Heat sinks with interdigitated heat pipes
A chip package includes adjacent integrated circuits on a circuit board, and separate heat sinks are thermally coupled to the integrated circuits. Because the integrated circuits are in close proximity, heat pipes in the separate heat sinks are interdigitated to prevent mechanical interference between the heat sinks. The amount of interdigitation depends on the separation between the integrated circuits and how the integrated circuits are arranged relative to an external fluid (such as flowing air). At the minimum, the heat pipes in fin regions of the heat sinks (which include fins for convective heat transfer to the external fluid) are interdigitated. However, the heat pipes may be interdigitated in pedestal regions of the heat sinks (which are thermally coupled to the integrated circuits) and/or in ramp regions of the heat sinks (in which vertical positions of the heat sinks change from the pedestal regions to the fin regions).
1. A chip package, comprising:
a circuit board;
a first integrated circuit and a second integrated circuit disposed on the circuit board, wherein the first integrated circuit is adjacent to the second integrated circuit;
a first heat sink having a first set of heat pipes, wherein the first set of heat pipes conducts heat away from the first integrated circuit; and
a second heat sink having a second set of heat pipes, wherein the second set of heat pipes conducts heat away from the second integrated circuit;
wherein each heat sink for each integrated circuit includes:
a pedestal region comprising a pedestal mechanically coupled to the integrated circuit, wherein each heat pipe in the pedestal region of the heat sink is attached to the pedestal;
a ramp region comprising a ramp for each heat pipe in the heat sink, wherein the ramp for each heat pipe extends a vertical position of a portion of the given heat sink; and
a fin region having fins, wherein the fins convectively transfer the heat to an external fluid; and
wherein the first set of heat pipes in the fin region of the first heat sink are interdigitated with the second set of heat pipes in the fin region of the second heat sink.
2. The chip package of claim 1 , wherein the fins in the fin region of the first heat sink and the fins in the fin region of the second heat sink are one of: aligned, staggered and overlapped.
3. The chip package of claim 1 , wherein the external fluid has a flow direction; and
wherein the first integrated circuit and the second integrated circuit are arranged along the flow direction.
4. The chip package of claim 1 , wherein the chip package further includes a lid.
5. The chip package of claim 1 , wherein the external fluid has a flow direction;
wherein the first integrated circuit and the second integrated circuit are arranged perpendicular to the flow direction; and
wherein the first set of heat pipes in at least a portion of the ramp region of the first heat sink are interdigitated with the second set of heat pipes in at least a portion of the ramp region of the second heat sink.
6. The chip package of claim 5 , wherein the first set of heat pipes in at least a portion of the pedestal region of the first heat sink are interdigitated with the second set of heat pipes in at least a portion of the pedestal region of the second heat sink.
7. The chip package of claim 5 , wherein the first set of heat pipes in the pedestal region of the first heat sink are aligned with the second set of heat pipes in the pedestal region of the second heat sink.
8. The chip package of claim 5 , wherein the first set of heat pipes in the pedestal region of the first heat sink are staggered between the second set of heat pipes in the pedestal region of the second heat sink.
9. The chip package of claim 5 , wherein a cross-section of the first set of heat pipes in the pedestal region of the first heat sink and a cross-section of the second set of heat pipes in the pedestal region of the second heat sink are modified at interdigitated locations.
10. The chip package of claim 5 , wherein the chip package further includes a lid.
11. The chip package of claim 10 , wherein a width of at least a subset of the pipes of the first heat sink is varied over lengths of at least the subset of the heat pipes.
12. The chip package of claim 10 , wherein a thickness of the pedestal is varied over a width of the pedestal.
13. The chip package of claim 5 , wherein the fin region of the first heat sink has a different vertical position than the fin region of the second heat sink.
14. The chip package of claim 5 , wherein the heat pipes in each heat sink include a vertical portion and bends so that the first heat sink and the second heat sink are interdigitated in pedestal regions, ramp regions and fin regions of the first heat sink and the second heat sink.
15. A system, comprising a chip package, wherein the chip package includes:
a circuit board;
a first integrated circuit and a second integrated circuit disposed on the circuit board, wherein the first integrated circuit is adjacent to the second integrated circuit;
a first heat sink having a first set of heat pipes, wherein the first set of heat pipes conducts heat away from the first integrated circuit; and
a second heat sink having a second set of heat pipes, wherein the second set of heat pipes conducts heat away from the second integrated circuit;
wherein each heat sink for each integrated circuit includes:
a pedestal region comprising a pedestal mechanically coupled to the integrated circuit, wherein each heat pipe in the pedestal region of the heat sink is attached to the pedestal;
a ramp region comprising a ramp for each heat pipe in the heat sink, wherein the ramp for each heat pipe extends a vertical position of a portion of the heat sink; and
a fin region having fins, wherein the fins convectively transfer the heat to an external fluid; and
wherein the first set of heat pipes in the fin region of the first heat sink are interdigitated with the second set of heat pipes in the fin region of the second heat sink.
16. The system of claim 15 , wherein the external fluid has a flow direction; and
wherein the first integrated circuit and the second integrated circuit are arranged along the flow direction.
17. The system of claim 15 , wherein the external fluid has a flow direction;
wherein the first integrated circuit and the second integrated circuit are arranged perpendicular to the flow direction; and
wherein the first set of heat pipes in at least a portion of the ramp region of the first heat sink are interdigitated with the second set of heat pipes in at least a portion of the ramp region of the second heat sink.
18. A method for cooling a first integrated circuit and a second integrated circuit during operation of the first integrated circuit and the second integrated circuit, wherein the method comprises:
conducting heat away from the first integrated circuit using a first heat sink mechanically coupled to the first integrated circuit; and
conducting heat away from the second integrated circuit using a second heat sink mechanically coupled to the second integrated circuit, wherein the first integrated circuit is adjacent to the second integrated circuit;
wherein each heat sink for each integrated circuit includes:
a pedestal region comprising a pedestal mechanically coupled to the integrated circuit, wherein each heat pipe in the pedestal region of the heat sink is attached to the pedestal;
a ramp region comprising a ramp for each heat pipe in the heat sink, wherein the ramp for each heat pipe extends a vertical position of a portion of the heat sink; and
a fin region having fins, wherein the fins convectively transfer the heat to an external fluid; and
wherein a first set of heat pipes in the fin region of the first heat sink are interdigitated with a second set of heat pipes in the fin region of the second heat sink.