Collars for under-bump metal structures and associated systems and methods
The present technology is directed to manufacturing collars for under-bump metal (UBM) structures for die-to-die and/or package-to-package interconnects and associated systems. A semiconductor die includes a semiconductor material having solid-state components and an interconnect extending at least partially through the semiconductor material. An under-bump metal (UBM) structure is formed over the semiconductor material and is electrically coupled to corresponding interconnects. A collar surrounds at least a portion of the side surface of the UBM structure, and a solder material is disposed over the top surface of the UBM structure.
1. A semiconductor die, comprising:
a semiconductor material having solid-state components;
an interconnect extending at least partially through the semiconductor material;
an under-bump metal (UBM) structure electrically coupled to the interconnect, wherein the UBM structure has a top surface, a bottom surface, and a sidewall extending between the top and bottom surfaces, and wherein the UBM structure comprises a first conductive material and a second conductive material disposed over the first conductive material;
a collar surrounding at least a portion of the sidewall of the UBM structure such that the collar contacts at least a portion of the first conductive material and at least a portion of the second conductive material, wherein the collar does not extend above the top surface of the UBM structure; and
a solder material disposed over the top surface of the UBM structure,
wherein the collar comprises an anti-wetting material to which the solder material does not readily wet in liquid phase.
2. The semiconductor die of claim 1 wherein the collar comprises at least one of: an oxide, a nitride, or polyimide.
3. The semiconductor die of claim 1 wherein the collar has a thickness of between about 2000 and about 2500 Å.
4. The semiconductor die of claim 1 wherein the UBM structure is a pillar, and wherein the collar covers only the sidewall of the pillar.
5. The semiconductor die of claim 1 wherein the collar extends along only a portion of a height of the sidewall of the UBM structure and does not cover the top surface of the UBM structure.
6. The semiconductor die of claim 5 wherein the collar extends along at least 80% of the height of the sidewall of the UBM structure.
7. The semiconductor die of claim 1 wherein a top surface of the collar is substantially coplanar with the top surface of the UBM structure.
8. The semiconductor die of claim 1 wherein the UBM structure has a height of between about 1-100 microns, and wherein the UBM structure has a thickness of between about 1-100 microns.
9. The semiconductor die of claim 1 wherein the first conductive material comprises copper, the second conductive material comprises nickel, and the collar comprises at least one of an oxide, a nitride, or polyimide.
10. A semiconductor die, comprising:
a semiconductor material having solid-state components;
an interconnect extending at least partially through the semiconductor material;
an under-bump metal (UBM) structure electrically coupled to the interconnect, wherein the UBM structure has a top surface, a bottom surface, and a sidewall extending between the top and bottom surfaces, and wherein the UBM structure comprises a first conductive material and a second conductive material disposed over the first conductive material;
a collar surrounding at least a portion of the sidewall of the UBM structure such that the collar contacts at least a portion of the first conductive material and at least a portion of the second conductive material, wherein the collar extends along a portion of a height of the sidewall of the UBM structure and does not extend above the top surface of the UBM structure; and
a solder material disposed over the top surface of the UBM structure.
11. The semiconductor die of claim 10 wherein the collar comprises an anti-wetting material to which the solder material does not readily wet in liquid phase.
12. The semiconductor die of claim 10 wherein the collar comprises at least one of: an oxide, a nitride, or polyimide.
13. The semiconductor die of claim 10 wherein the collar extends along at least 80% of the height of the sidewall of the UBM structure.
14. The semiconductor die of claim 10 wherein a top surface of the collar is substantially coplanar with the top surface of the UBM structure.
15. The semiconductor die of claim 1 , wherein the collar does not extend laterally beyond the solder material.
16. The semiconductor die of claim 1 , wherein a side surface of the collar is substantially coplanar with a side surface of the solder material.
17. The semiconductor die of claim 1 , wherein the UBM structure comprises a pillar including:
a lower portion comprising copper and having a first side surface; and
an upper portion comprising nickel formed over the lower portion, the upper portion having a second side surface,
wherein the first side surface is substantially coplanar with the second side surface.
18. The semiconductor die of claim 10 , wherein the collar does not extend laterally beyond the solder material.
19. The semiconductor die of claim 10 , wherein a side surface of the collar is substantially coplanar with a side surface of the solder material.
20. The semiconductor die of claim 10 , wherein the UBM structure comprises a pillar including:
a lower portion comprising copper and having a first side surface; and
an upper portion comprising nickel formed over the lower portion, the upper portion having a second side surface,
wherein the first side surface is substantially coplanar with the second side surface.
21. The semiconductor die of claim 1 wherein the second conductive material comprises a top surface, a bottom surface, and a side surface extending between the top surface and the bottom surface, and wherein the collar completely surrounds the side surface of the second conductive material.
22. The semiconductor die of claim 1 wherein the collar has a thickness of between about 1000-5000Å.
23. The semiconductor die of claim 10 wherein the second conductive material comprises a top surface, a bottom surface, and a side surface extending between the top surface and the bottom surface, and wherein the collar completely surrounds the side surface of the second conductive material.
24. The semiconductor die of claim 10 wherein the collar has a thickness of between about 1000-5000 Å.