Immersion cooling system for integrated circuit

1 . A cooling system, comprising:

a coolant tank containing a coolant;

a reservoir in fluid communication with the coolant tank via a tank inlet and a tank outlet;

a cooling coil disposed within the coolant tank and over the coolant;

a refrigerant circulating in the cooling coil;

a circulation pump disposed in the coolant tank and configured to circulate the coolant within the coolant tank;

a device package disposed in the coolant tank and comprising:

a package substrate,

an interposer over the package substrate, and

a plurality of integrated circuit dies over the interposer;

a molding layer covering a top surface and sidewalls of the device package; and

a heat sink covering a top surface and sidewalls of the molding layer,

wherein the reservoir is external to the coolant tank,

wherein the heat sink comprises a plurality of conformal channels and a plurality of straight channels,

wherein the plurality of conformal channels track a profile of the molding layer.

2 . The cooling system of claim 1 , further comprising:

a temperature sensor disposed within the coolant tank; and

a management module electrically coupled to the temperature sensor and the circulation pump.

3 . The cooling system of claim 2 , wherein the management module is configured to:

provide a first power output to the circulation pump when the temperature sensor detects a temperature above a pre-determined temperature; and

provide a second power output to the circulation pump when the temperature sensor detects a temperature below the pre-determined temperature,

wherein the first power output is greater than the second power output.

4 . The cooling system of claim 1 , wherein the coolant is water.

5 . The cooling system of claim 4 , wherein the refrigerant comprises chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs).

6 . The cooling system of claim 1 , wherein the coolant tank comprises a vent configured to release a pressure in the coolant tank when the pressure exceeds a pre-determined level.

7 . The cooling system of claim 1 , further comprising:

a first compressor having a first inlet;

a second compressor having a second inlet; and

a three-way valve coupled to the cooling coil,

wherein the three-way valve is configured to switch between a first position where the first inlet is in fluid communication with the cooling coil and a second position where the second inlet is in fluid communication with the cooling coil.

8 . The cooling system of claim 1 , further comprising:

a heat exchanger mechanically coupled to the reservoir.

9 . The cooling system of claim 1 , wherein the heat sink comprises copper, aluminum, aluminum nitride, or silicon carbide.

10 . A system, comprising:

a coolant tank containing a coolant;

a cooling coil disposed within the coolant tank;

a refrigerant circulating in the cooling coil;

a temperature sensor disposed within the coolant tank;

a circulation pump disposed in the coolant tank;

a management module electrically coupled to the temperature sensor and the circulation pump;

a device package disposed within the coolant tank and comprising:

a package substrate,

a silicon interposer over the package substrate,

a plurality of integrated circuit (IC) chips over the silicon interposer, and

an encapsulant disposed among the plurality of IC chips;

an external shield covering the plurality of IC chips, the encapsulant, sidewalls of the package substrate, and sidewalls of the silicon interposer; and

a heat sink covering a top surface and sidewalls of the external shield,

wherein the heat sink comprises a plurality of conformal channels that track a profile of the external shield.

11 . The system of claim 10 ,

wherein the external shield comprises a polymer matrix and thermally conductive particles embedded in the polymer matrix,

wherein the polymer matrix comprises epoxy, polyimide, silicone resin, polyurethane, or polyacrylate,

wherein the thermally conductive particles comprise titanium, tantalum, aluminum, aluminum copper, aluminum silicon copper, copper, manganese, carbon, silicon, silicon germanium, tungsten, zinc, or nickel.

12 . The system of claim 10 ,

wherein the coolant comprises water,

wherein the refrigerant comprises chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs).

13 . The system of claim 10 , wherein the heat sink further comprises a plurality of straight channels.

14 . The system of claim 10 , wherein the device package further comprises an underfill disposed between the package substrate and the silicon interposer.

15 . The system of claim 10 , wherein the plurality of IC chips comprise at least a photonic IC chip, an electronic IC chip, and a memory IC chip.

16 . A system, comprising:

a coolant tank containing a coolant;

a reservoir external to the coolant tank;

a cooling coil disposed within the coolant tank and over the coolant;

a refrigerant circulating in the cooling coil;

a coolant resistance sensor disposed within the coolant tank;

a circulation pump disposed in the coolant tank;

a management module coupled to the coolant resistance sensor and the circulation pump;

a device package immersed in the coolant and comprising:

a package substrate,

an interposer bonded to the package substrate by way of bumps, and

a plurality of integrated circuit (IC) chips over the interposer;

an external shield covering the plurality of IC chips, sidewalls of the package substrate, and sidewalls of the interposer; and

a heat sink covering a top surface and sidewalls of the external shield,

wherein the reservoir is in fluid communication with the coolant tank by way of an inlet and an outlet such that the coolant in the coolant tank is drainable to the reservoir,

wherein the heat sink comprises a plurality of conformal channels that track a profile of the external shield,

wherein the heat sink comprises copper, aluminum, aluminum nitride, or silicon carbide.

17 . The system of claim 16 , wherein the management module is configured to:

provide a first power output to the circulation pump when the coolant resistance sensor detects an electrical resistance smaller than a pre-determined resistance; and

provide a second power output to the circulation pump when the coolant resistance sensor detects an electrical resistance greater than the pre-determined resistance,

wherein the first power output is greater than the second power output.

18 . The system of claim 16 ,

wherein the coolant is water, and

wherein the refrigerant comprises chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ammonia, water, carbon dioxide, a refrigerant-grade propane, or a refrigerant-grade isobutane.

19 . The system of claim 16 , wherein the device package further comprises an encapsulant surrounding sidewalls of the plurality of IC chips.

20 . The system of claim 16 , wherein the plurality of IC chips comprise at least a photonic IC chip, an electronic IC chip, and a memory IC chip.