Systems and methods for cooling heat generating components in immersion-cooling systems

Abstract

Systems and methods for cooling one or more computing components, such as a semiconductor die, in an immersion-cooling system are disclosed. The immersion-cooling system may be a two-phase immersion cooling system. Cooling of the one or more computing components may include transferring heat from one or more of the heat generating components in the immersion-cooling system.

Description

Systems and Methods For Cooling Heat Generating Components in Immersion-Cooling SystemsCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the priority benefit of U.S. Application No. 63 / 655,858, filed June 4, 2024; U.S. Application No. 63 / 658,220, filed June 10, 2024; U.S. Application No. 63 / 662,021, filed June 20, 2024; U.S. Application No. 63 / 677,188, filed July 30, 2024; U.S. Application No. 63 / 783,546, filed April 4, 2025; U.S. Application No. 63 / 786,748, filed April 10, 2025; each of which is incorporated herein by reference in its entirety for all purposes.BACKGROUND

[0002] As feature sizes and transistor sizes have decreased for integrated circuits (ICs), the amount of heat generated by a single chip, such as a microprocessor, has increased. Chips that once were air cooled have evolved to chips needing more heat dissipation than can be provided by air alone. In some cases, immersion cooling of chips in a tank containing a coolant liquid is employed to maintain IC chips at appropriate operating temperatures.

[0003] One type of immersion cooling is two-phase immersion cooling, in which heat from a semiconductor die is high enough to boil the coolant liquid. The boiling creates a coolantliquid vapor in the tank, which is condensed by cooling coils back to liquid form that flows back into the tank. Heat from the semiconductor dies can then be sunk into the liquid-to-gas and gas-to-liquid phase transitions of the coolant liquid.SUMMARY

[0004] The present disclosure relates to cooling assemblies, apparatus, and methods for cooling heat generating components (e.g., one or more computing components) in immersion-cooling systems. Computing hardware such as ICs, chips, and semiconductor dies generate heat during operation. Computing hardware may be cooled using ambient or chilled air; however, high-powered computing hardware may produce more heat than air alone can dissipate. Immersion cooling systems may utilize a dielectric liquid to provide better heat dissipation than air, while still electrically insulating computing hardware within the immersion cooling fluid.

[0005] In a two-phase immersion cooling system, power and computing components may receive cooling through boiler plates. In pool boiling, an immersion coolant liquid absorbs heat from the power component via the boiler plate. This absorbed heat causes the immersion coolant liquid to transition into the vapor phase, including immersion cooling vapor bubbles. These immersion cooling vapor bubbles depart from the boiler plate driven by buoyancy. The boiled immersion coolant liquid is then replenished to the boiler plate. Pool boiling utilizes the fluid phase change latent heat to transfer the heat to the immersion coolant liquid.However, cooling efficiency may be constrained by the natural convection mechanism and liquid / vapor bubble interaction. The liquid / vapor movement on the surface of the boiler plates is solely driven by buoyancy and gravity. If the vapor bubbles don’t leave the boiler surface quickly enough, they can block activated nucleation sites that reduce the heat transfer coefficient, and eventually cause film boiling that causes the system to reach critical heat flux (CHF; where an amount of heat transfer into a liquid via boiling is maximized) prematurely.

[0006] Some implementations of the present disclosure relate to increasing convective cooling of heat-generating devices (such as semiconductor dies) in immersion-cooling systems for integrated circuits. A submersible pump can be arranged to force a flow of coolant liquid across at least one heat-generating device immersed in the immersion-cooling system. In some cases, the pump can be mounted to the same printed circuit board as the heat-generating device to be cooled. In some implementations, the pump can contact and thermally couple to the heat-generating device.

[0007] Some implementations relate to assemblies for forcing flow of a coolant liquid across a surface of a heat-generating device in an immersion-cooling system for integrated circuits. Such assemblies can include the heat-generating device mounted to a printed circuit board (PCB) and a pump arranged to force the flow of the coolant liquid across the surface of the heat-generating device, wherein the heat-generating device and the pump are configured to be immersed in the coolant liquid during operation of the immersion-cooling system.

[0008] Some implementations relate to assemblies for forcing flow of a coolant liquid to cool a heat-generating device in an immersion-cooling system for integrated circuits. Such assemblies can include the heat-generating device mounted to a printed circuit board (PCB) and a pump contacting and thermally coupled to the heat-generating device, wherein (a) the pump is configured to remove heat from the heat-generating device by forcing the flow of the coolant liquid through the pump and (b) the heat-generating device and the pump areconfigured to be immersed in the coolant liquid during operation of the immersion-cooling system.

[0009] Some implementations relate to methods for cooling a heat-generating device with coolant liquid in an immersion-cooling system for integrated circuits. Such methods can include acts of creating a flow of the coolant liquid with a pump immersed in the coolant liquid of the immersion-cooling system and using the flow of the coolant liquid to remove heat from the heat-generating device, wherein the heat-generating device is immersed in the coolant liquid.

[0010] Some implementations relate to cooling assemblies, apparatus, and methods for cooling densely-packed, high-power IC chips in a two-phase immersion-cooling system. A heat spreader that is thermally coupled to one or more semiconductor dies can include a vapor-shedding structure to wet at least a portion of a surface of the heat spreader and divert bubbles and vapor from boiled coolant liquid away from the surface to reduce or prevent dryout of the surface. The vapor-shedding structure can be vertically asymmetric.

[0011] Some implementations relate to heat spreaders for two-phase immersion-cooling systems. An example implementation of a heat spreader can include a vapor-shedding structure extending from a boiling surface of the heat spreader to guide bubbles away from the boiling surface of the heat spreader when the heat spreader boils a liquid coolant in the two-phase immersion-cooling system and creates the bubbles.

[0012] Some implementations relate to methods of cooling at least one semiconductor die with a heat spreader in a two-phase immersion-cooling system. An example method can include acts of receiving heat in the heat spreader from the at least one semiconductor die, boiling a liquid coolant that contacts a boiling surface of the heat spreader, the boiling creating a plurality of bubbles, and guiding, with a vapor-shedding structure that extends from the boiling surface, at least a portion of the bubbles away from the boiling surface of the heat spreader.

[0013] Some implementations relate to methods of making heat spreaders for two-phase immersion-cooling systems. Example methods can include an act of attaching a vaporshedding structure to the heat spreader, such that the vapor-shedding structure extends from a boiling surface of the heat spreader to guide bubbles away from the boiling surface of the heat spreader when the heat spreader boils a liquid coolant in the two-phase immersioncooling system and creates the bubbles.

[0014] Some implementations relate to boiler plates for cooling a plurality of semiconductor dies. Such boiler plates can include a first heat-dissipation region configured to thermally couple to a first semiconductor die of the plurality of semiconductor dies with a first thermal interface material, a second heat-dissipation region configured to thermally couple to a second semiconductor die of the plurality of semiconductor dies with a second thermal interface material, at least one connecting structure that connects the first heat-dissipation region to the second heat-dissipation region, and at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region. The at least one thermal impedance element can be configured to reduce thermal coupling between the first heat-dissipation region and the second heat-dissipation region as compared to thermal coupling if the first heat-dissipation region were in direct physical contact with the second heat-dissipation region.

[0015] Some implementations relate to packaged devices for operating in an immersion cooling system. Such packaged devices can include a package substrate, a first semiconductor die mounted to the package substrate, a second semiconductor die mounted to the package substrate, a first heat-dissipation region of a boiler plate, wherein the first heatdissipation region is thermally coupled to the first semiconductor die, a second heatdissipation region of the boiler plate, wherein the second heat-dissipation region is thermally coupled to the second semiconductor die, at least one connecting structure that connects the first heat-dissipation region to the second heat-dissipation region, and at least one thermal impedance element disposed between the first heat-dissipation region and the second heatdissipation region. The at least one thermal impedance element can be configured to reduce thermal coupling between the first heat-dissipation region and the second heat-dissipation region as compared to thermal coupling if the first heat-dissipation region were in direct physical contact with the second heat-dissipation region.

[0016] Some implementations relate to methods of cooling a first semiconductor die and a second semiconductor die. Such methods can include acts of receiving first heat, from the first semiconductor die, into a first heat-dissipation region of a boiler plate, receiving second heat, from the second semiconductor die, into a second heat-dissipation region of the boiler plate, and impeding flow of the first heat in the first heat-dissipation region into the second heat-dissipation region with at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region, wherein the thermal impedance element has a lower value of thermal conductivity than a first value of thermalconductivity for the first heat-dissipation region and a second value of thermal conductivity for the second heat-dissipation region.

[0017] In some aspects, the techniques described herein relate to an assembly for forcing flow of a coolant liquid across a surface of a heat-generating device in an immersion-cooling system for integrated circuits, the assembly including the heat-generating device mounted to a printed circuit board (PCB) and a pump arranged to force the flow of the coolant liquid across the surface of the heat-generating device, wherein the heat-generating device and the pump are configured to be immersed in the coolant liquid during operation of the immersioncooling system.

[0018] In some aspects, the techniques described herein relate to an assembly wherein the pump is mounted to the PCB.

[0019] In some aspects, the techniques described herein relate to an assembly, further including a manifold fluidically coupled to the pump and a plurality of conduits fluidically coupled to the manifold, wherein a first conduit of the plurality of conduits is arranged to direct at least a portion of the coolant liquid that exits from the first conduit to flow across the surface of the heat-generating device.

[0020] In some aspects, the techniques described herein relate to an assembly wherein the pump is oriented such that an intake of the pump forces the flow of the coolant liquid across the surface of the heat-generating device.

[0021] In some aspects, the techniques described herein relate to an assembly wherein the pump is oriented such that an exhaust of the pump forces the flow of the coolant liquid across the surface of the heat-generating device.

[0022] In some aspects, the techniques described herein relate to an assembly, wherein the pump is mounted a distance d away from the heat-generating device, the distance d being no greater than 10 mm.

[0023] In some aspects, the techniques described herein relate to an assembly wherein the heat-generating device includes at least one of a heat-dissipative element disposed on a semiconductor die and a boiler enhancement coating disposed on the semiconductor die.

[0024] In some aspects, the techniques described herein relate to an assembly wherein the boiler enhancement coating includes a three-dimensional printed structure.

[0025] In some aspects, the techniques described herein relate to an assembly for forcing flow of a coolant liquid to cool a heat-generating device in an immersion-cooling system for integrated circuits, the assembly including the heat-generating device mounted to a printed circuit board (PCB) and a pump contacting and thermally coupled to the heat-generating device, wherein the pump is configured to remove heat from the heat-generating device by forcing the flow of the coolant liquid through the pump and the heat-generating device and the pump are configured to be immersed in the coolant liquid during operation of the immersion-cooling system.

[0026] In some aspects, the techniques described herein relate to an assembly wherein the pump includes a wall or a plate wherein the wall or the plate each includes an exterior surface and an interior surface, the exterior surface is thermally coupled to the heat-generating device, and the pump forces the flow of the coolant liquid across the interior surface to remove the heat from the heat-generating device.

[0027] In some aspects, the techniques described herein relate to an assembly wherein the heat-generating device includes at least one of a heat-dissipative element disposed on a semiconductor die and a boiler enhancement coating disposed on the semiconductor die.

[0028] In some aspects, the techniques described herein relate to an assembly wherein the heat-generating device includes a three-dimensional printed boiler enhancement coating.

[0029] In some aspects, the techniques described herein relate to an assembly wherein the heat-generating device includes a semiconductor die having neither a heat-dissipative element disposed on the semiconductor die nor a boiler enhancement coating disposed on the semiconductor die.

[0030] In some aspects, the techniques described herein relate to a method for cooling a heatgenerating device with coolant liquid in an immersion-cooling system for integrated circuits, the method including creating a flow of the coolant liquid with a pump immersed in the coolant liquid of the immersion-cooling system and using the flow of the coolant liquid to remove heat from the heat-generating device, wherein the heat-generating device is immersed in the coolant liquid.

[0031] In some aspects, the techniques described herein relate to a method, wherein the pump includes an intake and an exhaust for the coolant liquid, the method further including creating the flow of the coolant liquid across a surface of the heat-generating device with the intake of the pump.

[0032] In some aspects, the techniques described herein relate to a method wherein the pump includes an intake and an exhaust for the coolant liquid, the method further including creating the flow of the coolant liquid across a surface of the heat-generating device with the exhaust of the pump.

[0033] In some aspects, the techniques described herein relate to a method wherein the pump includes a wall or a plate, the wall or the plate each having an interior surface and an exterior surface, wherein the exterior surface contacts and is thermally coupled to the heat-generating device, the method further including creating the flow of the coolant liquid across the interior surface to remove heat from the heat-generating device.

[0034] In some aspects, the techniques described herein relate to a method wherein the heatgenerating device includes at least one of a heat-dissipative element disposed on a semiconductor die and a boiler enhancement coating disposed on the semiconductor die.

[0035] In some aspects, the techniques described herein relate to a method, wherein the heatgenerating device includes a semiconductor die having neither a heat-dissipative element disposed on the semiconductor die nor a boiler enhancement coating disposed on the semiconductor die.

[0036] In some aspects, the techniques described herein relate to a heat spreader for a two- phase immersion-cooling system including a vapor-shedding structure extending from a boiling surface of the heat spreader to guide bubbles away from the boiling surface of the heat spreader when the heat spreader boils a liquid coolant in the two-phase immersioncooling system and creates the bubbles.

[0037] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure, in at least one characteristic, is asymmetric in a vertical direction, wherein the vertical direction is a direction extending along the boiling surface of the heat spreader in a direction which the bubbles would rise when the heat spreader is oriented for operation in a tank of the two-phase immersion-cooling system.

[0038] In some aspects, the techniques described herein relate to a heat spreader wherein the at least one characteristic is thickness and the thickness increases with an increase in the vertical direction.

[0039] In some aspects, the techniques described herein relate to a heat spreader wherein the at least one characteristic is porosity and the porosity increases with an increase in the vertical direction.

[0040] In some aspects, the techniques described herein relate to a heat spreader wherein the at least one characteristic is a pattern of the vapor-shedding structure on the heat spreader and wherein the pattern of the vapor-shedding structure changes on the heat spreader with an increase in the vertical direction.

[0041] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure includes a mesh of material.

[0042] In some aspects, the techniques described herein relate to a heat spreader wherein the mesh includes metallic material.

[0043] In some aspects, the techniques described herein relate to a heat spreader wherein the mesh includes nonmetallic material.

[0044] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure includes a woven material.

[0045] In some aspects, the techniques described herein relate to a heat spreader wherein the woven material includes metallic material.

[0046] In some aspects, the techniques described herein relate to a heat spreader wherein the woven material includes nonmetallic material.

[0047] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure includes a porous material.

[0048] In some aspects, the techniques described herein relate to a heat spreader wherein the porous material includes metallic material.

[0049] In some aspects, the techniques described herein relate to a heat spreader wherein the porous material includes nonmetallic material.

[0050] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure is disposed in a plurality of strips on the heat spreader or the vaporshedding structure is disposed on a boiling enhancement coating that is thermally coupled to the heat spreader.

[0051] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure is disposed in a lattice on the heat spreader or the vapor-shedding structure is disposed in a lattice on a boiling enhancement coating that is thermally coupled to the heat spreader.

[0052] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure is disposed in a grid on the heat spreader or the vapor-shedding structure is disposed in a grid on a boiling enhancement coating that is thermally coupled to the heat spreader.

[0053] In some aspects, the techniques described herein relate to a heat spreader wherein the vapor-shedding structure includes fins extending from the heat spreader or the vaporshedding structure includes fins extending from a boiling enhancement coating that is thermally coupled to the heat spreader.

[0054] In some aspects, the techniques described herein relate to a heat spreader further including a boiling enhancement coating contacting at least a portion of the heat spreader.

[0055] In some aspects, the techniques described herein relate to a method of cooling at least one semiconductor die with a heat spreader in a two-phase immersion-cooling system the method including receiving heat in the heat spreader from the at least one semiconductor die, boiling a liquid coolant that contacts a boiling surface of the heat spreader, the boiling creating bubbles, and guiding, with a vapor-shedding structure that extends from the boiling surface, the bubbles away from the boiling surface of the heat spreader.

[0056] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure is vertically asymmetric in at least one characteristic wherein a vertical direction is a direction extending along the boiling surface of the heat spreader in a direction which the bubbles would rise when the heat spreader is oriented for operation in a tank of the two-phase immersion-cooling system.

[0057] In some aspects, the techniques described herein relate to a method wherein the at least one characteristic is thickness and the thickness increases with an increase in the vertical direction.

[0058] In some aspects, the techniques described herein relate to a method wherein the at least one characteristic is porosity and the porosity increases with an increase in the vertical direction.

[0059] In some aspects, the techniques described herein relate to a method wherein the at least one characteristic is a pattern of the vapor-shedding structure on the heat spreader and wherein the pattern of the vapor-shedding structure changes on the heat spreader with an increase in the vertical direction.

[0060] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure includes a mesh of material.

[0061] In some aspects, the techniques described herein relate to a method wherein the mesh includes metallic material.

[0062] In some aspects, the techniques described herein relate to a method wherein the mesh includes nonmetallic material.

[0063] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure includes a woven material.

[0064] In some aspects, the techniques described herein relate to a method wherein the woven material includes metallic material.

[0065] In some aspects, the techniques described herein relate to a method wherein the woven material includes nonmetallic material.

[0066] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure includes a porous material.

[0067] In some aspects, the techniques described herein relate to a method, wherein the porous material includes metallic material.

[0068] In some aspects, the techniques described herein relate to a method wherein the porous material includes nonmetallic material.

[0069] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure is disposed in a plurality of strips on the heat spreader or the vaporshedding structure is disposed on a boiling enhancement coating that is thermally coupled to the heat spreader.

[0070] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure is disposed in a lattice on the heat spreader or the vapor-shedding structure is disposed in a lattice on a boiling enhancement coating that is thermally coupled to the heat spreader.

[0071] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure is disposed in a grid on the heat spreader or the vapor-shedding structure is disposed in a grid on a boiling enhancement coating that is thermally coupled to the heat spreader.

[0072] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure includes fins extending from the heat spreader or the vaporshedding structure includes fins extending from a boiling enhancement coating that is thermally coupled to the heat spreader.

[0073] In some aspects, the techniques described herein relate to a method further including a boiling enhancement coating contacting at least a portion of the heat spreader.

[0074] In some aspects, the techniques described herein relate to a method of making a heat spreader for a two-phase immersion-cooling system, the method including attaching a vaporshedding structure to the heat spreader, such that the vapor-shedding structure extends from a boiling surface of the heat spreader to guide bubbles away from the boiling surface of the heat spreader when the heat spreader boils a liquid coolant in the two-phase immersioncooling system and creates the bubbles.

[0075] In some aspects, the techniques described herein relate to a method wherein the vapor-shedding structure, in at least one characteristic, is asymmetric in a vertical direction, wherein the vertical direction is a direction extending along the boiling surface of the heat spreader in a direction which the bubbles would rise when the heat spreader is oriented for operation in a tank of the two-phase immersion-cooling system.

[0076] In some aspects, the techniques described herein relate to a method wherein the at least one characteristic is thickness and the thickness increases with an increase in the vertical direction.

[0077] In some aspects, the techniques described herein relate to a method wherein the at least one characteristic is porosity and the porosity increases with an increase in the vertical direction.

[0078] In some aspects, the techniques described herein relate to a method wherein the at least one characteristic is a pattern of the vapor-shedding structure on the heat spreader and wherein the pattern of the vapor-shedding structure changes on the heat spreader with an increase in the vertical direction.

[0079] In some aspects, the techniques described herein relate to a method further including forming a boiling enhancement coating on the boiling surface of the heat spreader.

[0080] In some aspects, the techniques described herein relate to a boiler plate for cooling a plurality of semiconductor dies, the boiler plate including a first heat-dissipation regionconfigured to thermally couple to a first semiconductor die of the plurality of semiconductor dies with a first thermal interface material, a second heat-dissipation region configured to thermally couple to a second semiconductor die of the plurality of semiconductor dies with a second thermal interface material, at least one connecting structure that connects the first heat-dissipation region to the second heat-dissipation region, and at least one thermal impedance element disposed between the first heat-dissipation region and the second heatdissipation region, wherein the at least one thermal impedance element is configured to reduce thermal coupling between the first heat-dissipation region and the second heatdissipation region as compared to thermal coupling if the first heat-dissipation region were in direct physical contact with the second heat-dissipation region.

[0081] In some aspects, the techniques described herein relate to a boiler plate wherein the at least one connecting structure includes the at least one thermal impedance element.

[0082] In some aspects, the techniques described herein relate to a boiler plate wherein the at least one thermal impedance element has a lower value of thermal conductivity than a first value of thermal conductivity for the first heat-dissipation region and a second value of thermal conductivity for the second heat-dissipation region.

[0083] In some aspects, the techniques described herein relate to a boiler plate wherein the at least one thermal impedance element includes a void formed between the first heatdissipation region and the second heat-dissipation region.

[0084] In some aspects, the techniques described herein relate to a boiler plate wherein the at least one connecting structure includes a ceramic or a glass.

[0085] In some aspects, the techniques described herein relate to a boiler plate wherein the at least one connecting structure includes a portion of material remaining after fabrication of the first heat-dissipation region and the second heat-dissipation region from the material and the fabrication includes forming voids between the first heat-dissipation region and the second heat-dissipation region to define the first heat-dissipation region and the second heatdissipation region.

[0086] In some aspects, the techniques described herein relate to a boiler plate wherein the at least one connecting structure includes a resilient metallic member.

[0087] In some aspects, the techniques described herein relate to a boiler plate wherein a first thickness of the first heat-dissipation region is different from a second thickness of the second heat-dissipation region.

[0088] In some aspects, the techniques described herein relate to a boiler plate further including a boiler enhancement coating disposed on at least the first heat-dissipation region.

[0089] In some aspects, the techniques described herein relate to a boiler plate wherein the first heat-dissipation region is formed from a first material having a first thermal conductivity value, the second heat-dissipation region is formed from a second material having a second thermal conductivity value, and the second thermal conductivity value is different from the first thermal conductivity value.

[0090] In some aspects, the techniques described herein relate to a packaged device for operating in an immersion cooling system, the packaged device including a package substrate, a first semiconductor die mounted to the package substrate, a second semiconductor die mounted to the package substrate, a first heat-dissipation region of a boiler plate, wherein the first heat-dissipation region is thermally coupled to the first semiconductor die, a second heat-dissipation region of the boiler plate, wherein the second heat-dissipation region is thermally coupled to the second semiconductor die, at least one connecting structure that connects the first heat-dissipation region to the second heat-dissipation region, and at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region, wherein the at least one thermal impedance element is configured to reduce thermal coupling between the first heat-dissipation region and the second heat-dissipation region as compared to thermal coupling if the first heat-dissipation region were in direct physical contact with the second heat-dissipation region.

[0091] In some aspects, the techniques described herein relate to a packaged device wherein a first edge of the first semiconductor die closest to a second edge of the second semiconductor die is spaced a distance di from the second edge, which is an edge of the second semiconductor die that is closest to the first semiconductor die and di has a value from 0.25 mm to 5 mm.

[0092] In some aspects, the techniques described herein relate to a packaged device wherein the package substrate is a printed circuit board.

[0093] In some aspects, the techniques described herein relate to a packaged device wherein the first semiconductor die is a microprocessor and the second semiconductor die is a high bandwidth memory die.

[0094] In some aspects, the techniques described herein relate to a packaged device wherein the first heat-dissipation region is thermally coupled to the first semiconductor die with athermal interface material disposed between the first heat-dissipation region and the first semiconductor die.

[0095] In some aspects, the techniques described herein relate to a packaged device wherein no other material is disposed between the first heat-dissipation region and the first semiconductor die.

[0096] In some aspects, the techniques described herein relate to a packaged device wherein the second heat-dissipation region is thermally coupled to at least one additional semiconductor die.

[0097] In some aspects, the techniques described herein relate to a packaged device wherein the at least one connecting structure includes the at least one thermal impedance element.

[0098] In some aspects, the techniques described herein relate to a packaged device wherein the at least one connecting structure has a lower thermal conductivity value than a value of thermal conductivity for the first heat-dissipation region or the second heat-dissipation region.

[0099] In some aspects, the techniques described herein relate to a packaged device wherein the at least one thermal impedance element includes a void formed between the first heatdissipation region and the second heat-dissipation region.

[0100] In some aspects, the techniques described herein relate to a packaged device wherein the at least one connecting structure includes a ceramic or a glass.

[0101] In some aspects, the techniques described herein relate to a packaged device wherein the at least one connecting structure includes a portion of material remaining after fabrication of the first heat-dissipation region and the second heat-dissipation region from the material and the fabrication includes forming voids between the first heat-dissipation region and the second heat-dissipation region to define the first heat-dissipation region and the second heat-dissipation region.

[0102] In some aspects, the techniques described herein relate to a packaged device wherein the portion of material is located a distance 1 away from the first semiconductor die or the second semiconductor die, whichever is closest to the portion of material and 1 has a value from 2 mm to 10 mm.

[0103] In some aspects, the techniques described herein relate to a packaged device wherein the at least one connecting structure includes a resilient metallic member.

[0104] In some aspects, the techniques described herein relate to a packaged device wherein a first thickness of the first heat-dissipation region is different from a second thickness of the second heat-dissipation region.

[0105] In some aspects, the techniques described herein relate to a packaged device further including a boiler enhancement coating disposed on at least the first heat-dissipation region.

[0106] In some aspects, the techniques described herein relate to a packaged device wherein the first heat-dissipation region is formed from a first material having a first thermal conductivity value, the second heat-dissipation region is formed from a second material having a second thermal conductivity value, and the second thermal conductivity value is different from the first thermal conductivity value.

[0107] In some aspects, the techniques described herein relate to a method of cooling a first semiconductor die and a second semiconductor die, the method including receiving first heat, from the first semiconductor die, into a first heat-dissipation region of a boiler plate, receiving second heat, from the second semiconductor die, into a second heatdissipation region of the boiler plate, and impeding flow of the first heat in the first heatdissipation region into the second heat-dissipation region with at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region, wherein the thermal impedance element has a lower value of thermal conductivity than a first value of thermal conductivity for the first heat-dissipation region and a second value of thermal conductivity for the second heat-dissipation region.

[0108] In some aspects, the techniques described herein relate to a method wherein the first heat is received from a first thermal interface material which thermally couples the first heat-dissipation region to the first semiconductor die and the second heat is received from a second thermal interface material which thermally couples the second heat-dissipation region to the second semiconductor die.

[0109] In some aspects, the techniques described herein relate to a method wherein no other material is disposed between the first heat-dissipation region and the first semiconductor die.

[0110] In some aspects, the techniques described herein relate to a method wherein the first semiconductor die is a microprocessor and the second semiconductor die is a high bandwidth memory die.

[0111] In some aspects, the techniques described herein relate to a method wherein a first edge of the first semiconductor die closest to a second edge of the second semiconductor die is spaced a distance di from the second edge, which is an edge of the second semiconductor die that is closest to the first semiconductor die and di has a value from 0.25 mm to 5 mm.

[0112] In some aspects, the techniques described herein relate to a method further including dissipating the first heat from the first heat-dissipation region into a coolant liquid contacting the first heat-dissipation region and dissipating the second heat from the second heat-dissipation region into the coolant liquid.

[0113] In some aspects, the techniques described herein relate to a method wherein a distance < / ? between a first edge of the first heat-dissipation region and a second closest edge of the second heat-dissipation region is such that changing an operating temperature of the first semiconductor die by 10° C affects a change in the operating temperature of the second semiconductor die by no more than 1° C.

[0114] In some aspects, the techniques described herein relate to a method further including operating the first semiconductor die at a first operating temperature and operating the second semiconductor die at a second operating temperature wherein the second operating temperature is no less than 15 °C different from the first operating temperature.

[0115] In some aspects, the techniques described herein relate to a system for thermal management of computing hardware, the system including a dispersion conduit disposed in an immersion coolant liquid, the dispersion conduit including a plurality of holes, a distribution conduit fluidically coupled to the dispersion conduit, and a pump fluidically coupled to the distribution conduit, the pump configured to pump a portion of the immersion coolant liquid through the distribution conduit, wherein the plurality of holes are shaped to guide at least part of the pumped portion of the immersion coolant liquid toward a predetermined area of one or more computing hardware components.

[0116] In some aspects, the techniques described herein relate to a system, wherein a first end of the distribution conduit is fluidically coupled to a filter assembly configured to filter the pumped portion of the immersion coolant liquid and the pump is disposed within the filter assembly.

[0117] In some aspects, the techniques described herein relate to a system, wherein a first end of the distribution conduit is fluidically coupled to a filter assembly configured tofilter the pumped portion of the immersion coolant liquid and the pump is disposed outside of the filter assembly and is fluidically coupled to the distribution conduit through the filter assembly.

[0118] In some aspects, the techniques described herein relate to a system, wherein at least one of the dispersion conduit or the distribution conduit includes a contaminationresistant surface treatment.

[0119] In some aspects, the techniques described herein relate to a system, wherein at least one of the dispersion conduit or the distribution conduit includes copper, stainless steel, aluminum, titanium, or polycarbonate.

[0120] In some aspects, the techniques described herein relate to a system, wherein the one or more computing hardware components includes a logic integrated circuit (IC), a network switch, a printed circuit board (PCB), a boiling enhancement coating (BEC), or a ball grid array (BGA).

[0121] In some aspects, the techniques described herein relate to a system, wherein the pump is configured to pump the portion of the immersion coolant liquid through the distribution conduit at a predetermined flow rate.

[0122] In some aspects, the techniques described herein relate to a system, wherein the predetermined flow rate is between about 1 milliliter per minute and about 200 milliliters per minute.

[0123] In some aspects, the techniques described herein relate to a method for thermal management of computing hardware, the method including pumping, by a pump, a portion of an immersion coolant liquid into a distribution conduit, routing the portion of immersion coolant liquid into a dispersion conduit including a plurality of holes, and guiding, by the plurality of holes, at least part of the portion of the immersion coolant liquid toward a predetermined area of one or more computing hardware components.

[0124] In some aspects, the techniques described herein relate to a method, further including filtering, by a filter assembly, the portion of the immersion coolant liquid, prior to the step of guiding.

[0125] In some aspects, the techniques described herein relate to a method, wherein a first end of the distribution conduit is fluidically coupled to the filter assembly and the pump is disposed within the filter assembly.

[0126] In some aspects, the techniques described herein relate to a method, wherein a first end of the distribution conduit is fluidically coupled to the filter assembly and the pump is disposed outside of the filter assembly and is fluidically coupled to the distribution conduit through the filter assembly.

[0127] In some aspects, the techniques described herein relate to a method, wherein at least one of the dispersion conduit or the distribution conduit includes a contaminationresistant surface treatment.

[0128] In some aspects, the techniques described herein relate to a method, wherein the one or more computing hardware components includes a logic integrated circuit (IC), a network switch, a printed circuit board (PCB), a boiling enhancement coating (BEC), or a ball grid array (BGA).

[0129] In some aspects, the techniques described herein relate to a method, wherein the pump is configured to pump the portion of the immersion coolant liquid at a predetermined flow rate.

[0130] In some aspects, the techniques described herein relate to a method, wherein the predetermined flow rate is between about 1 milliliter per minute and about 200 milliliters per minute.

[0131] In an aspect, an impingement cooling device may be mounted on or adjacent to an SoW in a two-phase immersion system. The device may include an array of jet nozzles, with each jet nozzle positioned to direct a flow of immersion coolant liquid at a respective IC on the SoW. The flow of immersion coolant liquid may be generated by a pump or other mechanism. The flow of immersion coolant liquid has the benefit of replacing immersion cooling bubbles and / or an immersion cooling film adjacent to a surface of a computing hardware or other heat generating component and thereby increasing a heat flux out of the component. In particular, the present technology prevents a blanket of immersion cooling vapor from forming at the center of an IC (where a majority of the heat generated by the IC may reside) and preventing immersion cooling vapor bubbles from a first IC from displacing immersion coolant liquid around one or more adjacent ICs, improving a cooling efficiency.

[0132] In some aspects, the techniques described herein relate to a system for heat transfer, the system including a container at least partially filled with an immersion coolant liquid, a heat generating component disposed within the immersion coolant liquid, the heat generating component causing a first portion of the immersion coolant liquid to boil andconvert to an immersion cooling vapor, a nozzle configured to direct a second portion of the immersion coolant liquid toward the heat generating component, and a pump fluidically coupled to the nozzle and configured to pump the second portion of the immersion coolant liquid at a predetermined velocity or a predetermined flow rate.

[0133] In some aspects, the techniques described herein relate to a system, wherein the predetermined velocity is between about 0.1 mm / s and about 10 m / s.

[0134] In some aspects, the techniques described herein relate to a system, wherein the predetermined flow rate is between about 0.1 mL / s and about 200 mL / s.

[0135] In some aspects, the techniques described herein relate to a system, wherein the nozzle includes an exit and the exit includes a characteristic size between about 0.1 mm and about 10 mm.

[0136] In some aspects, the techniques described herein relate to a system, wherein the heat generating component includes an integrated circuit (IC).

[0137] In some aspects, the techniques described herein relate to a system, further including a boiler plate disposed in thermal contact with the heat generating component.

[0138] In some aspects, the techniques described herein relate to a system, further including an interface material disposed between the heat generating component and the boiler plate.

[0139] In some aspects, the techniques described herein relate to a system, wherein the interface material includes at least one of a thermal interface material (TIM), a thermal grease, a thermal paste, or a gap pad.

[0140] In some aspects, the techniques described herein relate to a system, wherein the boiler plate includes at least one of copper, stainless steel, aluminum, tungsten, or titanium.

[0141] In some aspects, the techniques described herein relate to a system, wherein at least one of the heat generating component or the boiler plate includes a surface treatment.

[0142] In some aspects, the techniques described herein relate to a system, wherein the surface treatment includes at least one of a surface topology modification or a coating.

[0143] In some aspects, the techniques described herein relate to a system, wherein the nozzle is configured to direct the second portion of the immersion coolant liquid substantially orthogonal to the heat generating component.

[0144] In some aspects, the techniques described herein relate to a system, wherein the nozzle is configured to direct the second portion of the immersion coolant liquid toward the heat generating component at an angle to a surface of the heat generating component at between about 5° and about 89°.

[0145] In some aspects, the techniques described herein relate to a method for heat transfer, the method including generating heat from a heat generating component disposed in an immersion coolant liquid, causing, based on the generated heat, a first portion of the immersion coolant liquid to boil and convert to an immersion cooling vapor, pumping, by a pump fluidically coupled to a nozzle disposed at a first angle to the heat generating component, a second portion of the immersion coolant liquid through the nozzle, directing, by the nozzle, a second portion of the immersion coolant liquid toward the heat generating component at a predetermined velocity or a predetermined flow rate, and displacing, by the second portion of the immersion coolant liquid, at least a portion of the immersion cooling vapor away from the heat generating component.

[0146] In some aspects, the techniques described herein relate to a method, wherein the predetermined velocity is between about 0.1 mm / s and about 2500 mm / s.

[0147] In some aspects, the techniques described herein relate to a method, wherein the predetermined flow rate is between about 0.1 mL / s and about 200 mL / s.

[0148] In some aspects, the techniques described herein relate to a method, wherein the nozzle includes an exit and the exit includes a characteristic size between about 0.1 mm and about 10 mm.

[0149] In some aspects, the techniques described herein relate to a method, wherein the heat generating component includes an integrated circuit (IC).

[0150] In some aspects, the techniques described herein relate to a method, wherein causing the first portion of immersion coolant liquid to boil includes transferring the heat through a boiler plate disposed in thermal contact with the heat generating component.

[0151] In some aspects, the techniques described herein relate to a method, wherein an interface material is disposed between the heat generating component and the boiler plate.

[0152] In some aspects, the techniques described herein relate to a method, wherein the interface material includes at least one of a thermal interface material (TIM), a thermal grease, a thermal paste, or a gap pad.

[0153] In some aspects, the techniques described herein relate to a method, wherein the boiler plate includes at least one of copper, stainless steel, aluminum, tungsten, or titanium.

[0154] In some aspects, the techniques described herein relate to a method, wherein at least one of the heat generating component or the boiler plate includes a surface treatment.

[0155] In some aspects, the techniques described herein relate to a method, wherein the surface treatment includes at least one of a surface topology modification or a coating.

[0156] In some aspects, the techniques described herein relate to a method, wherein the nozzle is configured to direct the second portion of the immersion coolant liquid substantially orthogonal to the heat generating component.

[0157] In some aspects, the techniques described herein relate to a method, wherein the nozzle is configured to direct the second portion of the immersion coolant liquid toward the heat generating component at an angle to a surface of the heat generating component at between about 5° and about 89°.

[0158] In some aspects, the techniques described herein relate to a system for heat transfer, the system including a container at least partially filled with an immersion coolant liquid and a heat generating component disposed within the immersion coolant liquid and in thermal contact with a boiling surface, the boiling surface forming at least a portion of an inner surface of a conduit, wherein the conduit is configured to at least partially enclose a first portion of the immersion coolant liquid flowing across the boiling surface and the boiling surface is in contact with at least a first portion of the immersion coolant liquid and is configured to cause the first portion of the immersion coolant liquid to be converted into an immersion cooling vapor.

[0159] In some aspects, the techniques described herein relate to a system, further including a pump fluidically coupled to the conduit and configured to flow a second portion of the immersion coolant liquid through the conduit.

[0160] In some aspects, the techniques described herein relate to a system, wherein the pump is configured to flow the second portion of the immersion coolant liquid through the conduit at a velocity of between about 0.1 mm / s and about 2500 mm / s.

[0161] In some aspects, the techniques described herein relate to a system, wherein the pump is configured to flow the second portion of the immersion coolant liquid through the conduit at a flow rate of between about 0.1 mL / s and about 200 mL / s.

[0162] In some aspects, the techniques described herein relate to a system, wherein the second portion of the immersion coolant liquid displaces a first portion of the immersion cooling vapor from the boiling surface.

[0163] In some aspects, the techniques described herein relate to a system, wherein the conduit further includes an inlet and an outlet.

[0164] In some aspects, the techniques described herein relate to a system, wherein the immersion coolant liquid flows through the inlet in a substantially same direction as the immersion coolant liquid flows through the outlet.

[0165] In some aspects, the techniques described herein relate to a system, wherein the immersion coolant liquid flows through the inlet in a substantially different direction than the immersion coolant liquid flows through the outlet.

[0166] In some aspects, the techniques described herein relate to a system, wherein the conduit includes at least one convex wall.

[0167] In some aspects, the techniques described herein relate to a system, wherein the conduit includes a surface modification.

[0168] In some aspects, the techniques described herein relate to a system, wherein the surface modification includes at least one of a surface topology modification or a coating.

[0169] In some aspects, the techniques described herein relate to a system, wherein the coating includes at least one of polytetrafluoroethylene, silane, or cerium oxide.

[0170] In some aspects, the techniques described herein relate to a system, wherein the conduit includes at least one of copper, stainless steel, aluminum, tungsten, or titanium.

[0171] In some aspects, the techniques described herein relate to a method for heat transfer, the method including generating, by a heat generating component disposed in an immersion coolant liquid, heat, causing, based on the generated heat, a second portion of theimmersion coolant liquid to boil and convert to an immersion cooling vapor, pumping, by a pump fluidically coupled to a conduit, a second portion of the immersion coolant liquid across a boiling surface of the conduit, wherein the boiling surface is thermally coupled to the heat generating component, and displacing at least a portion of the immersion cooling vapor with the second portion of the immersion coolant liquid.

[0172] In some aspects, the techniques described herein relate to a method, wherein pumping the second portion of the immersion coolant liquid across the boiling surface includes pumping the second portion of the immersion coolant liquid through the conduit at a velocity of between about 0.1 mm / s and about 2500 mm / s.

[0173] In some aspects, the techniques described herein relate to a method, wherein pumping the second portion of the immersion coolant liquid across the boiling surface includes pumping the second portion of the immersion coolant liquid through the conduit at a flow rate of between about 0.1 mL / s and about 200 mL / s.

[0174] In some aspects, the techniques described herein relate to a method, wherein the conduit further includes an inlet and an outlet and a third portion of the immersion coolant liquid flows through the inlet in a substantially same direction as the third portion of the immersion coolant liquid flows through the outlet.

[0175] In some aspects, the techniques described herein relate to a method, wherein the conduit further includes an inlet and an outlet and a third portion of the immersion coolant liquid flows through the inlet in a substantially different direction than the third portion of the immersion coolant liquid flows through the outlet.

[0176] In some aspects, the techniques described herein relate to a method, wherein the conduit includes at least one convex wall.

[0177] In some aspects, the techniques described herein relate to a method, wherein the conduit includes a surface modification.

[0178] In some aspects, the techniques described herein relate to a method, wherein the surface modification includes at least one of a surface topology modification or a coating.

[0179] In some aspects, the techniques described herein relate to a method, wherein the coating includes at least one of polytetrafluoroethylene, silane, or cerium oxide.

[0180] In some aspects, the techniques described herein relate to a method, wherein the conduit includes at least one of copper, stainless steel, aluminum, tungsten, or titanium.

[0181] All combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are part of the inventive subject matter disclosed herein. In particular, all combinations of subject matter appearing in this disclosure are part of the inventive subject matter disclosed herein. The terminology used herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0182] The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally and / or structurally similar elements).

[0183] FIG. 1 depicts an example of a two-phase immersion-cooling system that can be used to cool semiconductor dies.

[0184] FIG. 2 depicts a tank for cooling semiconductor dies in assembled units and also illustrates an assembled unit installed in the tank.

[0185] FIG. 3A depicts another example of a two-phase immersion-cooling system that can be used to cool semiconductor dies as described herein.

[0186] FIG. 3B depicts a plurality of packaged semiconductor dies mounted on a printed circuit board suitable for use in the immersion-cooling system of FIG. 3A.

[0187] FIG. 4 depicts an example of apparatus to force a flow of coolant liquid across heat-generating devices in an immersion-cooling system.

[0188] FIG. 5 depicts another example of apparatus to force a flow of coolant liquid across heat-generating devices in an immersion-cooling system.

[0189] FIG. 6A depicts an example of liquid pumps that contact and thermally couple to heat-generating devices to increase convective cooling of the heat-generating devices in an immersion cooling system.

[0190] FIG. 6B depicts an example of liquid pumps that contact and thermally couple directly to semiconductor dies to increase convective cooling of the semiconductor dies in an immersion cooling system.

[0191] FIG. 7 depicts an example of a pump that can be used for the implementations of FIG. 6A and FIG. 6B

[0192] FIG. 8 shows a flow chart for an example method of improving convection in an immersion cooling system according to the inventive concepts disclosed herein.

[0193] FIG. 9 depicts cooling of a plurality of semiconductor dies in coolant liquid of the two-phase immersion-cooling system of FIG. 3A and illustrates dry-out on a heat spreader’s surface.

[0194] FIG. 10A depicts an example of a vapor-shedding structure on a heat spreader that can be used in the two-phase immersion-cooling system of FIG. 3A.

[0195] FIG. 10B depicts another implementation of a vapor-shedding structure.

[0196] FIG. 10C depicts another implementation of a vapor-shedding structure.

[0197] FIG. 10D depicts another implementation of a vapor-shedding structure.

[0198] FIG. 10E depicts a different elevation view of the vapor-shedding structure ofFIG. 10C

[0199] FIG. 10F depicts another implementation of a vapor-shedding structure.

[0200] FIG. 10G depicts another implementation of a vapor-shedding structure.

[0201] FIG. 11 depicts example plots of how a characteristic of the vapor-shedding structure can change with height.

[0202] FIG. 12 depicts an implementation of a vapor-shedding structure adapted for a horizontal orientation of the heat spreader.

[0203] FIG. 13 shows an example method for assembling a computing system with a vapor-shedding structure according to the inventive concepts disclosed herein.

[0204] FIG. 14 depicts a device package comprising a plurality of semiconductor dies mounted in close proximity to each other on a package substrate.

[0205] FIG. 15A depicts an example of a dynamic boiler plate.

[0206] FIG. 15B depicts the boiler plate of FIG. 15A mounted on the device package of FIG. 14

[0207] FIG. 15C depicts another example of a dynamic boiler plate.

[0208] FIG. 15D depicts another example of a dynamic boiler plate and indicates the positions of the semiconductor dies of FIG. 14 beneath the boiler plate.

[0209] FIG. 15E depicts another example of a dynamic boiler plate.

[0210] FIG. 16 shows an example method for assembling a device package with a dynamic boiler plate according to the inventive concepts disclosed herein.

[0211] FIG. 17 illustrates a thermal distribution system in accordance with the present technology.

[0212] FIG. 18 depicts an immersion cooling system in accordance with the present technology.

[0213] FIG. 19 plots wall heat flux (log scale) from a semiconductor die as a function of wall superheat temperature (log scale) for an example heat-dissipative element such as a boiling enhancement coating.

[0214] FIG. 20 shows an example method for assembling an immersion cooling system including one or more computing components and a thermal distribution system according to the inventive concepts disclosed herein.

[0215] FIG. 21A illustrates a system for heat transfer in accordance with the present technology.

[0216] FIG. 21B illustrates a system including a boiler plate in accordance with the present technology.

[0217] FIG. 21C illustrates a conduit with a nozzle disposed at an angle to a respective heat generating component.

[0218] FIG. 22 shows an example method for assembling an immersion cooling system including one or more computing components and a jet impingement array according to the inventive concepts disclosed herein.

[0219] FIG. 23A illustrates a system for heat transfer in accordance with the present technology.

[0220] FIG. 23B illustrates a system for heat transfer in accordance with the present technology.

[0221] FIG. 23C illustrates a cutaway view of a conduit in which a wall of the conduit has a convex shape.

[0222] FIG. 24 shows an example method for increasing a flow rate across one or more computing components in an immersion cooling system disclosed herein.DETAILED DESCRIPTION

[0223] Some semiconductor dies have advanced to the point where air cooling is insufficient for operating the semiconductor dies to their full potential. Such semiconductor dies may then be cooled in an immersion-cooling system in which the semiconductor dies are immersed in a coolant liquid. The coolant liquid can transport heat away from the semiconductor dies more quickly than air. One type of immersion-cooling system is a two- phase immersion-cooling system in which the coolant liquid boils due to the heat provided by the semiconductor dies. The boiling occurs in a closed tank and produces coolant liquid vapor which is subsequently condensed back to coolant liquid by condenser tubes. The cyclic phase transitions from liquid to vapor and back to liquid can further remove heat from the semiconductor dies. In single-phase immersion cooling, coolant liquid flows over the semiconductor die and carries away heat but does not boil. In both cases, the flow of liquid over the semiconductor die is passive (e.g., produced by thermal gradients in the liquid).

[0224] The inventors have recognized and appreciated that in some cases, thermal gradients to establish passive, convective flow of liquid over a semiconductor die may not provide a desired amount of cooling for the semiconductor die. In two-phase immersion cooling, the flow of liquid may be low enough that a condition of “dry-out” can occur over the semiconductor die or over a heat-spreader that is thermally coupled to the semiconductor die. When dry-out occurs, boiling is so vigorous, and the semiconductor die or heat- dissipative element becomes so hot, that a film of air forms over the hot surface. The film of air can undesirably impede heat flow to the coolant liquid.

[0225] 1. Overview of Immersion-Cooling System

[0226] FIG. 1 depicts several aspects of a two-phase immersion-cooling system 160 for dissipating heat from one or more semiconductor die packages 105 via immersion cooling. The immersion-cooling system 160 includes a tank 107 partially filled with coolantliquid 164 into which die packages 105 needing cooling are immersed. Each die package 105 can include one or more semiconductor dies 150 that produce heat when the semiconductor dies are in operation. Each semiconductor die 150 can be thermally coupled to and in thermal communication with a heat-dissipative element 110, which in some cases can include a “protective lid” or “lid” alone or in combination with a “boiler plate” or “heat spreader.” The heat-dissipative element 110 can be formed from at least one material having high thermal conductivity (such as copper, a copper alloy, aluminum, an aluminum alloy, semiconductor, ceramic, etc.). In a two-phase immersion-cooling system, the temperature of the heat-dissipative element 110 can become high enough during operation of the semiconductor die 150 to boil coolant liquid 164 that contacts the heat-dissipative element 110 within the system’s tank 107. The heat-dissipative element 110 can include a boiler enhancement coating (BEC) formed on at least one surface of the heat-dissipative element 110.

[0227] The die packages 105 can be part of a larger assembled unit, such as a server. For example, die packages 105 can include components of a server such as, but not limited to, central processing units (CPUs), graphical processing units (GPUs), application-specific integrated circuits (ASICs), network devices, random access memory (RAM), high- bandwidth memory (HBM), memory, and power converters. The package 105 can be made commercially available as an off-the-shelf (OTS) product. The package 105 can be used for single-phase or two-phase immersion cooling of at least one semiconductor die 150, such as a microprocessor (e.g., a central processing unit (CPU) and / or graphics processing unit (GPU)), voltage regulator (VR), high bandwidth memory (HBM), a digital signal processing (DSP) die, an artificial intelligence (Al) accelerator, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or other densely patterned semiconductor die.

[0228] One or more semiconductor die packages 105 may be 3DIC stacks in accordance with the present technology. For example, one or more semiconductor die packages 105 may include a logic IC and at least one memory module bonded to the logic IC using a hybrid bond or micro-bump bond.

[0229] FIG. 1 depicts a two-phase immersion-cooling system 160 at a time when the semiconductor dies are operating and generating enough heat to boil coolant liquid 164 in an immersion-cooling tank 107. The immersion cooling system 160 in the illustrated exampleof FIG. 1 is a two-phase immersion cooling system, though the invention may also be implemented in a single-phase immersion cooling system.

[0230] The two-phase immersion-cooling system 160 includes a tank 107 filled, at least in part, with coolant liquid 164. The two-phase immersion-cooling system 160 can further include at least one chiller 180 that flows a heat-transfer fluid through at least one condenser coil 170 or condenser tubes located in the head space 109 of the tank 107. The condenser coil(s) 170 or condenser tubes can condense coolant liquid vapor 166 into droplets 168 that return to the coolant liquid 164 (e.g., are collected in a basin at the bottom of the tank). The die packages 105 can be mounted on one or more printed circuit boards (PCBs) 157 that are immersed, at least in part, in the coolant liquid 164. In some implementations, a foam or froth 167 can form in the tank 107 above the coolant liquid 164 when the system is in operation. The froth 167 can include mostly bubbles 165 that collect across the surface of the coolant liquid 164 as the coolant liquid boils.

[0231] Immersion-cooling system 160 may further include a filter 175 disposed adjacent to the tank 107. Filter 175 may include a filtration media, a housing, and a pump configured to force immersion coolant liquid 164 through filter 175 to remove contaminants, particulates, or other impurities that may be added to immersion coolant liquid 164 during use. Filter 175 may be housed outside of tank 107 while being in fluidic communication with immersion coolant liquid 164 in tank 107. Alternatively, filter 175 may be submerged within immersion coolant liquid 164 inside of tank 107.

[0232] Immersion coolant liquid 164 may be a hydrocarbon, a fluoroketone, an oil, or a similar dielectric liquid that will act as an insulator while simultaneously transferring heat from package 105 more efficiently than air. Examples of immersion coolant liquid 164 include, but are not limited to, Novec™ 649, Novec™ 7000, and Novec™ 7100 produced by 3M™. An exemplary immersion coolant liquid 164 used in accordance with embodiments of the present invention may have a dielectric constant baseline value of about 1.8-2 at a frequency of about 1 kHz.

[0233] In an embodiment of the invention, immersion coolant liquid 164 may be considered unacceptably contaminated if the dielectric constant and / or dielectric loss tangent of immersion cooling fluid being used in an immersion cooling system 160 differs by a threshold amount as compared to unused or pure immersion coolant liquid 164. For example, immersion coolant liquid 164 may be considered unacceptably contaminated or degraded ifthe dielectric constant and / or dielectric loss tangent differs by a threshold of 10% or more as compared to unused or pure immersion coolant liquid 164. In an embodiment, a dielectric constant and / or dielectric loss tangent variation threshold may be 20%, 15%, 5%, 3%, 1%, or any suitable threshold.

[0234] Contamination of the immersion coolant liquid 164 and resulting changes to dielectric constant and / or dielectric loss tangent may alter or negatively impact operation of components within immersion coolant liquid 164 including semiconductor die(s) 150. An altered dielectric constant and / or dielectric loss tangent may result in undesirable cross-talk between components on a PCB, additional noise or reduction in signal strength transmitted along exposed wires of a PCB or semiconductor die(s) 150 submerged in immersion fluid, and / or signal dissipation through the immersion coolant liquid 164. Signal loss may be severe enough that two elements may be effectively represented as being separated by an open circuit despite being physically connected. In an embodiment, a dielectric constant and / or dielectric loss tangent variation threshold may be selected based on an observed or inferred effect on one or more submerged semiconductor die(s) 150. For example, an increase in PCIe bit error rate above an error rate baseline may be correlated with an increase in dielectric constant and / or dielectric loss tangent above a dielectric constant and / or dielectric loss tangent baseline. Accordingly, operation of semiconductor die(s) 150 may be throttled or suspended when a dielectric constant and / or dielectric loss tangent of immersion coolant liquid 164 exceeds a predetermined threshold.

[0235] Changes to dielectric constant and / or dielectric loss tangent may be caused by contaminants within immersion coolant liquid 164. In some cases, changes to dielectric constant and / or dielectric loss tangent may be reversed by filtering the contaminants from immersion coolant liquid 164. In some embodiments, upon detecting an increase in dielectric constant and / or dielectric loss tangent of immersion coolant liquid 164, controller 102 may instruct filter 175 to increase filtration throughput or notify a user that an immersion coolant liquid 164 filtration media may need to be replaced. If a dielectric constant and / or dielectric loss tangent exceeds a predetermined threshold, controller 102 may throttle or shut down one or more semiconductor die(s) 150, generate a notification that immersion coolant liquid 164 should be replaced, trigger an alarm, etc.

[0236] Further examples of sensors and methods for immersion cooling contamination monitoring may include probes for monitoring immersion coolant liquid parameters such as dielectric constant and dielectric loss tangent, and processors configuredto identify trends in sensor data, model immersion cooling system behavior as a function of contamination, and alter operations of immersion cooling systems based on detected levels and / or states of contamination may be found in U.S. Provisional Patent Application 63 / 516,748, filed July 31, 2023 and entitled “Di-Electric Monitoring of Immersion Fluid During Cooling Operation,” the entirety of which is incorporated herein by reference.

[0237] The example of FIG. 1 is not intended to be illustrated to scale. The immersion-cooling system 160 may house and provide coolant liquid 164 to tens, hundreds, or even thousands of die packages 105. According to some implementations, the die packages 105 can be included in assembled units, such as server units. The total amount of electrical power drawn by the die packages 105 in one tank 107 of an immersion-cooling system can be from 100,000 Watts to 600,000 Watts. In some cases, the total amount of electrical power can be over 600,000 Watts.

[0238] According to some implementations, the tank 107 of an immersion-cooling system 160 can be small (e.g., up to the size of a floor unit air conditioner, approximately 1 meter high, 0.5 meter width, 0.5 meter depth or length). In some implementations, the tank 107 of an immersion-cooling system can be large (e.g., up to the size of an automotive van, approximately 2.5 meters high, 2.5 meters width, 4 meters depth or length). In some cases, the tank 107 of an immersion-cooling system 160 can be larger than an automotive van.

[0239] The immersion-cooling system 160 can also include at least one controller 102 (e.g., a microcontroller, programmable logic controller, microprocessor, field-programmable gate array, logic circuitry, memory, or some combination thereof) to manage operation of at least the immersion-cooling system 160. The controller 102 can perform various system functions such as monitoring temperatures of system components, coolant liquid fluid level, technician access to the interior of the tank, chiller operation etc. The controller 102 can further issue commands to control system operation such as executing a start-up sequence, executing a shut-down sequence, assigning workloads among the die packages 105 and / or assembled units, changing coolant liquid fluid level, changing the temperature of the heattransfer fluid circulated by the chiller 180, etc. In some implementations, the controller 102 can include (or be included in) a baseboard management controller (BMC) 104. That is, the BMC 104 may monitor and control all aspects of system operation for the immersion-cooling system 160 in addition to monitoring and controlling workloads of the semiconductor dies 150 in the die packages 105 and / or workloads among the assembled units cooled by the immersion-cooling system 160. The immersion-cooling system 160 can also include anetwork interface controller (NIC) 103 to allow the system to communicate over a network, such as a local area network or wide area network.

[0240] The immersion cooling system 160 can further include a fluid sensor array 190 having a plurality of fluid sensors 191. Fluid sensors 191 may include one or more leak detection sensors at least partially submerged in immersion coolant liquid 164. The fluid sensor array 190 may be mounted on or attached to a printed circuit board (PCB) 157.

[0001] In operation of the two-phase immersion cooling system 160 of FIG. 1, heat flows from the semiconductor die 150 where it is generated into the heat-dissipative element 110. The heat-dissipative element 110 is in thermal contact with an immersion coolant liquid 164 that can flow over and extract heat from the heat-dissipative element 110. The amount of heat delivered by the heat-dissipative element 110 to the immersion coolant liquid 164 is enough to boil the immersion coolant liquid 164 that contacts the heat-dissipative element 110 (creating bubbles 165 and potentially creating froth 167 when bubbles 165 reach the surface of immersion coolant liquid 164). The vapor 166 from the boiled immersion coolant liquid 164 can be cooled and condensed back to liquid droplets 168, for example, by the condenser coil 170. The heat-transfer fluid, such as chilled water, from the chiller 180 can be circulated through the condenser coil 170 to lower the temperature of the condenser coil 170 below the condensation point in the head space 109 of the tank 107. As a result, vapor 166 condenses on exterior surfaces of the condenser coil 170 and liquid droplets 168 from the condensed vapor can drip and / or flow back to the immersion coolant liquid 164. There may be a plurality of condenser coils 170 in tank 107 to condense the vapor 166 into droplets. Some or all of the condenser coil(s) 170 may or may not be located directly over the PCBs 157. Instead, the condenser coil(s) 170 can be located near one or more walls of the tank 107, such that the condenser coils (s) 170 are not directly over the PCBs 157 on which the packages 105 are mounted.

[0002] To improve thermal performance in two-phase immersion cooling system 160, the heat- dissipative element 110 can include a boiling enhancement coating (BEC) on at least one surface. The BEC can be formed from copper or a copper alloy and can be porous, for example, though BECs can take various forms. In some cases, the BEC is a micro porous copper coating having a thickness from approximately or exactly 50 microns to 500 microns thick (which may be produced by electroplating and / or etching). In some implementations, the BEC includes a mesh copper layer bonded (e.g., via resistance heating) to at least an outer surface of the heat- dissipative element 110. In some cases, the BEC is applied as particulates to at least one smoothsurface of the heat-dissipative element 110 and then subsequently sintered to adhere to one another and to the heat-dissipative element 110. The BEC provides an improved surface area to contact the immersion coolant liquid 164 and can increase the heat transfer coefficient from the heat-dissipative element 110 to the immersion coolant liquid 164 by up to a factor of 15 versus a smooth surface on the heat-dissipative element 110. Accordingly, BECs can increase thermal conductivity to, and accelerate the boiling of, the immersion coolant liquid 164.

[0003] Further implementations of boiling enhancement coatings and enclosures are possible. Additional arrangements, applications, and methods of use of boiling enhancement coatings and enclosures, including with semiconductor dies and 3DIC stacks, are described in the below U.S. Patent Applications.

[0004] U.S. Patent Application No. 18 / 327,615, filed June 1, 2023 and entitled "Boiler Enhancement Coatings with Active Boiling Management,” discloses heat spreader and boiling enhancement enclosure architectures thermally and / or mechanically coupled to one or more semiconductor dies or logic ICs that may be used for passive and / or active management of immersion cooling fluid boiling, including through the use of valves to control pressure of boiling immersion cooling fluid within a boiling enhancement chamber, particularly in paragraphs

[0018] -

[0039] and FIGS. 3-5B. The entirety of U.S. Patent Application No. 18 / 327,615 is incorporated herein by reference.

[0005] U.S. Provisional Patent Application No. 63 / 500,167, filed May 4, 2023 and entitled “Direct to Chip Heat Spreader and Boiler Enhancement Coatings for Microelectronics,” discloses heat spreader and BECs thermally and / or mechanically coupled to one or more semiconductor dies, logic ICs, and / or 3DIC stacks, particularly in paragraphs

[0015] -

[0033] and FIGS. 2A-4. BEC form factors may include graphite heat spreader architectures, vapor chambers, heat pipes, copper plates, fins, and the like. BEC form factors may be thermally and / or mechanically coupled to the one or more semiconductor dies, logic ICs, and / or 3DIC stacks through a thermally conductive epoxy, and may have varying dimensions relative to a surface to which the semiconductor dies and / or logic ICs are mounted. The entirety of U.S. Provisional Patent Application No. 63 / 500,167 is incorporated herein by reference.

[0006] U.S. Patent Application No. 18 / 460,091, filed September 1, 2023 and entitled “Direct to Chip Application of Boiling Enhancement Coating,” discloses BECs and methods for applying BECs to semiconductor dies, logic ICs, and / or 3DIC stacks in accordance with the present technology. In particular, paragraphs

[0024] -

[0046] and FIGS. 2A-5 discloseembodiments of BEC layers, adhesives, solders, sintering, laser ablation, meshes, and other BECs and BEC application methods. The entirety of U.S. Patent Application No. 18 / 460,091 is incorporated herein by reference.

[0007] U.S. Provisional Patent Application No. 63 / 506,945, filed June 8, 2023 and entitled “Vapor- Shedding Structures for Boiler Plates in Two-Phase Immersion Cooling Systems,” discloses structures that may be thermally and / or mechanically coupled to computing hardware such as one or more semiconductor dies, logic ICs, and / or 3DIC stacks to enable the shedding of immersion cooling vapors generated from the boiling of immersion cooling fluid during operation of the computing hardware. In particular, paragraphs

[0021] -

[0039] and FIGS. 3A-5 disclose vapor-shedding structures including varying porosities, constituent materials, and geometries relative to the computing hardware on which they are mounted. The entirety of U.S. Provisional Patent Application No. 63 / 506,945 is incorporated herein by reference.

[0008] U.S. Provisional Application No. 63 / 513,828, filed July 14, 2023 and entitled “Grinding Apparatuses and Methods for Mechanically Modifying Surfaces of Processors to Promote Boiling of a Coolant Liquid,” discloses methods for creating boiling enhancement modifications to surfaces such as the surfaces of computing hardware such as one or more semiconductor dies, logic ICs, and / or 3DIC stacks, particularly in paragraphs

[0036] -

[0095] and FIGS. 2A-8. For example, grooves, patterns, gouges, trenches, or other structures may be added to a surface or lid of a processor, semiconductor die, logic IC, 3DIC stack component, and / or BEC to encourage nucleation sites for bubbles of immersion cooling vapor to form during a cooling process, thus decreasing the thermal resistance between the processor, semiconductor die, logic IC, and / or 3DIC stack component and the surrounding immersion cooling fluid. The entirety of U.S. Provisional Application No. 63 / 513,828 is incorporated herein by reference.

[0009] U.S. Provisional Patent Application No. 63 / 513,829, filed July 14, 2023 and entitled “Electrical Connector Having a Heater to Facilitate Boiling of a Coolant Liquid to Improve Signal Integrity in Immersion Cooling Environment,” discloses heaters for promoting boiling of immersion cooling fluid near electrical connectors such as connections between components of a 3DIC stack and enable improved impedances at those connectors, particularly in paragraphs

[0019] -

[0052] and FIGS. 1A-3B. The entirety of U.S. Provisional Patent Application No. 63 / 513,829 is incorporated herein by reference.

[0241] U.S. Provisional Patent Application No. 63 / 603,242, filed November 28, 2023 and entitled “Woven Boiler Enhancement Coatings,” provides additional examples of BECs including woven BECs with variable weave patterns, densities, attachment mechanisms, and materials (including copper and tungsten) that may be attached to computing hardware such as one or more semiconductor dies, logic ICs, and / or 3DIC stacks in order to promote more efficient heat transfer and immersion cooling vapor nucleation, particularly in paragraphs [003 l]-

[0055] and FIGS. 3-7. The entirety of U.S. Provisional Patent Application No. 63 / 603,242 is incorporated herein by reference.

[0242] 2. Example Tank for a Two-Phase Immersion-Cooling System

[0243] FIG. 2 depicts an example tank 207 for an immersion-cooling system 260 that can cool a plurality of assembled units 210. The tank 207 can be one of many installed in a data center, for example. The assembled units 210 can each be servers, dedicated processing units, data-mining units, high bandwidth memory units, or other types of processing and / or memory units. Each assembled unit 210 can include a plurality of semiconductor dies 150 in die packages 105 that are cooled by the coolant liquid 164.

[0244] In some implementations, the tank 207 can be formed to include compartments 205 that are not filled with coolant liquid 164. The compartments 205 can be outside a main, enclosed volume of the tank that is at least partially filled with coolant liquid 164, for example. The compartments 205 can be used to house server components that need not be cooled by liquid (e.g., signal routing electronics and connectors). Condenser tubes 270 can be located above and to the side of the assembled units 210 so that the assembled units can be lowered into and removed from the tank 207 through an opening 220 in the tank 207 without contacting the condenser tubes 270. There can be many more condenser tubes than the number shown in FIG. 2. The opening 220 can be covered and sealed by an access door 212 when the immersion-cooling system is in operation. In some implementations, the access door 212 can include glass so that the assembled units 210 can be viewed inside the tank during operation of the system (e.g., to view indicator LEDs on the assembled units 210).

[0245] In operation, the condenser tubes 270 convey a heat-transfer liquid to cool the condenser tubes to a temperature below the dew point of the coolant-liquid vapor 166 in the environment surrounding the condenser tubes 270. The condenser tubes 270 are exposed to the coolant-liquid vapor 166 in the within the tank 207 in a closed environment. The coolant-liquid vapor 166 can then condense onto the condenser tubes 270 and form liquid droplets 168 that can drip down and be collected in a basin of the tank 207.

[0246] A single tank 207 can be sized to contain 10 or more assembled units 210 (e.g., at least from 10 to 70 assembled units 210). In some cases, a tank 207 can be sized to contain more than 70 units. Power to the assembled units 210 can be provided by one or more busbars 230 that run(s) along a base of the tank 207 in the ± x direction. The assembled units 210 can be placed in one or more rows (e.g., extending in the ± x direction in the illustration) within the tank 207. In a data center, there can be a plurality of tanks 207 each containing a plurality of assembled units 210. The immersion-cooling tanks 207 can be operated continuously for days, weeks, months, or even longer in some cases, before substantial servicing of any of the tanks is needed.

[0247] 3. Example Cooling Assembly for a Two-Phase Immersion-CoolingSystem

[0248] FIG. 3A depicts aspects of an immersion-cooling system 360 and a cooling assembly 300 for dissipating heat from one or more semiconductor dies 350 via immersion cooling (such as two-phase immersion cooling). Although two-phase immersion cooling is shown in the drawings, the cooling assemblies described herein could be used in single-phase immersion cooling.

[0249] The immersion-cooling system 360 includes a tank 307 containing a coolant liquid 164 in which one or more cooling assemblies 300 are immersed. Each cooling assembly 300 can include one or more semiconductor dies 350 that are cooled with the coolant liquid 164. The immersion-cooling system 360 can include a controller 302 (e.g., a microcontroller, programmable logic controller, microprocessor, field-programmable gate array, logic circuitry, memory, or some combination thereof) to monitor temperatures within the system and to manage system operation. In some cases, the cooling assemblies 300 can be part of a larger device (e.g., a server, an inference engine, etc.).

[0250] The illustrated example is not to scale and depicts the cooling assembly 300 much larger in the immersion-cooling system than it would be in an actual implementation. Typically, the two-phase immersion-cooling system 360 is much larger than the cooling assembly 300. For example, the immersion-cooling system 360 may house and provide coolant liquid 164 to tens, hundreds, or even thousands of cooling assemblies 300. Thecooling assemblies 300 can be mounted on one or more printed circuit boards (PCBs) that are installed within the tank 307 of the immersion-cooling system 360.

[0251] The cooling assembly 300 can include a heat spreader 310 (which may also be referred to as a “boiler plate” or “heat-dissipative element” in some applications) that may thermally couple to a protective lid 330 with a first thermal interface material (TIM) 320, according to some implementations. The protective lid 330 (if present) can thermally couple to the semiconductor die(s) 350 with a second TIM 340. In some implementations, the heat spreader 310 can thermally couple directly to the semiconductor die(s) 350, as described in U.S. provisional patent application serial No. 63 / 500,167 titled “Direct to Chip Heat Spreader and Boiler Enhancement Coatings for Microelectronics,” filed May 4, 2023, and in international patent application PCT / US2023 / 67058 titled “Electronic Package Construction for Immersion Cooling of Integrated Circuits,” filed May 16, 2023, both of which applications are herein incorporated by reference in their entirety.

[0252] The semiconductor die(s) 350 and protective lid(s) 330 (if present) can be mounted on and attached to a printed circuit board (PCB) 355 in a device package 305 that can be made commercially available. A plurality of the device packages 305 can be populated onto a larger printed circuit board 357, as depicted in FIG. 3B. A plurality of the larger printed circuit boards 357 (e.g., a host PCB) can be installed within the tank 307 of the immersion-cooling system 360 and may include boards of a server or high-performance computing system, for example. At least one of the host PCBs 357 installed in the immersion-cooling system 360 can include a baseboard management controller (BMC) 351 to monitor and manage operation of the host system. For example, the BMC 351 can monitor workloads and temperatures of semiconductor dies 350 in device packages 305 on the host PCB(s) 357.

[0253] The cooling assembly 300 of FIG. 3A can be used for two-phase immersion cooling of at least one semiconductor die 350, such as a microprocessor e.g., a central processing unit (CPU) and / or graphic processing unit (GPU)), voltage regulator (VR), high bandwidth memory (HBM), a digital signal processing (DSP) die, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or other densely patterned semiconductor die.

[0254] In a two-phase immersion-cooling system 360, heat flows from the semiconductor die 350 where it is generated, through the second TIM 340 (if present) into theprotective lid 330 (if present), through the first TIM 320, and into the heat spreader 310. The heat spreader 310 is in thermal contact with a coolant liquid 164 that can flow over and extract heat from the heat spreader 310. For two-phase immersion cooling, the amount of heat delivered by the heat spreader 310 to the coolant liquid 164 is enough to boil the coolant liquid 164 that contacts the heat spreader 310 (creating bubbles 165). The vapor 166 from the boiled coolant liquid 164 can be cooled and condensed back to liquid droplets 168, for example, by a condenser coil 370. A heat transfer fluid, such as chilled water, from a chiller 380 can be circulated through the condenser coil 370 to condense the vapor 166 on exterior surfaces of the condenser coil 370. Liquid droplets 168 from the condensed vapor can drip and / or flow back to the coolant liquid 164 that contacts the heat spreader 310. Although a single condenser coil 370 is depicted directly over the cooling assembly 300 in FIG. 3A, there can be a plurality of condenser coils 370 in the tank 307 to condense the vapor 166 into droplets. Some or all of the condenser coils 370 may not be located directly over the cooling assembly 300. Instead, the condenser coil(s) 370 can be located near one or more walls of the tank 307, such that the condenser coil(s) 370 are not directly over the cooling assemblies 300 and printed circuit boards on which the cooling assemblies are mounted.

[0255] To improve thermal performance in two-phase immersion-cooling system 360, the heat spreader 310 can include a boiling enhancement coating (BEC) 315 on at least one surface. The BEC 315 can be formed from copper or a copper alloy and can be porous, for example, though BECs can take various forms. In some cases, the BEC is a micro porous copper coating having a thickness from approximately or exactly 50 microns to 500 microns thick (which may be produced by electroplating and / or etching). In some implementations, the BEC 315 includes a mesh copper layer bonded (e.g., via resistance heating) to at least a top surface of the heat spreader 310. In some cases, the BEC 315 is applied as particulates to at least one smooth surface of the heat spreader 310 and then subsequently sintered to adhere to one another and to the heat spreader 310. The BEC 315 provides a large surface area to contact the coolant liquid 164 and can increase the heat transfer coefficient from the heat spreader 310 to the coolant liquid 164 by up to a factor of 15 versus a smooth surface on the heat spreader 310. Accordingly, BECs 315 can increase thermal conductivity to, and accelerate the boiling of, the coolant liquid 164.

[0256] 4. Improved Convection in Immersion-Cooling Systems

[0257] The inventors have recognized and appreciated that increasing convection by coolant liquid for an immersion-cooled device can improve cooling of heat-generatingdevices. Convection can be increased by forcibly increasing fluid flow over a heatgenerating device beyond what can be achieved by passive convection. When fluid flow is increased, more heat can be carried away from the device by convection. In some cases, the increased fluid flow can prevent dry-out from occurring in two-phase immersion cooling systems.

[0258] FIG. 4 depicts one example of apparatus 1300 that can increase fluid flow over a heat-generating device 1305 and improve cooling of heat-generating devices in an immersion-cooling system (e.g., immersion cooling systems 160, 260, and / or 360). The heatgenerating device 1305 can be, for example, a semiconductor die package 105 / 305 that can include a heat-dissipative element 110 / 310 and / or a boiler enhancement coating (BEC) (e.g., BEC 315). The apparatus 1300 includes a pump 1310, a manifold 1320, and one or more conduits 1330 for directing coolant liquid 164 from the manifold 1320 to one or more heatgenerating devices 1305. Although depicted as mounted to the same PCB 157, the pump 1310 may or may not be mounted to the same PCB 157 as the heat-generating devices 1305. For example, the pump 1310 may be mounted to host PCB 357. The pump 1310 can draw in coolant liquid 164 and pump the coolant liquid 164 into the manifold 1320. The manifold 1320 fluidically couples to the one or more conduits 1330 and to the pump 1310. The manifold 1320 distributes liquid from the pump 1310 into each of the conduits 1330. The conduits 1330 can direct coolant liquid 164 in a forced flow 1340, exiting the conduits 1330, across the heat-generating devices 1305 due to pressure provided by the pump 1310. The conduits 1330 can be formed from metal or plastic and can be tubular to convey the coolant liquid from the manifold 1320 to the heat-generating devices 1305.

[0259] The pump 1310 can be a miniature fluidic pump, for example, which is powered with electricity. The pump 1310 can be a submersible pump such that it can be fully immersed in the coolant liquid 164. An example of a submersible pump that may be used in the immersion-cooling systems disclosed herein is the miniature submersible pump model No. 4546 available from Adafruit Industries LLC of New York, though other miniature submersible pumps can be used. Preferably, the pump 1310 is small in size such that it can be mounted on the PCB 157 and be powered with electricity e.g., 3 volts or 5 volts) available from circuitry on the PCB 157. The height of the pump from the surface of the PCB 157 may be no greater than 50 mm in some implementations, no greater than 25 mm in some implementations, and even no greater than 10 mm in some implementations. The pump 1310can employ one of several types of pumping mechanisms such as, but not limited to, a rotary vane, diaphragm, lobe, centrifugal, auger, and peristaltic pumping mechanism.

[0260] FIG. 5 illustrates another arrangement for forcing flow of coolant liquid 164 over a heat-generating device 1305. A portion of a PCB 157 is shown in FIG. 5 having two heat-generating devices 1305 mounted thereon. More heat-generating devices 1305 and pumps 1410 can be mounted on the PCB 157. Any of the miniature pumps described in connection with the implementation of FIG. 4 can be used for the implementation of FIG. 5 and need not be described again.

[0261] In the illustrated implementation, a pump 1410 is mounted in close proximity to each heat-generating device 1305. For example, the pump 1410 can be mounted such that an intake 1412 or exhaust 1416 of the pump 1410 forces the flow 1340 of coolant liquid 164 across at least a portion of the heat-generating device 1305. In the illustration of FIG. 5, the pump is mounted such that its intake 1412 is located a short distance d from the nearest surface of the heat-generating device 1305. When the pump 1410 draws in liquid, it pulls coolant liquid 164 across a surface of the heat-generating device 1305, thereby increasing heat flow and dissipation from the heat-generating device 1305 into the moving coolant liquid 164 (increasing convective cooling of the heat-generating device 1305). Coolant liquid 164 heated by the heat-generating device 1305 can be exhausted from the pump 1410 away from the heat-generating device 1305.

[0262] The pump 1410 can be mounted on posts 1420, a cage, or other structure that couples to the PCB 157. Preferably, the pump’s intake 1412 or exhaust 1416 is located in close proximity to the heat-generating device 1305. The distance d can be a value between approximately or exactly 1 mm and 10 mm, for example. In an alternative configuration to that illustrated in FIG. 5, the pump’s exhaust 1416 can be mounted the distance d from the nearest surface of the heat-generating device 1305 such that the pump 1410 pushes coolant liquid 164 across the surface of the heat-generating device 1305 (e.g., an orientation reversed from that illustrated in FIG. 5).

[0263] According to some implementations, the pump 1410 can include a propeller that moves the coolant liquid 164 from the intake 1412 to the exhaust 1416.

[0264] In some cases, the pump 1410 can be directly contacted to the heat-generating device 1305, as depicted in FIG. 6A. The heat-generating device 1305 for any of the implementations described herein can include a heat-dissipative element 110 / 310 and / or aboiling enhancement coating (e.g., BEC 315). The BEC may be a three-dimensional printed BEC, for example, as described in U.S. provisional patent application Ser. No. 63 / 612,711, titled “3D-Printed Boiler Enhancement Coatings,” filed December 20, 2023, which application is herein incorporated by reference in its entirety. In implementations where the pump contacts the heat-generating device 1305, the pump 1410 includes a wall or plate 1520 having high thermal conductivity e.g., a metal plate comprising copper, a copper alloy, aluminum, an aluminum alloy, or other material having a thermal conductivity greater than 10 W m'1K'1). An exterior surface 1522 of the wall or plate 1520 can contact and be thermally coupled to the heat-generating device 1305 by direct, intimate contact (with no other material between the two surfaces) or by using a thermal interface material (TIM) between the two surfaces. The pump 1410 can internally move coolant liquid to force a flow 1340 across an interior surface 1524 of the wall or plate 1520 to cool the wall or plate and thereby cool the thermally coupled heat-generating device 1305.

[0265] In some cases, the wall or plate 1520 can replace, take the place of, and perform functionality of a heat-dissipative element 110 / 310 when mounted directly to a semiconductor die 150 / 350, as depicted in FIG. 6B. In such implementations, a BEC (e.g., BEC 315) can be disposed on the interior surface 1524 of the wall or plate 1520.

[0266] An example design for a pump 1310 that can be contacted to the heatgenerating device 1305 or semiconductor die 150 / 350 is the Engine 27 model, low-profile, CPU cooler currently available from Thermaltake of Taipei City, Taiwan. Although designed for air, it could be adapted for use in the immersion-cooling systems disclosed herein. The pump 1310 may include an open centrifugal pumping blade 1610 that can force coolant liquid 164 through heat-dissipation fins 1620 surrounding the blade 1610. The fins 1620 thermally couple to a copper base plate 1630 that in turn can thermally couple to the heat-generating device 1305. The pump design is depicted in FIG. 7. The pump 1310 can be adapted for submersible operation by including watertight seals around the drive shaft and around the pump’s internal motor.

[0267] Also considered by the inventors are methods of operating the abovedescribed apparatus for improving convective cooling of heat-generating devices. FIG. 8 shows an example method 800 for improving convection in an immersion cooling system according to the inventive concepts disclosed herein. The method 800 begins at step 802 by mounting a heat generating device (e.g., heat-generating devices 1305 and / or semiconductor die package 105 / 305) to a substrate (e.g., PCB 157) to form a computing system. In someimplementations, the computing system may include multiple surface-mounted devices.Accordingly, each of these devices may be mounted at step 802.

[0268] Thereafter, at step 804, a pump (e.g., pump 1310) operably coupled to a manifold (e.g., manifold 1320) and to at least one conduit (e.g., conduit 1330) may be mounted to the substrate to form an apparatus for convective cooling of the computing system. In some implementations, the apparatus for convective cooling of the computing system may be mounted to a different PCB than the heat generating device. At step 806, the apparatus for convective cooling of the computing system and the computing system may be installed in an immersion cooling system (e.g., a two-phase immersion cooling system), in part, by submerging the computing system into coolant liquid stored in a tank in a two-phase immersion cooling system.

[0269] At step 808, which may be performed in combination with steps 802-806 and / or independently of steps 802-806, the apparatus may be used to improve cooling of the computing system during operation of the immersion cooling system by directing flow of coolant liquid to the computing system via the apparatus. In operation, as described above, the pump 1310 can draw in coolant liquid 164 and pump the coolant liquid 164 into the manifold 1320. The manifold 1320 fluidically couples to the one or more conduits 1330 and to the pump 1310. The manifold 1320 distributes liquid from the pump 1310 into each of the conduits 1330. The conduits 1330 can then direct coolant liquid 164 in a forced flow 1340, exiting the conduits 1330, across the heat-generating devices 1305 due to pressure provided by the pump 1310. Thus, the apparatus can be used to create a flow of the coolant liquid with a pump immersed in the coolant liquid of the immersion-cooling system and using the flow of the coolant liquid to remove heat from the computing system, wherein the computing system is also immersed in the coolant liquid. The flow of coolant liquid can be forced across a surface of the computing system or across an interior surface of the pump, as described above.

[0270] 5. Vapor-Shedding Structures for Boiler Plates in Two-Phase ImmersionCooling Systems

[0271] The inventors have recognized and appreciated that boiling of the coolant liquid 164 may relatively uncontrolled in the arrangement shown in FIGS. 1 and / or 3A, for example. The following vapor shedding structures are described using the arrangementshown in FIG. 3A as an example. However, the vapor shedding structures disclosed herein may also be used in the immersion cooling system 160 and / or 260.

[0272] In some circumstances, the temperature of the semiconductor dies 350-1, 350- 2, 350-3 can be so high and the generation of bubbles 165 so rapid that a condition of “dryout” occurs on an upper region of the heat spreader 310. Dry-out is depicted in the illustration of FIG. 9. When dry-out occurs, coolant liquid 164 cannot contact the heat spreader 310 at the affected dry-out region 2210, causing an unfavorable temperature rise in the nearby semiconductor die 350-1, opposite the dry-out region 2210, and also causing an uneven temperature across the heat spreader (e.g., cooler at the bottom (-z direction) and hotter at the top (+z direction)). Even if dry-out does not occur, there can be a thermal gradient across the heat spreader 310 from top to bottom. For example, a thermal gradient can arise due to more bubbles 165 (and less coolant liquid 164) being adjacent to and in thermal contact with the heat spreader 310 in upper regions compared to lower regions (as depicted in FIG. 3A). Such thermal gradients can be unfavorable in multichip modules where multiple chips cooled by a heat spreader 310 are arrayed vertically on a PCB in a two- phase immersion-cooling system 360. Such thermal gradients can affect clock frequencies on the different chips and cause loss of clock frequency synchronization across the chips.

[0273] The references to “top” or “upper” and “bottom” or “lower” of the vaporshedding structure 2310 are to be understood when the device is oriented for operation in a two-phase immersion-cooling system 360. When oriented for operation in the tank 307 of a two-phase immersion-cooling system 360 (see FIG. 3A), “bottom” and “lower” refer to locations and / or directions nearer or toward a base of the tank 307 or floor on which the tank rests (~z direction in the drawing). “Top” and “upper” refer to locations and / or directions nearer or toward a top of the tank 307, in the direction to which the bubbles 165 rise (+z direction in the drawing).

[0274] In view of the foregoing, the inventors conceived vapor-shedding structures 2310 to shed bubbles 165 away from upper portions of the heat spreader 310. FIG. 10A depicts an example of such a vapor shedding structure 2310. The vapor-shedding structure 2310 can include mesh material, woven material, and / or porous material that is attached to the heat spreader 310 directly (e.g., adhered or sintered directly to the heat spreader) or indirectly (e.g., adhered to a BEC that is on the heat spreader 310). In some implementations, the vapor-shedding structure 2310 can be 3D printed onto the heat spreader 310 or BEC 315. In some cases, the BEC can be formed on the vapor-shedding structure 2310. The vapor-shedding structure 2310 can include at least one metal (e.g., copper, aluminum, titanium, steel). In some implementations, the vapor-shedding structure 2310 can be formed from a nonmetallic material (e.g., fiberglass, a ceramic) that is not reduced when exposed to the coolant liquid 164, which may be fluorinated.

[0275] The vapor-shedding structure 2310 can be asymmetric vertically (from its bottom edge 2312 to top edge 2318) in at least one characteristic (e.g., thickness, lay-out pattern on the heat spreader 310, material, and / or porosity). In the illustration of FIG. 10A, the vapor-shedding structure 2310 includes a wedge that is thicker near its top edge 2318 than near its bottom edge 2312. The angle of the wedge (between the two non-parallel surfaces) can be in a range from 2 degrees to 30 degrees or in a sub-range of this range. The vaporshedding structure 2310 can be configured such that bubbles generated via boiling are forced away (in the +y direction, a direction normal to the boiling surface 312 of the heat spreader 310) from the boiling surface 312 of the heat spreader 310 as the bubbles rise. This motion is indicated by the longer, gray arrow in FIG. 10A. The boiling surface 312 is a surface of the heat spreader 310 that nucleates and releases the most bubbles 165. The boiling surface 312 may or may not include a BEC 315, which enhances the boiling action at the boiling surface.

[0276] In some implementations, the vapor-shedding structure 2310 can be porous such that it wicks coolant liquid 164 into the vapor-shedding structure 2310 and across the boiling surface 312 of the heat spreader 310. The wicking of coolant liquid 164 is indicated by the short, black arrow in FIG. 10A. The wicking action can be from the top, bottom, and side edges of the vapor-shedding structure 2310.

[0277] In operation, the heat spreader 310 can receive heat from the semiconductor die(s) 350. As coolant liquid 164 is wicked across the boiling surface 312 of the heat spreader 310, it is raised to a boiling temperature creating bubbles at the boiling surface or at a BEC (if present). Roughness of the boiling surface 312, BEC 315 (if present), and / or vapor-shedding structure 2310 can nucleate the bubbles that subsequently travel outward (+y direction) and upward (+z direction) through pores of the vapor-shedding structure until they reach the outer surface of the vapor-shedding structure 2310. The bubbles 165 can then travel outward and upward along the surface of the vapor-shedding structure 2310, as indicated in FIG. 10A, rather than coalescing along the upper surface of the heat spreader 310 forming a dry-out region 2210, as depicted in FIG. 9.

[0278] In some implementations, the vapor-shedding structure 2310 can be formed from the same material used to make the BEC 315, such that the vapor-shedding structure 2310 also functions as a BEC.

[0279] Other vapor-shedding structures 2310 are possible, as depicted in FIG. 10B through FIG. 10F. FIG. 10B depicts a vapor-shedding structure 2310 that has a uniform thickness along its height in the z direction. The vertical asymmetry of this structure can be its porosity. For example, the vapor-shedding structure 2310 of FIG. 10B can have a gradient in porosity with a higher porosity near the top edge 2318 reducing to a lower porosity near the bottom edge 2312. If the vapor-shedding structure 2310 is made by a subtractive process, more material can be removed near the top edge than near the bottom edge to establish a gradient in porosity. Material removal can be done by microstructure subtractive manufacturing via electrical (electron beam or electro discharge machining), mechanical (scratching, machining, skiving), chemical etching, laser milling, or some combination thereof. If the vapor-shedding structure 2310 is made by an additive process, less material can be added near the top edge 2318 than near the bottom edge 2312 to establish a gradient in porosity. Material addition can be done by metal 3D printing, diffusion bonding with sintered powders having variations in particle sizes, diffusion bonding with meshes, or some combination thereof to generate different pore sizes and three-dimensional porous geometries. The higher porosity near the top edge 2318 can allow more coolant liquid 164 to contact and cool the upper region of the heat spreader, which would normally become hotter. In this way, the temperature of the heat spreader 310 and thermally-coupled semiconductor die(s) 350 (not shown in FIG. 10B) can be made more uniform from top to bottom of the heat spreader 310. Again, bubbles can travel outward from the boiling surface 312 and upward along the outer surface of the vapor-shedding structures 2310.

[0280] FIG. 10C depicts a vapor-shedding structure 2310 that is formed with strips 2313 (of mesh material, woven material, or porous material) extending across the heat spreader 310. An elevation view of the same structure, viewed from the +y direction is shown in FIG. 10E. The strips 2313 can be thicker and / or more porous towards the top edge 2318 of the vapor-shedding structure 2310 (arrow referring to the collection of strips) and thinner near the bottom edge 2312. The thicker strips 2313 can force upward-traveling bubbles 165 farther from the heat spreader. BEC 315 may or may not cover at least a portion of the heat spreader’s boiling surface (e.g., in regions around the vapor-shedding strips 2313).

[0281] FIG. 10D depicts a vapor-shedding structure 2310 (arrow referring to a collection of fins) that includes a plurality of fins 2315 extending from the heat spreader 310. The fins 2315 can be formed from a metal, may be solid or porous, and can extend across the heat spreader (in the x direction) like the strips 2313 of FIG. 10E. The fins 2315 can attach to the heat spreader 310 or to the BEC 315 and guide rising bubbles away from the boiling surface 312 of the heat spreader. The fins 2315 can all have the same extension length I from the surface of the heat spreader 310 or may have different extension lengths (e.g., longer near the top edge 2318 and shorter near the bottom edge 2312). In some implementations, the BEC 315 can be formed after the fins are attached to the heat spreader 310 and the BEC 315 can be formed around the fins 2315. In some cases, the BEC 315 can be formed on the fins 2315. In addition to deflecting bubbles 165 away from the boiling surface of the heat spreader 310, the fins 2315 can also provide some additional cooling by essentially increasing the surface area of the heat spreader 310.

[0282] FIG. 10F depicts another implementation of a vapor-shedding structure 2310 disposed on a heat spreader 310. In this implementation, the vapor-shedding structure 2310 includes a lattice 2317 of material (e.g., mesh material, woven material, or porous material as described above). In another implementation, the vapor-shedding structure 2310 can be disposed on a heat spreader 310 in a grid pattern, as depicted in FIG. 10G. The grid or lattice patterns need not be regular, periodic patterns. In some cases, the grid or lattice pattern can be a random pattern.

[0283] FIG. 11 is a plot indicating different ways in which the characteristic (e.g., thickness or porosity) of the vapor-shedding structure can change (e.g., increase) with height (z). For example, the characteristic can increase with height linearly (linear curve 2410), nonlinearly (nonlinear curve 2420), stepwise (stepwise curve (2430), in a modulated manner (modulated curve 2440), sinusoidally (sinusoidal curve 2450), or randomly (random curve 2460). Combinations of the types of changes in the characteristic are also possible.

[0284] Although the vapor-shedding structure 2310 is depicted in a vertical orientation in the drawings, the vapor-shedding structure 2310 can also be adapted for use in a horizontal orientation. In a horizontal orientation, the boiling surface 312 of the vaporshedding structure 2310 faces upward (+ z direction). FIG. 12 depicts an example implementation of a vapor-shedding structure 2310 adapted for use on a heat spreader 310 oriented horizontally. The vapor-shedding structure 2310 can be thicker and / or have a different porosity at its center than at edges of the heat spreader 310. The vapor-sheddingstructure 2310 can be conical in shape with a curved slope toward its edges as illustrated or a straight slope to the edges. The vapor-shedding structure 2310 can shed bubbles centrally from the heat spreader 310 and wick coolant liquid towards the center of the heat spreader from edges of the heat spreader. The central plume 2505 of bubbles can help increase circular flow 2520 of coolant liquid 164 around the heat spreader 310 that aids in supplying lower temperature coolant liquid 164 to the heat spreader.

[0285] Also considered by the inventors are methods of assembling a computing system including the vapor-shedding structure disclosed herein. FIG. 13 shows an example method 1380 for assembling a computing system according to the inventive concepts disclosed herein. The method 1380 begins at step 1382 applying a vapor-shedding structure to a heat spreader either directly or indirectly. As described above, the vapor-shedding structure may be applied directly to the heat spreader or indirectly (e.g., adhered to a BEC that is on the heat spreader, for example). Thereafter, at step 1384, the heat spreader may be thermally coupled to a heat generating device (e.g., a semiconductor die). Then, at step 1386, the heat generating device may be mounted to a substrate (e.g., a PCB) to form a computing system. In some implementations, the computing system may include multiple surfacemounted devices. Accordingly, each of these devices may be mounted at step 1386. Then, at step 1388, the computing system may be installed, in part, by submerging the computing system into coolant liquid stored in a tank in a two-phase immersion cooling system.

[0286] 6. Dynamic Boiler Plates

[0287] In some applications, different semiconductor dies can be positioned on a circuit board in close proximity to each other for improved system performance (e.g., increased data transfer speeds between the semiconductor dies). An example of closely positioned semiconductor dies is a microprocessor and high-bandwidth memory (HBM). Even though located near each other (e.g., a few millimeters apart), the different types of semiconductor dies can operate at different temperatures.

[0288] The inventors have recognized and appreciated that it can be advantageous to inhibit thermal coupling between the different semiconductor dies during their operation (e.g., to avoid inhibiting performance of at least one of the semiconductor dies). This example describes dynamic boiler plates that provide at least some amount of thermal isolation between adjacent semiconductor dies.

[0289] For example, the inventors have recognized and appreciated that configurations can arise in cooling assemblies, such as cooling assembly 300 shown in FIG. 3A, where at least one of the semiconductor dies 350 (each referred to as a “hot semiconductor die”) spanned by the heat spreader (e.g., boiler plate) 310 produces more heat than one or more other semiconductor dies 350 (each referred to as a “cool semiconductor die”) spanned by the same heat spreader (e.g., boiler plate) 310. The cool semiconductor dies can be in close proximity to the hot semiconductor die(s). Because the heat spreader (e.g., boiler plate) 310 typically has a high thermal conductivity to dissipate heat efficiently, heat spreader (e.g., boiler plate) 310 can undesirably couple some of the heat from the hot semiconductor die(s) to the cool semiconductor dies. This coupling of heat may cause an overtemperature condition at the cool semiconductor dies. To avoid causing overtemperatures at the cool semiconductor dies, the hot semiconductor die(s) may need to be throttled back, operating below their maximum performance capability. The inventors recognized and appreciated that such throttling back results in an undesirable reduction in system performance (e.g., the hot semiconductor die, which could be a microprocessor, is restricted from operating at its full potential).

[0290] The dynamic boiler plates described herein are described using the arrangement shown in FIG. 3A. However, the dynamic boiler plates disclosed herein may also be used in the immersion cooling system 160 and / or 260.

[0291] FIG. 14 is a plan-view depiction of an example of packaged semiconductor dies 350-1, 350-2 mounted in close proximity on a package PCB 355. The device package 305 includes one hot semiconductor die 350-1 and six cool semiconductor dies 350-2, though a package could include multiple hot semiconductor dies 350-1 (e.g., 2 to 20) and one or more cool semiconductor dies 350-2 (e.g., 1 to 50). In an example implementation of such a package 305, the hot semiconductor die 350-1 can be a microprocessor and the cool semiconductor dies 350-2 can be memory dies (e.g., HBM dies). The device package 305 can include additional circuitry 3211 for interfacing with and providing power to the semiconductor dies 350-1, 350-2. The additional circuitry 3211 can include, but is not limited to, metal traces on and / or in the package PCB 355 (or the package substrate if not a PCB), conductive vias in the package PCB 355 or package substrate, transistors, signal drivers, voltage regulators, resistors, capacitors, transceiver chips, SerDes chips, etc.

[0292] As shown in FIG. 14, the hot semiconductor die 350-1 can be in close proximity to one or more cool semiconductor die(s) 350-2. For example, the spacing dibetween adjacent, closest edges of the semiconductor dies 350-1, 350-2 can be from 0.25 mm to 5 mm. With such close spacing, heat can couple from the hot semiconductor die 350-1, through a boiler plate (not shown in FIG. 14) and / or through the protective lid 330 (shown in FIG. 3A) if present, and into the cool semiconductor die(s) 350-2. This coupling and flow of heat through the heat spreader (e.g., boiler plate) 310 is more problematic when the protective lid 330 is omitted and the same heat spreader (e.g., boiler plate) 310 is thermally coupled directly to the semiconductor dies.

[0293] FIG. 15A depicts, in plan view, an example of a dynamic boiler plate 3310 that can mitigate thermal coupling of heat from one or more hot semiconductor die(s) 350-1 to one or more cool semiconductor die(s) 350-2 through the boiler plate in a device package 305. The dynamic boiler plate 3310 includes a plurality of heat-dissipation regions 3320-1, 3320-2 and connecting structure 3330. The connecting structure holds adjacent heatdissipation regions to each other so that the dynamic boiler plate 3310 is an integrated, monolithic structure that can be mounted to the package substrate and thermally coupled to the semiconductor dies 350-1, 350-2 as a single unit. The connecting structures 3330 can be bonded to the heat-dissipation regions 3320-1, 3320-2 e.g., by an adhesive or by a sintering process).

[0294] The connecting structures 3330 can be implemented in various ways, some of which are depicted in FIG. 15A, FIG. 15B, FIG. 15C, FIG. 15D, and FIG. 15E. The connecting structures 3330 can have different shapes and sizes. The shapes can be elongated rectangular bars, extending along most or all of the edges between adjacent, connected heatdissipation region 3320-1, 3320-2, as in FIG. 15A and FIG. 15B. In some cases, the shapes can be small, rectangular, square, or cylindrical posts extending between adjacent, connected heat-dissipation region 3320-1, 3320-2, as in FIG. 15C. In some implementations, the shapes can be residual flexural members or tabs of material remaining after a machining process, as in FIG. 15D. In yet other implementations, the shapes can be spring members that connect the adjacent, connected heat-dissipation region 3320-1, 3320-2, as in FIG. 15E.

[0295] The sizes of the connecting structures 3330 can also vary. The length of the connecting structures 3330 (measured in the z direction according to the drawings) can be from approximately or exactly 1 mm to the full length of the adjacent, connected heatdissipation region 3320-1, 3320-2 (which could be as much as approximately or exactly 50 mm, or even longer in some cases). The height of the connecting structures 3330 (measured in the direction, extending away from the PCB 355) can be from approximately or exactly0.25 mm to approximately or exactly 10 mm. The width of the connection structures 3330 (measured in the x direction), can be from approximately or exactly 0.025 mm to approximately or exactly 10 mm.

[0296] The connecting structures 3330 can hold adjacent heat-dissipation regions 3320-1, 3320-2 a distance <7? apart at the closest edges of the adjacent heat-dissipation regions. The distance <7? can be the same as, less than, or greater than the separation distance di of the underlying semiconductor dies 350-1, 350-2 to which the heat-dissipation regions 3320-1, 3320-2 can thermally couple. For example, the distance <7? can have a value from 0.025 mm to 10 mm. In some implementations, <7? is no greater than 5 mm, no greater than 2 mm, or no greater than 1 mm.

[0297] The dynamic boiler plate 3310 includes at least one thermal impedance element disposed between each adjacent pair of heat-dissipation regions 3320-1, 3320-2. A thermal impedance element can reduce thermal coupling between the adjacent heatdissipation regions compared to thermal coupling when the adjacent heat-dissipation regions intimately contact each other. One example of a thermal impedance element is connecting structure 3330 that can inhibit thermal coupling between the heat-dissipation regions. As an example, the connecting structures 3330 can each include a low-thermal-conductivity material (having a lower value of thermal conductivity compared to the thermal conductivity, or thermal conductivities, of the heat-dissipation regions 3320-1, 3320-2). Examples of ceramics having low thermal conductivity that can be used for the connecting structures 3330 are Zirconia and Macor®. In some cases, a silicate glass can be used for the connecting structures 3330. Use of other materials for the connecting structures 3330 may be possible. According to some implementations, the materials used for the connecting structures 3330 have a thermal conductivity value that is 50% or less (and in some cases 25% or less) than the thermal conductivity of the heat-dissipation regions 3320-1, 3320-2.

[0298] Preferably, the coefficient of thermal expansion (CTE) for the connecting structures 3330 and for the heat-dissipation regions 3320-1, 3320-2 are similar to (e.g., within a factor of 4 of) the coefficient of thermal expansion for silicon or for the semiconductor material from which the semiconductor dies 350-1, 350-2 are fabricated. Larger differences in CTE between the connecting structure 3330 and semiconductor material of the semiconductor dies can be tolerated with closer spacings between the semiconductor dies, which could result in narrower strips of connecting structure 3330 between the heatdissipation regions 3320-1, 3320-2 of the dynamic boiler plate 3310.

[0299] The size of each heat-dissipation region (in the x and z directions in FIG. 15A) can be the same as, larger than, or smaller than the size of the semiconductor’s surface to which the heat-dissipation region is thermally coupled. In some implementations, the size of at least one of the heat-dissipation regions is larger than the semiconductor’s surface to which the heat-dissipation region is thermally coupled, so that fastening hardware (such as screws, pins, clamps, clips, springs) can be used to retain the dynamic boiler plate 3310 to the package PCB 355 or package substrate at locations away from the semiconductor dies 350-1, 350-2.

[0300] The thicknesses (in they direction in FIG. 15A) of the plurality of heatdissipation regions 3320-1, 3320-2 can be the same or different. Different thicknesses can be employed to accommodate differences in height of the semiconductor dies 350-1, 350-2, as depicted in FIG. 15B.

[0301] Each heat-dissipation region 3320-1, 3320-2 can be configured to thermally couple to an underlying semiconductor die. For example, a lower surface or thermalcoupling surface 3325 can be flat to promote thermal coupling to a flat semiconductor die surface with a TIM 320. In some implementations, the thermal-coupling surface can be textured, though flat overall, where the textured surface increases the surface area for improved coupling of heat into the heat-dissipation region. The TIM can include a polymer (such as silicone, a urethane, or epoxy) in which highly conductive particles (e.g., aluminum, silver, beryllium, silicon, boron nitride, or copper particles) are suspended. In some cases, the TIM 320 can be in the form of a thermally-conductive adhesive or thermally -conductive gel that retains sufficient flexibility to allow for differences in thermal expansion of the heatdissipation region and the semiconductor die to which the heat-dissipation region is thermally coupled. In some implementations, the TIM 320 includes a malleable material, such as a silver foil and / or an indium foil. In some cases, there is no other material (apart from the TIM 320) disposed between the heat-dissipation region 3320-1, 3320-2 and the semiconductor die 350-1, 350-2 to which the heat-dissipation region is thermally coupled. In some implementations, a portion of a protective lid 330 and an additional TIM can be disposed between the heat-dissipation regions and semiconductor dies (e.g., if sealing of the semiconductor dies with the protective lid is needed to prevent their contacting the coolant liquid when deployed in an immersion-cooling system).

[0302] The heat-dissipation regions 3320-1, 3320-2 can be formed from any suitable material, or materials, having a high thermal conductivity and a CTE similar (within a factorof 4) to that of the semiconductor material from which the semiconductor dies 350-1, 350-2 are fabricated. Example materials include, but are not limited to, copper, copper alloys, aluminum alloys, silicon carbide, graphene, and certain high thermal conductivity ceramics. The heat-dissipation regions 3320-1, 3320-2 can be formed from the same material (e.g., all formed from a copper alloy) in some implementations. In other implementations, the heatdissipation regions 3320-1, 3320-2 can be formed from different materials. For example, the heat-dissipation region 3320-1 can be formed from a first material having a high thermal conductivity and the heat-dissipation regions 3320-2 can be formed from a second material having a lower thermal conductivity.

[0303] FIG. 15B is an elevation view depicting the boiler plate 3310 of FIG. 15A mounted to the device package of FIG. 14. Each heat-dissipation region 3320-1, 3320-2 is thermally coupled to an underlying semiconductor die 350-1, 350-2 with a TIM 320. For the illustrated example, the thicknesses of the heat-dissipation regions 3320-2 are different from the thicknesses of the heat-dissipation region 3320-1 to accommodate height differences in the underlying semiconductor dies 350-2, 350-1. However, the thicknesses of the heat dissipation regions 3320-1, 3320-2 can all be the same when there is no height difference in the semiconductor dies 350-1, 350-2. A BEC 315 can be deposited on the dynamic boiler plate 3310 to improve nucleation and boiling of coolant liquid 164 when the dynamic boiler plate 3310 and device package 305 are operating in an immersion-cooling system 360. In some implementations, the BEC 315 can be deposited on some of the heat-dissipation regions and not on other heat-dissipation regions (e.g., on heat-dissipation region 3320-1, but not on heat-dissipation regions 3320-2).

[0304] Fastening hardware is not shown in the illustration of FIG. 15A or FIG. 15B. In some implementations, fastening hardware described above can be used to retain the dynamic boiler plate 3310 to the package PCB 355 or package substrate. In some implementations, the TIM 320 includes a thermally-conductive adhesive that retains the dynamic boiler plate 3310 to the semiconductor dies 350-1, 350-2, and no other fastening hardware is used.

[0305] The illustrations of FIG. 14, FIG. 15A, and FIG. 15B indicate that two of the heat-dissipation regions 3320-2 span and are thermally coupled to a plurality of semiconductor dies 350-2 (see size of semiconductor dies 350-2 in FIG. 14). In such implementations, heat can be thermally coupled between semiconductor dies spanned by the same heat-dissipation region. This thermal coupling may be beneficial for identicalsemiconductor dies operating similarly. For example, the thermal coupling can help remove heat from the middle semiconductor die 350-2 which may run hotter than the outlying semiconductor dies 350-2 due to its position between the outlying semiconductor dies rather than its workload. Some of its heat can be shifted outward toward the outlying semiconductor dies 350-2.

[0306] In some implementations, the dynamic boiler plate 3310 includes individual heat-dissipation regions (separated from each other by connecting structure 3330) for each semiconductor die in a device package 305. For the example device package 305 of FIG. 14, the dynamic boiler plate 3310 would have seven distinct heat-dissipation regions.

[0307] FIG. 15C depicts another way in which the dynamic boiler plate 3310 can be implemented. In this configuration, isolated regions of connecting structures 3330 separated by voids 3332 (regions of little or no material) are disposed between adjacent heat-dissipation regions 3320-1, 3320-2. The voids 3332 can be used provided the underlying circuitry can be exposed to coolant liquid 164 (e.g., when the device package is placed in an immersioncooling system 360). The voids 3332 are another example of thermal impedance elements that reduce thermal coupling between the adjacent heat-dissipation regions 3320-1, 3320-2. In some cases where the voids 3332 extend completely through the heat-dissipation regions 3320-1, 3320-2, the voids 3332 can allow better exchange of coolant liquid 164 that contacts additional sides of the heat-dissipation regions 3320-1, 3320-2 and portions of the semiconductor dies 350-1, 350-2 for improved cooling. In other implementations where the voids only extend part way through the heat-dissipation regions 3320-1, 3320-2 and leave a small amount of material, the voids 3332 reduce thermal coupling laterally between heatdissipation regions and also provide a seal to prevent coolant liquid from contacting the underlying semiconductor dies 350-1, 350-2 (e.g., to prevent contaminants from accumulating on the semiconductor dies 350-1, 350-2). If the voids 3332 extend part way through the material between the heat-dissipation regions, a thin membrane (e.g., no thicker than 2 mm) can remain between the adjacent heat-dissipation regions and connect the heatdissipation regions to provide the seal between the adjacent heat-dissipation regions 3320-1, 3320-2.

[0308] FIG. 15D depicts another implementation of a dynamic boiler plate 3310. For this implementation, the dynamic boiler plate can be fabricated from a single piece of material. For example, voids 3332 can be milled, cut, or otherwise formed through a slab of thermally-conductive material. The voids 3332 can be formed to define the adjacent heat-dissipation regions 3320-1, 3320-2. The voids 3332 (also thermal impedance elements) can inhibit heat flow between the heat-dissipation regions 3320-1, 3320-2. Each connecting structure 3330 includes small portions of the slab (from which the boiler plate 3310 is fabricated) that remain between the larger heat-dissipation regions 3320-1, 3320-2 after forming the voids 3332. The connecting structures 3330 can each be located a distance I away from the underlying semiconductor dies (indicated by the gray dashed lines in the drawing) to reduce heat transfer between the heat-dissipation regions and the underlying semiconductor dies. The distance I can be from 2 mm to 10 mm.

[0309] FIG. 15E illustrates another example of a dynamic boiler plate 3310 in which the heat-dissipation regions 3320-1, 3320-2 are joined together with resilient connecting structures 3330. In some implementations, the connecting structures 3330 each includes a leaf spring formed from a metal (essentially a thin, resilient metallic member). Each connecting structure 3330 can be bonded (e.g., brazed, sintered, welded, or soldered) to its adjoining heat-dissipation regions. The resiliency of the connecting structures 3330 allows them to flex and accommodate thermal expansion of each heat-dissipation region during operation. In some implementations, the connecting structures 3330 and heat-dissipation regions 3320-1, 3320-2 are all formed from the same block of material (e.g., from a same slab of a copper alloy). For example, the block of material is machined to remove material, forming the voids 3332, and to leave material that forms the resilient connecting structures 3330. Electrical discharge machining (EDM) may be used to form the thin, resilient connecting structures 3330 for such implementations.

[0310] Methods of cooling semiconductor dies with dynamic boiler plates described above are also contemplated.

[0311] Example methods for cooling semiconductor dies with a dynamic boiler plate 3310 can include acts of receiving first heat from the first semiconductor die 350-1 into a first heat-dissipation region 3320-1 of the boiler plate 3310, receiving second heat from the second semiconductor die 350-2 into a second heat-dissipation region 3320-2 of the boiler plate 3310, and impeding the flow of the first heat in the first heat-dissipation region 3320-1 into the second heat-dissipation region 3320-2 with at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region. The first heat can be received from a first TIM 320 which thermally couples the first heatdissipation region 3320-1 to the first semiconductor die 350-1 (FIG. 15B). The second heat can be received from a second TIM 322 which thermally couples the second heat-dissipationregion 3320-2 to the second semiconductor die 350-2. The second TIM 322 and first TIM 320 can be formed from the same material. The first heat-dissipation region 3320-1 can be connected to the second heat-dissipation region 3320-2 with connecting structures 3330.

[0312] The thermal impedance element can have a lower value of thermal conductivity than either value of thermal conductivity for the first heat-dissipation region 3320-1 and the second heat-dissipation region 3320-2. The thermal impedance element can include connecting structures 3330 that hold the first heat-dissipation region 3320-1 to the second heat-dissipation region 3320-2 in an integrated, monolithic boiler plate 3310.

[0313] Example methods for cooling semiconductor dies with a dynamic boiler plate 3310 can further include acts of dissipating the first heat from the first heat-dissipation region 3320-1 into a coolant liquid 164 contacting the first heat-dissipation region and dissipating the second heat from the second heat-dissipation region 3320-2 into the coolant liquid 164.

[0314] According to some implementations, a distance ch between the first heatdissipation region and the second heat-dissipation (described in connection with FIG. 15A) is selected such that changing an operating temperature of the first semiconductor die by 10° C affects a change in the operating temperature of the second semiconductor die by no more than 1° C due to reduced thermal coupling of heat between the two semiconductor dies through the boiler plate 3310. In such implementations, the first semiconductor die can be operated at a first operating temperature and the second semiconductor die can be operated at a second, different operating temperature. The second operating temperature can be no less than 15 °C different from the first operating temperature in some cases, and no less than 20 °C different from the first operating temperature in some cases. In such implementations, ch (the separation distance of adjacent heat-dissipation regions) may be no greater than 5 mm, no greater than 2 mm, or no greater than 1 mm.

[0315] Also considered by the inventors are methods of assembling a computing system including the dynamic boiler plate disclosed herein. FIG. 16 shows an example method 1600 for assembling a computing system according to the inventive concepts disclosed herein. The method 1600 begins at step 1602 by mounting a heat generating device to a substrate (e.g., a PCB) to form a computing system. In some implementations, the computing system may include multiple surface-mounted devices. Accordingly, each of these devices may be mounted at step 1602. Thereafter, at step 1604, a dynamic boiler plate including one or more heat-dissipation regions and connecting structure as described abovemay be mounted to the heat generating device(s) of the computing system to form a device package. Then, at step 1606, the device package may be installed, in part, by submerging the computing system into coolant liquid stored in a tank in a two-phase immersion cooling system.

[0316] 7. Systems and Methods for Chassis Integrated Spray Jets for Two-PhaseImmersion Cooling Systems

[0317] Computing hardware such as ICs, chips, and semiconductor dies (e.g., semiconductor dies 150 / 350) generate heat during operation. Computing hardware may be cooled using ambient or chilled air; however, high-powered computing hardware may produce more heat than air alone can dissipate. Immersion cooling systems (e.g., immersion cooling system 160 / 260 / 360) may utilize a dielectric liquid (e.g., coolant liquid 164) to provide better heat dissipation than air, while still electrically insulating computing hardware within the immersion cooling fluid (e.g., coolant liquid 164).

[0318] Some portions of this computing hardware may experience “hot spots,” or areas of higher relative temperature compared to other portions of the same computer hardware component. In some cases, the natural flow and convection of coolant liquid 164 may not provide enough heat transfer for these hot spots, or may even cause the hot spots in the first place (e.g., if too much immersion cooling vapor (e.g., vapor 166) is generated and displaces the coolant liquid 164 from a surface of a computing hardware component).

[0319] The inventors have recognized and appreciated that providing forced directional flows of coolant liquid 164 to specific areas of computing hardware may improve the transfer of heat from these components. Coolant liquid 164 is pumped from a first area of a reservoir of coolant liquid 164 (e.g., the output of a filtration system) to one or more second areas within the reservoir, particularly around computing hardware disposed within the coolant liquid 164.

[0320] FIG. 17 illustrates a thermal distribution system 4100 in accordance this example. Thermal distribution system 4100 may be configured to increase a heat transfer out of one or more computing components at least partially disposed in a reservoir of immersion coolant liquid 164. The system 4100 directs a flow of a portion of the immersion coolant liquid at the one or more computing components in the form of liquid jets 4120. The one or more computing components may include one or more logic ICs 4130, which may be mounted to one or more printed circuit boards (PCBs 4140), the PCBs 4140, networkswitches, boiling enhancement coatings (BECs), ball grid arrays (BGAs), or any suitable computing components.

[0321] One or more logic ICs 4130 may include processors or microprocessors, such as a system-on-a-chip (SoC), three-dimensional integrated circuit (3DIC) stack, central processing unit (CPU), graphics processing unit (GPU), tensor processing unit (TPU), data processing unit (DPU), voltage regulator (VR), high bandwidth memory (HBM), digital signal processor (DSP), artificial intelligence (Al) accelerator, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or other densely patterned semiconductor die.

[0322] Logic ICs 4130 may further include one or more memory modules such as a dynamic random access memory (DRAM), dual in-line memory module (DIMM), fieldeffect transistor (FET), static random access memory (SRAM), flash memory, solid-state memory (SSD), non-volatile random access memory (NVRAM), read-only memory (ROM, such as a floating-gate ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), one-time programmable ROM (OTPROM), or the like), or any suitable type of memory module. A logic IC may include one or more registers, data buffers, inputs and / or outputs (e.g., inter-integrated circuit ports, serial ports, busses, parallel ports, wireless transmitters and receivers, universal serial bus (USB) ports, controller area network (CAN) busses, etc.), sensors (e.g., temperature, voltage, current, or similar sensors), and the like.

[0323] The one or more logic ICs 4130 and one or more PCBs 4140 may together be part of a server such as a GPU server configured to perform computing tasks such as video processing, Al training and inference, mathematical model calculation, and the like.

[0324] Heat generated by logic ICs 4130 may cause at least a portion of the immersion coolant liquid to boil. This portion of the immersion coolant liquid may change phase into an immersion cooling vapor and may rise above the immersion coolant liquid. The immersion cooling vapor may then contact one or more condenser coils within an immersion cooling tank and recondense back into an immersion coolant liquid. The recondensed immersion coolant liquid may subsequently drip back into the reservoir of immersion coolant liquid contained within container 4107. As illustrated in FIG. 19, a variety of boiling regimes are possible depending on at least an operating temperature of logic ICs 4130 and flow of immersion coolant liquid 164. In particular, boiling regime between a transition boilingregime 4330 and film boiling regime 4340 provides significantly less cooling than one at around the transition between a nucleate boiling regime 4320 and transition boiling regime 4330.

[0325] Liquid jets 4120 provide a mechanism to disrupt a film boiling regime 4340 by displacing an immersion cooling vapor film or force a shedding of vapor bubbles with a flow of immersion coolant liquid 164, thus moving the heat flux back toward a critical heat flux point.

[0326] Thermal distribution system 4100 may include a dispersion conduit 4110 (equivalently, manifold) that includes at least one interior path (such as a conduit) for transporting a flow of immersion coolant liquid. Dispersion conduit 4110 may be a single pipe having holes 4112. Dispersion conduit 4110 may be two or more sheets of material that are rolled into a conduit form and joined by a suitable process such as brazing, hot rolling, laser welding, tacking, soldering, welding, stamping, fastening, injection molding (if using polymers), or any suitable process. The two or more sheets of material may include rolled steel (e.g., stainless steel), rolled sheet metal, copper, titanium, aluminum, polycarbonate, or any suitable material that is compatible with immersion coolant liquid 164. Dispersion conduits 4110 may additionally or alternatively be integrated into an immersion cooling container such as immersion cooling container 4207 or tank 107 / 207 / 207.

[0327] Dispersion conduit 4110 may include or be embodied as microchannels distributed throughout dispersion conduit 4110 and configured to provide a plurality of paths for immersion coolant liquid 164 to spread throughout dispersion conduit 4110 and on to holes 4112. Microchannels within dispersion conduit 4110 may have a characteristic dimension of about 1 mm or less. For example, an inner surface of immersion cooling container 4207, tank 107 / 207 / 207, or similar portion of an immersion cooling system (e.g., immersion cooling systems 160, 260, and / or 360) may include one or more sheets of metal having microchannels configured to transport an immersion coolant liquid from a reservoir throughout the microchannels and to one or more holes 4112 disposed at an end of respective microchannels. This may provide a chassis-integrated transport path for immersion coolant liquid 164 and may assist in delivering additional cooling to areas of relatively high heat flux within an immersion cooling system (e.g., immersion cooling systems 160, 260, and / or 360).

[0328] Dispersion conduit 4110 may include one or more hydrophobic and / or contamination-resistant surface treatments to prevent a buildup of particulates orcontaminants on an inner surface of dispersion conduit 4110 (which may clog dispersion conduit 4110). For example, when water is introduced to an immersion cooling system (for example, from the atmosphere when an immersion cooling tank lid is open or from an accidental spillage of water into an immersion cooling tank from cooling pipes), the water may mix with immersion coolant liquid and form acidic or corrosive compounds. These compounds may significantly disrupt the operation of components within an immersion cooling system (e.g., immersion cooling systems 160, 260, and / or 360) or destroy components entirely. A coating in accordance with the present technology may help mitigate or impede a deposition or corrosion associated with a contaminant in an immersion coolant liquid in which thermal distribution system 4100 is immersed.

[0329] Examples of hydrophobic surface treatments used in accordance with the present technology may include polytetrafluoroethylene (PTFE, e.g., Teflon™), silane, cerium oxide, or any suitable hydrophobic coating. Additionally or alternatively, dispersion conduit 4110 or other suitable component of thermal distribution system 4100 may include surface modifications such as laser surface topology modification or other etching processes that create surface features having a pitch, scale, and / or major dimension configured to reduce a surface energy of dispersion conduit 4110 or other suitable component of thermal distribution system 4100. For example, a laser may be used to selectively remove material in a predetermined pattern (e.g., cross hatching, a grid defined by repeated volumes of removed material, lines, etc.) from dispersion conduit 4110 such that one or more surfaces of dispersion conduit 4110 become more hydrophobic and / or contamination resistant.

[0330] Dispersion conduit 4110 may be fluidically coupled at a first end with a distribution conduit 4114. Immersion coolant liquid 164 may flow through distribution conduit 4114 and into dispersion conduit 4110 at the first end of dispersion conduit 4110 and may subsequently exist dispersion conduit 4110 through a plurality of holes 4112. Holes 4112 may be shaped to guide or route a flow of immersion coolant liquid toward a component and may be nozzles, circular openings, ovular openings, square openings, or openings with any suitable shape for producing liquid jets 4120 when immersion coolant liquid 164 is forced through the holes 4112. A position of holes 4112 within dispersion conduit 4110 may be designed such that liquid jets 4120 are only directed substantially toward heat-generating components such as logic ICs and not low-heat-flux components such as cables and structural members.

[0331] In an embodiment, holes 4112 may have a largest dimension (e.g., a diameter) of about 1 / 64”, about 1 / 32”, about 1 / 16”, about 1 / 8”, about 0.25 mm, about 0.5 mm, about 0.75 mm, about 1 mm, about 1.25 mm, about 1.5 mm, about 1.75 mm, about 2 mm, about 2.25 mm, about 2.5 mm, about 2.75 mm, about 3 mm, about 3.25 mm, about 3.5 mm, between about 1 / 64” and about 1 / 32”, between about 1 / 32” and about 1 / 16”, between about 1 / 16” and about 1 / 8”, between about 0.25 mm and about 1.25 mm, between about 0.5 mm and about 1.5 mm, between about 0.75 mm and about 1.75 mm, between about 1 mm and about 2 mm, between about 1.25 mm and about 2.25 mm, between about 1.5 mm and about 2.5 mm, between about 1.75 mm and about 2.75 mm, between about 2 mm and about 3 mm, between about 2.25 mm and about 3.25 mm, between about 2.5 mm and about 3.5 mm, or any suitable largest dimension.

[0332] Distribution conduit 4114 may be fluidically coupled to one or more dispersion conduits 4110. Distribution conduit 4114 may have an analogous construction to that of dispersion conduit 4110. For example, distribution conduit 4114 may be two or more sheets of material that are rolled into a conduit form and joined by a suitable process such as brazing, hot rolling, laser welding, tacking, soldering, welding, stamping, fastening, or any suitable process. The two or more sheets of material may include rolled steel (e.g., stainless steel), rolled sheet metal, copper, titanium, aluminum, polycarbonate, or any suitable material that is compatible with immersion coolant liquid 164. Distribution conduit 4114 may be a pipe having a single wall of any suitable cross-sectional shape (e.g., circular, ovular, square, triangular, etc.) and thickness and which forms a conduit in a central portion of distribution conduit 4114. For example, distribution conduit 4114 may be a copper pipe having 1” outer diameter and a wall thickness of 1 / 8”.

[0333] A distal end of distribution conduit 4114 may be communicatively coupled with a flow generation means such as a pump. Such a flow generation means may cause a portion of immersion coolant liquid 164 to move through distribution conduit 4114 and into one or more dispersion conduits 4110, where the portion of immersion coolant liquid 164 then flows out of holes 4112 and onto a surface of one or more computing components such as logic ICs 4130, PCBs 4140, or the like. An immersion cooling system 4200 including thermal distribution system 4205 having distribution conduit 4214 fluidically coupled to filter assembly 4232 and pump 4234 is illustrated in FIG. 18.

[0334] FIG. 18 depicts an immersion cooling system 4200 in accordance with the this example. Immersion cooling system 4200 may include a thermal distribution system 4205analogous to thermal distribution system 4100 in FIG. 17. Immersion cooling system 4200 includes immersion cooling container 4207, which may be at least partially filled with immersion coolant liquid 164. Thermal distribution system 4205 may include servers 4218 (including server 4218a, server 4218b, server 4218c, and server 4218d) disposed at least partially within immersion coolant liquid 164. Each server of servers 4218 may include one or more logic ICs and PCBs analogous to logic ICs 4130 and PCBs 4140. Servers 4218 may be CPU head node servers, GPU servers, Al accelerator servers, or any suitable server including computing hardware that generates enough heat to boil immersion coolant liquid 164.

[0335] Immersion cooling system 4200 may include a filter assembly 4232 including pump 4234. Pump 4234 may be a submersible pump, a rotary pump, a centrifugal pump, or any suitable pump. Pump 4234 may be disposed within a housing of filter assembly 4232, or may be disposed outside of filter assembly 4232. A distal end of distribution conduit 4214 may be fluidically coupled to filter assembly 4232 such that any portion of immersion coolant liquid 164 flowing into distribution conduit 4214 (and subsequently flowing into thermal distribution system 4205) may be filtered by filter assembly 4232. Pump 4234 may cause a portion of immersion coolant liquid 164 to flow through distribution conduit 4214 and into dispersion conduits 4210. The portion of immersion coolant liquid 164 may then flow through holes 4212 in dispersion conduits 4210 and form liquid jets 4220. Liquid jets 4220 may impinge on one or more heat generating and / or heat distributing components of servers 4218 (e.g., logic ICs, semiconductor dies, memory modules, traces, BECs, and the like) and provide improved contact between the components and immersion coolant liquid, for example by displacing immersion cooling vapor formed during boiling of the immersion coolant liquid.

[0336] Pump 4234 may generate a flow of the at least a portion of immersion coolant liquid 164 with a predetermined flow rate. For example, pump 4234 may generate a flow of about 0.001 milliliters per minute (mLPM), about 0.01 mLPM, about 0.1 mLPM, about 1 mLPM, about 2 mLPM, about 5 mLPM, about 8 mLPM, about 10 mLPM, about 20 mLPM, about 25 mLPM, about 50 mLPM, about 100 mLPM, about 120 mLPM, about 140 mLPM, about 160 mLPM, about 180 mLPM, about 200 mLPM, about 1 LPM, about 5 LPM, about 10 LPM, about 15 LPM, about 20 LPM, about 25 LPM, about 35 LPM, about 50 LPM, about 75 LPM, about 100 LPM, between about 0.001 mLPM and about 0.01 mLPM, between about 0.01 mLPM and about 0.1 mLPM, between about 0.1 mLPM and about 1 mLPM, betweenabout 1 mLPM and about 2 mLPM, between about 2 mLPM and about 5 mLPM, between about 3 mLPM and about 8 mLPM, between about 5 mLPM and about 10 mLPM, between about 10 mLPM and about 25 mLPM, between about 25 mLPM and about 50 mLPM, between about 50 mLPM and about 100 mLPM, between about 100 mLPM and about 150 mLPM, between about 150 mLPM and about 200 mLPM, between about 0.1 LPM and about 1 LPM, between about 1 LPM and about 5 LPM, between about 5 LPM and about 15 LPM, between about 10 LPM and about 20 LPM, between about 15 LPM and about 25 LPM, between about 25 LPM and about 50 LPM, between about 35 LPM and about 75 LPM, between about 50 LPM and about 80 LPM, between about 75 LPM and about 100 LPM, or any suitable flow rate or range of flow rates. Preferably, the flow rate is between about 1 mLPM and about 200 mLPM.

[0337] FIG. 19 is a modified version of a plot appearing in Pool boiling critical heat flux (CHF) - Part 1: Review of mechanisms, models, and correlations published in the International Journal of Heat and Mass Transfer, 117 (2018) 1352-1367 and is used merely as an aid to describe wall (equivalently, surface) heat flux in a variety of boiling regimes. FIG. 19 plots wall heat flux (log scale) from a heat source as a function of wall superheat temperature (log scale). The plot may be used to describe and understand wall heat flux (e.g., heat flux from a surface such as an IC surface, a surface of one or more heat generating components, a surface of boiler plate, a surface of a BEC, etc.) in an exemplary immersion cooling system such as an immersion cooling system 160 / 260 / 360 / 4200 disclosed herein. Reference numbers 4310-4340 and a description of a relationship between heat flux and wall superheat temperature for boiling enhancement coatings (BECs) and semiconductor dies has been added to the plot.

[0338] The wall heat flux can be expressed in units of W / m2 and represents a rate of heat transfer per unit area from the heat-dissipative element into the immersion coolant liquid 164. The superheat temperature can be expressed in degrees Celsius and represents a difference in the wall temperature over the adjacent immersion coolant liquid 164’s saturation temperature (which is the boiling temperature of the immersion coolant liquid 164 under the ambient environmental conditions).

[0339] The plot of FIG. 19 shows four different regions of boiling: (1) single-phase regime 4310, (2) nucleate boiling regime 4320, (3) transition boiling regime 4330, and (4) film boiling regime 4340. In the single-phase regime 4310, isolated bubble formation occurs. The surface temperature may be several degrees above the immersion coolant liquid 164’ssaturation temperature. The surface of the BEC is not fully boiling the immersion coolant liquid 164. A desirable operating regime is the nucleate boiling regime 4320, where the wall temperature has increased to nucleate bubbles across the majority of the surface of the BEC (e.g., across 80% or more of the BEC’s surface). This regime can include a mix of boiling characteristics (e.g., isolated small-bubble nucleation and larger jets and vapor column formations).

[0340] The boundary of the nucleate boiling regime 4320 with the transition boiling regime 4330 is the critical heat flux (CHF) point for the system at which a maximum in wall heat flux is achieved. However, if the wall temperature increases beyond the CHF point, the wall flux decreases as shown in FIG. 19. The decrease in wall flux can be due to “dry out” of the surface that would otherwise contact and boil the immersion coolant liquid 164. The boiling becomes so active that a significant portion of the surface no longer comes into physical contact with the immersion coolant liquid 164. In the film boiling regime, the surface is so hot that a film of vapor spreads across the entire surface of the surface and none of the immersion coolant liquid 164 contacts the surface.

[0341] In a two-phase immersion-cooling system, it is beneficial to choose an immersion coolant liquid 164 having a boiling point within a selected number of degrees of the maximum wall temperature of the heat dissipative element (e.g., one or more heat generating components, boiler plate, and / or a BEC, etc.) that boils the immersion coolant liquid 164 when the one or more heat generating components (e.g., logic IC(s)) coupled to a boiler plate and / or BEC is (are) operating a maximum power. The selected number of degrees can preferably be chosen such that the wall superheat temperature for the system is less than or equal to the wall superheat temperature at the CHF point for the system.

[0342] For example, if a wall superheat temperature at the CHF point is 80 °C and the maximum temperature of the surface (e.g., of a heat generating component such as an IC) is 120 °C when operating at full power, then an immersion coolant liquid 164 with a boiling point of 40 °C or higher should be chosen. In a related approach, if the boiling point of the fluid is given as 50 °C and the maximum allowable surface temperature is 90 °C for safe operation of the heat generating component, then the maximum allowable wall superheat temperature will be 40 °C. The CHF point is then preferably at or above 40 °C wall superheat for this device. In another example considering the use of a BEC to maintain one or more heat generating components (e.g., logic IC 4130) in a safe operating regime, the wall heat flux from the BEC to the immersion coolant liquid 164 is preferably equal to or greaterthan the heat flux from the one or more heat generating components (e.g., logic IC 4130) into the BEC. This allows the full amount of heat generated by the one or more heat generating components (e.g., logic IC 4130) to be removed by the BEC and immersion coolant liquid 164.

[0343] When a BEC is added to a one or more heat generating components (e.g., logic IC 4130), boiling nucleation can occur at lower temperatures, moving the CHF point to the left. Further, the increased surface area of the one or more heat generating components (e.g., logic IC 4130) that includes a BEC can increase heat flux from the wall of the BEC, moving the CHF point upward. Both of these effects beneficially move the CHF point upwards and to the left, as illustrated by the dashed line in FIG. 19, which improve cooling of the one or more heat generating components (e.g., logic IC 4130) that are thermally coupled to the BEC. Additionally, an impingement of immersion coolant liquid 164 from liquid jets such as liquid jets 4120 and liquid jets 4220 may displace a film of superheated immersion cooling vapor, moving heat transfer conditions away from film boiling regime 4340 and towards the CHF point.

[0344] Also considered by the inventors are methods of assembling an immersion cooling system including one or more computing components and the thermal distribution system disclosed herein. FIG. 20 shows an example method 2000 for assembling an immersion cooling system including one or more computing components and a thermal distribution system according to the inventive concepts disclosed herein. The method 2000 begins at step 2002 by mounting a heat generating device to a substrate (e.g., a PCB) to form a computing system. In some implementations, the computing system may include multiple surface-mounted devices. Accordingly, each of these devices may be mounted at step 2002. Then, at step 2004, the computing system may be installed, in part, by submerging the computing system into coolant liquid stored in a tank in a two-phase immersion cooling system. Thereafter, at step 2006, the thermal distribution system may be installed, in part, by submerging the thermal distribution system into the coolant liquid stored in the tank in the two-phase immersion cooling system. The thermal distribution system may be installed such that the one or more liquid jets of the thermal distribution system are facing the computing system(s).

[0345] 8. Jet Impingement Array for Silicon on Wafer Cooling in Two PhaseImmersion System

[0346] Computing hardware such as system-on-a-wafer (SoW) packages may consist of arrays of high power integrated circuits (ICs) with small gaps in between. Two phase pool boiling may be less effective for cooling densely packed ICs due to limited chip surface available for boiling. Heat spreading with devices like vapor chamber becomes less practical due to the small distance between chips and larger overall SoW package. Moreover, vapor bubbles generated by adjacent chips can adversely affect boiling cooling efficiency and CHF.

[0347] This example is directed toward systems and methods for removing heat from a computing component such as a semiconductor die or integrated circuit (IC) in an immersion-cooled computing system. Traditional techniques may rely on buoyancy and gravity -based vapor bubble dynamics to transport immersion cooling vapor away from a heat generating component after boiling; however, if vapor is not effectively removed from a surface of a heat generating component (or material in thermal contact with the heat generating component), the vapor may begin to impede effective heat transfer and lower an amount of heat that can be removed from the heat generating component per unit time. This example is directed towards systems and methods for mitigating inefficiencies due to insufficient vapor movement.

[0348] FIG. 21 A illustrates a system 5100a for heat transfer in accordance with this example. System 5100a may include a container 5107 at least partially filled with immersion coolant liquid 164. System 5100a may further include one or more components such as system-on-a-wafer (SoW 5110). SoW 5110 may include semiconductor wafer 5112 on which one or more heat generating components 5114 are disposed. Heat generating components 5114 may be integrated circuits (ICs), computing components such as network interface cards (NICs), connectors, power modules, batteries, transistors, capacitors, resistors, or any suitable component that may be used with or as part of a computing system such as an immersion cooled computing system.

[0349] One or more heat generating components 5114 may be disposed throughout system 5100a, for example, as part of or as the entirety of a server, a baseboard management controller (BMC), a cable, a sensor, a printed circuit board (PCB), or other suitable electrical component. One or more heat generating components 5114 may be part of an SoW 5110, or may not be part of an SoW 5110.

[0350] One or more heat generating components 5114 may include any suitable computing hardware configured to perform calculations and / or logic such as central processing units (CPU), graphics processing units (GPU), tensor processing units (TPU), data processing units (DPU), digital signal processors (DSP), artificial intelligence (Al) accelerators, three-dimensional integrated circuit (3DIC) stacks, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGA), and / or other densely patterned semiconductor die.

[0351] One or more heat generating components 5114 may additionally or alternatively include one or more memory modules. A memory module may be an IC configured to store data and may include a dynamic random access memory (DRAM) module, a static random access memory (SRAM) module, a flash memory module, a solid- state drive (SSD), a non-volatile random access memory (NVRAM) module, a read-only memory (ROM) module (such as a floating-gate ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), onetime programmable ROM (OTPROM), or the like), or any suitable type of memory module.

[0352] One or more heat generating components 5114 may generate heat at any suitable power level, for example about 1 W, about 10 W, about 100 W, about 200 W, about 300 W, about 400 W, about 500 W, about 600 W, about 700 W, about 800 W, about 900 W, about 1000 W, about 1100 W, about 1200 W, about 1300 W, about 1400 W, about 1500 W, about 1750 W, about 2000 W, about 2500 W, between about 1 W and about 10 W, between about 10 W and about 100 W, between about 50 W and about 250 W, between about 100 W and about 500 W, between about 250 W and about 750 W, between about 500 W and about 1000 W, between about 750 W and about 1500 W, between about 1000 W and about 2000 W, between about 1500 W and about 2500 W, or any suitable power level.

[0353] The one or more heat generating components 5114 may generate heat as a result of normal operation. For example, an IC may generate heat as a result of performing computations, or a NIC may generate heat as a result of transferring data in the form of electrical signals. The heat generated by one or more heat generating components 5114 may create immersion cooling vapor 166 by boiling a first portion of immersion coolant liquid 164.

[0354] System 5100a may further include conduit 5120, which may be configured to guide a flow 5124 of immersion coolant liquid 164 through one or more nozzles 5122.Conduit 5120 may be fluidically coupled to a pump 5130. Conduit 5120 may have a substantially cylindrical cross section, a substantially rectangular cross section, a substantially ovular cross section, an arbitrary cross section, or any suitable cross section. Conduit 5120 may be made of a suitable material or combination of materials, such as copper, aluminum, stainless steel, titanium, tungsten, polycarbonate, or any other suitable material. Conduit 5120 may include one or more nozzles 5122, which may be configured to guide a flow 5124 of immersion coolant liquid 164 and create jets 5126. The flow 5124 and / or jets 5126 may include a first portion of immersion coolant liquid 164.

[0355] One or more nozzles 5122 may be disposed at a first distance d from a respective heat generating component of the one or more heat generating components 5114 (or other material in thermal contact with both immersion coolant liquid 164 and one or more heat generating components 5114 such as boiler plate 5116). For example, a first distance may be about 0.1 mm, about 1 mm, about 2 mm, about 5 mm, about 10 mm, about 15 mm, about 20 mm, about 25 mm, about 50 mm, about 75 mm, about 100 mm, about 150 mm, about 200 mm, about 500 mm, between about 0.1 mm and about 2 mm, between about 1 mm and about 5 mm, between about 2 mm and about 10 mm, between about 5 mm and about 25 mm, between about 15 mm and about 50 mm, between about 25 mm and about 75 mm, between about 50 mm and about 100 mm, between about 75 mm and about 150 mm, between about 100 mm and about 200 mm, between about 200 mm and about 500 mm, or any suitable distance.

[0356] One or more nozzles 5122 include an exit / . having a characteristic size and shape. An exit may have a circular, square, ovular, rectangular, star, or any suitable shape. In an embodiment, an exit of one or more nozzles 5122 may be substantially circular and have a characteristic size (e.g., a diameter) of about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, about 1.5 mm, about 2 mm, about 2.5 mm, about 5 mm, about 8 mm, about 10 mm, about 15 mm, about 20 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, between about 0.8 mm and about 1.5 mm, between about 1 mm and about 2 mm, between about 1.5 mm and about 2.5 mm, between about 2 mm and about 5 mm, between about 2.5 mm and about 8 mm, between about 5 mm and about 10 mm, between about 8 mm and about 15 mm, between about 10 mm and about 20 mm, or any suitable characteristic size.

[0357] Flow 5124 (including a second portion of immersion coolant liquid 164) may be guided by one or more nozzles 5122 to create jets 5126. Jets 5126 may displace immersioncooling vapor bubbles 165 generated by heat from one or more heat generating components 5114. In some boiling regimes (e.g., as described with respect to FIG. 19), immersion cooling vapor generated as a result of heat generated by the operation of one or more heat generating components 5114 may become substantially trapped near, or impeded from moving away from, a surface one or more heat generating components 5114 (or a surface of a material in thermal contact with the one or more heat generating components 5114). This trapped immersion cooling vapor may reduce an efficiency of heat transfer out of one or more heat generating components 5114. Jets 5126 may displace at least a portion (preferably a majority or substantially all) of the generated immersion cooling vapor bubbles 165 with a second portion of immersion coolant liquid 164, which may accordingly improve a heat transfer out of one or more heat generating components 5114.

[0358] Jets 5126 may exit one or more nozzles 5122 at a velocity. For example, the jets 5126 may exit one or more nozzles 5122 at a velocity sufficient to displace at least a portion (preferably a majority or substantially all) of the immersion cooling vapor bubbles 165 generated by heat from one or more heat generating components 5114. In particular, immersion cooling vapor bubbles 165 may occupy a space adjacent to a surface of one or more heat generating components 5114 (or a boiler plate 5116 [shown in FIG. 21B], BEC, or other material disposed on or in thermal contact with one or more heat generating components 5114) such that no immersion coolant liquid 164 contacts the surface. Jets 5126 may exit one or more nozzles 5122 at a velocity sufficient to displace at least a portion (preferably a majority or substantially all) of the immersion cooling vapor bubbles 165 from the surface.

[0359] Jets 5126 may exit one or more nozzles 5122 at a velocity of about 0.1 mm / s, about 1 mm / s, about 2 mm / s, about 5 mm / s, about 10 mm / s, about 15 mm / s, about 20 mm / s, about 25 mm / s, about 50 mm / s, about 75 mm / s, about 100 mm / s, about 150 mm / s, about 200 mm / s, about 500 mm / s, about 1 m / s, about 1.5 m / s, about 2 m / s, about 2.5 m / s, about 5 m / s, about 7.5 m / s, about 10 m / s, about 15 m / s, about 20 m / s, about 25 m / s, between about 0.1 mm / s and about 2 mm / s, between about 1 mm / s and about 5 mm / s, between about 2 mm / s and about 10 mm / s, between about 5 mm / s and about 25 mm / s, between about 15 mm / s and about 50 mm / s, between about 25 mm / s and about 75 mm / s, between about 50 mm / s and about 100 mm / s, between about 75 mm / s and about 150 mm / s, between about 100 mm / s and about 200 mm / s, between about 200 mm / s and about 500 mm / s, between about 500 mm / s and about 1 m / s, between about 1 m / s and about 2 m / s, between about 1.5 m / s and about 2.5 m / s,between about 2 m / s and about 5 m / s, between about 2.5 m / s and about 7.5 m / s, between about 5 m / s and about 10 m / s, between about 7.5 m / s and about 15 m / s, between about 10 m / s and about 25 m / s, or any suitable velocity.

[0360] Jets 5126 may have may exit one or more nozzles 5122 at a flow rate. For example, the jets 5126 may exit one or more nozzles 5122 at a flow rate sufficient to displace at least a portion (preferably a majority or substantially all) of the immersion cooling vapor bubbles 165 generated by heat from one or more heat generating components 5114. For example, the jets 5126 may have a flow rate of about 0.1 mL / s, about 1 mL / s, about 2 mL / s, about 5 mL / s, about 10 mL / s, about 15 mL / s, about 20 mL / s, about 25 mL / s, about 50 mL / s, about 75 mL / s, about 100 mL / s, about 150 mL / s, about 200 mL / s, between about 0.1 mL / s and about 2 mL / s, between about 1 mL / s and about 5 mL / s, between about 2 mL / s and about 10 mL / s, between about 5 mL / s and about 25 mL / s, between about 15 mL / s and about 50 mL / s, between about 25 mL / s and about 75 mL / s, between about 50 mL / s and about 100 mL / s, between about 75 mL / s and about 150 mL / s, between about 100 mL / s and about 200 mL / s, or any suitable flow rate.

[0361] Pump 5130 may be fluidically coupled to both conduit 5120 and immersion coolant liquid 164 and configured to draw in a portion of immersion coolant liquid 164 to generate flow 5124. Pump 5130 may optionally include a filter (not shown) to remove contaminants and / or particulates from flow 5124. Pump 5130 may be any suitable type of pump, such as a submersible pump.

[0362] In an embodiment, one or more nozzles 5122 may be oriented substantially orthogonal to a surface of one or more heat generating components 5114. For example, one or more heat generating components 5114 may include one or more ICs each having a respective first surface that is affixed to a PCB or other computing component and a respective second surface opposite the first surface and which is exposed to the ambient environment (e.g., exposed to immersion coolant liquid 164). The one or more heat generating components 5114 may be oriented such that the respective second surface is orthogonal to a horizontal plane, e.g., at 90° from a gravity vector. One or more nozzles 5122 may be oriented so that they are orthogonal to respective second surfaces of the one or more heat generating components 5114. Further, each of the one or more nozzles 5122 may be substantially aligned with a geometric center of a respective component of the one or more heat generating components 5114 such that a jet 5126 guided by a respective nozzle 5122 is directed toward the geometric center of the respective component. FIG. 21C illustrates anadditional embodiment where a nozzle 5122 is disposed at an angle to a respective heat generating component 5114.

[0363] Conduit 5120 may include one or more surface treatments to provide a hydrophobic and / or contamination-resistant effect to a surface to prevent a buildup of particulates or contaminants on an inner surface of conduit 5120 (which may clog conduit 5120). For example, when water is introduced to an immersion cooling system (for example, from the atmosphere when an immersion cooling tank lid is open or from an accidental spillage of water into an immersion cooling tank from cooling pipes), the water may mix with immersion coolant liquid 164 and form acidic or corrosive compounds. These compounds may significantly disrupt the operation of components within an immersion cooling system (e.g., immersion cooling systems 160, 260, 360 and / or 4200) or destroy components entirely. A coating in accordance with the present technology may help mitigate or impede a deposition or corrosion associated with a contaminant in an immersion coolant liquid 164 in which system 5100a is immersed.

[0364] Examples of hydrophobic surface treatments used in accordance with the present technology may include coatings such as polytetrafluoroethylene (PTFE, e.g., Teflon™), silane, cerium oxide, or any suitable hydrophobic coating. Additionally or alternatively, one or more heat generating components 5114, conduit 5120, or other suitable component of system 5100a may include surface topology modifications such as laser surface topology modification or other etching processes that create surface features having a pitch, scale, and / or major dimension configured to reduce a surface energy of conduit 5120 or other suitable component of system 5100a. For example, a laser may be used to selectively remove material in a predetermined pattern (e.g., cross hatching, a grid defined by repeated volumes of removed material, lines, etc.) from conduit 5120 such that one or more surfaces of conduit 5120 become more hydrophobic and / or contamination resistant.

[0365] FIG. 21B illustrates a system 5100b analogous to system 5100a, which may include each of the components of system 5100a (or components analogous to those of system 5100a). System 5100b may further include a boiler plate 5116 disposed in contact with the one or more heat generating components 5114. Boiler plate 5116 may be copper, aluminum, tungsten, titanium, stainless steel, or any suitable material that may help promote heat transfer from one or more heat generating components 5114 to immersion coolant liquid 164. Boiler plate 5116 may include one or more surface treatments such as a surface topology modification to increase a number of nucleation sites for immersion cooling vapor bubbles165 as compared to a flat or otherwise unmodified surface. For example, a surface of boiler plate 5116 disposed in contact with immersion coolant liquid 164 may include a laser surface topology modification that increases a total surface area of boiler plate 5116 in contact with immersion coolant liquid 164.

[0366] A material such as a thermal interface material (TIM), thermal paste or thermal grease, gap pad, epoxy, or other material may be disposed between one or more heat generating components 5114 and boiler plate 5116 to improve a thermal transfer path between one or more heat generating components 5114 and boiler plate 5116. A material disposed between one or more heat generating components 5114 and boiler plate 5116 may provide a larger contact area as compared to direct contact between one or more heat generating components 5114 and boiler plate 5116, which may provide a corresponding increase in heat flux between one or more heat generating components 5114 and boiler plate 5116.

[0367] An interface material may have a thickness between about 0.01 mm and about 5 mm. For example, An interface material may include a TIM having a thickness of about 0.05 mm, about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, about 1.2 mm, about 1.5 mm, about 2 mm, between about 0.05 mm and about 0.2 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, between about 0.8 mm and about 1.2 mm, between about 1 mm and about 1.5 mm, between about 1.2 mm and about 2 mm, or any suitable thickness.

[0368] An interface material may include a gap pad having a thickness of about 0.05 mm, about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, about 1.2 mm, about 1.5 mm, about 2 mm, between about 0.05 mm and about 0.2 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, between about 0.8 mm and about 1.2 mm, between about 1 mm and about 1.5 mm, between about 1.2 mm and about 2 mm, or any suitable thickness.

[0369] An interface material may include an epoxy having a thickness of about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, between about 0.05 mm and about 0.2 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, or any suitable thickness.

[0370] An interface material may include a thermal grease or thermal paste having a thickness of about 0.01 mm, about 0.02 mm, about 0.05 mm, about 0.08 mm, about 0.1 mm,about 0.2 mm, about 0.5 mm, between about 0.01 mm and about 0.02 mm, between about 0.02 mm and about 0.05 mm, between about 0.02 mm and about 0.08 mm, between about 0.05 mm and about 0.1 mm, between about 0.08 mm and about 0.2 mm, or any suitable thickness.

[0371] FIG. 21C illustrates a cutaway view of a conduit 5120c (which may be analogous to conduit 5120 in system 5100a and / or system 5100b) disposed in an immersion coolant liquid. Conduit 5120c may include one or more nozzles 5122c which may be analogous to one or more nozzles 5122 in system 5100a and system 5100b. Conduit may guide a flow 5124c of immersion coolant liquid 164 through nozzle 5122c to create a jet 5126c. One or more nozzles 5122c may be disposed at an angle 5140 to a surface of heat generating component 5114c.

[0372] One or more nozzles 5122c may be disposed at a first distance d from a respective heat generating component of the one or more heat generating components 5114c (or other material in thermal contact with both immersion coolant liquid 164 and one or more heat generating components 5114c such as a boiler plate). For example, a first distance d may be about 0.1 mm, about 1 mm, about 2 mm, about 5 mm, about 10 mm, about 15 mm, about 20 mm, about 25 mm, about 50 mm, about 75 mm, about 100 mm, about 150 mm, about 200 mm, about 500 mm, between about 0.1 mm and about 2 mm, between about 1 mm and about 5 mm, between about 2 mm and about 10 mm, between about 5 mm and about 25 mm, between about 15 mm and about 50 mm, between about 25 mm and about 75 mm, between about 50 mm and about 100 mm, between about 75 mm and about 150 mm, between about 100 mm and about 200 mm, between about 200 mm and about 500 mm, or any suitable distance.

[0373] One or more nozzles 5122c include an exit / . having a characteristic size and shape. An exit may have a circular, square, ovular, rectangular, star, or any suitable shape. In an embodiment, an exit of one or more nozzles 5122c may be substantially circular and have a characteristic size (e.g., a diameter) of about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, about 1.5 mm, about 2 mm, about 2.5 mm, about 5 mm, about 8 mm, about 10 mm, about 15 mm, about 20 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, between about 0.8 mm and about 1.5 mm, between about 1 mm and about 2 mm, between about 1.5 mm and about 2.5 mm, between about 2 mm and about 5 mm, between about 2.5 mm andabout 8 mm, between about 5 mm and about 10 mm, between about 8 mm and about 15 mm, between about 10 mm and about 20 mm, or any suitable characteristic size.

[0374] One or more nozzles 5122c may be configured to guide a flow 5124c of immersion coolant liquid at substantially a first angle with respect to one or more heat generating components 5114c (including a first angle with respect to a surface of one or more heat generating components 5114c and / or a material disposed in thermal contact with one or more heat generating components 5114c). For example, a central axis 5142 of nozzle 5122c may be disposed at an angle 5140 to an orthogonal axis 5144 of heat generating component 5114c. Angling nozzle 5122c such that jet 5126c is directed partially in the same direction that bubbles of immersion cooling vapor tend to rise may beneficially help clear the bubbles of immersion cooling vapor more quickly than via buoyancy effects alone.

[0375] When bubbles of immersion cooling vapor (such as immersion cooling vapor bubbles 165) are generated and detach or otherwise move away from a surface at which they were generated, they may tend to float upwards opposite a direction of gravity as illustrated in FIG. 21C. If a jet 5126c impinges on one or more heat generating components 5114 orthogonally to an exposed surface of one or more heat generating components 5114, some immersion cooling vapor bubbles 165 may be temporarily pushed down instead of floating up, which may cause the immersion cooling vapor bubbles 165 to disrupt contact between one or more heat generating components 5114 and immersion coolant liquid 164. However, angling nozzle 5122c and jet 5126c such that jet 5126c is directed at least partly in the same direction as immersion cooling vapor bubbles 165 tend to float may displace immersion cooling vapor bubbles 165 more quickly and efficiently from a surface of heat generating component 5114c.

[0376] An angle 5140 may be between about 5° and about 89°, for example about 5°, about 10°, about 15°, about 20°, about 25°, about 30°, about 35°, about 40°, about 45°, about 50°, about 55°, about 60°, about 65°, about 70°, about 75°, about 80°, about 85°, about 89°, between about 5° and about 20°, between about 10° and about 25°, between about 20° and about 45°, between about 30° and about 60°, between about 45° and about 75°, between about 60° and about 89°, or any suitable angle.

[0377] Also considered by the inventors are methods of assembling an immersion cooling system including one or more computing components and a jet impingement array disclosed herein. FIG. 22 shows an example method 2200 for assembling an immersioncooling system including one or more computing components and a jet impingement array according to the inventive concepts disclosed herein. The method 2200 begins at step 2202 by mounting a heat generating device to a substrate (e.g., a PCB) to form a computing system. In some implementations, the computing system may include multiple surfacemounted devices. Accordingly, each of these devices may be mounted at step 2202. Then, at step 2204, the computing system may be installed, in part, by submerging the computing system into coolant liquid stored in a tank in a two-phase immersion cooling system. Thereafter, at step 2206, a jet impingement array including a conduit with one or more nozzles may be installed, in part, by submerging the jet impingement array into coolant liquid stored in a tank in a two-phase immersion cooling system. The jet impingement array may be installed such that the one or more nozzles of the jet impingement array are facing the computing system(s). As described above, the conduit may be fluidically coupled to a pump to provide a flow of coolant liquid 164 and the one or more nozzles may be configured to guide a flow of coolant liquid and create jets.

[0378] 9. Pumped Flow Boiling Cold Plate in Two Phase Immersion System

[0379] This example is directed toward systems and methods for removing heat from a computing component such as a semiconductor die or integrated circuit (IC) in an immersion-cooled computing system. Traditional techniques may rely on buoyancy and gravity -based vapor bubble dynamics to transport immersion cooling vapor away from a heat generating component after boiling; however, if vapor is not effectively removed from a surface of a heat generating component (or material in thermal contact with the heat generating component), the vapor may begin to impede effective heat transfer and lower an amount of heat that can be removed from the heat generating component per unit time. This example is directed towards systems and methods for mitigating inefficiencies due to insufficient vapor movement.

[0380] FIG. 23A illustrates a system 6100a for heat transfer in accordance with this example. System 6100a may include a container 6107a at least partially filled with immersion coolant liquid 164. One or more heat generating components 6114a may be disposed within the immersion coolant liquid 164 in order to remove waste heat from the one or more heat generating components 6114a more efficiently than would be possible with air alone. The one or more heat generating components 6114a may be integrated circuits (ICs), computing components such as network interface cards (NICs), connectors, power modules, batteries,transistors, capacitors, resistors, or any suitable component that may be used with or as part of a computing system such as an immersion cooled computing system.

[0381] One or more heat generating components 6114a may be disposed throughout system 6100a, for example, as part of or as the entirety of a server, a system-on-a- wafer (SoW), a baseboard management controller (BMC), a cable, a sensor, a printed circuit board (PCB), or other suitable electrical component.

[0382] One or more heat generating components 6114a may include any suitable computing hardware configured to perform calculations and / or logic such as central processing units (CPU), graphics processing units (GPU), tensor processing units (TPU), data processing units (DPU), digital signal processors (DSP), artificial intelligence (Al) accelerators, three-dimensional integrated circuit (3DIC) stacks, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGA), and / or other densely patterned semiconductor die.

[0383] One or more heat generating components 6114a may additionally or alternatively include one or more memory modules. A memory module may be an IC configured to store data and may include a dynamic random access memory (DRAM) module, a static random access memory (SRAM) module, a flash memory module, a solid- state drive (SSD), a non-volatile random access memory (NVRAM) module, a read-only memory (ROM) module (such as a floating-gate ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), onetime programmable ROM (OTPROM), or the like), or any suitable type of memory module.

[0384] One or more heat generating components 6114a may generate heat at any suitable power level, for example about 1 W, about 10 W, about 100 W, about 200 W, about 300 W, about 400 W, about 500 W, about 600 W, about 700 W, about 800 W, about 900 W, about 1000 W, about 1100 W, about 1200 W, about 1300 W, about 1400 W, about 1500 W, about 1750 W, about 2000 W, about 2500 W, between about 1 W and about 10 W, between about 10 W and about 100 W, between about 50 W and about 250 W, between about 100 W and about 500 W, between about 250 W and about 750 W, between about 500 W and about 1000 W, between about 750 W and about 1500 W, between about 1000 W and about 2000 W, between about 1500 W and about 2500 W, or any suitable power level.

[0385] The one or more heat generating components 6114a may generate heat as a result of normal operation. For example, an IC may generate heat as a result of performingcomputations, or a NIC may generate heat as a result of transferring data in the form of electrical signals. The heat generated by one or more heat generating components 6114a may create immersion cooling vapor 166 by boiling a first portion of immersion coolant liquid 164.

[0386] System 6100a may include a conduit 6120a configured to guide a flow 6124a of immersion coolant liquid 164. Conduit 6120a may be fluidically coupled to a pump 6130a. Conduit 6120a may have a substantially cylindrical cross section, a substantially rectangular cross section, a substantially ovular cross section, an arbitrary cross section, or any suitable cross section. Conduit 6120a may be made of a suitable material or combination of materials, such as copper, aluminum, stainless steel, titanium, tungsten, polycarbonate, or any other suitable material.

[0387] Conduit 6120a may guide and / or partially enclose flow 6124a (including a second portion of immersion coolant liquid 164) into contact with boiling surface 6122a. When one or more heat generating components 6114a are operating, the heat generated by the components may cause a temperature of a portion of the immersion coolant liquid 164 to rise enough to boil the immersion coolant liquid and convert it into an immersion cooling vapor 166 (which may take the form of immersion cooling vapor bubbles 165). Flow 6124a may displace at least a portion (preferably a majority or substantially all) of the generated immersion cooling vapor bubbles 165 with a second portion of immersion coolant liquid 164, which may accordingly improve a heat transfer out of one or more heat generating components 6114a.

[0388] Boiling surface 6122a may form an inner surface of conduit 6120a. Additionally or alternatively, boiling surface 6122a may be part of a separate structure, object, or material and may be attached to conduit 6120a via any suitable securement mechanism (e.g., one or more fasteners, screws, nails, adhesives, clips, welding, braising, tacking, soldering, press fitting, or the like). Boiling surface 6122a may be disposed in thermal contact with conduit 6120a and / or one or more heat generating components 6114a. For example, heat generated by one or more heat generating components 6114a may be transferred to boiling surface 6122a through conduction. Additionally or alternatively, one or more heat generating components 6114a may be disposed in thermal contact with one or more heat generating components 6114a through convection or radiation. Boiling surface 6122a may be an inner portion of conduit 6120a (e.g., conduit 6120a and boiling surface6122a may be contiguous), or boiling surface 6122a may be physically distinct from conduit 6120a.

[0389] For example, conduit 6120a may be an aluminum cylinder and boiling surface 6122a may be a copper cylinder configured to interface with an inner surface of conduit 6120a by press fitting. Alternatively, boiling surface 6122a may be a material coating on an inner surface of conduit 6120a, for example copper that has been sputter coated onto the inner surface of conduit 6120a.

[0390] Conduit 6120a may include inlet 6126a and outlet 6128a. In an embodiment, an inlet 6126a and outlet 6128a may be positioned in such a way that a flow 6124a through both inlet 6126a and outlet 6128a travels in substantially the same direction (e.g., a vector orthogonal to a plane passing through the edges of inlet 6126a is parallel to a vector orthogonal to a plane passing through the edges of outlet 6128a).

[0391] Inlet 6126a and / or outlet 6128a may have a characteristic size and shape. Inlet 6126a and / or outlet 6128a may have a circular, square, ovular, rectangular, star, or any suitable shape. In an embodiment, inlet 6126a and / or outlet 6128a may be substantially circular and have a characteristic size (e.g., a diameter) of about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, about 1.5 mm, about 2 mm, about 2.5 mm, about 5 mm, about 8 mm, about 10 mm, about 15 mm, about 20 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, between about 0.8 mm and about 1.5 mm, between about 1 mm and about 2 mm, between about 1.5 mm and about 2.5 mm, between about 2 mm and about 5 mm, between about 2.5 mm and about 8 mm, between about 5 mm and about 10 mm, between about 8 mm and about 15 mm, between about 10 mm and about 20 mm, or any suitable characteristic size.

[0392] FIG. 23A illustrates a flow 6124a of immersion coolant liquid 164 substantially parallel to boiling surface 6122a and substantially opposite a direction of gravity. For example, immersion cooling vapor bubbles 165 may tend to float upwards due to buoyancy and providing flow 6124a in the same direction as immersion cooling vapor bubbles 165 tend to flow may increase a heat transfer efficiency by assisting a natural buoyancy-driven flow of immersion cooling vapor bubbles 165 away from boiling surface 6122a.

[0393] Flow 6124a may have any suitable velocity to sufficient to displace at least a portion (preferably a majority or substantially all) immersion cooling vapor bubbles 165 fromboiling surface 6122a. In particular, immersion cooling vapor bubbles 165 may occupy a space adjacent to boiling surface 6122a such that no immersion coolant liquid 164 contacts the surface. Flow 6124a travel through conduit 6120a at a velocity sufficient to displace at least a portion (preferably a majority or substantially all) of the immersion cooling vapor bubbles 165 from boiling surface 6122a.

[0394] For example, flow 6124a may have a velocity of about 0.1 mm / s, about 1 mm / s, about 2 mm / s, about 5 mm / s, about 10 mm / s, about 15 mm / s, about 20 mm / s, about 25 mm / s, about 50 mm / s, about 75 mm / s, about 100 mm / s, about 150 mm / s, about 200 mm / s, about 500 mm / s, about 1000 mm / s, about 1500 mm / s, about 2000 mm / s, about 2500 mm / s, between about 0.1 mm / s and about 2 mm / s, between about 1 mm / s and about 5 mm / s, between about 2 mm / s and about 10 mm / s, between about 5 mm / s and about 25 mm / s, between about 15 mm / s and about 50 mm / s, between about 25 mm / s and about 75 mm / s, between about 50 mm / s and about 100 mm / s, between about 75 mm / s and about 150 mm / s, between about 100 mm / s and about 200 mm / s, between about 200 mm / s and about 500 mm / s, about 500 mm / s and about 1000 mm / s, about 1000 mm / s and about 2000 mm / s, about 1500 mm / s and about 2500 mm / s, or any suitable velocity.

[0395] Flow 6124a may have any suitable flow rate. In particular, flow 6124a may travel through conduit 6120a at a flow rate sufficient to displace at least a portion (preferably a majority or substantially all) of the immersion cooling vapor bubbles 165 generated by heat from boiling surface 6122a (the heat may be generated by heat generating components 6114a). For example, flow 6124a may have a flow rate of about 0.1 mL / s, about 1 mL / s, about 2 mL / s, about 5 mL / s, about 10 mL / s, about 15 mL / s, about 20 mL / s, about 25 mL / s, about 50 mL / s, about 75 mL / s, about 100 mL / s, about 150 mL / s, about 200 mL / s, between about 0.1 mL / s and about 2 mL / s, between about 1 mL / s and about 5 mL / s, between about 2 mL / s and about 10 mL / s, between about 5 mL / s and about 25 mL / s, between about 15 mL / s and about 50 mL / s, between about 25 mL / s and about 75 mL / s, between about 50 mL / s and about 100 mL / s, between about 75 mL / s and about 150 mL / s, between about 100 mL / s and about 200 mL / s, or any suitable flow rate.

[0396] Flow 6124a may be generated by pump 6130a. Pump 6130a may be fluidically coupled to both conduit 6120a and immersion coolant liquid 164 and may be configured to draw in a portion of immersion coolant liquid 164 to generate a flow 6124a. Pump 6130a may optionally include a filter (not shown) to remove contaminants and / or particulates from flow 6124a. Pump 6130a may be any suitable type of pump, such as a submersible pump.

[0397] Conduit 6120a and / or boiling surface 6122a may include one or more surface treatments to provide a hydrophobic and / or contamination-resistant effect to a surface to prevent a buildup of particulates or contaminants on an inner surface of conduit 6120a (which may clog conduit 6120a) and / or boiling surface 6122a. For example, when water is introduced to an immersion cooling system (for example, from the atmosphere when an immersion cooling tank lid is open or from an accidental spillage of water into an immersion cooling tank from cooling pipes), the water may mix with immersion coolant liquid and form acidic or corrosive compounds. These compounds may significantly disrupt the operation of components within an immersion cooling system (e.g., immersion cooling systems 160, 260, 360 and / or 4200) or destroy components entirely. A coating in accordance with the present technology may help mitigate or impede a deposition or corrosion associated with a contaminant in an immersion coolant liquid in which system 6100a is immersed.

[0398] Examples of hydrophobic surface treatments used in accordance with the present technology may include coatings such as polytetrafluoroethylene (PTFE, e.g., Teflon™), silane, cerium oxide, or any suitable hydrophobic coating. Additionally or alternatively, one or more heat generating components 6114a, conduit 6120a, boiling surface 6122a, or other suitable component of system 6100a may include surface topology modifications such as laser surface topology modification or other etching processes that create surface features having a pitch, scale, and / or major dimension configured to reduce a surface energy of conduit 6120a or other suitable component of system 6100a. For example, a laser may be used to selectively remove material in a predetermined pattern (e.g., cross hatching, a grid defined by repeated volumes of removed material, lines, etc.) from conduit 6120a such that one or more surfaces of conduit 6120a become more hydrophobic and / or contamination resistant.

[0399] A material such as a thermal interface material (TIM), thermal paste or thermal grease, gap pad, epoxy, or other material may be disposed between one or more heat generating components 6114a and conduit 6120a and / or boiling surface 6122a to improve a thermal transfer path between one or more heat generating components 6114a and flow 6124a. A material disposed between one or more heat generating components 6114a and conduit 6120a may provide a larger contact area as compared to direct contact between one or more heat generating components 6114a and conduit 6120a, which may provide a corresponding increase in heat flux between one or more heat generating components 6114a and conduit 6120a.

[0400] An interface material may have a thickness between about 0.01 mm and about 5 mm. For example, An interface material may include a TIM having a thickness of about 0.05 mm, about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, about 1.2 mm, about 1.5 mm, about 2 mm, between about 0.05 mm and about 0.2 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, between about 0.8 mm and about 1.2 mm, between about 1 mm and about 1.5 mm, between about 1.2 mm and about 2 mm, or any suitable thickness.

[0401] An interface material may include a gap pad having a thickness of about 0.05 mm, about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, about 1.2 mm, about 1.5 mm, about 2 mm, between about 0.05 mm and about 0.2 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, between about 0.8 mm and about 1.2 mm, between about 1 mm and about 1.5 mm, between about 1.2 mm and about 2 mm, or any suitable thickness.

[0402] An interface material may include an epoxy having a thickness of about 0.1 mm, about 0.2 mm, about 0.5 mm, about 0.8 mm, about 1 mm, between about 0.05 mm and about 0.2 mm, between about 0.1 mm and about 0.5 mm, between about 0.2 mm and about 0.8 mm, between about 0.5 mm and about 1 mm, or any suitable thickness.

[0403] FIG. 23B illustrates a system 6100b for transferring heat by guiding a flow of immersion coolant liquid 164 across a boiling surface 6122b. System 6100b may be analogous to system 6100a and have analogous components including container 6107b, one or more heat generating components 6114b, conduit 6120b, flow 6124b, pump 6130b, and immersion coolant liquid 164. One or more heat generating components 6114b may generate one or more immersion cooling vapor bubbles 165 due to heat generated through normal operation.

[0404] System 6100b may further include inlet 6126b and outlet 6128b. Inlet 6126b and outlet 6128b may be disposed such that a flow of immersion coolant liquid may flow in substantially different directions through inlet 6126b and outlet 6128b (e.g., a vector orthogonal to a plane passing through the edges of inlet 6126b is not parallel to a vector orthogonal to a plane passing through the edges of outlet 6128b such that a flow of immersion coolant liquid through inlet 6126b has a substantially different direction than a flow of immersion coolant liquid through outlet 6128b). A plane passing through the edges of inlet 6126b may have an orthogonal vector that differs by a threshold angle (e.g., 5°, 10°, 15°,20°, or any suitable difference in threshold angle) from a plane passing through the edges of outlet 6128b.

[0405] For example, FIG. 23B shows inlet 6126b directing a flow 6124b of immersion coolant liquid 164 toward a heat generating component 6114b. A bottom portion of conduit 6120b is closed and prevents any immersion coolant liquid from escaping the bottom, so immersion coolant liquid must flow out of conduit 6120b through outlet 6128b. A portion of immersion coolant liquid 164 that is pumped through conduit 6120b may come into contact with boiling surface 6122b, displacing one or more immersion cooling vapor bubbles 165 from the boiling surface 6122b. The flow 6124b may then exit conduit 6120b through outlet 6128b, which is disposed in a top portion of conduit 6120b. In an embodiment, outlet 6128b guides a flow 6124b of immersion coolant liquid 164 out of conduit 6120b in a substantially vertical direction (e.g., opposite a direction of gravity), although other directions are possible.

[0406] An arrangement as depicted in FIG. 23B may have an advantage of providing more flow toward boiling surface 6122b by directing flow 6124b directly at boiling surface 6122b instead of at an angle to boiling surface 6122b.

[0407] FIG. 23C illustrates a cutaway view of a conduit 6120c in which a wall (convex wall 6121) of conduit 6120c has a convex shape and a cross-sectional area of 6120c at bisection line A-A is smaller than a cross-sectional area at bisection line B-B. This shape will force a flow 6124c to increase in velocity as the cross-sectional area of conduit 6120c decreases. The decreasing cross-sectional area followed by a subsequent increase in cross- sectional area results in a higher flow velocity at the narrowest portion of conduit 6120c (e.g., at A-A) as compared to wider portions (e.g., at B-B) and may provide additional cooling for boiling surface 6122c (and heat generating component 6114c) by providing a higher velocity flow of immersion coolant liquid across boiling surface 6122c than without convex wall 6121. The higher velocity of the flowing immersion coolant liquid may more effectively displace immersion cooling vapor bubbles 165 and replace them with immersion coolant liquid.

[0408] Convex wall 6121 may provide a mechanism for increasing a flow rate across boiling surface 6122c without increasing a pump power. Additionally, the convex shape may partially change a direction of flow 6124c to at least partially direct it toward boiling surface6122c and assist in displacing immersion cooling vapor bubbles 165 from boiling surface 6122c.

[0409] Also considered by the inventors are methods of assembling an immersion cooling system for increasing a flow rate across one or more computing components disclosed herein. FIG. 24 shows an example method 2400 for assembling an immersion cooling system with an increased flow rate across one or more computing components according to the inventive concepts disclosed herein. The method 2400 begins at step 2402 by installing a conduit in a tank of a two-phase immersion cooling system. As described above, the conduit may be fluidically coupled to a pump to pump liquid coolant through the conduit. Then, at step 2404, the tank may be at least partially filled with coolant liquid. Then, at step 2406, a heat generating device can be mounted to a substrate (e.g., a PCB) to form a computing system. In some implementations, the computing system may include multiple surface-mounted devices. Accordingly, each of these devices may be mounted at step 2406. Thereafter, at step 2408, the computing system may be installed, in part, by submerging the computing system into the coolant liquid of the tank such that a boiling surface of the computing system is substantially parallel to the conduit. As described above, the conduit may be configured to guide a flow of coolant liquid substantially opposite a direction of gravity against the boiling surface of the computing system to displace at least a portion of the immersion cooling vapor generated by the computing system with liquid coolant supplied by the conduit.

[0410] 10. Conclusion

[0411] While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the function and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the inventive teachings is / are used. Those skilled in the art will recognize or be able to ascertain, using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that inventive embodiments may bepracticed otherwise than as specifically described. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0412] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0413] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0414] Unless stated otherwise, the terms “approximately” and “about” are used to mean within ± 20% of a target (e.g., dimension or orientation) in some embodiments, within ± 10% of a target in some embodiments, within ± 5% of a target in some embodiments, and yet within ± 2% of a target in some embodiments. The terms “approximately” and “about” can include the target. The term “essentially” is used to mean within ± 3% of a target.

[0415] The indefinite articles “a” and “an,” as used herein, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0416] The phrase “and / or,” as used herein, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0417] As used herein, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of’ or “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” shall have its ordinary meaning as used in the field of patent law.

[0418] As used herein, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0419] In the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semiclosed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMS1. A boiler plate for cooling a plurality of semiconductor dies, the boiler plate comprising: a first heat-dissipation region configured to thermally couple to a first semiconductor die of the plurality of semiconductor dies with a first thermal interface material; a second heat-dissipation region configured to thermally couple to a second semiconductor die of the plurality of semiconductor dies with a second thermal interface material; at least one connecting structure that connects the first heat-dissipation region to the second heat-dissipation region; and at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region; wherein the at least one thermal impedance element is configured to reduce thermal coupling between the first heat-dissipation region and the second heat-dissipation region as compared to thermal coupling if the first heat-dissipation region were in direct physical contact with the second heat-dissipation region.

2. The boiler plate of claim 1, wherein the at least one connecting structure comprises the at least one thermal impedance element.

3. The boiler plate of claim 1 or 2, wherein the at least one thermal impedance element has a lower value of thermal conductivity than a first value of thermal conductivity for the first heat-dissipation region and a second value of thermal conductivity for the second heatdissipation region.

4. The boiler plate of any one of claims 1 through 3, wherein the at least one thermal impedance element comprises a void formed between the first heat-dissipation region and the second heat-dissipation region.

5. The boiler plate of any one of claims 1 through 4, wherein the at least one connecting structure comprises a ceramic or a glass.

6. The boiler plate of any one of claims 1 through 5, wherein: the at least one connecting structure comprises a portion of material remaining after fabrication of the first heat-dissipation region and the second heat-dissipation region fromthe material; and the fabrication comprises forming voids between the first heat-dissipation region and the second heat-dissipation region to define the first heat-dissipation region and the second heat-dissipation region.

7. The boiler plate of any one of claims 1 through 6, wherein the at least one connecting structure comprises a resilient metallic member.

8. The boiler plate of any one of claims 1 through 7, wherein a first thickness of the first heat-dissipation region is different from a second thickness of the second heat-dissipation region.

9. The boiler plate of any one of claims 1 through 8, further comprising a boiler enhancement coating disposed on at least the first heat-dissipation region.

10. The boiler plate of any one of claims 1 through 9, wherein: the first heat-dissipation region is formed from a first material having a first thermal conductivity value; the second heat-dissipation region is formed from a second material having a second thermal conductivity value; and the second thermal conductivity value is different from the first thermal conductivity value.

11. A packaged device for operating in an immersion cooling system, the packaged device comprising: a package substrate; a first semiconductor die mounted to the package substrate; a second semiconductor die mounted to the package substrate; a first heat-dissipation region of a boiler plate, wherein the first heat-dissipation region is thermally coupled to the first semiconductor die; a second heat-dissipation region of the boiler plate, wherein the second heatdissipation region is thermally coupled to the second semiconductor die; at least one connecting structure that connects the first heat-dissipation region to the second heat-dissipation region; and at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region;wherein the at least one thermal impedance element is configured to reduce thermal coupling between the first heat-dissipation region and the second heat-dissipation region as compared to thermal coupling if the first heat-dissipation region were in direct physical contact with the second heat-dissipation region.

12. The packaged device of claim 11, wherein: a first edge of the first semiconductor die closest to a second edge of the second semiconductor die is spaced a distance di from the second edge, which is an edge of the second semiconductor die that is closest to the first semiconductor die; and di has a value from 0.25 mm to 5 mm.

13. The packaged device of claim 11 or 12, wherein the package substrate is a printed circuit board.

14. The packaged device of any one of claims 11 through 13, wherein: the first semiconductor die is a microprocessor; and the second semiconductor die is a high bandwidth memory die.

15. The packaged device of any one of claims 11 through 14, wherein the first heatdissipation region is thermally coupled to the first semiconductor die with a thermal interface material disposed between the first heat-dissipation region and the first semiconductor die.

16. The packaged device of claim 15, wherein no other material is disposed between the first heat-dissipation region and the first semiconductor die.

17. The packaged device of any one of claims 11 through 16, wherein the second heatdissipation region is thermally coupled to at least one additional semiconductor die.

18. The packaged device of any one of claims 11 through 17, wherein the at least one connecting structure comprises the at least one thermal impedance element.

19. The packaged device of claim 18, wherein the at least one connecting structure has a lower thermal conductivity value than a value of thermal conductivity for the first heatdissipation region or the second heat-dissipation region.

20. The packaged device of any one of claims 11 through 19, wherein the at least one thermal impedance element comprises a void formed between the first heat-dissipation region and the second heat-dissipation region.

21. The packaged device of any one of claims 11 through 20, wherein the at least one connecting structure comprises a ceramic or a glass.

22. The packaged device of any one of claims 11 through 21, wherein: the at least one connecting structure comprises a portion of material remaining after fabrication of the first heat-dissipation region and the second heat-dissipation region from the material; and the fabrication comprises forming voids between the first heat-dissipation region and the second heat-dissipation region to define the first heat-dissipation region and the second heat-dissipation region.

23. The packaged device of claim 22, wherein: the portion of material is located a distance I away from the first semiconductor die or the second semiconductor die, whichever is closest to the portion of material; andI has a value from 2 mm to 10 mm.

24. The packaged device of any one of claims 11 through 23, wherein the at least one connecting structure comprises a resilient metallic member.

25. The packaged device of any one of claims 11 through 24, wherein a first thickness of the first heat-dissipation region is different from a second thickness of the second heatdissipation region.

26. The packaged device of any one of claims 11 through 25, further comprising a boiler enhancement coating disposed on at least the first heat-dissipation region.

27. The packaged device of any one of claims 11 through 26, wherein: the first heat-dissipation region is formed from a first material having a first thermal conductivity value; the second heat-dissipation region is formed from a second material having a second thermal conductivity value; andthe second thermal conductivity value is different from the first thermal conductivity value.

28. A method of cooling a first semiconductor die and a second semiconductor die, the method comprising: receiving first heat, from the first semiconductor die, into a first heat-dissipation region of a boiler plate; receiving second heat, from the second semiconductor die, into a second heatdissipation region of the boiler plate; and impeding flow of the first heat in the first heat-dissipation region into the second heatdissipation region with at least one thermal impedance element disposed between the first heat-dissipation region and the second heat-dissipation region, wherein the at least one thermal impedance element has a lower value of thermal conductivity than a first value of thermal conductivity for the first heat-dissipation region and a second value of thermal conductivity for the second heat-dissipation region.

29. The method of claim 28, wherein: the first heat is received from a first thermal interface material which thermally couples the first heat-dissipation region to the first semiconductor die; and the second heat is received from a second thermal interface material which thermally couples the second heat-dissipation region to the second semiconductor die.

30. The method of claim 29, wherein no other material is disposed between the first heatdissipation region and the first semiconductor die.

31. The method of any one of claims 28 through 30, wherein: the first semiconductor die is a microprocessor; and the second semiconductor die is a high bandwidth memory die.

32. The method of any one of claims 28 through 31, wherein: a first edge of the first semiconductor die closest to a second edge of the second semiconductor die is spaced a distance di from the second edge, which is an edge of the second semiconductor die that is closest to the first semiconductor die; and di has a value from 0.25 mm to 5 mm.

33. The method of any one of claims 28 through 32, further comprising: dissipating the first heat from the first heat-dissipation region into a coolant liquid contacting the first heat-dissipation region; and dissipating the second heat from the second heat-dissipation region into the coolant liquid.

34. The method of any one of claims 28 through 33, wherein a distance ch between a first edge of the first heat-dissipation region and a second closest edge of the second heatdissipation region is such that changing an operating temperature of the first semiconductor die by 10° C affects a change in the operating temperature of the second semiconductor die by no more than 1° C.

35. The method of any one of claims 28 through 34, further comprising: operating the first semiconductor die at a first operating temperature; and operating the second semiconductor die at a second operating temperature, wherein the second operating temperature is no less than 15 °C different from the first operating temperature.

36. An assembly for forcing flow of a coolant liquid across a surface of a heat-generating device in an immersion-cooling system for integrated circuits, the assembly comprising: the heat-generating device mounted to a printed circuit board (PCB); and a pump arranged to force the flow of the coolant liquid across the surface of the heatgenerating device, wherein the heat-generating device and the pump are configured to be immersed in the coolant liquid during operation of the immersion-cooling system.

37. The assembly of claim 36, wherein the pump is mounted to the PCB.

38. The assembly of claim 36 or 37, further comprising: a manifold fluidically coupled to the pump; and a plurality of conduits fluidically coupled to the manifold, wherein a first conduit of the plurality of conduits is arranged to direct at least a portion of the coolant liquid that exits from the first conduit to flow across the surface of the heat-generating device.

39. The assembly of claim 36 or 37, wherein the pump is oriented such that an intake of the pump forces the flow of the coolant liquid across the surface of the heat-generating device.

40. The assembly of claim 36 or 37, wherein the pump is oriented such that an exhaust of the pump forces the flow of the coolant liquid across the surface of the heat-generating device.

41. The assembly of any one of claims 36, 37, 39, and 40, wherein the pump is mounted a distance d away from the heat-generating device, the distance d being no greater than 10 mm.

42. The assembly of any one of claims 36 through 41, wherein the heat-generating device comprises at least one of: a heat-dissipative element disposed on a semiconductor die; and a boiler enhancement coating disposed on the semiconductor die.

43. The assembly of claim 42, wherein the boiler enhancement coating comprises a three- dimensional printed structure.

44. An assembly for forcing flow of a coolant liquid to cool a heat-generating device in an immersion-cooling system for integrated circuits, the assembly comprising: the heat-generating device mounted to a printed circuit board (PCB); and a pump contacting and thermally coupled to the heat-generating device, wherein: the pump is configured to remove heat from the heat-generating device by forcing the flow of the coolant liquid through the pump; and the heat-generating device and the pump are configured to be immersed in the coolant liquid during operation of the immersion-cooling system.

45. The assembly of claim 44, wherein the pump comprises: a wall or a plate; wherein: the wall or the plate each comprises an exterior surface and an interior surface; the exterior surface is thermally coupled to the heat-generating device; and the pump forces the flow of the coolant liquid across the interior surface to remove the heat from the heat-generating device.

46. The assembly of claim 44 or 45, wherein the heat-generating device comprises at least one of: a heat-dissipative element disposed on a semiconductor die; and a boiler enhancement coating disposed on the semiconductor die.

47. The assembly of claim 46, wherein the heat-generating device comprises a three- dimensional printed boiler enhancement coating.

48. The assembly of claim 44 or 45, wherein the heat-generating device comprises a semiconductor die having neither: a heat-dissipative element disposed on the semiconductor die; nor a boiler enhancement coating disposed on the semiconductor die.

49. A method for cooling a heat-generating device with coolant liquid in an immersioncooling system for integrated circuits, the method comprising: creating a flow of the coolant liquid with a pump immersed in the coolant liquid of the immersion-cooling system; and using the flow of the coolant liquid to remove heat from the heat-generating device, wherein the heat-generating device is immersed in the coolant liquid.

50. The method of claim 49, wherein the pump comprises an intake and an exhaust for the coolant liquid, the method further comprising: creating the flow of the coolant liquid across a surface of the heat-generating device with the intake of the pump.

51. The method of claim 49, wherein the pump comprises an intake and an exhaust for the coolant liquid, the method further comprising: creating the flow of the coolant liquid across a surface of the heat-generating device with the exhaust of the pump.

52. The method of claim 49, wherein the pump comprises a wall or a plate, the wall or the plate each having an interior surface and an exterior surface, wherein the exterior surface contacts and is thermally coupled to the heat-generating device, the method further comprising: creating the flow of the coolant liquid across the interior surface to remove heat from the heat-generating device.

53. The method of any one of claims 49 through 52, wherein the heat-generating device comprises at least one of: a heat-dissipative element disposed on a semiconductor die; and a boiler enhancement coating disposed on the semiconductor die.

54. The method of claim 52, wherein the heat-generating device comprises a semiconductor die having neither: a heat-dissipative element disposed on the semiconductor die; nor a boiler enhancement coating disposed on the semiconductor die.

55. A heat spreader for a two-phase immersion-cooling system comprising: a vapor-shedding structure extending from a boiling surface of the heat spreader to guide bubbles away from the boiling surface of the heat spreader when the heat spreader boils a liquid coolant in the two-phase immersion-cooling system and creates the bubbles.

56. The heat spreader of claim 55, wherein the vapor-shedding structure, in at least one characteristic, is asymmetric in a vertical direction, wherein the vertical direction is a direction extending along the boiling surface of the heat spreader in a direction which the bubbles would rise when the heat spreader is oriented for operation in a tank of the two-phase immersion-cooling system.

57. The heat spreader of claim 56, wherein the at least one characteristic is thickness and the thickness increases with an increase in the vertical direction.

58. The heat spreader of claim 56, wherein the at least one characteristic is porosity and the porosity increases with an increase in the vertical direction.

59. The heat spreader of claim 56, wherein the at least one characteristic is a pattern of the vapor-shedding structure on the heat spreader and wherein the pattern of the vapor-shedding structure changes on the heat spreader with an increase in the vertical direction.

60. The heat spreader of claim 55, wherein the vapor-shedding structure comprises a mesh of material.

61. The heat spreader of claim 60, wherein the mesh comprises metallic material.

62. The heat spreader of claim 60, wherein the mesh comprises nonmetallic material.

63. The heat spreader of claim 55, wherein the vapor-shedding structure comprises a woven material.

64. The heat spreader of claim 63, wherein the woven material comprises metallic material.

65. The heat spreader of claim 63, wherein the woven material comprises nonmetallic material.

66. The heat spreader of claim 55, wherein the vapor-shedding structure comprises a porous material.

67. The heat spreader of claim 66, wherein the porous material comprises metallic material.

68. The heat spreader of claim 66, wherein the porous material comprises nonmetallic material.

69. The heat spreader of claim 55, wherein: the vapor-shedding structure is disposed in a plurality of strips on the heat spreader; or the vapor-shedding structure is disposed on a boiling enhancement coating that is thermally coupled to the heat spreader.

70. The heat spreader of claim 55, wherein: the vapor-shedding structure is disposed in a lattice on the heat spreader: or the vapor-shedding structure is disposed in a lattice on a boiling enhancement coating that is thermally coupled to the heat spreader.

71. The heat spreader of claim 55, wherein: the vapor-shedding structure is disposed in a grid on the heat spreader; or the vapor-shedding structure is disposed in a grid on a boiling enhancement coating that is thermally coupled to the heat spreader.

72. The heat spreader of claim 55, wherein: the vapor-shedding structure comprises fins extending from the heat spreader; or the vapor-shedding structure comprises fins extending from a boiling enhancement coating that is thermally coupled to the heat spreader.

73. The heat spreader of claim 55, further comprising a boiling enhancement coating contacting at least a portion of the heat spreader.

74. A method of cooling at least one semiconductor die with a heat spreader in a two-phase immersion-cooling system, the method comprising: receiving heat in the heat spreader from the at least one semiconductor die;boiling a liquid coolant that contacts a boiling surface of the heat spreader, wherein the boiling creates a plurality of bubbles; and guiding, with a vapor-shedding structure that extends from the boiling surface, at least a portion of the plurality of bubbles away from the boiling surface of the heat spreader.

75. The method of claim 74, wherein the vapor-shedding structure is vertically asymmetric in at least one characteristic, wherein a vertical direction is a direction extending along the boiling surface of the heat spreader in a direction which the plurality of bubbles would rise when the heat spreader is oriented for operation in a tank of the two-phase immersion-cooling system.

76. The method of claim 75, wherein the at least one characteristic is thickness and the thickness increases with an increase in the vertical direction.

77. The method of claim 75, wherein the at least one characteristic is porosity and the porosity increases with an increase in the vertical direction.

78. The method of claim 75, wherein the at least one characteristic is a pattern of the vaporshedding structure on the heat spreader and wherein the pattern of the vapor-shedding structure changes on the heat spreader with an increase in the vertical direction.

79. The method of claim 74, wherein the vapor-shedding structure comprises a mesh of material.

80. The method of claim 79, wherein the mesh comprises metallic material.

81. The method of claim 79, wherein the mesh comprises nonmetallic material.

82. The method of claim 74, wherein the vapor-shedding structure comprises a woven material.

83. The method of claim 82, wherein the woven material comprises metallic material.

84. The method of claim 82, wherein the woven material comprises nonmetallic material.

85. The method of claim 74, wherein the vapor-shedding structure comprises a porous material.

86. The method of claim 85, wherein the porous material comprises metallic material.

87. The method of claim 85, wherein the porous material comprises nonmetallic material.

88. The method of claim 74, wherein: the vapor-shedding structure is disposed in a plurality of strips on the heat spreader; or the vapor-shedding structure is disposed on a boiling enhancement coating that is thermally coupled to the heat spreader.

89. The method of claim 74, wherein: the vapor-shedding structure is disposed in a lattice on the heat spreader: or the vapor-shedding structure is disposed in a lattice on a boiling enhancement coating that is thermally coupled to the heat spreader.

90. The method of claim 74, wherein: the vapor-shedding structure is disposed in a grid on the heat spreader; or the vapor-shedding structure is disposed in a grid on a boiling enhancement coating that is thermally coupled to the heat spreader.

91. The method of claim 74, wherein: the vapor-shedding structure comprises fins extending from the heat spreader; or the vapor-shedding structure comprises fins extending from a boiling enhancement coating that is thermally coupled to the heat spreader.

92. The method of claim 74, further comprising a boiling enhancement coating contacting at least a portion of the heat spreader.

93. A method of making a heat spreader for a two-phase immersion-cooling system, the method comprising: attaching a vapor-shedding structure to the heat spreader, such that the vaporshedding structure extends from a boiling surface of the heat spreader to guide bubbles away from the boiling surface of the heat spreader when the heat spreader boils a liquid coolant in the two-phase immersion-cooling system and creates the bubbles.

94. The method of claim 93, wherein the vapor-shedding structure, in at least one characteristic, is asymmetric in a vertical direction, wherein the vertical direction is a direction extending along the boiling surface of the heat spreader in a direction which thebubbles would rise when the heat spreader is oriented for operation in a tank of the two-phase immersion-cooling system.

95. The method of claim 94, wherein the at least one characteristic is thickness and the thickness increases with an increase in the vertical direction.

96. The method of claim 94, wherein the at least one characteristic is porosity and the porosity increases with an increase in the vertical direction.

97. The method of claim 94, wherein the at least one characteristic is a pattern of the vaporshedding structure on the heat spreader and wherein the pattern of the vapor-shedding structure changes on the heat spreader with an increase in the vertical direction.

98. The method of claim 93, further comprising forming a boiling enhancement coating on the boiling surface of the heat spreader.

99. A system for thermal management of computing hardware, the system comprising: a dispersion conduit disposed in an immersion coolant liquid, the dispersion conduit comprising a plurality of holes; a distribution conduit fluidically coupled to the dispersion conduit; and a pump fluidically coupled to the distribution conduit, the pump configured to pump a pumped portion of the immersion coolant liquid through the distribution conduit; wherein: the plurality of holes are shaped to guide at least part of the pumped portion of the immersion coolant liquid toward a predetermined area of one or more computing hardware components.

100. The system of claim 99, wherein: a first end of the distribution conduit is fluidically coupled to a filter assembly configured to filter the pumped portion of the immersion coolant liquid; and the pump is disposed within the filter assembly.

101. The system of claim 99, wherein: a first end of the distribution conduit is fluidically coupled to a filter assembly configured to filter the pumped portion of the immersion coolant liquid; and the pump is disposed outside of the filter assembly and is fluidically coupled to the distribution conduit through the filter assembly.

102. The system of claim 99, wherein at least one of the dispersion conduit or the distribution conduit comprises a contamination-resistant surface treatment.

103. The system of claim 99, wherein at least one of the dispersion conduit or the distribution conduit comprises copper, stainless steel, aluminum, titanium, or polycarbonate.

104. The system of claim 99, wherein the one or more computing hardware components comprises a logic integrated circuit (IC), a network switch, a printed circuit board (PCB), a boiling enhancement coating (BEC), or a ball grid array (BGA).

105. The system of claim 99, wherein the pump is configured to pump the pumped portion of the immersion coolant liquid through the distribution conduit at a predetermined flow rate.

106. The system of claim 105, wherein the predetermined flow rate is between about 1 milliliter per minute and about 200 milliliters per minute.

107. A method for thermal management of computing hardware, the method comprising: pumping, by a pump, a portion of an immersion coolant liquid into a distribution conduit; routing the portion of immersion coolant liquid into a dispersion conduit comprising a plurality of holes; and guiding, by the plurality of holes, at least part of the portion of the immersion coolant liquid toward a predetermined area of one or more computing hardware components.

108. The method of claim 107, further comprising filtering, by a filter assembly, the portion of the immersion coolant liquid, prior to the step of guiding.

109. The method of claim 108, wherein: a first end of the distribution conduit is fluidically coupled to the filter assembly; and the pump is disposed within the filter assembly.

110. The method of claim 108, wherein: a first end of the distribution conduit is fluidically coupled to the filter assembly; and the pump is disposed outside of the filter assembly and is fluidically coupled to the distribution conduit through the filter assembly.

111. The method of claim 107, wherein at least one of the dispersion conduit or the distribution conduit comprises a contamination-resistant surface treatment.

112. The method of claim 107, wherein the one or more computing hardware components comprises a logic integrated circuit (IC), a network switch, a printed circuit board (PCB), a boiling enhancement coating (BEC), or a ball grid array (BGA).

113. The method of claim 107, wherein the pump is configured to pump the portion of the immersion coolant liquid at a predetermined flow rate.

114. The method of claim 113, wherein the predetermined flow rate is between about 1 milliliter per minute and about 200 milliliters per minute.

115. A system for heat transfer, the system comprising: a container at least partially filled with an immersion coolant liquid; a heat generating component disposed within the immersion coolant liquid, the heat generating component causing a first portion of the immersion coolant liquid to boil and convert to an immersion cooling vapor; a nozzle configured to direct a second portion of the immersion coolant liquid toward the heat generating component; and a pump fluidically coupled to the nozzle and configured to pump the second portion of the immersion coolant liquid at a predetermined velocity or a predetermined flow rate.

116. The system of claim 115, wherein the predetermined velocity is between about 0.1 mm / s and about 10 m / s.

117. The system of claim 115, wherein the predetermined flow rate is between about 0.1 mL / s and about 200 mL / s.

118. The system of claim 115, wherein: the nozzle comprises an exit; and the exit comprises a characteristic size between about 0.1 mm and about 10 mm.

119. The system of claim 115, wherein the heat generating component comprises an integrated circuit (IC).

120. The system of claim 115, further comprising a boiler plate disposed in thermal contact with the heat generating component.

121. The system of claim 120, further comprising an interface material disposed between the heat generating component and the boiler plate.

122. The system of claim 121, wherein the interface material comprises at least one of a thermal interface material (TIM), a thermal grease, a thermal paste, or a gap pad.

123. The system of claim 120, wherein the boiler plate comprises at least one of copper, stainless steel, aluminum, tungsten, or titanium.

124. The system of claim 120, wherein at least one of the heat generating component or the boiler plate comprises a surface treatment.

125. The system of claim 124, wherein the surface treatment comprises at least one of a surface topology modification or a coating.

126. The system of claim 115, wherein the nozzle is configured to direct the second portion of the immersion coolant liquid substantially orthogonal to the heat generating component.

127. The system of claim 115, wherein the nozzle is configured to direct the second portion of the immersion coolant liquid toward the heat generating component at an angle to a surface of the heat generating component at between about 5° and about 89°.

128. A method for heat transfer, the method comprising: generating heat from a heat generating component disposed in an immersion coolant liquid; causing, based on the generated heat, a first portion of the immersion coolant liquid to boil and convert to an immersion cooling vapor; pumping, by a pump fluidically coupled to a nozzle disposed at a first angle to the heat generating component, a second portion of the immersion coolant liquid through the nozzle; directing, by the nozzle, a second portion of the immersion coolant liquid toward the heat generating component at a predetermined velocity or a predetermined flow rate; and displacing, by the second portion of the immersion coolant liquid, at least a portion of the immersion cooling vapor away from the heat generating component.

129. The method of claim 128, wherein the predetermined velocity is between about 0.1 mm / s and about 2500 mm / s.

130. The method of claim 128, wherein the predetermined flow rate is between about 0.1 mL / s and about 200 mL / s.

131. The method of claim 128, wherein:the nozzle comprises an exit; and the exit comprises a characteristic size between about 0.1 mm and about 10 mm.

132. The method of claim 128, wherein the heat generating component comprises an integrated circuit (IC).

133. The method of claim 128, wherein causing the first portion of immersion coolant liquid to boil comprises transferring the heat through a boiler plate disposed in thermal contact with the heat generating component.

134. The method of claim 133, wherein an interface material is disposed between the heat generating component and the boiler plate.

135. The method of claim 134, wherein the interface material comprises at least one of a thermal interface material (TIM), a thermal grease, a thermal paste, or a gap pad.

136. The method of claim 133, wherein the boiler plate comprises at least one of copper, stainless steel, aluminum, tungsten, or titanium.

137. The method of claim 133, wherein at least one of the heat generating component or the boiler plate comprises a surface treatment.

138. A system for heat transfer, the system comprising: a container at least partially filled with an immersion coolant liquid; and a heat generating component disposed within the immersion coolant liquid and in thermal contact with a boiling surface, the boiling surface forming at least a portion of an inner surface of a conduit; wherein: the conduit is configured to at least partially enclose a first portion of the immersion coolant liquid flowing across the boiling surface; and the boiling surface is in contact with the first portion of the immersion coolant liquid and is configured to cause some or all of the first portion of the immersion coolant liquid to be converted into an immersion cooling vapor.

139. The system of claim 138, further comprising a pump fluidically coupled to the conduit and configured to flow a second portion of the immersion coolant liquid through the conduit.

140. The system of claim 139, wherein the pump is configured to flow the second portion of the immersion coolant liquid through the conduit at a velocity of between about 0.1 mm / s and about 2500 mm / s.

141. The system of claim 139, wherein the pump is configured to flow the second portion of the immersion coolant liquid through the conduit at a flow rate of between about 0.1 mL / s and about 200 mL / s.

142. The system of claim 139, wherein the second portion of the immersion coolant liquid displaces the immersion cooling vapor from the boiling surface.

143. The system of claim 138, wherein the conduit further comprises an inlet and an outlet.

144. The system of claim 143, wherein the immersion coolant liquid flows through the inlet in a substantially same direction as the immersion coolant liquid flows through the outlet.

145. The system of claim 143, wherein the immersion coolant liquid flows through the inlet in a substantially different direction than the immersion coolant liquid flows through the outlet.

146. The system of claim 138, wherein the conduit comprises at least one convex wall.

147. The system of claim 138, wherein the conduit comprises a surface modification.

148. The system of claim 147, wherein the surface modification comprises at least one of a surface topology modification or a coating.

149. The system of claim 148, wherein the coating comprises at least one of polytetrafluoroethylene, silane, or cerium oxide.

150. The system of claim 138, wherein the conduit comprises at least one of copper, stainless steel, aluminum, tungsten, or titanium.

151. A method for heat transfer, the method comprising:generating, by a heat generating component disposed in an immersion coolant liquid, heat; causing, based on the generated heat, a second portion of the immersion coolant liquid to boil and convert to an immersion cooling vapor; pumping, by a pump fluidically coupled to a conduit, the second portion of the immersion coolant liquid across a boiling surface of the conduit, wherein the boiling surface is thermally coupled to the heat generating component; and displacing at least a portion of the immersion cooling vapor with the second portion of the immersion coolant liquid.

152. The method of claim 151, wherein pumping the second portion of the immersion coolant liquid across the boiling surface comprises pumping the second portion of the immersion coolant liquid through the conduit at a velocity of between about 0.1 mm / s and about 2500 mm / s.

153. The method of claim 151, wherein pumping the second portion of the immersion coolant liquid across the boiling surface comprises pumping the second portion of the immersion coolant liquid through the conduit at a flow rate of between about 0.1 mL / s and about 200 mL / s.

154. The method of claim 151, wherein: the conduit further comprises an inlet and an outlet; and a third portion of the immersion coolant liquid flows through the inlet in a substantially same direction as the third portion of the immersion coolant liquid flows through the outlet.

155. The method of claim 151, wherein: the conduit further comprises an inlet and an outlet; and a third portion of the immersion coolant liquid flows through the inlet in a substantially different direction than the third portion of the immersion coolant liquid flows through the outlet.

156. The method of claim 151, wherein the conduit comprises at least one convex wall.

157. The method of claim 151, wherein the conduit comprises a surface modification.

158. The method of claim 157, wherein the surface modification comprises at least one of a surface topology modification or a coating.

159. The method of claim 158, wherein the coating comprises at least one of polytetrafluoroethylene, silane, or cerium oxide.

160. The method of claim 151, wherein the conduit comprises at least one of copper, stainless steel, aluminum, tungsten, or titanium.

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