Thermal vias disposed in a substrate proximate to a well thereof
An apparatus relates generally to a three-dimensional stacked integrated circuit. In such an apparatus, the three-dimensional stacked integrated circuit has at least a first die and a second die interconnected to one another using die-to-die interconnects. A substrate of the first die has at least one thermal via structure extending from a lower surface of the substrate toward a well of the substrate without extending to the well and without extending through the substrate. A first end of the at least one thermal via structure is at least sufficiently proximate to the well of the substrate for conduction of heat away therefrom. The substrate has at least one through substrate via structure extending from the lower surface of the substrate to an upper surface of the substrate. A second end of the at least one thermal via structure is coupled to at least one through die via structure of the second die for thermal conductivity.
1. An apparatus, comprising:
a three-dimensional stacked integrated circuit having a first die;
wherein a substrate of the first die has at least one thermal via structure extending from a first surface of the substrate toward a well of the substrate without extending to the well and without extending through the substrate;
wherein a first end of the at least one thermal via structure is proximate to the well of the substrate for conduction of heat away therefrom through the at least one thermal via structure to a second end of the at least one thermal via structure;
wherein the substrate includes a semiconductor-on-insulator substrate having a buried dielectric layer; and
wherein the first end stops on the buried dielectric layer of the substrate.
2. The apparatus according to claim 1 , further comprising:
a pad associated with a second surface of the substrate opposite the first surface of the substrate;
wherein the at least one thermal via structure is a plurality of thermal via structures;
wherein widths of the plurality of thermal via structures are each less than widths of through substrate via structures of the substrate; and
wherein the pad is an etch stop layer for the through substrate via structures.
3. The apparatus according to claim 2 , wherein the widths of the plurality of thermal via structures are in a range of approximately 0.5 to 100 microns.
4. The apparatus according to claim 3 , wherein:
the plurality of thermal via structures are in a high-density array with a pitch in a range of approximately 1 to 200 microns; and
the width of the at least one through substrate via structure is in a range of approximately 1 to 5 times any of the widths of the plurality of thermal via structures.
5. The apparatus according to claim 1 , wherein depth of the at least one thermal via structure is approximately 1 to 200 microns which is approximately 1 to 20 microns less than a depth of the at least one through substrate via structure.
6. The apparatus according to claim 1 , wherein the at least one through substrate via structure is a signal via structure.
7. The apparatus according to claim 1 , wherein the at least one through substrate via structure is a thermal via structure.
8. The apparatus according to claim 1 , wherein the first end is within 20 microns inclusive of the well.
9. The apparatus according to claim 1 , wherein the buried dielectric layer is of a partial silicon-on-insulator wafer.
10. The apparatus according to claim 1 , wherein the at least one through substrate via structure extends through the buried dielectric layer.
11. The apparatus according to claim 10 , wherein the at least one through substrate via structure extends through a gap between dielectric islands of the buried dielectric layer.
12. The apparatus according to claim 1 , further comprising:
a pad associated with a second surface of the substrate opposite the first surface of the substrate;
wherein the at least one thermal via structure is a plurality of thermal via structures;
the plurality of thermal via structures extending from the first surface of the substrate toward the well of the substrate without extending to the well and without extending through the substrate;
first ends of the plurality of thermal via structures are proximate to the well of the substrate for conduction of heat away therefrom through the plurality of thermal via structures to corresponding second ends of the plurality of thermal via structures; and
the second ends of the plurality of thermal via structures are coupled to a heat sink.
13. The apparatus according to claim 12 , wherein an air gap is located between sidewalls of the plurality of thermal via structures and the substrate to provide fins.