3D trench capacitor for integrated passive devices
Various embodiments of the present disclosure are directed towards a three-dimensional (3D) trench capacitor, as well as methods for forming the same. In some embodiments, a first substrate overlies a second substrate so a front side of the first substrate faces a front side of the second substrate. A first trench capacitor and a second trench capacitor extend respectively into the front sides of the first and second substrates. A plurality of wires and a plurality of vias are stacked between and electrically coupled to the first and second trench capacitors. A first through substrate via (TSV) extends through the first substrate from a back side of the first substrate, and the wires and the vias electrically couple the first TSV to the first and second trench capacitors. The first and second trench capacitors and the electrical coupling therebetween collectively define the 3D trench capacitor.
1. A semiconductor structure, comprising:
a first substrate and a second substrate underlying the first substrate;
a first trench capacitor and a second trench capacitor between the first and second substrates and extending respectively into the first and second substrates;
a plurality of wires and a plurality of vias stacked between and electrically coupled to the first and second trench capacitors;
a through substrate via (TSV) extending through the first substrate from a top of the first substrate to a bottom of the first substrate, wherein the plurality of wires and the plurality of vias electrically couple the TSV to the first and second trench capacitors; and
a dielectric layer between the second trench capacitor and the second substrate, wherein the second trench capacitor extends completely through the dielectric layer into the second substrate.
2. The semiconductor structure according to claim 1 , wherein the TSV is closer to the second substrate than the first trench capacitor.
3. The semiconductor structure according to claim 1 , wherein the second substrate and the dielectric layer form a common sidewall, and wherein the second trench capacitor lines the common sidewall from top to bottom.
4. The semiconductor structure according to claim 1 , wherein the second trench capacitor wraps around a corner of the dielectric layer from a sidewall of the dielectric layer to a top surface of the dielectric layer.
5. The semiconductor structure according to claim 1 , wherein the second trench capacitor has a T-shaped profile.
6. The semiconductor structure according to claim 1 , wherein the plurality of wires comprises a first wire and a second wire, wherein the first and second wires are at a common elevation and comprise individual pluralities of fingers that are interdigitated, and wherein the TSV extends to and terminates at the first wire.
7. The semiconductor structure according to claim 6 , further comprising:
a second TSV extending through the first substrate from the top of the first substrate to the second wire.
8. A semiconductor structure, comprising:
a substrate;
a first trench capacitor overlying and extending into the substrate; and
a plurality of wires and a plurality of vias alternatingly stacked over and electrically coupled to the first trench capacitor;
wherein the first trench capacitor comprises a bottom electrode, wherein the bottom electrode comprises a first surface recessed relative to a top surface of the substrate and a second surface elevated relative to the top surface of the substrate, and wherein the first and second surfaces face the substrate in a common direction extending parallel to a thickness of the substrate and are separated from each other in the common direction by a distance greater than the thickness.
9. The semiconductor structure according to claim 8 , further comprising:
a dielectric layer directly between the second surface of the bottom electrode and the substrate, wherein the dielectric layer and the substrate have individual sidewalls facing the first trench capacitor, and wherein the individual sidewalls are vertically stacked and edge to edge.
10. The semiconductor structure according to claim 8 , wherein the substrate has a sidewall facing and bordering the first trench capacitor, and wherein the sidewall has a height that is about 40-80 percent of the distance.
11. The semiconductor structure according to claim 8 , wherein the first trench capacitor further comprises a top electrode overlying the bottom electrode, wherein the plurality of wires comprises a first wire and a second wire that are at a common elevation and that comprise individual pluralities of fingers that are interdigitated, and wherein the first and second wires are respectively electrically coupled to the top and bottom electrodes.
12. The semiconductor structure according to claim 11 , further comprising:
a second trench capacitor overlying and extending into the substrate, wherein the second trench capacitor comprises a bottom electrode and a top electrode, and wherein the first and second wires are respectively electrically coupled to the top and bottom electrodes of the second trench capacitor.
13. The semiconductor structure according to claim 8 , wherein the bottom electrode further comprises a sidewall facing the substrate and extending from the first surface of the bottom electrode to the second surface of the bottom electrode.
14. An integrated circuit (IC), comprising:
a first IC die comprising a first substrate, a first trench capacitor underlying the first substrate and recessed into a bottom of the first substrate, and a first interconnect structure underlying the first trench capacitor;
a second IC die under the first IC die, wherein the second IC die comprises a second substrate, a second trench capacitor overlying the second substrate and recessed into a top of the second substrate, and a second interconnect structure overlying the second trench capacitor, wherein the second interconnect structure directly contacts the first interconnect structure at a bond interface, which has a metal-to-metal portion and a dielectric-to-dielectric portion; and
a first through substrate via (TSV) extending through the first substrate and electrically coupled to the first and second trench capacitors by the first and second interconnect structures, wherein a bottom surface of the first TSV is elevated above the bond interface.
15. The IC according to claim 14 , wherein the first interconnect structure comprises a first alternating stack of wires and vias, wherein the second interconnect structure comprises a second alternating stack of wires and vias, and wherein the first and second alternating stacks of wires have individual wires directly contacting at the bond interface to form the metal-to-metal portion of the bond interface.
16. The IC according to claim 14 , wherein the first interconnect structure comprises a wire underlying and directly contacting the TSV and further comprises a via extending from the wire to the first trench capacitor.
17. The IC according to claim 14 , wherein the first substrate has a thickness less than a thickness of the second substrate, and wherein the first trench capacitor has a height greater than or equal to a height of the second trench capacitor.
18. The IC according to claim 14 , wherein a vertical separation between the first substrate and a bottom surface of the first trench capacitor is greater than a vertical separation between the second substrate and a top surface of the second trench capacitor.
19. The IC according to claim 14 , further comprising:
a second TSV extending through the second substrate and electrically coupled to the first and second trench capacitors by the first and second interconnect structures, wherein a top surface of the second TSV is recessed relative to the bond interface.
20. The IC according to claim 14 , further comprising:
a second TSV extending through the first substrate and electrically coupled to the first and second trench capacitors by the first and second interconnect structures, wherein the second TSV extends through the first substrate, from an upper side of the first substrate, and terminates between the bond interface and the first substrate.