Thermoelectric cooling using through-silicon vias
Structures that include thermoelectric couples and methods for fabricating such structures. A device level and a back-end-of-line (BEOL) interconnect structure are fabricated at a front side of a substrate. A thermoelectric couple is formed that is coupled with the substrate. The thermoelectric couple includes a first through-silicon via extending through the device level and the substrate to a back side of the substrate, a second through-silicon via extending through the device level and the substrate to the back side of the substrate, an n-type thermoelectric pillar coupled with the first through-silicon via, and a p-type thermoelectric pillar coupled with the second through-silicon via. The BEOL interconnect structure includes a wire that couples the first through-silicon via in series with the second through-silicon via.
1. A structure formed using a substrate having a front side and a back side opposite from the front side, the structure comprising:
a device level at the front side of the substrate;
a first thermoelectric couple coupled with the substrate, the first thermoelectric couple including a first through-silicon via in a first trench extending through the device level and the substrate to the back side of the substrate, a second through-silicon via in a second trench extending through the device level and the substrate to the back side of the substrate, an n-type thermoelectric pillar coupled with the first through-silicon via, and a p-type thermoelectric pillar coupled with the second through-silicon via;
a third through-silicon via in a third trench extending through the device level and the substrate;
a first liner comprised of a first dielectric material arranged in the first trench between the substrate and the first through-silicon via and arranged in the second trench between the substrate and the second through-silicon via;
a second liner arranged in the third trench between the substrate and the third through-silicon via; and
a back-end-of-line (BEOL) interconnect structure at the front side of the substrate, the BEOL interconnect structure including a wire that couples the first through-silicon via in series with the second through-silicon via,
wherein the second liner is comprised of a second dielectric material having a thermal conductivity that is less than a thermal conductivity of the first dielectric material, and the first dielectric material is aluminum nitride.
2. A structure formed using a substrate having a front side and a back side opposite from the front side, the structure comprising:
a device level at the front side of the substrate;
a first thermoelectric couple coupled with the substrate, the first thermoelectric couple including a first through-silicon via in a first trench extending through the device level and the substrate to the back side of the substrate, a second through-silicon via in a second trench extending through the device level and the substrate to the back side of the substrate, an n-type thermoelectric pillar coupled with the first through-silicon via, and a p-type thermoelectric pillar coupled with the second through-silicon via;
a first liner comprised of a first dielectric material arranged in the first trench between the substrate and the first through-silicon via and arranged in the second trench between the substrate and the second through-silicon via;
a back-end-of-line (BEOL) interconnect structure at the front side of the substrate, the BEOL interconnect structure including a wire that couples the first through-silicon via in series with the second through-silicon via; and
a dielectric layer applied to the back side of the substrate,
wherein the first dielectric material is aluminum nitride, the n-type thermoelectric pillar and the p-type thermoelectric pillar are located at the back side of the substrate, the n-type thermoelectric pillar is located in a first opening extending through the dielectric layer to a tip of the first through-silicon via, and the p-type thermoelectric pillar is located in a second opening extending through the dielectric layer to a tip of the second through-silicon via.
3. The structure of claim 1 further comprising:
a first wire coupled with the n-type thermoelectric pillar;
a second wire coupled with the p-type thermoelectric pillar; and
a heat sink coupled with the first wire and the second wire.
4. The structure of claim 3 wherein the first wire and the second wire are located between the heat sink and the back side of the substrate.
5. The structure of claim 3 wherein the heat sink is a heat sink ceramic layer.
6. The structure of claim 5 wherein the heat sink ceramic layer is comprised of aluminum nitride.
7. The structure of claim 1 further comprising:
a first wire coupled with the n-type thermoelectric pillar;
a second wire coupled with the p-type thermoelectric pillar; and
a second thermoelectric couple daisy-chained in series with the first thermoelectric couple by either the first wire or the second wire.
8. The structure of claim 7 wherein the n-type thermoelectric pillar and the p-type thermoelectric pillar are located at the back side of the substrate.
9. The structure of claim 1 further comprising:
a power supply; and
a conductive path in the BEOL interconnect structure, the conductive path arranged to couple the power supply with the first through-silicon via at the front side of the substrate for supplying power to the n-type thermoelectric pillar or with the second through-silicon via at the front side of the substrate for supplying power to the p-type thermoelectric pillar.
10. The structure of claim 9 wherein the n-type thermoelectric pillar and the p-type thermoelectric pillar are located at the back side of the substrate.
11. A method comprising:
forming a device level at a front side of a substrate that is opposite from a back side of the substrate;
forming a first trench extending through the device level and the substrate to the back side of the substrate;
forming a second trench extending through the device level and the substrate to the back side of the substrate;
forming a third trench extending through the device level and the substrate to the back side of the substrate;
forming a first liner comprised of a first dielectric material in the first trench and in the second trench;
after forming the first liner in the first trench and in the second trench, forming a first through-silicon via in the first trench and a second through-silicon via in the second trench;
forming a second liner comprised of a second dielectric material in the third trench;
after the forming second liner in the third trench, forming a third through-silicon via in the third trench;
depositing an n-type thermoelectric pillar coupled with the first through-silicon via;
depositing a p-type thermoelectric pillar coupled with the second through-silicon via; and
forming a back-end-of-line (BEOL) interconnect structure at the front side of the substrate,
wherein the second dielectric material has a thermal conductivity that is less than a thermal conductivity of the first dielectric material, the BEOL interconnect structure includes a wire that couples the first through-silicon via in series with the second through-silicon via, and the first dielectric material is aluminum nitride.
12. The method of claim 11 wherein the n-type thermoelectric pillar and the p-type thermoelectric pillar are located at the back side of the substrate.
13. The method of claim 12 further comprising:
depositing a dielectric layer on the back side of the substrate;
forming a first opening extending through the dielectric layer to a tip of the first through-silicon via; and
forming a second opening extending through the dielectric layer to a tip of the second through-silicon via,
wherein the n-type thermoelectric pillar is located in the first opening and the p-type thermoelectric pillar is located in the second opening.
14. The method of claim 11 further comprising:
forming a first wire coupled with the n-type thermoelectric pillar;
forming a second wire coupled with the p-type thermoelectric pillar; and
depositing a heat sink ceramic layer on the back side of the substrate,
wherein the heat sink ceramic layer is coupled with the first wire and the second wire, and the first wire and the second wire are located between the heat sink ceramic layer and the back side of the substrate.
15. The method of claim 11 further comprising:
forming a conductive path in the BEOL interconnect structure that couples a power supply with the first through-silicon via for supplying power to the n-type thermoelectric pillar or the second through-silicon via for supplying power to the p-type thermoelectric pillar.
16. The structure of claim 1 wherein the second dielectric material is silicon dioxide.
17. The method of claim 11 wherein the second dielectric material is silicon dioxide.
18. The structure of claim 1 wherein the n-type thermoelectric pillar and the p-type thermoelectric pillar are located at the back side of the substrate.
19. The structure of claim 18 further comprising:
a dielectric layer applied to the back side of the substrate,
wherein the n-type thermoelectric pillar is located in a first opening extending through the dielectric layer to a tip of the first through-silicon via and the p-type thermoelectric pillar is located in a second opening extending through the dielectric layer to a tip of the second through-silicon via.