Low capacitance interconnect structures and associated systems and methods

1. A method of manufacturing a semiconductor device, the method comprising:

forming an opening in a surface of a semiconductor die, wherein the opening includes a sidewall; and

forming an interconnect structure at least within the opening, wherein forming the interconnect structure includes

depositing a first insulator material on both the surface and the sidewall, wherein the first insulator material has a first portion on the surface and a second portion on the sidewall, and wherein the second portion has a first thickness,

selectively removing the first portion over the second portion,

depositing a second insulator material on the second portion, wherein the second insulator material has a second thickness,

depositing a conductive material on the second insulator material, and

selecting at least one of the first thickness and the second thickness based on a threshold level of capacitance between the sidewall and the conductive material.

2. The method of claim 1 wherein:

depositing the first insulator material includes depositing the first insulator material via chemical vapor deposition (CVD); and

depositing the second insulator material includes depositing the second insulator material via CVD.

3. The method of claim 1 wherein:

depositing the first insulator material includes depositing the first insulator material via chemical vapor deposition (CVD); and

depositing the second insulator material includes depositing the second insulator material via atomic layer deposition (ALD).

4. The method of claim 1 wherein at least one of the first and second insulator materials is silicon oxide.

5. The method of claim 1 wherein one of the first and second insulator materials is silicon oxide, while the other is a material different than silicon oxide.

6. The method of claim 1 wherein the first insulator material is silicon carbide or silicon nitride.

7. The method of claim 6 wherein the second insulator material is silicon oxide.

8. The method of claim 1 where selectively removing the first portion over the second portion includes removing the first portion with an anisotropic etch.

9. The method of claim 1 wherein the surface is at a first side of the semiconductor die, and wherein the method further comprises removing material at a second side of the semiconductor die opposite the first side to expose a portion of the second insulator material.

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

forming an opening in a semiconductor die, wherein the semiconductor die includes an upper surface outside the opening, a lower surface at a base of the opening, and a sidewall adjacent to the lower surface; and

forming an interconnect structure at least within the opening, wherein forming the interconnect structure includes

covering the sidewall and the upper and lower surfaces with a first insulator, wherein a first portion of the insulator covers the sidewall,

depositing a second insulator in the opening, wherein a second portion of the second insulator covers the first portion to define a composite insulator composed of the first portion of the first insulator and the second portion of the second insulator,

selectively removing insulator material on the upper surface and insulator material on the lower surface without substantially removing the first and second portions,

depositing a conductive material on the second portion, and

selecting a composite thickness of the composite insulator based on a threshold level of capacitance between the sidewall and the conductive material.

11. The method of claim 10 wherein selectively removing the insulator material includes removing portions of the first insulator.

12. The method of claim 11 wherein removing the portions of the first insulator includes exposing the upper surface and the lower surface.

13. The method of claim 11 wherein removing the portions of the first insulator includes exposing the upper surface, but not the lower surface.

14. The method of claim 10 wherein selectively removing the insulator material includes removing portions of the second insulator.

15. The method of claim 14 wherein removing the portions of the second insulator includes exposing the first insulator, but not the upper and lower surfaces.

16. The method of claim 10 wherein the first insulator is an etch stop material.

17. A method of manufacturing an interconnect structure, the method comprising:

forming an opening in a semiconductor die;

depositing a first insulator material in the opening, wherein the first insulator material has a first thickness in a range between about 0.01 μm and 2 μm;

depositing a second insulator material in the opening and on the first insulator material, the second insulator material having a second thickness in a range between about 0.01 μm to 2 μm;

selectively removing insulator material from a base of the opening; and

depositing a conductive material in the opening.

18. The method of claim 17 wherein the first and second thickness form a composite thickness that is greater than about 0.1 μm.

19. The method of claim 17 wherein the first thickness is greater than 0.01 μm.

20. The method of claim 19 wherein the second thickness is greater than 0.01 μm.

21. The method of claim 17 wherein a portion of the first insulator material covers a sidewall of the opening, and wherein the method further comprises selecting a composition of the first insulator material and a composition of the second insulator material based on a threshold level of capacitance between the sidewall and the conductive material.