 16 , comprising:

forming a cap layer over the first conductive feature, the second conductive feature, and the etch stop layer before forming the second dielectric layer, wherein forming the contact opening comprises:

removing a portion of the cap layer overlying the first conductive feature and a portion of the cap layer overlying the etch stop layer.

18. The method of claim 17 , wherein forming the contact comprises:

forming the contact to contact the top surface of the first conductive feature, a top surface of the etch stop layer, and a sidewall of the cap layer.

19. The method of claim 17 , wherein the top surface of the first conductive feature and the top surface of the second conductive feature are exposed after removing the blocking layer and before forming the cap layer.

20. The method of claim 16 , wherein forming the contact comprises forming the contact to contact with a sidewall of the etch stop layer.