Substrates with through vias with conductive features for connection to integrated circuit elements, and methods for forming through vias in substrates
A through via ( 144 ) contains a conductor ( 244, 276 ) passing through a substrate ( 140 ) for connection to an integrated circuit element. The through via consists of two segments ( 144.1, 144.2 ) formed from respective different sides ( 140.1, 140.2 ) of the substrate and meeting inside the substrate. Each segment is shorter than the entire via, so via formation is facilitated. The second segment is etched after deposition of an etch stop layer ( 214 ) into the first segment. Due to the etch stop layer, the first segment's depth does not have to be rigidly controlled. The conductor is formed by separate depositions of conductive material into the via from each side of the substrate. From each side, the conductor is deposited to a shallower depth than the via depth, so the deposition is facilitated. Other embodiments are also provided.
1. A structure comprising:
(1) a substrate having a first side and a second side opposite to the first side, the substrate comprising a first material;
(2) a through via passing through the first material of the substrate between the first and second sides, the through via having a first segment and a second segment joining the first segment inside the substrate, the first segment extending from the first side to the second segment, the second segment extending from the first segment to the second side, the first segment having an end adjacent to the second segment, the second segment having an end adjacent to the first segment;
wherein when viewed from the first side, said end of the first segment completely laterally surrounds said end of the second segment but is laterally spaced from said end of the second segment;
(3) a conductive feature passing through the through via and forming at least a part of a conductive path provided for connection to a circuit element of an integrated circuit, the conductive feature comprising:
a first conductive section present in the first segment;
a second conductive section present in the second segment and extending into the first segment, wherein when viewed from the first side, a portion of the second conductive section in the first segment spreads laterally beyond said end of the second segment; and
a first conductive layer separating the first conductive section from the second conductive section and present in the first segment but not in the second segment, the first conductive layer being a material not present in the first segment in the first and second conductive sections.
2. The structure of claim 1 wherein the first material is semiconductor, and the structure comprises an insulator insulating the conductive feature from the substrate.
3. The structure of claim 1 wherein the second segment is shorter than the first segment.
4. The structure of claim 1 further comprising said integrated circuit having the circuit element connected to the conductive feature.
5. The structure of claim 1 wherein the first conductive layer separates the first section from an entire sidewall surface of the first segment.
6. The structure of claim 1 wherein the first conductive layer is a barrier layer.
7. The structure of claim 1 wherein the first conductive section comprises copper, and the first conductive layer comprises titanium-tungsten.
8. The structure of claim 1 wherein the first conductive layer physically contacts the first and second conductive sections.
9. The structure of claim 1 further comprising a second conductive layer separating the second conductive section from an entire sidewall surface of the second segment, the second conductive layer being a material not present in the second conductive section, the second conductive layer not reaching the first conductive layer.
10. The structure of claim 9 wherein the second conductive layer is a barrier layer.
11. The structure of claim 9 wherein the second conductive section comprises copper, and the second conductive layer comprises titanium-tungsten.
12. A structure comprising:
(1) a substrate having a first side and a second side opposite to the first side, the substrate comprising a first material;
(2) a through via passing through the first material of the substrate between the first and second sides, the through via comprising a first region between the first and second sides, the through via widening when passing through the first region from the second side to the first side;
wherein when the structure is viewed with the first side at the top and the second side at the bottom, then for any planar vertical cross section of the through via, when the through via is traced from the second side to the first side, a change in the through via's width (measured in the planar vertical cross section) per unit height is greater in the first region than immediately below the first region;
(3) a conductive feature passing through the through via and forming at least a part of a conductive path provided for connection to a circuit element of an integrated circuit, the conductive feature comprising:
a first conductive section present between the first region and the first side;
a second conductive section present between the first conductive section and the second side and passing through the first region towards the first side, the second conductive section widening when passing through the first region from the second side to the first side; and
a first conductive layer separating the first conductive section from the second conductive section and from an entire sidewall surface of the through via, the first conductive layer being a material not present between the first region and the first side in the first and second conductive sections.
13. The structure of claim 12 wherein the first material is semiconductor.
14. The structure of claim 12 wherein the first conductive layer is a barrier layer.
15. The structure of claim 12 wherein the first conductive section comprises copper, and the first conductive layer comprises titanium-tungsten.
16. The structure of claim 12 further comprising a second conductive layer separating the second conductive section from an entire sidewall surface of the second region, the second conductive layer being a material not present in the second conductive section, the second conductive layer not reaching the first conductive layer.
17. The structure of claim 16 wherein the second conductive layer is a barrier layer.
18. The structure of claim 16 wherein the second conductive section comprises copper, and the second conductive layer comprises titanium-tungsten.
19. A structure comprising:
(1) a substrate having a first side and a second side opposite to the first side, the substrate comprising a first material;
(2) a through via passing through the first material of the substrate between the first and second sides, the through via comprising a first region between the first and second sides, the through via widening when passing through the first region from the second side to the first side;
wherein when the structure is viewed with the first side at the top and the second side at the bottom, and the through via is traced from the second side to the first side, a change in the through via's minimum width per unit height is greater in the first region than immediately below the first region;
(3) a conductive feature passing through the through via and forming at least a part of a conductive path provided for connection to a circuit element of an integrated circuit, the conductive feature comprising:
a first conductive section present between the first region and the first side;
a second conductive section present between the first conductive section and the second side and passing through the first region towards the first side, the second conductive section widening when passing through the first region from the second side to the first side; and
a first conductive layer separating the first conductive section from the second conductive section and from an entire sidewall surface of the through via, the first conductive layer being a material not present between the first region and the first side in the first and second conductive sections.
20. The structure of claim 19 wherein the first material is semiconductor.
21. The structure of claim 19 wherein the first conductive layer is a barrier layer.
22. The structure of claim 19 wherein the first conductive section comprises copper, and the first conductive layer comprises titanium-tungsten.
23. The structure of claim 19 further comprising a second conductive layer separating the second conductive section from an entire sidewall surface of the second region, the second conductive layer being a material not present in the second conductive section, the second conductive layer not reaching the first conductive layer.
24. The structure of claim 23 wherein the second conductive layer is a barrier layer.
25. The structure of claim 23 wherein the second conductive section comprises copper, and the second conductive layer comprises titanium-tungsten.