Cooling of substrate using interposer channels

1. A method of cooling a substrate, comprising:

providing a substrate comprising N continuous substrate channels on a first side of the substrate, said substrate having a heat source therein, said N being at least 2;

providing an interposer comprising N continuous interposer channels, said N interposer channels being coupled to the N substrate channels so as to form M continuous loops such that 1≦M≦N, each loop of the M loops independently consisting of K substrate channels of the N substrate channels and K interposer channels of the N interposer channels in an alternating sequence of substrate channels and interposer channels, for each loop of the M loops said K is at least 1 and is subject to an upper limit consistent with a constraint of having the M loops collectively consist of the N interposer channels and the N substrate channels, each loop of the M loops independently being open ended or closed, said first side of the substrate being connected to the interposer, said interposer being thermally coupled to a heat sink such that the interposer is interposed between the substrate and the heat sink;

generating heat by the heat source; and

circulating fluid in the N interposer channels and the N substrate channels, wherein a portion of the heat generated by the heat source is transferred to the fluid in the N substrate channels, and wherein a percentage of the portion of the heat is transferred from the fluid in the N interposer channels to the heat sink.

2. The method of claim 1 , wherein said M=N.

3. The method of claim 1 , wherein said M=1 such that the M continuous loops consist of one continuous loop.

4. The method of claim 3 , wherein the one continuous loop is open ended.

5. The method of claim 1 , wherein 1<M<N.

6. The method of claim 5 , wherein K>1 in each loop of the M loops.

7. The method of claim 5 , wherein K=1 in at least one loop of the M loops.

8. The method of claim 1 , wherein a first loop of the M loops comprises a first interposer channel of the N interposer channels, wherein the first interposer channel comprises a first channel segment and a second channel segment, and wherein the first channel segment is about perpendicular to the second channel segment.

9. The method of claim 1 , wherein each substrate channel of the N substrate channels has a larger flow area than each interposer channel of the N interposer channels.

10. The method of claim 1 , wherein the interposer is thermally coupled to the heat sink by a thermally conductive cover that is sandwiched between the heat sink and the interposer.

11. The method of claim 1 , wherein a coefficient of thermal expansion (CTE) of the interposer is substantially equal to a CTE of the substrate.

12. The method of claim 1 , wherein the N substrate channels and the N interposer channels are hermetically sealed with a vacuum therein.

13. The method of claim 12 , wherein a fluid partially but not totally fills each substrate channel of the N substrate channels and each interposer channel of the N interposer channels, and wherein the fluid is adapted to transfer heat from the heat source to the interposer.

14. The method of claim 1 , wherein the substrate comprises a semiconductor chip, wherein the semiconductor chip comprises active electronic devices on a second side of the substrate that is opposite the first side of the substrate, and wherein the heat source comprises the active electronic devices.

15. The method of claim 1 , wherein the portion of the heat transferred from the heat source to the fluid is by a heat transfer mechanism that includes a phase change from a liquid phase of the fluid to a vapor phase of the fluid, and wherein the percentage of the portion of the heat transferred from the fluid to the heat sink is by a heat transfer mechanism that includes a phase change from the vapor phase of the fluid to the liquid phase of the fluid.

16. A method of cooling a structure, comprising:

providing a heat source, a heat sink, and an interposer, said the interposer being interposed between the heat sink and the heat source, said interposer comprising an enclosure that encloses a cavity, said enclosure being made of a thermally conductive material, said cavity comprising a thermally conductive foam material therein, said foam material comprising pores and comprising at least one serpentine channel, each serpentine channel having a plurality of contiguously connected channel segments, each serpentine channel independently forming a closed loop or an open ended loop, said foam being soaked by a liquid filling said pores;

generating heat by the heat source; and

providing a fluid in each serpentine channel, wherein a portion of the heat generated by the heat source is transferred to the fluid, and wherein a percentage of the portion of the heat is transferred from the fluid to the heat sink.

17. The structure of claim 16 , wherein the substrate comprises a semiconductor chip, wherein a first side of the semiconductor chip is in mechanical and thermal contact with the interposer, wherein the semiconductor chip comprises active electronic devices on a second side of the semiconductor chip that is opposite the first side of the semiconductor chip, and wherein the heat source comprises the active electronic devices.