Systems and methods for heat transfer in immersion cooling systems

Abstract

Systems, methods, and apparatuses for removing excess heat from components of a computing system are disclosed. The present technology includes baffles for redirecting falling immersion cooling liquid from condenser tubes. Immersion cooling vapor contacts the condenser tubes and recondenses into immersion cooling liquid. The liquid then drips off of the condenser tubes and falls downwards. The baffles prevent the liquid from preventing immersion cooling vapor from contacting the condenser tubes. The present technology further includes heat pipes with a wicking foil to promote movement of a heat carrying working fluid. The present technology further includes fins and plena for the redirection of immersion cooling vapor away from a surface of a heat generating component such as a graphics processing unit (GPU), thus promoting contact with immersion cooling liquid and improving heat transfer.

Description

SYSTEMS AND METHODS FOR HEAT TRANSFER TN IMMERSION COOLINGSYSTEMSCROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the priority benefit of U.S. Application No. 63 / 556,210, filed February 21, 2024, U.S. Application No. 63 / 564,836, filed March 13, 2024, and U.S. Application No. 63 / 564,796, filed March 13, 2024, 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 computing hardware such as integrated circuits (ICs) including chips and semiconductor dies, the amount of heat generated by a single chip, such as a microprocessor, has increased. Computing hardware that has traditionally been air cooled has evolved to levels of power consumption requiring more heat dissipation than can be provided by air alone. In some cases, immersion cooling of ICs in a tank containing a coolant fluid is employed to maintain ICs 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 fluid. The boiling creates a coolant fluid vapor in the tank, which is condensed by cooling coils back to liquid form. Heat from the semiconductor dies can then be sunk into the liquid-to-gas and gas-to-liquid phase transitions of the coolant fluid with the result that the semiconductor dies are kept at an acceptable temperature.|0004| Two-phase immersion cooling systems may utilize condenser coils to recondense the boiled immersion cooling vapor back into liquid form. However, the efficiency of the condenser tubes may suffer when recondensed immersion cooling liquid droplets fall from a first condenser tube that is directly above a second condenser tube. If the droplets land on the second condenser tube, they may temporarily prevent immersion cooling vapor from contacting the condenser tube and may leave a film that additionally insulates the tube from the immersion cooling vapor. No solution currently exists to mitigate this loss of efficiency.

[0005] Further, the flow, movement, and circulation of immersion cooling vapor plays a significant role in a cooling system efficiency. In certain instances, immersion cooling vapor generated by a first semiconductor die may displace immersion cooling liquid from a second immersion cooling die. This displacement of immersion cooling liquid can negatively impact a cooling efficiency of the second immersion cooling die.

[0006] Other components that may be used with two-phase immersion cooling systems are heat pipes that carry a cooling fluid for cooling the immersion cooling vapor below its boiling temperature and recondensing the immersion cooling fluid back into liquid form. The heat pipes are also used for providing a heat transfer mechanism from a component disposed outside of an immersion cooling liquid to a reservoir of immersion cooling liquid. A traditional form of heatpipes uses wicks to carry the cooling fluid within a control volume from a recondensed location back to an area adjacent to a heat source. However, traditional heat pipes and wicks have shortcomings that reduce their effectiveness.SUMMARY

[0007] Two-phase immersion cooling has emerged as a highly promising technology for improving computational density by improving waste heat removal as compared to traditional server cooling technologies such as air cooling. Two-phase immersion cooling works by immersing computational hardware such as logic integrated circuits (ICs) in a dielectric fluid that has a boiling point below a maximum operating temperature of one or more immersed logic ICs. The phase transition between the liquid and vapor phases can provide orders of magnitude more efficient heat transfer between a logic 1C and a heat dissipation medium than air cooling. Two- phase immersion cooling systems provide distinct advantages over air-cooled computing systems for removing waste heat from semiconductor dies.

[0008] The present technology is generally directed toward improvements to the transfer of excess heat out of components of computing systems by changing a phase of a working fluid from a liquid phase to a gas phase and back again.

[0009] Heat from semiconductor dies, graphics processing units (GPUs), and other computing hardware causes an immersion cooling liquid to boil and convert to a vapor phase. However, in some arrangements, immersion cooling vapor generated by the operation of a first semiconductor die may rise and displace immersion cooling liquid from the surface of a second semiconductor die. This may reduce an efficiency of waste heat transfer from the second semiconductor die.

[0010] The inventors have noticed and appreciated that existing systems lack sufficient structures for ensuring a proper interfacing and circulation of immersion cooling vapor around condenser tubes, semiconductor dies, and other structures. The techniques described herein introduce the addition of vapor management structures to allow for a redirection of immersion cooling vapor generated by a first semiconductor die away from a second semiconductor die and prevent the immersion cooling vapor from displacing immersion cooling liquid at a surface of the second immersion cooling die.

[0011] The present technology includes louvers, plenums, baffles, and / or pathways for immersion cooling vapor generated by the operation of semiconductor dies, particularly in vertical servers having semiconductor dies or other heat-generating components disposed substantially above other heat-generating components. The present technology reduces dryout (where immersion cooling liquid no longer effectively contacts a surface to be cooled due to displacement by immersion cooling vapor), improves immersion cooling liquid recirculation and transport to high-heat areas, and mitigates flow-induced vibrations and oscillations that may mechanically destabilize an immersion cooling system over time.100121 The present technology additionally includes improvements for removing excess heat from components that may not be fully immersed in immersion cooling liquid, may be exposed toimmersion cooling liquid only part of the time, may not be regularly exposed to immersion cooling liquid, etc. Heat pipes or thermosiphons move a cooling fluid in a control volume via two-phase heat transfer. Traditional heat pipes use meshes or sinter powder wicks to move condensed fluid via capillary forces to the evaporator. An amount of heat that a heat pipe is capable of transferring may be limited by dry out, entrainment, capillary imperfections, sonic limitations, and the like.

[0013] To address this issue, a two-sided enhanced foil is disclosed herein. The foil may include etched hydrophilic or superhydrophilic properties that enhance heat pipe performance well above commercial heat pipes. The performance can also be enhanced by having superhydrophilic tracks and / or channels that increase the directionality of the working fluid due to Laplace pressure and capillary forces. These tracks may have the additional advantage of providing improved hydrophilicity while reducing an associated pressure drop.

[0014] In some aspects, the techniques described herein relate to a system for condensing a vapor, the system including: a plurality of condenser tubes including at least a first condenser tube and a second condenser tube, the first condenser tube being disposed at least partially above the second condenser tube in a direction of gravity; a plurality of baffles including at least a first baffle positioned between the first condenser tube and the second condenser tube, such that the first baffle is configured to prevent a first droplet of liquid formed on the first condenser tube from falling onto the second condenser tube; and an immersion cooling reservoir positioned below the plurality of condenser tubes; wherein: the immersion cooling reservoir is configured to collect the first droplet after it falls from the first condenser tube and slides down the first baffle; a bottommost portion of the first baffle extends at least partially below both the first condenser tube and the second condenser tube in the direction of gravity; and the first baffle is sloped such that the first droplet is displaced laterally as well as vertically when the first droplet slides down the first baffle.

[0015] In some aspects, the techniques described herein relate to a method of using a system for condensing a vapor, the method including: flowing a coolant through a plurality of condenser tubes, the coolant flowing through an interior region of each condenser tube; contacting an exterior surface of each condenser tube with the vapor, the vapor changing from a vapor phase into liquid, the liquid including a plurality of liquid droplets formed on the exterior surface of each condenser tube; and collecting the plurality of liquid droplets in an immersion cooling reservoir positioned below the plurality of condenser tubes; wherein: before being collected in the immersion cooling reservoir, each respective liquid droplet falls from the exterior surface of each respective condenser tube without contacting any other condenser tube of the plurality of condenser tubes; and before being collected in the immersion cooling reservoir, each respective liquid droplet either (A) is displaced laterally as well as vertically as the droplet slides down a baffle or (B) falls into the immersion cooling reservoir without contacting any baffle.100161 In some aspects, the techniques described herein relate to an apparatus for transferring heat, the apparatus including: a housing including an inner volume, a first end, a second end, and a wall; the wall at least partially surrounding the inner volume of the housing; a working fluid partially occupying the inner volume of the housing; and a wicking foil disposed within the inner volume of the housing; wherein: the wicking foil, when viewed along a longitudinal axis of the housing,includes a spiral shape disposed within a portion of the inner volume between the wall and a distance from the longitudinal axis; the distance from the longitudinal axis through a centroid of the housing constitutes a percentage less than 100% of a total distance from the centroid to the wall; and the working fluid includes at least a liquid phase.

[0017] In some aspects, the techniques described herein relate to a method for transferring heat, the method including: transferring heat from a source into a working fluid within a first end of a housing, the housing including an inner volume, the first end, a second end, and a wall, wherein the wall at least partially surrounds the inner volume of the housing; causing a liquid portion of the working fluid to boil and transition to a gas phase working fluid; flowing the gas phase working fluid through at least a central portion of the housing; transferring heat out of the gas phase working fluid at the second end and causing the gas phase working fluid to recondense into a liquid phase; flowing the liquid phase working fluid along a wicking foil disposed within the housing from the second end to the first end.

[0018] In some aspects, the techniques described herein relate to a system for vapor redirection, the system including: a first semiconductor die disposed at least partially below a second semiconductor die, the first semiconductor die and the second semiconductor die being attached to a printed circuit board (PCB); an immersion cooling liquid in which each of the first semiconductor die, the second semiconductor die, and the PCB is at least partially immersed in the immersion cooling liquid; and a first fin, the first fin being disposed on the first semiconductor die; wherein: the first fin is disposed at an angle of about 30 degrees to about 60 degrees away from a vertical direction.|0019| In some aspects, the techniques described herein relate to a method of operating a system for vapor redirection, the method including: generating, by a first semiconductor die disposed at least partially below a second semiconductor die, bubbles of immersion cooling vapor by transferring heat from the first semiconductor die into an immersion cooling liquid; and laterally displacing, by at least a first fin disposed on the first semiconductor die, the bubbles of immersion cooling vapor; wherein: the first semiconductor die and the second semiconductor die are attached to a printed circuit board (PCB); the first semiconductor die, the second semiconductor die, and the PCB are at least partially immersed in the immersion cooling liquid; the first fin is disposed at an angle away from a vertical direction; the angle is configured such that the bubbles of immersion cooling vapor are laterally displaced by the first fin; and substantially all of the bubbles of immersion cooling vapor float in the vertical direction without contacting the second semiconductor die.

[0020] 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 claimed subject matter appearing at the end of 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

[0021] FIG. 1 illustrates a portion of an immersion cooling system.

[0022] FIG. 2 illustrates a plurality of droplets and / or beads that are prevented from falling from a first condenser tube to a second condenser tube directly or substantially below the first condenser tube.

[0023] FIG. 3 illustrates a perspective view of an immersion cooling system including condenser tubes and baffle.

[0024] FIG. 4 illustrates an apparatus for heat transfer in accordance with the present technology.

[0025] FIG. 5 illustrates a top view of an apparatus in accordance with the present invention.

[0026] FIGS. 6A and 6B illustrate a front and side view, respectively, of an immersion cooling system.

[0027] FIGS. 7A and 7B illustrate front and side views, respectively, of a system analogous to the system depicted in FIGS. 6A and 6B, further including vapor redirection system including a plenum and plurality of louvers that serve to funnel immersion cooling vapor generated by the operation of semiconductor dies away from a surface of the semiconductor dies.

[0028] FIGS. 8A and 8B illustrate front and side perspective views, respectively, of a system including a vapor redirection system analogous to vapor redirection system depicted in FIGS. 7A and 7B, but excluding a plenum.

[0029] FIG. 9 depicts aspects of an immersion cooling system for dissipating heat from one or more heat-generating components such as semiconductor die packages via immersion cooling.

[0030] FIG. 10 illustrates a flowchart of a method in accordance with the present technology.|00311 FIG. 11 illustrates a flowchart of a method in accordance with the present technology.

[0032] FIG. 12 illustrates a flowchart of a method in accordance with the present technology.DETAILED DESCRIPTION

[0033] FIG. 1 illustrates a portion of an immersion cooling system. Immersion cooling system 100 may include a container 110. Container 110 may house or otherwise contain immersion cooling fluid and one or more semiconductor dies or similar logic integrated circuits (ICs). These semiconductor dies generate heat during operation, and this heat may boil the immersion cooling fluid contained within container 110. The immersion cooling vapor may rise into an upper portion of container 110 referred to as the headspace.

[0034] A condenser assembly 120 may be disposed within the headspace. Condenser assembly 120 may include a plurality of condenser tubes 130, each condenser tube having an interior region through which a liquid is flowed. The liquid may be a coolant liquid, such as deionized water, having a temperature below a boiling point of the immersion cooling fluid. The immersion cooling vapor may contact the plurality of condenser tubes 130, which may reduce a temperatureof the immersion cooling vapor below the boiling point and cause the immersion cooling vapor to recondense into a liquid phase.

[0035] However, a potential disadvantage of condenser assembly 120 is that immersion cooling liquid that condenses on condenser tubes 130 near the top of condenser assembly 120 may drip onto each successive condenser tube below. This may temporarily prevent immersion cooling vapor from making contact with a condenser tube 130 and may thus reduce the rate at which a portion of immersion cooling vapor recondenses into immersion cooling liquid. This may lower the overall heat transfer efficiency of the system and reduce the rate at which the semiconductor dies operates.

[0036] To mitigate this drawback, a condenser assembly 200 is shown in FIG. 2. Condenser assembly 200 may include baffles 210 (including individual baffles 210a-d), which are positioned between condenser tubes 230. At least some of condenser tubes 230 may be at least partially vertically aligned (e.g., in a direction of gravity), and may include individual condenser tubes 230a-j. In operation, condenser tubes 230a-j may be filled with a flowing coolant liquid such as deionized water, the cooling fluid kept at a temperature below the boiling temperature of an immersion cooling fluid. The coolant liquid may in turn carry heat transferred from immersion cooling vapor out of the system and cause the immersion cooling vapor to recondense into immersion cooling liquid. In an embodiment, two or more condenser tubes may be vertically and / or laterally separated from one another. For example, condenser tube 230d is shown as being vertically separated from condenser tube 230i. Condenser tube 230e is shown as being vertically separated from condenser tube 230j . Condenser tube 230d is shown as being vertically and laterally separated from condenser tube 230j . Condenser tubes 230a, 230b, and 230c are shown as being laterally separated from one another.

[0037] This condensed immersion cooling liquid may form immersion cooling liquid beads 220 (including individual immersion cooling liquid beads 220a-d). When enough immersion cooling liquid has joined a bead and made it too heavy to continue to stick to a condenser tube, it may fall from the condenser tube as a droplet 222 (such as any of droplets 222a-c). In a condenser assembly such as condenser assembly 120, these droplets may fall from a first condenser tube onto a second condenser tube disposed below (in a gravitational direction) the first condenser tube.100381 These droplets 222 may temporarily form a layer that effectively insulates condenser tubes 230a-j from the surrounding immersion cooling vapor and prevents or slows the immersion cooling vapor from contacting condenser tubes 230a-j and recondensing. Further, some immersion cooling liquid from droplets 222 may remain on a condenser tube as a thin film and act as an insulating barrier to any further immersion cooling vapor, preventing the immersion cooling vapor from contacting condenser tubes 230 and recondensing into immersion cooling liquid.

[0039] To prevent the formation of an insulating layer or barrier discussed above, baffles 210 are placed between vertically aligned condenser tubes such as condenser tubes 230a and 230f; condenser tubes 230b and 230g; condenser tubes 230e and 23 Oj ; condenser tubes 230c and 230h,and so on. FIG. 2 illustrates a plurality of droplets and / or beads that are prevented from falling from a first condenser tube to a second condenser tube directly or substantially below the first condenser tube. For example, bead 220a has formed on condenser tube 230a and immersion cooling liquid droplet 222a has fallen from condenser tube 230a. Without baffle 210a, immersion cooling liquid droplet 222a would fall directly onto condenser tube 23 Of and potentially reduce a heat transfer efficiency of condenser tube 230f.

[0040] In an embodiment, adjacent baffles may be placed in physical contact. For example, baffle 210c is placed in physical contact with baffle 210d such that at a topmost portion of both baffles, there is substantially no space separating the two baffles and therefore liquid droplets cannot fall between them. Baffles 210 may be sloped (e.g., where one or more portions of the surface of the baffle has an angle greater than zero to a gravity vector). The slope of each baffle 210 may be constant along the length of each baffle 210; or the slope can vary along the length of each baffle 210. In FIG. 2, the baffles 210 are shown as having curvature because the slope varies along the length of each baffle. The slope and / or curvature may have any suitable profile that guides a falling droplet under the influence of gravity or other motive force, thereby displacing the droplet laterally as well as vertically as the droplet slides along the baffle 210. Additionally or alternatively, baffles 210 may be spaced apart such that one or more baffles of baffles 210 do not contact any other baffles.

[0041] FIG. 2 illustrates that immersion cooling liquid droplet 222a has a downward path from condenser tube 230a. After immersion cooling liquid droplet 222a lands on baffle 210a, droplet 222a will flow along baffle 210a as an immersion cooling liquid bead down and to the left and will not contact condenser tube 230f. In other words, immersion cooling liquid droplet 222a may be displaced laterally as well as vertically as it flows along baffle 210a.

[0042] Analogous interactions are further illustrated in FIG. 2. For example, when immersion cooling liquid bead 220c falls off of condenser tube 230e, it will fall onto baffle 210c and flow down and to the right instead of contacting condenser tube 230j . In an additional example, immersion cooling liquid droplet 222b is illustrated in the process of falling from condenser tube 230b. Immersion cooling liquid droplet 222b will continue to fall until it hits baffle 210c and will flow down and to the right accordingly.

[0043] Baffles 210 may be made of any suitable material including stainless steel, aluminum, polycarbonate, or the like. In an embodiment, a material for baffles 210 may be selected for compatibility with immersion cooling liquid. For example, compatibility with immersion cooling liquid may include materials that do not dissolve in immersion cooling liquid, do not corrode upon contact with immersion cooling liquid, do not leech impurities or other contaminants into immersion cooling liquid, have a surface energy lower than a surface tension of immersion cooling liquid, or any suitable intrinsic or extrinsic property.

[0044] Baffles 210 and / or condenser tubes 230 may include one or more coatings, treatments, or surface modifications to create a hydrophobic effect. For example, baffles 210 may include a hydrophobic coating such as silane, polytetrafluoroethylene (PTFE), cerium oxide, or any suitable hydrophobic coating. Additionally or alternatively, baffles 210 may include surfacemodification 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 the baffles 210. 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 baffles 210 such that the surface of baffles 210 becomes more hydrophobic.

[0045] Baffles 210 may be secured to one or more surfaces of an immersion cooling tank. Additionally or alternatively, baffles 210 may be secured to one or more portions of condenser tubes 230. For example, baffles 210 may be secured to one or more portions of condenser tubes 230 via one or more screws, ties, bands, clips, or similar attachment means.

[0046] Condenser assembly 200 may be utilized with a method in accordance with the present technology. For example, a method of using condenser assembly 200 may include flowing a coolant liquid through the plurality of condenser tubes, the coolant liquid having a temperature below a boiling temperature of an immersion cooling vapor. The immersion cooling vapor and condenser assembly 200 may be disposed within a headspace of an immersion cooling system, for example headspace 908 of immersion cooling system 900. Condenser assembly 200 may cause the immersion cooling vapor to change phase into an immersion cooling liquid through thermal contact with one or more of the condenser tubes 230. The recondensed immersion cooling liquid may form a droplet on the one or more condenser tubes 230. The droplet may drip from the condenser tube on which it formed. The droplet may be prevented from falling on any condenser tube of condenser tubes 230 by one or more of baffles 210. One or more of baffles 210 may deflect the droplet and cause the droplet to fall into an immersion cooling reservoir below the condenser assembly 200 (see, e.g., FIG. 9 - immersion cooling liquid 964 (reservoir) contained within tank 920 in FIG. 9; condenser tubes 970 may be analogous to condenser assembly 200). The immersion cooling vapor may be generated by the operation of one or more semiconductor dies in the immersion cooling reservoir (e g., semiconductor die(s) 950 in FIG. 9).|0047| FIG. 3 illustrates a perspective view of an immersion cooling system 300 including condenser tube 330a, condenser tube 330b, and baffle 310.

[0048] Baffle 3 10 may be attached to a wall of an immersion cooling container 340, or may additionally or alternatively be attached to one or more of condenser tube 330a and / or condenser tube 330b. Condenser tube 330a and condenser tube 330b (collectively condenser tubes 330) may be made of any suitable material including copper, stainless steel, or aluminum. Condenser tubes 330 may be solid, hollow, or may have a plurality of channels configured to transport a coolant liquid such as deionized water through the tubes in order to affect a transfer of heat from the environment surrounding the condenser tubes 330 into the coolant liquid; for example, from an immersion cooling vapor into the coolant liquid.

[0049] Baffle 310 is illustrated as being disposed between condenser tube 330a and condenser tube 330b such that any liquid that falls from condenser tube 330a cannot land on condenser tube 330b. This reduces an amount of immersion cooling liquid that comes into contact withcondenser tube 330b and improves a heat transfer efficiency of both condenser tube 330b and immersion cooling system 300 overall.

[0050] Additionally, a bottommost portion 312 of baffle 310 may be positioned substantially not above condenser tube 330a or condenser tube 330b. Accordingly, a bead or droplet of condensed immersion cooling liquid that falls onto baffle 310 and subsequently drips off of baffle 310 will not fall onto another condenser tube after falling off of condenser tube 330a.

[0051] FIG. 4 illustrates an apparatus 400 for heat transfer in accordance with the present technology. Apparatus 400 may include a housing 410 and may have the form of a heat pipe or thermosiphon. Apparatus 400 may be a fluidically closed system in which a working fluid, such as deionized water, is heated above a boiling point by the addition of heat from a first region having a first temperature. A first end 412 of the housing 410 may be disposed within or adjacent to a first region, a first object, or a first environment (e.g., a headspace of an immersion cooling system, an internal portion of an immersion cooling tank, in contact with a heat-generating component, etc.).

[0052] The working fluid may be in a liquid phase as embodied by working liquid 422. The first temperature may increase a temperature of the working liquid 422 above a boiling point and may cause the working liquid 422 to transition to working gas 424. The working gas 424 may then rise or otherwise flow through housing 410 to a second end 414 of housing 410. The second end 414 of housing 410 may be disposed within or adjacent to a second region having a second temperature below the boiling point of the working fluid. For example, the second region may be within a reservoir of immersion cooling fluid, external to an immersion cooling tank, in contact with a heat sink such as a metal block or cooling pipe, etc. In an embodiment, second end 414 may be adjacent to or physically contacting a cold plate, heat sink, boiling enhancement coating, or other suitable heat transfer medium at a lower temperature than a temperature of the working gas 424, which may cause heat to be transferred out of working gas 424 and cause working gas 424 to recondense into working liquid 422.|0053| In an embodiment, first end 412 and second end 414 may include a hydrophobic coating on an inside portion of housing 410 to promote a flow of working liquid 422 away from first end 412 and / or second end 414. For example, a hydrophobic coating at second end 414 on the inside of housing 410 may facilitate a flow of recondensed working liquid 422 from the walls of housing 410 at second end 414 to the wicking foil 415, which may aid in more efficient flow back to first end 412. Examples of hydrophobic coatings used in accordance with the present technology may include polytetrafluoroethylene (PTFE, e.g., Teflon™) coatings or any coating having weak polarity (e g., hydrogen bonds) for working liquid 422, which may be deionized water.

[0054] Housing 410 may further include wicking foil 415. Wicking foil 415 may be disposed within housing 410 and may have a spiral shape. Housing 410 may include an inner volume, e.g. a volume encompassed by housing 410. In an embodiment, housing 410 may be a cylinder and / or have a cylindrical cross section. Wicking foil 415 may be disposed within an outer portion of the inner volume. This outer portion is the volume between a wall of housing 410 and a distance from a longitudinal axis through the centroid of the housing. An outer edge of wicking foil 415 may be seam welded to another portion of wicking foil 415 to prevent the foil from unrolling or deformingin operation. Wicking foil 415 may be attached to at least one of the wall of housing 410, the first end 412, and / or the second end 414. In an embodiment, a majority of working liquid 422 may be contained within wicking foil 415, although some liquid may also occupy the central portion of housing 410. Likewise, a majority of working gas 424 may occupy the central portion of housing 410, however, some trapped working gas 424 may be disposed within wicking foil 415 and / or between leaves of wicking foil 415.

[0055] The central portion of the inner volume of housing 410 may contain working gas 424 during operation such that working liquid 422 that has boiled and changed phase into working gas 424 may flow through housing 410 through the central adiabatic portion while working liquid 422 may flow through housing 410 by being wicked through wicking foil 415.

[0056] Wicking foil 415 may include one or more surface treatments to make one or more surfaces of wicking foil 415 hydrophilic. For example, wicking foil 415 may include a surface modification such as laser surface topology modification or other etching processes that create surface features having a pitch, scale, and / or major dimension configured to increase a surface energy of wicking foil 415 and increase a hydrophilicity of wicking foil 415 for working liquid 422. 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 wicking foil 415 such that the surface of wicking foil 415 becomes more hydrophilic.

[0057] Additionally or alternatively, wicking foil 415 may include one or more chemical surface treatments to one or both sides of wicking foil 415 such as one or more coatings, deposited materials, surface texturing or the like. For example, wicking foil 415 may include a surface roughness having a feature scale of pm, chemical coatings made from polyvinylpyrrolidone, polyurethane, polyacrylic acid, polyethylene oxide, polysaccharides, and the like.

[0058] Turning again to FIG. 4, QH represents a flow of heat from a high-temperature source into apparatus 400 via a first end 412 of housing 410 and into working liquid 422. For example, OH may come from a computing component such as a networking interface card (NIC), quad small form factor pluggable (QSFP) connector, or the like. This heat may cause working liquid 422 to boil and transition phase to working gas 424.

[0059] Working gas 424 may then flow through housing 410 to second end 414. A temperature of second end 414 and a region surrounding second end 414 may be lower than a boiling point of working gas 424, which may cause a flow of heat QL out of the working gas 424 and causing it to recondense back into working liquid 422.

[0060] This recondensed working liquid 422 may then flow along wicking foil 415 back towards first end 412 where it will be reheated by the high-temperature source and the process will begin again. One or more surface treatments of wicking foil 415 may help promote a flow of working liquid 422 from second end 414 to first end 412.

[0061] FIG. 5 illustrates a top view of an apparatus 500 in accordance with the present invention. Apparatus 500 may be analogous to apparatus 400. Apparatus 500 may include housing 510, wicking foil 515, and a working fluid such as deionized water that may be in liquid form as working liquid 522 or vapor form as working gas 524. Wicking foil 515 may be analogous towi eking foil 415 and may include one or more surface treatments to make wi eking foil 515 hydrophilic. As depicted in FIG. 5, all or most of working gas 524 is disposed within a central portion that is not occupied by wicking foil 415, whereas all or most of working liquid 522 is disposed within an outer portion that is occupied by wicking foil 415.

[0062] Wicking foil 515 may be folded or rolled into a spiral shape with a predetermined distance between adjacent portions of wicking foil 515. For example, each overlapping portion of wicking foil 515 may be separated from an adjacent overlapping portion of wicking foil 515 by about 0.01 mm, about 0.1 mm, about 1 mm, about 2 mm, about 5 mm, or any suitable separation. Each overlapping portion of wicking foil 515 may be separated from an adjacent overlapping portion of wicking foil 515 by between about 0.01 mm and about 0.1 mm, about 0.05 mm and about 0.2 mm, between about 0.1 mm and about 0.4 mm, between about 0.25 mm and about 0.75 mm, between about 0.5 mm and about 1 mm, between about 0.5 mm and about 3 mm, or any suitable separation or range of separations.

[0063] Analogous to wicking foil 415, wicking foil 515 may be disposed within housing 510 and may have a spiral shape. Housing 510 includes an inner volume encompassed by housing 510. In an embodiment, housing 510 may be a cylinder and / or have a cylindrical cross section. Wicking foil 515 may be disposed within an outer portion of the inner volume. The outer portion is the volume between a wall of housing 510 and distance D from the wall of the housing. A total distance T from the centroid of the longitudinal axis to the wall of the housing is equal to D plus d, where d is the distance from the longitudinal axis through the centroid of the housing to the distance D from the wall of the housing. For example, wicking foil 515 may be disposed within a volume defined as being between the wall of housing 510 and a distance / ) of about 40% of T, about 30% of 7', about 25% of a 7 ', about 20% of 7', about 15% of 7', about 10% of 7', or any suitable percentage.

[0064] FIGS. 6A and 6B illustrate a front and side view, respectively, of an immersion cooling system 600. Immersion cooling system 600 may include an immersion cooling container 610 containing immersion cooling liquid 640. Immersion cooling system 600 may include one or more semiconductor dies 630 including semiconductor die 630a and semiconductor die 630b, which may be disposed on a printed circuit board (PCB 620) and are immersed within immersion cooling liquid 640. As depicted, PCB 620 is a single board shared commonly by both semiconductor die 630a and semiconductor die 630b. Semiconductor die 630a may be disposed at least partially below semiconductor die 630b. For example, a portion of semiconductor die 630a may be aligned (or overlap) with at least a portion of semiconductor die 630b in a direction of gravity, while the remaining (non-overlapping) portion of semiconductor die 630a may be disposed below semiconductor die 630b. Alternatively, as shown in FIGS. 6A and 6B, all of semiconductor die 630a may be disposed below semiconductor die 630b.|0065| Immersion cooling container 610 may be an immersion cooling tank such as tank 920 in FIG. 9.

[0066] One or more semiconductor dies 630 may be any suitable semiconductor die such as a logic integrated circuit (IC), logic chips, microprocessors (e g., a central processing unit (CPU) and / or graphics processing unit (GPU)), data processing unit (DPU), tensor processing unit(TPU), 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, input / output (I / O) controllers, and / or other chips.[00011 Semiconductor dies 630 may further include one or more memory modules, which may be an IC configured to store data. Examples of memory modules used in accordance with the present technology 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), one-time programmable ROM (OTPROM), or the like), or any suitable type of memory module.

[0067] Semiconductor dies 630 may generate waste heat during operation. This waste heat is transferred to immersion cooling liquid 640 and causes it to boil, forming bubbles 650 of immersion cooling vapor. While bubbles 650 have better heat transfer capacities than air, they still have orders of magnitude less heat transfer capacity than immersion cooling liquid 640. Thus, these bubbles 650 may significantly impede a heat transfer capability of semiconductor dies 630.

[0068] FIGS. 6A and 6B illustrate how bubbles 650 from semiconductor die 630a rise and displace immersion cooling liquid 640 from portions of the surface of semiconductor die 630b. This may decrease a thermal transfer efficiency out of semiconductor die 630b and cause semiconductor die 630b to overheat and be damaged. In an embodiment, one or more additional semiconductor dies may be disposed above semiconductor die 630a and semiconductor die 630b, and may likewise experience a similar reduction in thermal transfer efficiency due to bubbles 650 created by both semiconductor die 630a and semiconductor die 630b displacing immersion cooling liquid 640.[0069| FIGS. 7A and 7B illustrate a system 700 analogous to immersion cooling system 600, and further including vapor redirection system 760 including a plenum and plurality of louvers that serve to funnel immersion cooling vapor generated by the operation of semiconductor dies 730 away from a surface of the semiconductor dies 730. System 700 may include an immersion cooling container 710 containing immersion cooling liquid 740. System 700 may further include one or more semiconductor dies 730 (including semiconductor die 730a and semiconductor die 730b) disposed on a PCB 720. Analogously to immersion cooling system 600, semiconductor die 730a and semiconductor die 730b may be GPUs, CPUs, or any suitable semiconductor. Semiconductor die 730a may be disposed at least partially below semiconductor die 730b. For example, a portion of semiconductor die 730a may be aligned (or overlap) with at least a portion of semiconductor die 730b in a direction of gravity, while the remaining (non-overlapping) portion of semiconductor die 730a may be disposed below semiconductor die 730b.Alternatively, as shown in FIGS. 7A and 7B, all of semiconductor die 730a may be disposed below semiconductor die 730b.

[0070] System 700 may further include a plenum 762 and a plurality of fins 764. The plurality of fins 764 may be disposed in contact with semiconductor die 730a and semiconductor die 730b, for example contacting a surface such that immersion cooling vapor in the form of bubbles 750 formed during operation of semiconductor die 730a and semiconductor die 730b are directed away from (e.g. laterally displaced) the semiconductor dies and into plenum 762. FIG. 7A illustrates bubbles 750 being displaced to the left as they float upward away from a surface of semiconductor die 730a and semiconductor die 730b. In particular, semiconductor die 730a, semiconductor die 730b, plenum 762, and plurality of fins 764 may be arranged such that semiconductor die 730b is not disposed above an opening of plenum 762 or an upper edge of one or more fins 764. Semiconductor die 730b may be disposed outside of a path bubbles 750 that have been laterally displaced by plurality of fins 764 disposed on semiconductor die 730a, the path being defined by a volume through which bubbles 750 will rise after they are no longer being displaced by plurality of fins 764. The plurality of fins 764 thereby reduce or eliminate the number of bubbles making contact with the semiconductor die(s) above the die where the bubbles originated. Preferably, substantially all (e.g., 90% or more) of the bubbles float up in a vertical direction away from semiconductor die 730a without contacting semiconductor die 730b.

[0071] Plurality of fins 764 may be angled fins. The angled fins may have been punched out of plenum 762. The angle of the plurality of fins 764 may be 20 degrees to 70 degrees, or 30 degrees to 60 degrees, or 35 degrees to 55 degrees, or 40 degrees to 50 degrees, or about 45 degrees. The angle is measured away from a vertical direction 770 (opposite the direction of gravity), where 0 degrees is parallel to vertical direction 770, and 680 degrees is parallel to the direction of gravity. Plurality of fins 764 may have a fin length of about 0.2 cm, about 0.5 cm, about 1 cm, about 1.5 cm, about 2 cm, about 3 cm, about 5 cm, about 10 cm, between about 0.2 cm and about 10 cm, between about 0.5 cm and about 5 cm, between about 1 cm and about 3 cm, or any suitable length or range of lengths. In an embodiment, plurality of fins 764 may each have substantially the same length, or may have different lengths. For example, the length of the fins on each semiconductor die can increase as a function of the die’s position with respect to the vertical direction 770 (e.g., fins positioned on the lower portion of a die are shorter than fins positioned on a higher position of the die). Plenum 762 may be a tube, channel, conduit, or other partially-enclosed object including an opening at a top portion of the plenum to allow bubbles 750 to escape. In an embodiment, a bottom portion of plenum 762 may be open or may be closed. Plenum 762 may further include openings at the locations of fins 764. These openings may allow bubbles 750 generated at the surface of operation semiconductor dies 730 to float up and into the plenum upon being laterally displaced by fins 764.

[0072] Plenum 762 and plurality of fins 764 may be made from a material having suitable compatibility with immersion cooling liquid. For example, plenum 762 and plurality of fins 764 may be made of aluminum, stainless steel, copper, polycarbonate, or any suitable material. One or more materials of plenum 762 and plurality of fins 764 may be chosen for suitable thermal transfer properties. For example, plurality of fins 764 may be made of copper, which may enhance a heat transfer away from a surface of semiconductor dies 730 through conductive heat transfer.

[0073] Plenum 762 and / or plurality of fins 764 may additionally include one or more coatings to help prevent an accumulation of contamination and / or deposition of impurities dissolved in immersion cooling liquid 740. 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 cooling liquid and form acidic or corrosive compounds. These compounds may significantly disrupt the operation of components within an immersion cooling system 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 immersion cooling liquid 740 and help prevent damage to plenum 762 and / or plurality of fins 764.

[0074] Immersion cooling vapor displaced by boiling of immersion cooling liquid 740 may be replaced by additional immersion cooling liquid 740 that flows between adjacent fins 764. This guided flow may aid circulation of immersion cooling liquid 740 and promote improved heat transfer throughout system 700 as compared to an analogous system lacking plenum 762 and plurality of fins 764, e.g., immersion cooling system 600.

[0075] FIGS. 8A and 8B illustrate front and side perspective views of a system 800 including a vapor redirection system 860 analogous to vapor redirection system 760, but excluding plenum 762. System 800 may include an immersion cooling container 810 and one or more semiconductor dies 830 disposed on a PCB 820. The container 810 may contain immersion cooling liquid 840. The plurality of fins 864 may be secured directly to semiconductor dies 830. Excluding plenum 762 may have the benefit of reducing an overall amount of space required by a vapor redirection system. Fins 864 may be made of any suitable material including aluminum, stainless steel, copper, polycarbonate, or the like.

[0076] Semiconductor die 830a may be disposed at least partially below semiconductor die 830b, for example at least a portion of semiconductor die 830a may be aligned with at least a portion of semiconductor die 830b in a direction of gravity.

[0077] FIG. 8A illustrates bubbles 850 being displaced to the left as they float upward away from a surface of semiconductor die 830a and semiconductor die 830b. In particular, semiconductor die 830a, semiconductor die 830b, and plurality of fins 864 may be arranged such that semiconductor die 830b is not disposed above an upper edge of one or more fins 864. Semiconductor die 830b may be disposed outside of a path bubbles 850 that have been laterally displaced by plurality of fins 864 disposed on semiconductor die 830a, the path being defined by a volume through which bubbles 850 will rise after they are no longer being displaced by plurality of fins 864.

[0078] Semiconductor die 830a, semiconductor die 830b, and plurality of fins 864 may be arranged such that semiconductor die 830b is not disposed substantially above plurality of fins 864.

[0079] FIG. 9 depicts aspects of an immersion cooling system 900 for dissipating heat from one or more heat-generating components such as semiconductor die packages 905 via immersion cooling. Each package 905 can include one or more semiconductor dies that produce heat whenthe system is in operation. The immersion cooling system 900 in the illustrated example of FIG. 9 is a two-phase immersion cooling system, though the invention may also be implemented in a single-phase immersion cooling system.

[0080] Semiconductor die packages 905 may include one or more fins or plena for diverting or guiding bubbles 965 away from a surface of the one or more semiconductor die packages 905, such as fins and / or plena depicted with respect to FIGS. 7A, 7B, 8A, and 8B.

[0081] One or more semiconductor die packages 905 may be 3DIC stacks in accordance with the present technology. For example, one or more semiconductor die packages 905 may include a logic IC and at least one memory module bonded to the logic IC using a hybrid bond or microbump bond.

[0082] Immersion cooling systems may provide particular advantage to 3DIC stacks due to the lower surface area to volume ratio of a 3DIC stack compared to the individual components of the 3DIC stack (e.g., a bonded logic IC and memory module will have a lower surface area to volume ratio than the combined surface area to volume ratio of the physically separated logic IC and memory module) as well as the additional heat generated by state of the art logic ICs. This lower surface area to volume ratio means waste heat generated by the 3DIC stack may not be as efficiently dissipated and may require better cooling performance than air cooling can provide. Two-phase immersion cooling in particular can provide this additional heat removal required by 3DIC stacks.

[0083] Immersion cooling system 900 includes a container such as tank 920 filled, at least in part, with immersion cooling liquid 964. The immersion cooling system 900 can further include at least one chiller 980 that flows a heat-transfer fluid through at least one condenser tube 970 that is disposed in the tank 920 and headspace 908. Condenser tubes 970 and chiller 980 may be part of a heat exchanger. Condenser tubes 970 are illustrated as being arrayed in alternating, vertically offset rows, and may be separated by baffles in accordance with the present technology such as baffles 210 illustrated in FIGS. 2 and 3. The packages 905 can be mounted on one or more printed circuit boards (PCBs) 957 that are immersed, at least in part, in the immersion cooling liquid 964. Immersion-cooling system 900 may further include a filter 975 disposed adjacent to the tank 920.

[0084] Filter 975 may include a filtration media, a housing, and a pump configured to force immersion cooling liquid 964 through filter 975 to remove contaminants, particulates, or other impurities that may be added to immersion cooling liquid 964 during use. Filter 975 may be housed outside of tank 920 while being in fluidic communication with immersion cooling liquid 964 in tank 920. Alternatively, filter 975 may be submerged within immersion cooling liquid 964 inside of tank 920.

[0085] Immersion cooling liquid 964 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 905 more efficiently than air. Examples of immersion cooling liquid 964 are Novec™ 649, Novec™ 7000, and Novec™ 7100 produced by 3M™. An exemplary immersion cooling liquid 964 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.

[0086] In an embodiment of the invention, immersion cooling liquid 964 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 900 differs by a threshold amount as compared to unused or pure immersion cooling liquid 964. For example, immersion cooling liquid 964 may be considered unacceptably contaminated or degraded if the dielectric constant and / or dielectric loss tangent differs by a threshold of 10% or more as compared to unused or pure immersion cooling liquid 964. In an embodiment, a dielectric constant and / or dielectric loss tangent variation threshold may be 20%, 15%, 5%, 3%, 1%, or any suitable threshold.

[0087] Contamination of the immersion cooling liquid 964 and resulting changes to dielectric constant and / or dielectric loss tangent may alter or negatively impact operation of components within immersion cooling liquid 964 including semiconductor die(s) 950. 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) 950 submerged in immersion fluid, and / or signal dissipation through the immersion cooling liquid 964. 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) 950. 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) 950 may be throttled or suspended when a dielectric constant and / or dielectric loss tangent of immersion cooling liquid 964 exceeds a predetermined threshold.

[0088] Changes to dielectric constant and / or dielectric loss tangent may be caused by contaminants within immersion cooling liquid 964. In some cases, changes to dielectric constant and / or dielectric loss tangent may be reversed by filtering the contaminants from immersion cooling liquid 964. In some embodiments, upon detecting an increase in dielectric constant and / or dielectric loss tangent of immersion cooling liquid 964, controller 902 may instruct filter 975 to increase filtration throughput or notify a user that an immersion cooling liquid 964 filtration media may need to be replaced. If a dielectric constant and / or dielectric loss tangent exceeds a predetermined threshold, controller 902 may throttle or shut down one or more semiconductor die(s) 950, generate a notification that immersion cooling liquid 964 should be replaced, trigger an alarm, etc.

[0089] Further examples of sensors and methods for immersion cooling contamination monitoring may include probes for monitoring immersion cooling liquid parameters such as dielectric constant and dielectric loss tangent, and processors configured to 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.

[0090] The illustrated example of FIG. 9 is not intended to be to scale. The immersion coolingsystem 900 may house and provide immersion cooling liquid 964 to tens, hundreds, or even thousands of packages 905. In some cases, the immersion cooling system 900 can be small (e.g., 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 immersion cooling system can be large (e.g., the size of a van or larger, approximately 2.5 meters high, 2.5 meters width, 4 meters depth or length).

[0091] The immersion cooling system 900 can also include a controller 902 (e.g., a microcontroller, programmable logic controller (PLC), microprocessor, field-programmable gate array, logic circuitry, memory, or some combination thereof) to manage system operation. Controller 902 can perform various system functions such as monitoring temperatures of system components, cooling fluid level, tank access, chiller operation etc. The controller 902 can further issue commands to control system operation such as executing a start-up sequence, executing a shut-down sequence, assigning workloads among the packages, changing cooling fluid level, changing the temperature of the heat-transfer fluid circulated by the chiller 980, etc. In some implementations, controller 902 can include (or itself be) a baseboard management controller (BMC) 904. That is, the BMC 904 may monitor and control all aspects of system operation for the immersion cooling system 900 in addition to monitoring and controlling workloads of the semiconductor dies 950 in the packages 905 cooled by the system. The immersion cooling system 900 can also include a network interface controller (NIC 903) to allow the system to communicate over a network, such as a local area network or wide area network. The immersion cooling system 900 can further include a fluid sensor array 990 having a plurality of fluid sensors 910. Fluid sensors 910 may include one or more leak detection sensors at least partially submerged in immersion cooling liquid 964.

[0092] The semiconductor die(s) 950 and can be mounted on and attached to a printed circuit board (PCB) 955 (sometimes referred to as a substrate) in device package 905. The package 905 can be made commercially available as an off-the-shelf (OTS) product. The package 905 can be used for single-phase or two-phase immersion cooling of at least one semiconductor die 950, 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 (AT) accelerator, an application-specific integrated circuit (ASIC), field- programmable gate array (FPGA), and / or other densely patterned semiconductor die.

[0093] In the two-phase immersion cooling system 900 of FIG. 9, heat flows from the semiconductor die 950 where it is generated into the heat spreader 952. The heat spreader 952 is in thermal contact with an immersion cooling liquid 964 that can flow over and extract heat from the heat spreader 952. The amount of heat delivered by the heat spreader 952 to the immersion cooling liquid 964 is enough to boil the immersion cooling liquid 964 that contacts the heat spreader 952 (creating bubbles 965 and potentially creating froth 967 when bubbles 965 reach the surface of immersion cooling liquid 964).

[0094] The vapor 966 from the boiled immersion cooling liquid 964 can be cooled and condensed back to liquid droplets 968, for example, by the condenser tube 970. The heat-transfer fluid, such as chilled water, from the chiller 980 can be circulated through the condenser tube 970 to lower the temperature of the condenser tube 970 below the condensation point in the headspace 908 ofthe tank 920. As a result, vapor 966 condenses on exterior surfaces of the condenser tube 970 and liquid droplets 968 from the condensed vapor can drip and / or flow back to the immersion cooling liquid 964. There may be a plurality of condenser tubes 970 in tank 920 to condense the vapor 966 into droplets.

[0095] Some or all of the condenser tubes 970 may or may not be located directly over the PCBs 957. Instead, the condenser tube(s) 970 can be located near one or more walls of the tank 920, such that the condenser tube(s) 970 are not directly over the PCBs 957 on which the packages 905 are mounted. Immersion cooling system 900 may further include baffles 930 disposed among condenser tubes 970 to improve recondensation of immersion cooling vapor 966 into immersion cooling liquid droplets 968. Baffles 930 may be analogous to baffles 210 illustrated in FIG. 2 and / or baffle 310 illustrated in FIG. 3.

[0096] Immersion cooling system 900 may further include one or more heat transfer apparatuses 940 analogous to apparatus 400 illustrated in FIG. 4. An internal portion of one or more heat transfer apparatuses 940 may appear analogous to that depicted in FIG. 5 with respect to heat transfer apparatus 500. FIG. 9 illustrates heat transfer apparatus 940 in thermal contact with fluid sensor array 990. Because fluid sensor array 990 is disposed at least partially outside of immersion cooling liquid 964, fluid sensor array 990 may not fully benefit from the heat transfer provided by immersion cooling liquid 964. One or more heat transfer apparatuses 940 may provide more efficient cooling to fluid sensor array 990 and improve overall performance of fluid sensor array 990 and attached plurality of fluid sensors 910.

[0097] To improve thermal performance in two-phase immersion cooling system 900, the heat spreader 952 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 comprises a mesh copper layer bonded (e.g., via resistance heating) to at least an outer surface of the heat spreader 952. In some cases, the BEC is applied as particulates to at least one smooth surface of the heat spreader 952 and then subsequently sintered to adhere to one another and to the heat spreader 952. The BEC provides an improved surface area to contact the immersion cooling liquid 964 and can increase the heat transfer coefficient from the heat spreader 952 to the immersion cooling liquid 964 by up to a factor of 15 versus a smooth surface on the heat spreader 952. Accordingly, BECs can increase thermal conductivity to, and accelerate the boiling of, the immersion cooling liquid 964.

[0098] 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.

[0099] 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 moresemiconductor 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.

[0100] 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.

[0101] 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 disclose embodiments of BEC layers, adhesives, solders, sintering, laser ablation, meshes, and other BECs and BEC application methods. The entirety ofU.S. Patent Application No. 18 / 460,091 is incorporated herein by reference.

[0102] 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.

[0103] 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 3DICstack component and the surrounding immersion cooling fluid. The entirety of U.S. Provisional Application No. 63 / 513,828 is incorporated herein by reference.

[0104] 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.

[0105] 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

[0031] -

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

[0106] FIG. 10 is a flowchart of an example method 1000 of using a system for condensing a vapor. Method 1000 includes blocks 1010-1030.

[0107] Block 1010 includes flowing a coolant through a plurality of condenser tubes, the coolant flowing through an interior region of each condenser tube. The coolant may include deionized water, ionized water, antifreeze, ethylene glycol, as well as additives such as nitrites, phosphates, silicates, and borates. A coolant may include one or more organic acids to mitigate corrosion.

[0108] Block 1020 includes contacting an exterior surface of each condenser tube with the vapor, the vapor changing from a vapor phase into liquid, the liquid comprising a plurality of liquid droplets formed on the exterior surface of each condenser tube. The vapor may be generated by boiling a portion of the immersion cooling reservoir by operating a semiconductor die.

[0109] Block 1030 includes collecting the plurality of liquid droplets in an immersion cooling reservoir positioned below the plurality of condenser tubes. Before being collected in the immersion cooling reservoir, each respective liquid droplet may fall from the exterior surface of each respective condenser tube without contacting any other condenser tube of the plurality of condenser tubes. Additionally or alternatively, before being collected in the immersion cooling reservoir, each respective liquid droplet may either (A) be displaced laterally as well as vertically as the droplet slides down a baffle or (B) fall into the immersion cooling reservoir without contacting any baffle.

[0110] FIG. 11 is a flowchart of an example method 1100 for transferring heat. The method 1100 includes blocks 1 1 10-1 150.

[0111] Block 1110 includes transferring heat from a source into a working fluid within a first end of a housing, the housing comprising an inner volume, the first end, a second end, and a wall, wherein the wall at least partially surrounds the inner volume of the housing.

[0112] Block 1120 includes causing the working fluid to boil and transition to a gas phase.

[0113] Block 1130 includes flowing the gas phase working fluid through at least a central portion of the housing.

[0114] Block 1140 includes transferring heat out of the gas phase working fluid at the second end and causing the gas phase working fluid to recondense into a liquid phase.

[0115] Block 1150 includes flowing the liquid phase working fluid along a wicking foil disposed within the housing from the second end to the first end. The wicking foil, when viewed along a longitudinal axis of the housing, may have a spiral shape disposed within a portion of the inner volume between the wall and a distance from the longitudinal axis through a centroid of the housing. The distance from the longitudinal axis may constitute a percentage less than 100% of a total distance from the longitudinal axis to the wall. The distance from the longitudinal axis may be at least 60% of the total distance from the longitudinal axis to the wall. The wicking foil may include a hydrophilic surface treatment. The hydrophilic surface treatment may include at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching. The hydrophilic surface treatment may include a chemical treatment. A plurality of overlapping portions of the wicking foil are separated from each other by between 0.01 mm and 3 mm. The plurality of overlapping portions of the wicking foil may be separated from each other by between 0.1 mm and 1 mm.

[0116] FIG. 12 is a flowchart of an example method 1200 for operating a system for vapor redirection. Method 1200 includes blocks 1210-1220.

[0117] Block 1210 includes generating, by a first semiconductor die disposed at least partially below a second semiconductor die, bubbles of immersion cooling vapor by transferring heat from the first semiconductor die into an immersion cooling liquid. The first semiconductor die and the second semiconductor die are attached to a printed circuit board (PCB). The first semiconductor die, the second semiconductor die, and the PCB are at least partially immersed in the immersion cooling liquid. The first fin is disposed at an angle away from a vertical direction. The angle is configured such that the bubbles of immersion cooling vapor are laterally displaced by the first fin. Substantially all of the bubbles of immersion cooling vapor float in the vertical direction without contacting the second semiconductor die. The angle may be between about 30 degrees and about 60 degrees.|00118| Block 1220 includes laterally displacing, by at least a first fin disposed on the first semiconductor die, the bubbles of immersion cooling vapor. A second fin may be disposed on the second semiconductor die at the angle. A partially-enclosed plenum may be attached to the first fin and the second fin. The first fin and the second fin may include at least one of copper, aluminum, stainless steel, or polycarbonate. The plenum may include at least one of copper, aluminum, stainless steel, or polycarbonate. The plenum may include an opening at a top portion of the plenum.

[0119] Method 1200 may further include preventing a deposition of an impurity dissolved in the immersion cooling liquid using a coating disposed on at least one of the plenum, the first fin, or the second fin.Exemplary Claim Clauses

[0120] Clause 1. A system for condensing a vapor, the system comprising: a plurality of condenser tubes comprising at least a first condenser tube and a second condenser tube, the first condenser tube being disposed at least partially above the second condenser tube in a direction of gravity; a plurality of baffles comprising at least a first baffle positioned between the first condenser tube and the second condenser tube, such that the first baffle is configured to prevent a first droplet of liquid formed on the first condenser tube from falling onto the second condenser tube; and an immersion cooling reservoir positioned below the plurality of condenser tubes; wherein: the immersion cooling reservoir is configured to collect the first droplet after it falls from the first condenser tube and slides down the first baffle; a bottommost portion of the first baffle extends at least partially below both the first condenser tube and the second condenser tube in the direction of gravity; and the first baffle is sloped such that the first droplet is displaced laterally as well as vertically when the first droplet slides down the first baffle.|00121| Clause 2. The system of any suitable clause herein, including the foregoing clauses, wherein: the plurality of condenser tubes further comprises a third condenser tube and a fourth condenser tube; the third condenser tube is disposed at least partially above a fourth condenser tube; the third condenser tube is laterally separated from the first condenser tube; the fourth condenser tube is laterally separated from the second condenser tube; the plurality of baffles further comprises a second baffle disposed between the third condenser tube and the fourth condenser tube, such that the second baffle is configured to prevent a second droplet of liquid formed on the third condenser tube from falling onto the fourth condenser tube; wherein: a bottommost portion of the second baffle extends at least partially below both the third condenser tube and the fourth condenser tube in the direction of gravity; and the second baffle is sloped such that the second droplet is displaced laterally as well as vertically when the second droplet slides down the second baffle.

[0122] Clause 3. The system of any suitable clause herein, including the foregoing clauses, wherein a topmost portion of both the first baffle and the second baffle are in physical contact.

[0123] Clause 4. The system of any suitable clause herein, including the foregoing clauses, wherein the plurality of condenser tubes comprise at least one of copper, stainless steel, or aluminum.

[0124] Clause 5. The system of any suitable clause herein, including the foregoing clauses, wherein the plurality of baffles comprises at least one of copper, stainless steel, or aluminum.

[0125] Clause 6. The system of any suitable clause herein, including the foregoing clauses, further comprising a hydrophobic surface treatment on the plurality of baffles.

[0126] Clause 7. The system of any suitable clause herein, including the foregoing clauses, wherein the hydrophobic surface treatment comprises at least one of silane, polytetrafluoroethylene (PTFE), or cerium oxide.

[0127] Clause 8. The system of any suitable clause herein, including the foregoing clauses, wherein the hydrophobic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

[0128] Clause 9. The system of any suitable clause herein, including the foregoing clauses, wherein further comprising a hydrophobic surface treatment on the plurality of condenser tubes.

[0129] Clause 10. The system of any suitable clause herein, including the foregoing clauses, wherein the hydrophobic surface treatment comprises at least one of silane, polytetrafluoroethylene (PTFE), or cerium oxide.

[0130] Clause 11. The system of any suitable clause herein, including the foregoing clauses, wherein the hydrophobic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

[0131] Clause 12. A method of using a system for condensing a vapor, the method comprising: flowing a coolant through a plurality of condenser tubes, the coolant flowing through an interior region of each condenser tube; contacting an exterior surface of each condenser tube with the vapor, the vapor changing from a vapor phase into liquid, the liquid comprising a plurality of liquid droplets formed on the exterior surface of each condenser tube; and collecting the plurality of liquid droplets in an immersion cooling reservoir positioned below the plurality of condenser tubes; wherein: before being collected in the immersion cooling reservoir, each respective liquid droplet falls from the exterior surface of each respective condenser tube without contacting any other condenser tube of the plurality of condenser tubes; and before being collected in the immersion cooling reservoir, each respective liquid droplet either (A) is displaced laterally as well as vertically as the droplet slides down a baffle or (B) falls into the immersion cooling reservoir without contacting any baffle.

[0132] Clause 13. The method of any suitable clause herein, including the foregoing clauses, wherein the coolant comprises deionized water.|00133| Clause 14. The method of any suitable clause herein, including the foregoing clauses, further comprising generating the vapor by boiling a portion of the immersion cooling reservoir by operating a semiconductor die.

[0134] Clause 15. An apparatus for transferring heat, the apparatus comprising: a housing comprising an inner volume, a first end, a second end, and a wall; the wall at least partially surrounding the inner volume of the housing; a working fluid partially occupying the inner volume of the housing; and a wicking foil disposed within the inner volume of the housing; wherein: the wicking foil, when viewed along a longitudinal axis of the housing, comprises a spiral shape disposed within a portion of the inner volume between the wall and a distance from the longitudinal axis; the distance from the longitudinal axis through a centroid of the housing constitutes apercentage less than 100% of a total distance from the centroid to the wall; and the working fluid comprises at least a liquid phase.

[0135] Clause 16. The apparatus of any suitable clause herein, including the foregoing clauses, wherein the distance from the longitudinal axis comprises at least 60% of the total distance from the longitudinal axis to the wall.

[0136] Clause 17. The apparatus of any suitable clause herein, including the foregoing clauses, wherein the wicking foil comprises a hydrophilic surface treatment.

[0137] Clause 18. The apparatus of any suitable clause herein, including the foregoing clauses, wherein the hydrophilic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

[0138] Clause 19. The apparatus of any suitable clause herein, including the foregoing clauses, wherein the hydrophilic surface treatment comprises a chemical treatment.

[0139] Clause 20. The apparatus of any suitable clause herein, including the foregoing clauses, wherein the working fluid further comprises a gas phase.

[0140] Clause 21. The apparatus of any suitable clause herein, including the foregoing clauses, wherein a plurality of overlapping portions of the wicking foil are separated from each other by between 0.01 mm and 3 mm.

[0141] Clause 22. The apparatus of any suitable clause herein, including the foregoing clauses, wherein the plurality of overlapping portions of the wicking foil are separated from each other by between 0.1 mm and 1 mm.

[0142] Clause 23. A method for transferring heat, the method comprising: transferring heat from a source into a working fluid within a first end of a housing, the housing comprising an inner volume, the first end, a second end, and a wall, wherein the wall at least partially surrounds the inner volume of the housing; causing a liquid portion of the working fluid to boil and transition to a gas phase working fluid; flowing the gas phase working fluid through at least a central portion of the housing; transferring heat out of the gas phase working fluid at the second end and causing the gas phase working fluid to recondense into a liquid phase; flowing the liquid phase working fluid along a wicking foil disposed within the housing from the second end to the first end.

[0143] Clause 24. The method of any suitable clause herein, including the foregoing clauses, wherein: the wicking foil, when viewed along a longitudinal axis of the housing, comprises a spiral shape disposed within a portion of the inner volume between the wall and a distance from the longitudinal axis through a centroid of the housing; and the distance from the longitudinal axis constitutes a percentage less than 100% of a total distance from the longitudinal axis to the wall.

[0144] Clause 25. The method of any suitable clause herein, including the foregoing clauses, wherein the distance from the longitudinal axis comprises at least 60% of the total distance from the longitudinal axis to the wall.

[0145] Clause 26. The method of any suitable clause herein, including the foregoing clauses, wherein the wicking foil comprises a hydrophilic surface treatment.

[0146] Clause 27. The method of any suitable clause herein, including the foregoing clauses, wherein the hydrophilic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

[0147] Clause 28. The method of any suitable clause herein, including the foregoing clauses, wherein the hydrophilic surface treatment comprises a chemical treatment.

[0148] Clause 29. The method of any suitable clause herein, including the foregoing clauses, wherein a plurality of overlapping portions of the wicking foil are separated from each other by between 0.01 mm and 3 mm.

[0149] Clause 30. The method of any suitable clause herein, including the foregoing clauses, wherein the plurality of overlapping portions of the wicking foil are separated from each other by between 0.1 mm and 1 mm.

[0150] Clause 31. A system for vapor redirection, the system comprising: a first semiconductor die disposed at least partially below a second semiconductor die, the first semiconductor die and the second semiconductor die being attached to a printed circuit board (PCB); an immersion cooling liquid in which each of the first semiconductor die, the second semiconductor die, and the PCB is at least partially immersed in the immersion cooling liquid; and a first fin, the first fin being disposed on the first semiconductor die; wherein: the first fin is disposed at an angle of about 30 degrees to about 60 degrees away from a vertical direction.

[0151] Clause 32. The system of any suitable clause herein, including the foregoing clauses, further comprising: a second fin, the second fin being disposed on the second semiconductor die at the angle; and a partially-enclosed plenum attached to the first fin and the second fin.

[0152] Clause 33. The system of any suitable clause herein, including the foregoing clauses, wherein the first fin and the second fin comprise at least one of copper, aluminum, stainless steel, or polycarbonate.

[0153] Clause 34. The system of any suitable clause herein, including the foregoing clauses, wherein the plenum comprises at least one of copper, aluminum, stainless steel, or polycarbonate.

[0154] Clause 35. The system of any suitable clause herein, including the foregoing clauses, further comprising a coating disposed on at least one of the plenum, the first fin, or the second fin; the coating preventing a deposition of an impurity dissolved in the immersion cooling liquid.

[0155] Clause 36. The system of any suitable clause herein, including the foregoing clauses, wherein the plenum comprises an opening at a top portion of the plenum.

[0156] Clause 37. A method of operating a system for vapor redirection, the method comprising: generating, by a first semiconductor die disposed at least partially below a second semiconductor die, bubbles of immersion cooling vapor by transferring heat from the first semiconductor die into an immersion cooling liquid; and laterally displacing, by at least a first fin disposed on the first semiconductor die, the bubbles of immersion cooling vapor; wherein: the first semiconductor die and the second semiconductor die are attached to a printed circuit board (PCB); the first semiconductor die, the second semiconductor die, and the PCB are at least partially immersed in the immersion cooling liquid; the first fin is disposed at an angle away from a vertical direction;the angle is configured such that the bubbles of immersion cooling vapor are laterally displaced by the first fin; and substantially all of the bubbles of immersion cooling vapor float in the vertical direction without contacting the second semiconductor die.

[0157] Clause 38. The method of any suitable clause herein, including the foregoing clauses, wherein: a second fin is disposed on the second semiconductor die at the angle; and a partially- enclosed plenum is attached to the first fin and the second fin.

[0158] Clause 39. The method of any suitable clause herein, including the foregoing clauses, wherein the first fin and the second fin comprise at least one of copper, aluminum, stainless steel, or polycarbonate.

[0159] Clause 40. The method of any suitable clause herein, including the foregoing clauses, wherein the plenum comprises at least one of copper, aluminum, stainless steel, or polycarbonate.

[0160] Clause 41. The method of any suitable clause herein, including the foregoing clauses, further comprising preventing a deposition of an impurity dissolved in the immersion cooling liquid using a coating disposed on at least one of the plenum, the first fin, or the second fin.

[0161] Clause 42. The method of any suitable clause herein, including the foregoing clauses, wherein the plenum comprises an opening at a top portion of the plenum.

[0162] Clause 43. The method of any suitable clause herein, including the foregoing clauses, wherein the angle is between about 30 degrees and about 60 degrees.Conclusion

[0163] 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, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. 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.

[0164] 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 anysuitable 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.

[0165] 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.

[0166] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0167] The phrase “and / or,” as used herein in the specification and in the claims, 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.

[0168] As used herein in the specification and in the claims, “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, when used in the claims, “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,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0169] As used herein in the specification and in the claims, 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 thanone, 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.

[0170] In the claims, as well as 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 semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMS1 . A system for condensing a vapor, the system comprising: a plurality of condenser tubes comprising at least a first condenser tube and a second condenser tube, the first condenser tube being disposed at least partially above the second condenser tube in a direction of gravity; a plurality of baffles comprising at least a first baffle positioned between the first condenser tube and the second condenser tube, such that the first baffle is configured to prevent a first droplet of liquid formed on the first condenser tube from falling onto the second condenser tube; and an immersion cooling reservoir positioned below the plurality of condenser tubes; wherein: the immersion cooling reservoir is configured to collect the first droplet after it falls from the first condenser tube and slides down the first baffle; a bottommost portion of the first baffle extends at least partially below both the first condenser tube and the second condenser tube in the direction of gravity; and the first baffle is sloped such that the first droplet is displaced laterally as well as vertically when the first droplet slides down the first baffle.

2. The system of claim 1, wherein: the plurality of condenser tubes further comprises a third condenser tube and a fourth condenser tube; the third condenser tube is disposed at least partially above a fourth condenser tube; the third condenser tube is laterally separated from the first condenser tube; the fourth condenser tube is laterally separated from the second condenser tube; the plurality of baffles further comprises a second baffle disposed between the third condenser tube and the fourth condenser tube, such that the second baffle is configured to prevent a second droplet of liquid formed on the third condenser tube from falling onto the fourth condenser tube; wherein: a bottommost portion of the second baffle extends at least partially below both the third condenser tube and the fourth condenser tube in the direction of gravity; and the second baffle is sloped such that the second droplet is displaced laterally as well as vertically when the second droplet slides down the second baffle.

3. The system of claim 2, wherein a topmost portion of both the first baffle and the second baffle are in physical contact.

4. The system of claim 1, wherein the plurality of condenser tubes comprise at least one of copper, stainless steel, or aluminum.

5. The system of claim 1, wherein the plurality of baffles comprises at least one of copper, stainless steel, or aluminum.

6. The system of claim 1, further comprising a hydrophobic surface treatment on the plurality of baffles.

7. The system of claim 6, wherein the hydrophobic surface treatment comprises at least one of silane, polytetrafluoroethylene (PTFE), or cerium oxide.

8. The system of claim 6, wherein the hydrophobic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

9. The system of claim 1, wherein further comprising a hydrophobic surface treatment on the plurality of condenser tubes.

10. The system of claim 9, wherein the hydrophobic surface treatment comprises at least one of silane, polytetrafluoroethylene (PTFE), or cerium oxide.

11. The system of claim 9, wherein the hydrophobic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

12. A method of using a system for condensing a vapor, the method comprising: flowing a coolant through a plurality of condenser tubes, the coolant flowing through an interior region of each condenser tube; contacting an exterior surface of each condenser tube with the vapor, the vapor changing from a vapor phase into liquid, the liquid comprising a plurality of liquid droplets formed on the exterior surface of each condenser tube; and collecting the plurality of liquid droplets in an immersion cooling reservoir positioned below the plurality of condenser tubes; wherein: before being collected in the immersion cooling reservoir, each respective liquid droplet falls from the exterior surface of each respective condenser tube without contacting any other condenser tube of the plurality of condenser tubes; and before being collected in the immersion cooling reservoir, each respective liquid droplet either (A) is displaced laterally as well as vertically when sliding down a baffle or (B) falls into the immersion cooling reservoir without contacting any baffle.

13. The method of claim 12, wherein the coolant comprises deionized water.

14. The method of claim 12, further comprising generating the vapor by boiling a portion of the immersion cooling reservoir by operating a semiconductor die.

15. An apparatus for transferring heat, the apparatus comprising: a housing comprising an inner volume, a first end, a second end, and a wall; the wall at least partially surrounding the inner volume of the housing; a working fluid partially occupying the inner volume of the housing; and a wicking foil disposed within the inner volume of the housing; wherein: the wicking foil, when viewed along a longitudinal axis of the housing, comprises a spiral shape disposed within a portion of the inner volume between the wall and a distance from the longitudinal axis; the distance from the longitudinal axis through a centroid of the housing constitutes a percentage less than 100% of a total distance from the centroid to the wall; and the working fluid comprises at least a liquid phase.

16. The apparatus of claim 15, wherein the distance from the longitudinal axis comprises at least 60% of the total distance from the longitudinal axis to the wall.

17. The apparatus of claim 15, wherein the wicking foil comprises a hydrophilic surface treatment.

18. The apparatus of claim 17, wherein the hydrophilic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

19. The apparatus of claim 17, wherein the hydrophilic surface treatment comprises a chemical treatment.

20. The apparatus of claim 15, wherein the working fluid further comprises a gas phase.

21. The apparatus of claim 15, wherein a plurality of overlapping portions of the wicking foil are separated from each other by between 0.01 mm and 3 mm.

22. The apparatus of claim 21, wherein the plurality of overlapping portions of the wicking foil are separated from each other by between 0.1 mm and 1 mm.

23. A method for transferring heat, the method comprising: transferring heat from a source into a working fluid within a first end of a housing, the housing comprising an inner volume, the first end, a second end, and a wall, wherein the wall at least partially surrounds the inner volume of the housing; causing a liquid portion of the working fluid to boil and transition to a gas phase working fluid; flowing the gas phase working fluid through at least a central portion of the housing; transferring heat out of the gas phase working fluid at the second end and causing the gas phase working fluid to recondense into a liquid phase working fluid; andflowing the liquid phase working fluid along a wicking foil disposed within the housing from the second end to the first end.

24. The method of claim 23, wherein: the wicking foil, when viewed along a longitudinal axis of the housing, comprises a spiral shape disposed within a portion of the inner volume between the wall and a distance from the longitudinal axis through a centroid of the housing; and the distance from the longitudinal axis constitutes a percentage less than 100% of a total distance from the longitudinal axis to the wall.

25. The method of claim 24, wherein the distance from the longitudinal axis comprises at least 60% of the total distance from the longitudinal axis to the wall.

26. The method of claim 23, wherein the wicking foil comprises a hydrophilic surface treatment.

27. The method of claim 26, wherein the hydrophilic surface treatment comprises at least one of a surface pattern, a grid defined by repeated volumes of removed material, or cross hatching.

28. The method of claim 26, wherein the hydrophilic surface treatment comprises a chemical treatment.

29. The method of claim 23, wherein a plurality of overlapping portions of the wicking foil are separated from each other by between 0.01 mm and 3 mm.

30. The method of claim 29, wherein the plurality of overlapping portions of the wicking foil are separated from each other by between 0.1 mm and 1 mm.

31. A system for vapor redirection, the system comprising: a first semiconductor die disposed at least partially below a second semiconductor die, the first semiconductor die and the second semiconductor die being attached to a printed circuit board (PCB); an immersion cooling liquid in which each of the first semiconductor die, the second semiconductor die, and the PCB is at least partially immersed in the immersion cooling liquid; and a first fin, the first fin being disposed on the first semiconductor die; wherein: the first fin is disposed at an angle of about 30 degrees to about 60 degrees away from a vertical direction.

32. The system of claim 31 , further comprising:a second fin, the second fin being disposed on the second semiconductor die at the angle; and a partially-enclosed plenum attached to the first fin and the second fin.

33. The system of claim 32, wherein the first fin and the second fin comprise at least one of copper, aluminum, stainless steel, or polycarbonate.

34. The system of claim 32, wherein the plenum comprises at least one of copper, aluminum, stainless steel, or polycarbonate.

35. The system of claim 32, further comprising a coating disposed on at least one of the plenum, the first fin, or the second fin; the coating preventing a deposition of an impurity dissolved in the immersion cooling liquid.

36. The system of claim 32, wherein the plenum comprises an opening at a top portion of the plenum.

37. A method of operating a system for vapor redirection, the method comprising: generating, by a first semiconductor die disposed at least partially below a second semiconductor die, bubbles of immersion cooling vapor by transferring heat from the first semiconductor die into an immersion cooling liquid; and laterally displacing, by at least a first fin disposed on the first semiconductor die, the bubbles of immersion cooling vapor; wherein: the first semiconductor die and the second semiconductor die are attached to a printed circuit board (PCB); the first semiconductor die, the second semiconductor die, and the PCB are at least partially immersed in the immersion cooling liquid; the first fin is disposed at an angle away from a vertical direction; the angle is configured such that the bubbles of immersion cooling vapor are laterally displaced by the first fin; and substantially all of the bubbles of immersion cooling vapor float in the vertical direction without contacting the second semiconductor die.

38. The method of claim 37, wherein: a second fin is disposed on the second semiconductor die at the angle; and a partially-enclosed plenum is attached to the first fin and the second fin.

39. The method of claim 38, wherein the first fin and the second fin comprise at least one of copper, aluminum, stainless steel, or polycarbonate.

40. The method of claim 38, wherein the plenum comprises at least one of copper, aluminum, stainless steel, or polycarbonate.

41. The method of claim 38, further comprising preventing a deposition of an impurity dissolved in the immersion cooling liquid using a coating disposed on at least one of the plenum, the first fin, or the second fin.

42. The method of claim 38, wherein the plenum comprises an opening at a top portion of the plenum.

43. The method of claim 37, wherein the angle is between about 30 degrees and about 60 degrees.

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