Increased contact alignment tolerance for direct bonding
A bonded device structure including a first substrate having a first set of conductive contact structures, preferably connected to a device or circuit, and having a first non-metallic region adjacent to the contact structures on the first substrate, a second substrate having a second set of conductive contact structures, preferably connected to a device or circuit, and having a second non-metallic region adjacent to the contact structures on the second substrate, and a contact-bonded interface between the first and second set of contact structures formed by contact bonding of the first non-metallic region to the second non-metallic region. The contact structures include elongated contact features, such as individual lines or lines connected in a grid, that are non-parallel on the two substrates, making contact at intersections. Alignment tolerances are thus improved while minimizing dishing and parasitic capacitance.
1. A bonding method comprising:
providing a first element comprising a conductive first contact structure and a non-metallic first bonding region proximate the first contact structure, the first contact structure comprising a conductive first elongate contact feature;
providing a second element comprising a conductive second contact structure and a non-metallic second bonding region proximate the second contact structure, the second contact structure comprising a conductive second contact feature;
orienting and bringing together the first and second elements, such that the first elongate contact feature and the second contact feature are nonparallel;
directly bonding the first bonding region with the second bonding region without application of external pressure; and
directly bonding the first elongate contact feature and the second contact feature at an intersection between the first elongate contact feature and the second contact feature, the first elongate contact feature being elongated along an interface between the first and second elements.
2. The method of claim 1 , wherein directly bonding the first bonding region with the second bonding region comprises directly bonding the first bonding region with the second bonding region at room temperature.
3. The method of claim 1 , wherein directly bonding the first bonding region with the second bonding region comprises leaving an initial gap between the first elongate contact and the second contact feature, and heating the first and second elements to cause the first elongate contact feature to directly contact the second elongate contact feature.
4. The method of claim 1 , further comprising, before directly contacting, forming the first elongate contact feature directly on a corresponding trace, the trace aligned along a length of the first elongate contact feature.
5. A bonded structure comprising:
a first element comprising a conductive first contact structure and a non-metallic first bonding region proximate the first contact structure, the first contact structure comprising a conductive first elongate contact feature and the non-metallic first bonding region comprises silicon oxide; and
a second element comprising a conductive second contact structure and a non-metallic second bonding region proximate the second contact structure, the second contact structure comprising a conductive second contact feature,
wherein the first bonding region is in contact with and directly bonded to the second bonding region,
wherein the first elongate contact feature is oriented non-parallel with and directly contacts the second contact feature at an intersection between the first elongate contact feature and the second contact feature, the first elongate contact feature being elongated along an interface between the first and second elements.
6. The bonded structure of claim 5 , wherein a width of the first elongate contact feature is in a range of 0.01 microns to 10 microns.
7. The bonded structure of claim 5 , wherein the first element further comprises a trace extending laterally through the first element, the trace and the conductive first elongate contact feature are vertically stacked and electrically connected to each other.
8. The bonded structure of claim 5 , wherein the conductive first elongate contact feature comprises a heavily doped semiconductor material.
9. A bonded structure comprising:
a first element comprising a trace extending laterally through the first element, a conductive first contact structure and a non-metallic first bonding region proximate the first contact structure, the first contact structure comprising a conductive first elongate contact feature, the trace and the conductive first elongate contact feature being vertically stacked and electrically connected to each other; and
a second element comprising a conductive second contact structure and a non-metallic second bonding region proximate the second contact structure, the second contact structure comprising a conductive second contact feature,
wherein the first bonding region is in contact with and directly bonded to the second bonding region, and
wherein the first elongate contact feature is oriented non-parallel with and directly contacts the second contact feature at an intersection between the first elongate contact feature and the second contact feature, the first elongate contact feature being elongated along an interface between the first and second elements.
10. The bonded structure of claim 9 , wherein a width of the trace if within ±10% of a width of the first elongate contact feature.
11. The bonded structure of claim 10 , wherein the width of the first elongate contact feature is in a range of 0.01 microns to 10 microns.
12. The bonded structure of claim 11 , a length of the first elongate contact feature is in a range of 0.05 microns to 500 microns.
13. The bonded structure of claim 9 , wherein the conductive first elongate contact feature comprises a heavily doped semiconductor material.
14. The bonded structure of claim 13 , wherein the non-metallic first bonding region comprises a dielectric material.
15. The bonded structure of claim 9 , wherein a thickness of the conductive first elongate contact feature is more than 0.005 microns and a thickness of the trace is more than 0.005 microns.
16. The bonded structure of claim 15 , wherein the thickness of the conductive first elongate contact feature is in a range of 0.005 microns to 0.05 microns and the thickness of the trace is a range of 0.005 microns to 0.05 microns.
17. The bonded structure of claim 15 , wherein a thickness of a stacked of the trace and the conductive first elongate contact feature is more than 0.01 microns and less than or equal to a thickness of the first element.
18. A bonded structure comprising:
a first element comprising a conductive first contact structure and a non-metallic first bonding region proximate the first contact structure, the first contact structure comprising a conductive first elongate contact feature; and
a second element comprising a conductive second contact structure and a non-metallic second bonding region proximate the second contact structure, the second contact structure comprising a conductive second contact feature,
wherein the first bonding region is in contact with and directly bonded to the second bonding region,
wherein the first elongate contact feature is oriented non-parallel with and directly contacts the second contact feature at an intersection between the first elongate contact feature and the second contact feature, the first elongate contact feature being elongated along an interface between the first and second elements, and
wherein a width of the first elongate contact feature is in a range of 0.01 microns to 10 microns.
19. The bonded structure of claim 18 , wherein a length of the first elongate contact feature is in a range of 0.05 microns to 500 microns.
20. The bonded structure of claim 19 , wherein the width of the first elongate contact feature is in a range of 0.1 microns to 5 microns, and wherein the length of the first elongate contact feature is in a range of 5 microns to 50 microns.
21. The bonded structure of claim 18 , wherein the first elongate contact feature is directly bonded with the second contact feature at the intersection.
22. The bonded structure of claim 21 , wherein the first elongate contact feature is configured to be directly bonded with the second contact feature without application of external pressure.
23. The bonded structure of claim 18 , wherein the second contact feature comprises an elongate contact feature.
24. The bonded structure of claim 23 , wherein a silicon oxide region on a first side of the first elongate contact feature is bonded with corresponding silicon oxide regions on first and second sides of the second elongate contact feature.
25. The bonded structure of claim 18 , wherein the first contact structure comprises a plurality of lines in a grid pattern.
26. The bonded structure of claim 18 , wherein the first contact structure defines a boundary disposed about a central region and a plurality of conductive segments extending outwardly from the central region.
27. The bonded structure of claim 26 , further comprising a plurality of lateral connectors that connect the plurality of conductive segments.
28. The bonded structure of claim 27 , wherein the boundary comprises a polygonal or rounded pattern.
29. The bonded structure of claim 18 , wherein the first elongate contact feature has a length and a width, the length being at least twice the width.
30. The bonded structure of claim 29 , wherein the length of the first elongate contact feature is at least five times the width.
31. The bonded structure of claim 18 , wherein at least one of the first and second contact structures comprises at least one of a metal and a conductively-doped semiconductor material.
32. The bonded structure of claim 18 , further comprising a through-silicon via (TSV) disposed within the first element below the intersection of the first elongate contact feature and the second contact feature.
33. The bonded structure of claim 32 , further comprising one or more conductive traces disposed between and electrically connecting the TSV with the first elongate contact feature.
34. The bonded structure of claim 18 , wherein at least one of the first elongate contact feature and the second contact feature is curved.