Advanced copper interconnects with hybrid microstructure

1. An integrated circuit comprising:

a first wire, extending in a first direction parallel to a substrate, comprising a narrow-line bamboo microstructure integrated within a first metal layer of the integrated circuit, wherein the narrow-line bamboo microstructure has a depth, d 1 ; and a second wire, extending in the first direction parallel to the substrate, comprising a narrow-line polycrystalline microstructure, wherein the narrow line polycrystalline microstructure has a depth, d 2 , wherein d 1 is less than d 2 , wherein the first and second wires are integrated within the same metal layer, a third wire extending in a second direction parallel to the substrate, the third wire comprising a narrow-line bamboo microstructure integrated within a second metal layer of the integrated circuit, wherein the narrow-line bamboo microstructure has a depth, d 3 ; and a fourth wire, extending in the second direction parallel to the substrate, the fourth wire comprising a narrow-line polycrystalline microstructure, wherein the narrow-line polycrystalline microstructure has a depth, d 4 , wherein d 3 is less than d 4 , wherein the third and fourth wires are integrated within the same second metal layer, different from the first metal layer.

2. The integrated circuit of claim 1 , wherein the first and second wires comprise copper interconnects.

3. The integrated circuit of claim 1 , wherein a difference in aspect ratio between the narrow-line bamboo microstructure and the narrow-line polycrystalline microstructure is greater than 0.5.

4. The integrated circuit of claim 1 , wherein:

the first and second wires are disposed on a liner material; and

the liner material is disposed on trench sidewalls within a dielectric layer.

5. The integrated circuit of claim 4 , wherein the liner material comprises tantalum, titanium, tungsten, cobalt, ruthenium, and their nitrides thereof, or a combination comprising at least one of the foregoing.

6. The integrated circuit of claim 5 , wherein the dielectric layer comprises a low-K dielectric material.

7. The integrated circuit of claim 6 , wherein the dielectric layer comprises silicon dioxide, silsesquixoane, organosilicates, thermosetting polyarylene ethers, or a combination comprising at least one of the foregoing.

8. The integrated circuit of claim 7 , wherein the dielectric layer comprises silicon dioxide.

9. The integrated circuit of claim 1 , wherein the integrated circuit has reduced electromigration as compared to an integrated circuit without a narrow-line bamboo microstructure and a narrow-line polycrystalline microstructure.

10. The integrated circuit of claim 1 , wherein an electromigration resistance of the narrow-line bamboo microstructure is greater than 0.9 electron Volt of electromigration energy.

11. The integrated circuit of claim 1 , wherein the integrated circuit has a conductivity of less than 4 micro Ohm-centimeters copper resistivity in the narrow-line bamboo microstructure at a thickness of less than 100 nanometers.

12. The integrated circuit of claim 1 , wherein the substrate comprises Si, SiGe, SiGeC, SiC, Ge alloys, GaAs, InAs, InP and other 111/V or II/VI compound semiconductors, or a combination comprising at least one of the foregoing.

13. The integrated circuit of claim 4 , wherein the liner material comprises tantalum.

14. The integrated circuit of claim 4 , wherein the liner material comprises cobalt.

15. The integrated circuit of claim 4 , wherein the liner material comprises ruthenium.

16. The integrated circuit of claim 6 , wherein the low-K dielectric material has a dielectric constant of about 3.0 or less.

17. The integrated circuit of claim 6 , wherein the low-K dielectric material has a dielectric constant of about 2.8 or less.

18. The integrated circuit of claim 1 , wherein the narrow-line bamboo microstructure and the narrow-line polycrystalline microstructure each have a minimum width on a feature side of less than or equal to 75 nm.