Mixed-signal substrate with integrated through-substrate vias

1. A mixed-signal substrate providing multi-modal communication comprising:

three trenches each extending through the substrate from an upper surface of the substrate to a lower surface of the substrate; the substrate comprises low-resistivity silicon;

a photodefineable polymer extending the length of each trench and filling at least a portion of each trench; and

a conductive material extending the length of the trench and filling at least a portion of two trenches to form through-substrate vias;

wherein a first trench of the three trenches is configured to provide a first mode of communication;

wherein a second trench of the three trenches is configured to provide a second mode of communication and includes a different number of through-substrate vias than a third trench of the three trenches; and wherein the third trench is configured to provide a third mode of communication;

wherein the first mode of communication is optical;

wherein the second mode of communication is DC; and

wherein the third mode of communication is radio frequency.

2. The mixed-signal substrate of claim 1 , wherein the through-substrate via arrangements of the second trench are selected from the group consisting of a post via arrangement, and a via bundle; and

wherein the through-substrate via arrangements of the third trench are selected from the group consisting of a coaxial via arrangement having a solid ring via, and a coaxial via arrangement having a meshed via ring.

3. The mixed signal substrate of claim 1 , wherein the third trench includes a first through-substrate via having a different two-dimensional shape than a second through-substrate via in the second trench.

4. The mixed-signal substrate of claim 1 , wherein the second trench comprises a via bundle metal-plated to form a high-density decoupling capacitor.

5. The mixed-signal substrate of claim 1 , wherein the conductive material of the through-substrate vias is selected from the group consisting of a metal and a high-k dielectric material.

6. The mixed-signal substrate of claim 1 , wherein a through-substrate via in the third trench has a greater width than a through-substrate via in the second trench.

7. The mixed-signal substrate of claim 1 , wherein the third trench comprises a coaxial via arrangement.

8. The mixed-signal substrate of claim 7 , wherein the coaxial via arrangement comprises an inner through-substrate via and a plurality of outer through-substrate vias, the plurality of outer through-substrate vias disposed coaxially around the inner through-substrate via.

9. The mixed-signal substrate of claim 1 further comprising one or more through substrate vias coated in silicon dioxide.

10. The mixed-signal substrate of claim 1 , wherein the second trench comprises a post via arrangement, including a central through-substrate via having a liner comprising the photodefineable polymer.

11. A method of fabricating the mixed-signal substrate of claim 1 comprising:

etching the trenches in the substrate;

filling at least a portion of each of the trenches with the photodefineable polymer;

patterning the photodefineable polymer in each of the trenches, the patterning comprising forming one or more channels within the photodefineable polymer layer filling at least a portion of two of the trenches; and

filling at least a portion of one or more channels with the conductive material to form one or more through-substrate vias;

wherein patterning the photodefineable polymer comprises patterning a different arrangement of channels in the third trench than the second trench.

12. The method of claim 11 , wherein etching the trenches in the substrate comprises one of dry-etching or wet-etching.

13. The method of claim 11 , wherein one trench includes a different number of channels than another trench.

14. A mixed-signal substrate providing multi-modal communication comprising:

a first through-substrate trench configured to provide a first mode of communication;

a second through-substrate trench configured to provide a second mode of communication; and

a third through-substrate trench configured to provide a third mode of communication;

wherein each through-substrate trench extends through a substrate from an upper surface of the substrate to a lower surface of the substrate;

wherein each through-substrate trench comprises a photodefineable polymer extending the length of the trench and filling at least a portion of the trench;

wherein the first mode of communication is optical;

wherein the second through-substrate trench further comprises conductive material extending the length of the trench and filling at least a portion of the trench to form a through-substrate via; and

wherein the third through-substrate trench further comprises a coaxial arrangement of conductive material extending the length of the trench and filling at least a portion of the trench to form a coaxial arrangement of through-substrate vias.

15. The mixed-signal substrate of claim 14 , wherein the third through-substrate trench forms a high-density decoupling capacitor.

16. The mixed-signal substrate of claim 14 , wherein the coaxial arrangement of through-substrate vias of the third through-substrate trench comprise a center rod of conductive material and an annular ring of conductive material spaced apart from the center rod.

17. The mixed-signal substrate of claim 14 , wherein the coaxial arrangement of through-substrate vias of the third through-substrate trench comprise an inner through-substrate via and a plurality of outer through-substrate vias, the plurality of outer through-substrate vias disposed coaxially around the inner through-substrate via.

18. The mixed-signal substrate of claim 14 , wherein the second mode of communication is DC; and

wherein the third mode of communication is radio frequency.