Connector for communication having improved signal integrity in immersion cooling environments

Abstract

A connector to facilitate communication between components of a computing system submerged in a coolant liquid of a two-phase immersion cooling environment provides improved signal integrity. This is accomplished by the connector generating and / or maintaining an environment around a communication interface with dielectric properties similar to air. In one example, the connector includes a heater to boil the coolant liquid and, in turn, generate bubbles of coolant vapor that flow near and around electrical contacts in the connector. The bubbles of coolant vapor and the coolant liquid together form a mixture with an effective dielectric constant similar to air. In another example, the connector includes a sealed housing that contains electrical and / or optical connections and a desired fluid, such as air. The sealed housing further prevents infiltration of other fluids, such as the coolant liquid, thus maintaining an environment with desired dielectric properties.

Description

CONNECTOR FOR COMMUNICATION HAVING IMPROVED SIGNAL INTEGRITY IN IMMERSION COOLING ENVIRONMENTSCROSS-REFERENCE TO RELATED APPLICATION(S)|0001] This application claims the priority benefit, under 35 U.S.C. 119(e), of U.S. 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,” and U.S. Application No. 63 / 593,616, filed October 27, 2023 and entitled, “SEALED CONNECTOR ASSEMBLY FOR IMMERSION COOLING SYSTEMS.” Each of the aforementioned applications is incorporated herein by reference in its entirety.BACKGROUND[0002 Two-phase immersion cooling is a liquid cooling technique that utilizes a liquid-to-gas phase transition to remove heat from a heat-generating component, such as a processor or, more generally, an electronic device of a computing system. This is typically accomplished using a tank to submerge the heat-generating component in a pool of coolant liquid where the coolant liquid is a dielectric with a relatively low boiling point (e.g., 50°C). During operation, the coolant liquid in direct contact with the heat-generating component vaporizes (i.e., boils), producing coolant vapor that rises upwards within the tank. The coolant vapor thereafter transfers heat to a heat exchanger disposed above the coolant liquid, thus causing the coolant vapor to condense back to a liquid and thereafter fall into the pool of coolant liquid below. A two-phase immersion cooling system may be used to cool high density computing systems, such as an array of servers in a data center.SUMMARY

[0003] The Inventors have recognized and appreciated two-phase immersion cooling systems provide an energy efficient approach to cool computing systems, especially high-density computing systems. However, the Inventors have also recognized when electrical and / or optical components of a communication interface in a computing system are submerged in coolant liquid, the signal integrity of signals transmitted across these foregoing communication interfaces typically degrades. In some instances, the signal degradation may be so severe that a communication interface is rendered inoperable. High-speed communication interfaces, e.g., interfaces that provide connections directly to a processor or an interposer supporting theprocessor, are particularly susceptible to the adverse effects of signal degradation caused by exposure to the coolant liquid.10004] Herein, the signal integrity refers to the quality of a signal (e.g., an electrical signal, an optical signal), which can degrade as the signal propagates across different media due to noise, distortion, and / or loss. In practice, a signal with a relatively high signal integrity has a lower likelihood or, in some instances, no likelihood of causing an error or failure in the computing system. In contrast, a signal with a relatively low signal integrity is likely to cause an error or failure in the computing system.

[0005] Electrical and optical connections are typically optimized for operation in an environment with a specified dielectric constant to achieve the greatest signal integrity. When electrical and optical connections designed for one environment with a particular dielectric constant are deployed in another environment with an appreciably different dielectric constant, the signal integrity of any signals transmitted by these connections can suffer from appreciable degradation. For immersion cooling systems, the adverse effects on signal integrity are primarily due to the coolant liquid having a higher dielectric constant than air. For example, air has a static dielectric constant of about 1 and fluoroketone, which is a commonly used coolant liquid in two-phase immersion cooling systems, has a static dielectric constant of about 1.8-2.

[0006] Electrical communication interfaces (e.g., Peripheral Component Interconnect Express (PCIe) interface Gen5, an electrical interface that transmits millimeter / micrometer wave signals) are typically configured to have a characteristic impedance that matches the characteristic impedance of the transmission lines coupled at the electrical interface. This is accomplished, in part, by designing the electrical connectors so that the housing and the electrical contacts provide the desired characteristic impedance in the presence of air. When these same electrical connectors are submerged in a coolant liquid and the coolant liquid infiltrates and fills any cavities within the electrical connector or between a pair of mating electrical connectors, the characteristic impedance of the electrical interface changes due to the difference in the dielectric constant between the coolant liquid and air. This, in turn, creates an impedance mismatch between the electrical interface and the transmission lines, resulting in greater reflection losses and a reduction in signal integrity. ]0007{ Optical communication interfaces are even more sensitive to changes in the characteristic impedance that are brought on by alterations to the dielectric constant of the environment when compared to electrical communication interfaces. For example, alterations to the dielectricconstant of the media surrounding a fiber optic connection are often sufficient to inhibit transmission of optical signals across an interface between two mating fiber optic cables.10008] In view of the foregoing limitations, the present disclosure is directed to various inventive implementations of a connector to facilitate communication between components of a computing system that exhibits little to no degradation in signal integrity when submerged in a coolant liquid of an immersion cooling system. Specifically, the connector may generate and / or maintain an environment around the electrical or optical connection with desired dielectric properties to appreciably reduce or, in some instances, eliminate any impedance mismatch in the connection formed by the connector. This may be accomplished in several ways.

[0009] In one non-limiting example, the connector may include a heater to heat and boil the coolant liquid and thus produce bubbles of coolant vapor that flow near and around a communication interface (e.g., electrical contacts of an electrical connector). Compared to the coolant liquid, the bubbles typically have a dielectric constant closer to air (e.g., about 1). As the bubbles move around and past the communication interface of the connector, they displace the coolant liquid in physical contact with components of the communication interface. As a result, at least a portion of the communication interface is in physical contact with the bubbles of coolant vapor. This, in turn, changes the characteristic impedance of the communication interface making it similar to the characteristic impedance when the connector is operating in a gaseous medium (e g., air, an inert gas). In this manner, the difference between the characteristic impedance of the connector in air and in coolant liquid is appreciably reduced and, accordingly, the effect of the coolant liquid on the signal integrity of any signals transmitted by the connector is also appreciably reduced.

[0010] In one aspect, the connectors disclosed herein may include a housing to support the heater and one or more components forming the communication interface (e.g., electrical contacts). The housing may define a housing cavity that contains the heater and at least a portion of the components forming the communication interface. The housing may further include one or more openings that allow coolant liquid to flow into the housing cavity and / or coolant vapor to flow out of the housing cavity. Thus, in some implementations, the housing provides a localized volume of coolant liquid heated by the heater and pathways to vent coolant vapor (e.g., to avoid any pressure build up) and / or maintain a continuous supply of coolant liquid to the housing cavity for boiling.[00111 In another aspect, the connectors disclosed herein may include microstructures on one or more surface(s) to spatially control where boiling of the coolant liquid occurs within the connector. This is accomplished, in part, by the microstructures providing nucleation sites to promote boiling of the coolant liquid. For example, the connector may include a surface with microstructures located directly below the components of the communication interface (e.g., the electrical contact(s)) and in close proximity to the heater such that, during operation, the coolant liquid primarily boils at the microstructures resulting in bubbles rising upwards towards and past the communication interface. The placement of the microstructures may vary based on the orientation of the connector when mounted to a printed circuit board assembly (PCBA) and / or when installed in a two-phase immersion cooling system. The microstructures may include one or more grooves, a microporous structure, a mesh screen, and / or one or more particulates joined together. Moreover, microstructures may be formed on surfaces of various components in the connector including, but not limited to, the housing, the heater, and a boiling plate.

[0012] In another non-limiting example, a sealed connector assembly is disclosed herein that incorporates an electrical connector and / or an optical connector. The sealed connector assembly includes a housing, which when connected to a mating connector of a computing system, forms a sealed cavity. The electrical connector and / or the optical connector is disposed in the cavity together with a desired fluid medium (e.g., air, an inert gas). The seal formed around the cavity may reduce or, in some instances, mitigate the infiltration of external fluids (e.g., the coolant liquid) into the cavity.[001.3] The sealed connector assembly may thus preserve the desired fluid medium around the electrical and / or optical connections. This provides a way to maintain a desired characteristic impedance for the electrical and / or optical communication interface that is independent of the environment surrounding the sealed connector assembly. In this manner, the sealed connector assembly may appreciably reduce or, in some instances, prevent any reduction in signal integrity for any signals transmitted by the sealed connector assembly when the sealed connector assembly is submerged in coolant liquid.

[0014] In one illustrative example, a computing system immersed in a coolant liquid of a two- phase immersion cooling system comprises a PCBA and an electrical connector coupled to the PCBA. The electrical connector comprises a housing defining a housing cavity containing coolant liquid, one or more electrical contacts coupled to the housing, and a heater disposed within thehousing cavity and electrically coupled to at least one electrical contact of the electrical contacts. A method for operating the computing system comprises: A) generating, by the heater, heat to increase a temperature of the coolant liquid within the housing cavity; B) in response to the heat increasing a temperature of the coolant liquid above a liquid-to-gas phase transition temperature associated with the coolant liquid, boiling the coolant liquid; and C) while boiling the coolant liquid, generating a plurality of bubbles of coolant vapor to form a mixture with the coolant liquid near the one or more electrical contacts of the electrical connector. The plurality of bubbles of the coolant vapor has a first dielectric constant less than a second dielectric constant of the coolant liquid.[0015| In one example implementation, a system includes: a two-phase immersion cooling system, including: a tank defining a tank volume configured to contain a coolant liquid; and a computing system disposed within the tank volume and configured for submersion in the coolant liquid, the computing system including: a printed circuit board assembly (PCBA); and an electrical connector electrically coupled to the PCBA, the electrical connector including: a housing defining a housing cavity and having an opening configured for the coolant liquid to enter the housing cavity; a plurality of electrical contacts coupled to the housing; and a heater, at least partially disposed within the housing cavity, configured to boil the coolant liquid and generate a plurality of bubbles of coolant vapor such that: the plurality of bubbles forms a mixture with the coolant liquid near the plurality of electrical contacts; and the mixture has an effective dielectric constant less than a dielectric constant of the coolant liquid.[001.6] The system may further include the coolant liquid disposed in the tank volume of the tank. The coolant liquid may have a liquid-to-gas transition temperature ranging from about 45°C to about 60°C. The coolant liquid may be fluoroketone.

[0017] The heater may be configured to generate the mixture with a volume fraction of bubbles ranging from about 30 vol% to about 70 vol%. The heater may be configured to generate the mixture with the effective dielectric constant ranging from about 1.3 to about 1.7. The heater may receive electrical power from the PCBA. The electrical connector may not include another heater. The heater may be a first heater configured to boil the coolant liquid in a first portion of the housing cavity; and the electrical connector may further include: a second heater, at least partially disposed within the housing cavity, configured to boil the coolant liquid in second portion of the housing cavity, the first and second heaters together generating the plurality of bubbles of coolant vapor.The heater may be disposed below the plurality of electrical contacts such that the plurality of bubbles, when generated, rises up and surrounds the plurality of electrical contacts. The opening may be a first opening; and the housing may have a second opening configured for the plurality of bubbles to escape the housing cavity.[0018| The housing may have a plurality of interior surfaces defining the housing cavity; and at least one interior surface of the plurality of interior surfaces may have a plurality of microstructures providing a plurality of nucleation sites to promote boiling of the coolant liquid. The heater may include at least one surface having a plurality of microstructures providing a plurality of nucleation sites to promote boiling of the coolant liquid. The electrical connector may further include: a boiling plate directly coupled to the heater and configured to be in direct contact with the coolant liquid, the boiling plate including at least one surface having a plurality of microstructures providing a plurality of nucleation sites to promote boiling of the coolant liquid. The plurality of microstructures may be at least one of a plurality of grooves, a microporous structure, a mesh screen, or a plurality of particulates. Each microstructure of the plurality of microstructures may have a characteristic length less than or equal to about 500 pm. Each microstructure of the plurality of microstructures may have a characteristic length less than or equal to about 100 pm. The housing may be formed of a polymer. The housing may be formed of at least one of polybutylene terephthalate (PBT), acrylonitrile butadiene styrene (ABS), polyimide, or liquid-crystal polymer. [0019 The plurality of electrical contacts may include either electrical pins or electrical sockets. The electrical connector may be configured to operate at a frequency band ranging from about 3 GHz to about 30 GHz. The electrical connector may be configured to support a data transmission rate having an upper limit ranging from about 5 gigabits per second to about 50 gigabits per second. The electrical connector may be one of a pin header, a mezzanine connector, an edge card connector, or a backplane connector. The electrical connector may satisfy at least one of a VMEbus International Trade Association (VITA) standard, a Peripheral Component Interconnect Special Interest Group (PCI-SIG) standard, an Institute of Electrical and Electronics Engineers (IEEE) standard, a Joint Test Action Group (JTAG) standard, or a PC / 104 standard. The electrical connector may be directly mounted to the PCBA. The computing system may further include a cable to transmit a signal to or from the PCBA and the electrical connector may be directly coupled to the cable. The electrical connector may be a male connector. The electrical connector may be a female connector.[0020} The electrical connector may be a first electrical connector, the housing may be a first housing, and the plurality of electrical contacts may be a first plurality of electrical contacts; and the computing system may further include: a second electrical connector directly coupled to the first electrical connector, the first electrical connector and the second electrical connector forming an electrical interface, the second electrical connector including: a second housing; and a second plurality of electrical contacts coupled to the second housing, each electrical contact of the second plurality of electrical contacts being electrically coupled to a corresponding electrical contact of the first plurality of electrical contacts. The second electrical connector may not include a heater. The opening may be a first opening and the second housing may include a second opening configured for the plurality of bubbles to escape the housing cavity.[0021} The computing system may further include: a computing device, including: an interposer; a processor mounted to the interposer; and a connector assembly mounted to the interposer, the connector assembly including: a housing mechanically coupled to the interposer and defining a cavity, the housing being sealed to prevent infiltration of the coolant liquid into the cavity; an electrical connector, coupled to the housing and disposed within the cavity, to communicatively couple the connector assembly to the interposer and the processor; and one or more cables, coupled to the housing, configured to communicatively couple the connector assembly to another device.[0022} In another example implementation, a method is disclosed for operating a computing system immersed in a coolant liquid of a two-phase immersion cooling system where the computing system includes: a printed circuit board assembly (PCBA); and an electrical connector coupled to the PCBA, where the electrical connector includes: a housing defining a housing cavity containing the coolant liquid; one or more electrical contacts coupled to the housing; and a heater disposed within the housing cavity and electrically coupled to at least one electrical contact of the one or more electrical contacts. The method includes: generating, by the heater, heat to increase a temperature of the coolant liquid within the housing cavity; in response to the heat increasing a temperature of the coolant liquid above a liquid-to-gas phase transition temperature associated with the coolant liquid, boiling the coolant liquid; and while boiling the coolant liquid, generating a plurality of bubbles of coolant vapor to form a mixture with the coolant liquid near the one or more electrical contacts of the electrical connector, wherein the plurality of bubbles of the coolant vapor has a first dielectric constant less than a second dielectric constant of the coolant liquid.[0023} In another example implementation, an electrical connector configured for a computing system disposed in a coolant liquid of a two-phase immersion cooling system includes: a housing defining a housing cavity and having at least one opening to allow the coolant liquid to at least enter the housing cavity; one or more electrical contacts coupled to the housing; and a heater, disposed within the housing cavity and electrically coupled to at least one electrical contact of the one or more electrical contacts, to generate heat so as to boil the coolant liquid within the housing cavity.10024] The housing may have a plurality of interior surfaces defining the housing cavity; and at least one interior surface of the plurality of interior surfaces may have a plurality of microstructures and may be sufficiently close to the heater such that, during operation, the coolant liquid boils at the plurality of microstructures. The heater may include at least one surface having a plurality of microstructures such that, during operation, the coolant liquid boils at the plurality of microstructures. The electrical connector may further include: a boiling plate, coupled to the housing, having a plurality of microstructures, the boiling plate being positioned sufficiently close to the heater such that, during operation, the coolant liquid boils at the plurality of microstructures. The plurality of microstructures may be at least one of a plurality of grooves, a microporous structure, a mesh screen, or a plurality of particulates. Each microstructure of the plurality of microstructures may have a characteristic length less than or equal to about 500 pm. Each microstructure of the plurality of microstructures may have a characteristic length less than or equal to about 100 pm. The housing may be formed of a polymer. The housing may be formed of at least one of polybutylene terephthalate (PBT), acrylonitrile butadiene styrene (ABS), polyimide, or liquid-crystal polymer. The one or more electrical contacts may be either one or more electrical pins or one or more electrical sockets.[0025} A computing system may include: a printed circuit board assembly (PCBA) having one or more electronic circuit elements and a first electrical connector; and a cable having a second electrical connector coupled to the first electrical connector, wherein the first electrical connector is the electrical connector. A system may include: a two-phase immersion cooling system, including: a tank defining a tank volume; a coolant liquid disposed within the tank volume; and a heat exchanger partially disposed in the tank volume above the coolant liquid; and the computing system immersed in the coolant liquid within the tank volume. During operation, the heater of the first electrical connector may generate heat to boil the coolant liquid and thereby form a pluralityof bubbles; and the plurality of bubbles may form a mixture with the coolant liquid near the one or more electrical contacts of the first electrical connector. A volume fraction of bubbles in the mixture may range from about 30 vol% to about 70 vol%. The heater of the first electrical connector may be located below the one or more electrical contacts of the first electrical connector.

[0026] Inanother example implementation, a system includes: a two-phase immersion cooling system, including: a tank defining a tank volume configured to contain a coolant liquid; and a computing system disposed within the tank volume and configured for submersion in the coolant liquid, the computing system including: a computing device, including: an interposer; a processor mounted to the interposer; and a connector assembly mounted to the interposer, the connector assembly including: a housing mechanically coupled to the interposer and defining a cavity; a seal, disposed between the housing and the interposer, to prevent infiltration of the coolant liquid into the cavity; an electrical connector, coupled to the housing and disposed within the cavity, to communicatively couple the connector assembly to the interposer and the processor; and one or more cables, coupled to the housing, configured to communicatively couple the connector assembly to another device.

[0027] The system may further include the coolant liquid disposed in the tank volume of the tank. The coolant liquid may be fluoroketone. The cavity of the housing may be at a pressure lower than an ambient pressure of an environment surrounding the system. A difference between the pressure and the ambient pressure may range between about 5 pounds per square inch (psi) to about 10 psi. The seal may be sufficient to maintain the pressure for 5 or more years. The cavity of the housing may contain at least one of air or an inert gas. The seal may be formed using at least one of an epoxy, a solder joint, or a cold weld. The seal may include a gasket disposed between the housing and the interposer; and the connector assembly may further include a threaded fastener, to securely couple the connector assembly to the interposer and apply a force to compress the gasket. The connector assembly may further include one or more locking tabs to securely couple the connector assembly to the interposer. The one or more cables may include at least one of a cable with a copper wire or a fiber optic cable. The connector assembly may further include a port to facilitate removal of a fluid from the cavity. The port may include a one-way valve. The port may have a diameter less than or equal to 1 centimeter. The system may further include: a plurality of electrical interconnects, coupled to the interposer, configured to electrically couple the computing device to a substrate, wherein during operation of the computing device: one or more high-speed signals aretransmitted via the one or more cables; and one or more low-speed signals and / or power are transmitted via the plurality of electrical interconnects. The plurality of electrical interconnects may include a ball grid array. The one or more high-speed signals may be transmitted at a first frequency greater than or equal to 10 GHz; and the one or more low-speed signals may be transmitted at a second frequency less than 10 GHz.

[0028] In another example implementation, a computing device includes: an interposer; a processor mounted to the interposer; and a connector assembly mounted to the interposer, the connector assembly including: a housing mechanically coupled to the interposer and defining a cavity; a seal, disposed between the housing and the interposer, to mitigate infiltration of a fluid in an environment surrounding the computing device into the cavity; an electrical connector, coupled to the housing and disposed within the cavity, to communicatively couple the connector assembly to the interposer and the processor; and one or more cables, coupled to the housing, configured to communicatively couple the connector assembly to another device.

[0029] The cavity of the housing may be at a pressure lower than an ambient pressure of the environment. A difference between the pressure and the ambient pressure may range between about 5 pounds per square inch (psi) to about 10 psi. The seal may be sufficient to maintain the pressure for 5 or more years. The cavity of the housing may contain at least one of air or an inert gas. The seal may be formed using at least one of an epoxy, a solder joint, or a cold weld. The seal may include a gasket disposed between the housing and the interposer; and the connector assembly may further include a threaded fastener, to securely couple the connector assembly to the interposer and apply a force to compress the gasket. The connector assembly may further include one or more locking tabs to securely couple the connector assembly to the interposer. The one or more cables may include at least one of a cable with a copper wire or a fiber optic cable. The connector assembly may further include a port to facilitate removal of a fluid from the cavity. The connector assembly may further include: a plurality of electrical interconnects, coupled to the interposer, configured to electrically couple the computing device to a substrate, wherein during operation of the computing device: one or more high-speed signals are transmitted via the one or more cables; and one or more low-speed signals and / or power are transmitted via the plurality of electrical interconnects. The plurality of electrical interconnects may include a ball grid array. The one or more high-speed signals may be transmitted at a first frequency greater than or equal to 10 GHz; and the one or more low-speed signals may be transmitted at a second frequency less than 10 GHz.A system may include: a two-phase immersion cooling system, including: a tank defining a tank volume; coolant liquid disposed within the tank volume; and a heat exchanger partially disposed in the tank volume above the coolant liquid; and the computing device immersed in the coolant liquid within the tank volume.

[0030] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed 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[00311 The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally similar and / or structurally similar elements).[00321 FIG. 1 A shows a bottom perspective view of an example electrical connector.

[0033] FIG. IB shows a top perspective view of the electrical connector of FIG. 1A.

[0034] FIG. 1C shows a cross-sectional side view of the electrical connector of FIG. 1A corresponding to the cross-section A-A in FIG. 1A.

[0035] FIG. ID shows a cross-sectional side view of the electrical connector of FIG. 1A corresponding to the cross-section B-B in FIG. 1A.

[0036] FIG. 2 shows a cross-sectional view of another example electrical connector with a heater.

[0037] FIG. 3A shows a cross-sectional perspective view of the electrical connector of FIG. 1A mounted to a printed circuit board assembly (PCBA) and mated to another electrical connector.

[0038] FIG. 3B shows an example two-phase immersion cooling system with a tank containing the PCBA of FIG. 3A and the electrical connector of FIG. 1A.[0039| FIG. 4A shows an experimental setup to assess the effect of generating bubbles of coolant vapor via boiling of a coolant liquid on the signal integrity of a radio frequency (RF) signal.100401 FIG. 4B shows a chart of the test signal as a function of wavelength obtained at different temperatures of the coolant liquid.[00411 FIG. 5 A shows a perspective view of an example computing device mounted to a substrate (e.g., a printed circuit board).

[0042] FIG. 5B shows a front view of a connector assembly in the computing device of FIG. 5 A. 10043] FIG. 6 shows an example two-phase immersion cooling system with a tank containing the computing device of FIG. 5 A.DETAILED DESCRIPTION]0044] Following below are more detailed descriptions of various concepts related to, and implementations of, a connector to facilitate communication between components of a computing system that increases and / or preserves the signal integrity of any signals carried by the connector when the connector is submerged in a coolant liquid of an immersion cooling system. In one example, a connector may include a heater to facilitate boiling of the coolant liquid. The bubbles of coolant vapor generated by the heater may surround and physically contact the components of the connector that form a communication interface (e.g., electrical contacts), thus providing a fluid medium around the communication interface that has a dielectric constant appreciably smaller than coolant liquid and similar to air or an inert gas. In another example, a sealed connector assembly is disclosed herein that provides a sealed cavity containing components forming a communication interface and a desired fluid medium (e.g., air, an inert gas). The present disclosure is also directed to various inventive methods for using the connector and / or sealed connector assembly in a computing system submerged in a two-phase immersion cooling system. It should be appreciated that various concepts introduced above and discussed in greater detail below may be implemented in multiple ways. Examples of specific implementations and applications are provided primarily for illustrative purposes so as to enable those skilled in the art to practice the implementations and alternatives apparent to those skilled in the art.

[0045] The figures and example implementations described below are not meant to limit the scope of the present implementations to a single embodiment. Other implementations are possible by way of interchange of some or all of the described or illustrated elements. Moreover, where certain elements of the disclosed example implementations may be partially or fully implemented usingknown components, in some instances only those portions of such known components that are necessary for an understanding of the present implementations are described, and detailed descriptions of other portions of such known components are omitted so as not to obscure the present implementations.[0046 In the discussion below, various examples of a connector and / or a connector assembly are provided, wherein a given example or set of examples showcases a housing, an electrical connector (e.g., with one or more electrical contacts), an optical connector, a heater, a boiling plate, a plurality of microstructures (e.g., formed on the boiling plate, the heater, and / or the housing), a port, and a seal. It should be appreciated that one or more features discussed in connection with a given example of a connector or a connector assembly may be employed in other examples of connectors and connector assemblies according to the present disclosure, such that the various features disclosed herein may be readily combined in a given connector or connector assembly according to the present disclosure (provided that respective features are not mutually inconsistent).

[0047] Certain dimensions and features of the connector and the connector assembly are described herein using the terms “approximately,” “about,” “substantially,” and / or “similar.” As used herein, the terms “approximately,” “about,” “substantially,” and / or “similar” indicates that each of the described dimensions or features is not a strict boundary or parameter and does not exclude functionally similar variations therefrom. Unless context or the description indicates otherwise, the use of the terms “approximately,” “about,” “substantially,” and / or “similar” in connection with a numerical parameter indicates that the numerical parameter includes variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.1. An Example Electrical Connector with a Heater

[0048] FIGS. 1A-1D show an example electrical connector 1100a (hereafter referred to as the “connector 1100a”) with heaters 1152 to facilitate boiling of a coolant liquid in a two-phase immersion cooling system. In this non-limiting example, the connector 1100a is a female connector. However, it should be appreciated that, in other implementations, the electrical connectors disclosed herein may be a male connector with a heater.

[0049] As shown, the connector 1100a includes a housing 11 10 supporting an array of electrical contacts 1130. The housing 1110 includes a housing cavity 1111 within which a portion of the electrical contacts 1130 may be disposed and arranged to physically contact correspondingelectrical contacts of a mating electrical connector (e.g., a male electrical connector) inserted through an opening 1114 along an axis 1101. For example, FIG. 1C shows a portion of the electrical contacts 1130 may be disposed along interior surfaces 1112a and 1112b of the housing1110. FIGS. 1A and 1C further show the electrical contacts 1130 may pass through the housing 1110 and include a portion disposed outside the housing cavity 1111 to electrically couple the electrical contacts 1130 to corresponding pin connections on a printed circuit board (PCB) or a printed circuit board assembly (PCBA) (e.g., a PCB with other electronic components mounted thereto). The pin connections may include, for example, a contact pad or a through-hole to securely couple an electrical contact 1130 to the PCB or PCBA, e.g., by soldering the electrical contact 1130 to the pin connection.}0050| FIGS. IB and 1C show the housing cavity 1111 may further include multiple recesses 1113 where each recess 1113 contains a heater 1152. As shown, the heaters 1152 may primarily heat a localized volume of coolant liquid located within the housing cavity 1111. Each heater 1152 may include electrical leads to receive electrical power. For example, the connector 1100a may be mounted to a PCB or a PCBA with pin connections specifically for the electrical leads of the heater 1152. In some implementations, the connector 1100a may also include a boiling plate 1150 coupled to each heater 1152 and disposed within the recess 1113, which provides nucleation sites to facilitate boiling of the coolant liquid at desired locations within the housing cavity 1111, such as along the interior surface 1112c of the housing 1110.[0051J FIG. 1A further shows the housing 1110 may include multiple openings 1120 to allow coolant liquid to enter the housing cavity 1111 and / or coolant vapor (e.g., bubbles of coolant vapor generated when boiling the coolant liquid) to escape the housing cavity 1111. The openings 1120 may help maintain a continuous supply of coolant liquid to the heater, thus reducing or, in some instances, mitigating dry out, which occurs when the coolant liquid is unable to wet the surfaces heated by the heater 1152 due, for example, to an excess amount of coolant vapor in the housing cavity 1111. The openings 1120 may also help maintain a flow of coolant vapor across and around the electrical contacts 1130 in the housing cavity 1111 without accumulating in the housing cavity1111, thus reducing or, in some instances, preventing over pressure (e.g., a buildup of pressure within the housing cavity 1111) from occurring. In some implementations, the openings 1120 may be dimensioned to be sufficiently large to allow coolant liquid and / or coolant vapor to readily pass through without affecting the electromechanical design of the connector 1100a. For example, theopenings 1120 may not appreciably affect the mechanical rigidity of the housing 1 110 or alter the placement or geometry of the electrical contacts 1130.|0052] The openings 1120 may be formed on a portion of the housing 1110 that intersects the interior surface 1112c, as shown in FIGS. IB and ID. Thus, the heaters 1152 may be disposed between the openings 1120, as shown in FIG. IB. However, it should be appreciated that, in some implementations, the openings 1120 may be positioned in different locations on the housing 1110 (e.g., along the interior surfaces 1112a and / or 1112b). This, in turn, may allow relatively fewer heaters 1152 or, in some instances, a single heater 1152 to be used in the connector 1100a.[00531 For example, if the openings 1120 are formed on the sides of the housing 1110 that intersect the interior surfaces 1112a and / or 1112b, the connector 1100a may include a single heater 1152 that spans the length of the housing cavity 1111. In another example, FIG. 2 shows a connector 1100b with a heater 1152 disposed below a housing 1110 and spanning the length of the housing 1110. The heater 1152 may extend into the cavity 1111 of the housing 1110 through one or more openings (not shown) to directly heat coolant liquid within the cavity 1111. The housing 1110 may further include separate openings (e.g., openings 1120) for coolant liquid to enter the cavity 1111. The heater 1152 may be positioned below the electrical contacts 1130 so that bubbles of coolant vapor generated by the heater 1152 may rise up and surround the electrical contacts 1130 during operation.[0054| Returning to the example of the connector 1100a, although FIGS. 1 A-1D show the housing 1110 includes multiple openings 1120, it should be appreciated that, in some implementations, the housing 1110 may only include a single opening 1120. This may depend, in part, on the overall size of the connector 1100a where smaller connectors 1100a may include relatively fewer openings 1120 or, in some instances, a single opening 1120 while relatively larger connectors may include relative more openings 1120.

[0055] During operation, the heater 1152 generates heat to raise the temperature of the coolant liquid within at least the housing cavity 1111 to its liquid-to-gas phase transition temperature (i.e., the boiling point). Once this occurs, the coolant liquid begins to boil, preferably at the nucleation sites provided by the boiling plate 1150. As this occurs, bubbles of coolant vapor are generated and released into the coolant liquid still present in the housing cavity 1111. The bubbles of coolant vapor may then flow towards and around the electrical contacts 1130, thus altering the effective dielectric properties of the medium around the electrical contacts 1130 and, in turn, thecharacteristic impedance and signal integrity of any signals transmitted by the electrical contacts 1130.10056] The bubbles of coolant vapor form a mixture with the coolant liquid in the housing cavity 1111. In some implementations, the volume fraction of the bubbles in the mixture ranges from about 30 vol% to about 70 vol%, including all values and sub-ranges in between. The term “about,” when used to describe the volume fraction of bubbles in the mixture within the housing cavity 1111, is intended to cover fluctuations in the bubble generation rate, the number of bubbles in the housing cavity 1111, the size of the bubbles in the housing cavity 1111, and / or the distribution of bubbles in the housing cavity 1111. For example, “about 50 vol%” may correspond to the following ranges: 49.5 vol% to 50.5 vol% (+ / - 1% variation), 49 vol% to 51 vol% (+ / - 2% variation), 48.5 vol% to 51.5 vol% (+ / - 3% variation), 48 vol% to 52 vol% (+ / - 4% variation), 47.5 vol% to 52.5 vol% (+ / - 5% variation), including all values and sub-ranges in between.

[0057] Accordingly, the mixture of coolant liquid and coolant vapor may have an effective dielectric constant that varies based on the relative proportions of coolant liquid and coolant vapor present. In some implementations, the effective dielectric constant of the mixture ranges from about 1.3 to about 1.7, including all values and sub-ranges in between. The term “about,” when used to describe the effective dielectric constant of the mixture within the housing cavity 1111, is intended to cover fluctuations in the composition of the mixture due to variations in the bubble volume fraction described above. For example, “about 1.3” may correspond to the following ranges: 1.287 to 1.313 (+ / - 1% variation), 1.274 to 1.326 (+ / - 2% variation), 1.261 to 1.339 (+ / - 3% variation), 1.248 to 1.352 (+ / - 4% variation), 1.235 to 1.365 (+ / - 5% variation), including all values and sub-ranges in between.

[0058] The placement of the opening(s) 1120 and / or the recess(es) 1113 and, by extension, the heater(s) 1152 on the housing 1110 may also depend on the orientation of the electrical connector 1100a when mounted to a PCB or a PCBA and installed in a two-phase immersion cooling system. For example, the connector 1100a may be mounted to a PCB with the axis 1101 oriented parallel to a plane of the PCB. The PCB may then be placed in a tank of the two-phase immersion cooling system and immersed in coolant liquid with the PCB oriented vertically (see, for example, FIG. 3B) such that the axis 1101 of the connector 1100a is oriented vertically and the heater(s) 1152 are positioned below the portion of the electrical contacts 1130 within the housing cavity 1111. In this manner, the heater(s) 1152 may boil coolant liquid and generate bubbles that rise upwards towardsthe portion of the electrical contacts 1130 within the housing cavity 111 1. The openings 1120 may also facilitate an upward flow of coolant liquid from the interior surface 1112c into the housing cavity 1111.

[0059] It should be appreciated, however, that in some implementations, the connector 1100a may be mounted to a PCB or PCBA such that the axis 1101 is oriented perpendicular to the plane of the PCB. If the PCB is oriented vertically (i.e., the plane of the PCB is oriented vertically), the axis 1101 is oriented horizontally. Although the heater 1152 is disposed to the side of the electrical contacts 1130, the bubbles generated by the heater 1152 may nevertheless flow towards and surround the electrical contacts 1130 due to the confined geometry of the housing cavity 1111.

[11060] In some implementations, the connector 1100a may have a design that is similar to or, in some instances, the same as conventional electrical connectors typically mounted and / or coupled to a PCB or a PCBA. For example, the connector 1100a may be a multi-pin board-to-board electrical connector, as shown in FIGS. 1A-1D. In another example, the connector may be a bespoke connector for a purpose-built computing system, such as a server rack configured to train a machine learning model (see, for example, the connector 1100b in FIG. 2). More generally, the electrical connectors disclosed herein may be various types of electrical connectors including, but not limited to, a pin header, a mezzanine connector, an edge card connector, and a backplane connector. Moreover, the electrical connector may satisfy various industry standards including, but not limited to, a VMEbus International Trade Association (VITA) standard, a Peripheral Component Interconnect Special Interest Group (PCI-SIG) standard, an Institute of Electrical and Electronics Engineers (IEEE) standard, a Joint Test Action Group (JTAG) standard, and a PC / 104 standard.[006.1] The connector 1100a may also be configured to operate at a particular frequency or range of frequencies. In some implementations, the connector 1100a may be configured to transmit and receive radio frequency (RF) signals. For example, the connector 1100a may operate in the super high frequency band, i.e., from about 3 GHz to about 30 GHz, including all values and sub-ranges in between. In another example, the connector 1100a may operate at a frequency of about 24 GHz. The term “about,” when used to describe the operating frequency of the connector 1100a, is intended to cover the operating bandwidth of a transmitter or a receiver. For example, “about 24 GHz” may correspond to the following ranges: 23.76 GHz to 24.24 GHz (+ / - 1% variation), 23.52 GHz to 24.48 GHz (+ / - 2% variation), 23.28 GHz to 24.72 GHz (+ / - 3% variation), 23.04 GHz to24.96 GHz (+ / - 4% variation), 22.8 GHz to 25.2 GHz (+ / - 5% variation), including all values and sub-ranges in between.10062] The connector 1100a may form part of a high-speed electrical interface. In some implementations, the connector 1100a may support data transmission rates with an upper limit ranging from about 5 gigabits per second (Gbps) to about 50 Gbps, including all values and subranges in between. For example, the data transmission rate may have an upper limit of about 5 Gbps, about 10 Gbps, about 15 Gbps, about 20 Gbps, about 25 Gbps, about 30 Gbps, about 35 Gbps, about 40 Gbps, about 45 Gbps, or about 50 Gbps. The term “about,” when used to describe the upper limit in the data transmission rate supported by the connector 1100a, is intended to cover fluctuations caused, for example, by limitations in other hardware (e.g., available memory, performance of a processor). For example, “about 10 Gbps” may correspond to the following ranges: 9.9 Gbps to 10.1 Gbps (+ / - 1% variation), 9.8 Gbps to 10.2 Gbps (+ / - 2% variation), 9.7 Gbps to 10.3 Gbps (+ / - 3% variation), 9.6 Gbps to 10.4 Gbps (+ / - 4% variation), 9.5 Gbps to 10.5 Gbps (+ / - 5% variation), including all values and sub-ranges in between.[0063 The housing 1110 may be formed from various polymers including, but not limited to, polybutylene terephthalate (PBT), acrylonitrile butadiene styrene (ABS), polyimide, or liquidcrystal polymer. In some implementations, the housing 1110 may be a unitary component and the recess(es) 1113 and the opening(s) 1120 may be integrally formed in the housing 1110. For example, the housing 1110 may be formed via injection molding. In some implementations, the housing 1110 may also support a latching mechanism to facilitate coupling of the electrical connector 1100a to a mating electrical connector. For example, the latching mechanism may include a snap-fit mechanism.

[0064] The connector 1100a may generally include multiple electrical contacts 1130 that each transmit a signal at an electrical interface. The electrical contacts 1130 may include, but are not limited to, a socket, a pin, and the like. Each electrical contact 1130 may include a portion disposed within the housing cavity 1111. In some implementations, each electrical contact 1130 may also include a portion disposed outside the housing 1110 to facilitate attachment to a corresponding pin connection on a PCB or a PCBA (e.g., via soldering). For example, each electrical contact 1130 may include a tab or a pin shaped and / or dimensioned according to the pin connection on the PCB or the PCBA.[0065} The heater(s) 1152 may each be a ceramic heater mounted to the housing 11 10 via an adhesive (e.g., an epoxy). As described above, the heater(s) 1152 may include electrical leads to receive electrical power. The heater(s) 1152 may further be configured to receive a direct current (DC) input via its electrical leads. In some implementations, the electrical leads may be routed through feedthrough openings (not shown) in the housing 1110 for connection to a PCB or a PCBA. In some implementations, the electrical leads may be coupled to electrical contacts (not shown) mounted to the housing 1110 and the electrical contacts, in turn, may be connected to the PCB or the PCBA. During operation, the heater(s) 1152 may receive a constant electrical power input sufficient to increase the temperature of the coolant liquid to its liquid-to-gas phase transition temperature.[0066} The electrical connector 1100a may be configured to boil various coolant liquids used in a two-phase immersion cooling system. In one example, the coolant liquid may be fluoroketone, which has a liquid-to-gas transition temperature (i.e., a boiling point) of 49°C. More generally, the coolant liquid may have a liquid-to-gas transition temperature that ranges from about 45°C to about 60°C, including all values and sub-ranges in between. For example, the liquid-to-gas transition temperature may be 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, or 60°C. The term “about,” when used to describe the liquid-to-gas transition temperature of the coolant liquid, is intended to cover variations in the liquid-to-gas transition temperature that may arise due, for example, to fluctuations in a tank pressure of a two-phase immersion cooling system. For example, “about 50°C” may correspond to the following ranges: 49.5°C to 50.5°C (+ / - 1% variation), 49°C to 51°C (+ / - 2% variation), 48.5°C to 51.5°C (+ / - 3% variation), 48°C to 52°C (+ / - 4% variation), 47.5°C to 52.5°C (+ / - 5% variation), including all values and sub-ranges in between.[0067} The boiling plate 1150 may include microstructures that provide nucleation sites to promote boiling of the coolant liquid. The microstructures may come in various forms including, but not limited to, one or more grooves, a microporous structure, a mesh screen, and / or one or more particulates joined together. For example, the boiling plate 1150 may include a microporous structure formed from copper or a copper alloy. In some implementations, the boiling plate 1150 may include a micro porous copper coating having a thickness ranging from about 50 microns to about 500 microns thick. The copper coating may be produced, for example, by electroplating and / or etching. In another example, the boiling plate 1150 may include a mesh copper layer. In yetanother example, the boiling plate 1150 may include an agglomeration of metallic particles (e.g., copper) sintered together.10068] The microstructures may have a characteristic dimension chosen to facilitate nucleation of a bubble when the coolant liquid reaches its liquid-to-gas phase transition temperature. For example, if the microstructure is a groove, the characteristic dimension may be the width of the groove. In another example, if the microstructure is a pore, the characteristic dimension may be the diameter of the pore. In another example, if the microstructure is a mesh, the characteristic dimension may be the width of an opening in the mesh. In another example, if the microstructure is an agglomeration of particles, the characteristic dimension may be the diameter of a particle.

[11069] In some implementations, the characteristic dimension may be less than or equal to about 500 pm, including all values and sub-ranges in between. More preferably, the characteristic dimension may be less than or equal to about 100 pm, including all values and sub-ranges in between.

[0070] It should be appreciated that the boiling plate is one non-limiting example and that microstructures that provide nucleation sites to facilitate boiling of the coolant liquid may be formed on other components of the connector 1100a. For example, microstructures may be formed on a portion of the housing 1110, e.g., via a postprocessing manufacturing step where a portion of the interior surfaces 1112a-l 112c is roughened. In another example, microstructures may be formed on a portion of the heater 1152. In particular, a surface of the heater 1152 may include a microporous structure.

[0071] Further examples of boiling plates or, more generally, surfaces that provide nucleation sites to facilitate boiling of a coolant liquid in a two-phase immersion cooling system may be found in U.S. Provisional Application No. 63 / 500,167, filed on May 4, 2023 and entitled, “Direct to Chip Heat Spreader and Boiler Enhancement Coatings for Microelectronics,” International PCT Application No. PCT / US2023 / 067745, filed on June 1, 2023 and entitled, “BOILER ENHANCEMENT COATINGS WITH ACTIVE BOILING MANAGEMENT,” and U.S. Provisional Application No. 63 / 506,945, filed on June 8, 2023 and entitled, “Vapor-Shedding Structures for Boiler Plates in Two-Phase Immersion Cooling Systems.” Each of the aforementioned patent applications is incorporated by reference herein in its entirety.1.1 An Example Computing System with the Electrical Connector

[0072] FIG. 3A shows an example computing system 1200 that includes the electrical connector 1100a. As shown, the computing system 1200 may include a PCB 1210 with various electronic components mounted thereto to form a PCB A. The computing system 1200 may include an electrical connector 1100a-l and an electrical connector 1100a-2 mounted directly to the PCB 1210. The electrical connectors 1100a-l and 1100a-2 each correspond to the electrical connector 1100a described above. The heater 1152 in each of the electrical connectors 1100a- 1 and 1100a-2 may be electrically coupled to respective pin connections on the PCB 1210 to receive electrical power during operation.

[0073] The computing system 1200 may include multiple boards that each support various electronic components. The electrical connectors 1100a- 1 and 1100a-2 may facilitate connection between these boards. For example, the electrical connector 1100a-l may be coupled to another board via a mating electrical connector 1300-1. Likewise, the electrical connector 1100a-2 may be coupled to another board via a mating electrical connector 1300-2. In some implementations, the connectors 1300-1 and 1300-2 may each be directly coupled to a cable (see, for example, the cable 1340 in FIG. 3B). Thus, the electrical connectors 1100a-l and 1300-1 may form one electrical interface and the electrical connectors 1100a-2 and 1300-2 may form another electrical interface. In this example, the electrical connectors 1100a-l and 1100a-2 are female connectors, thus the electrical connectors 1300-1 and 1300-2 are male connectors. In particular, FIG. 3A shows the electrical connectors 1300-1 and 1300-2 each include a housing 1310 supporting electrical contacts 1330 that are insertable into the housing cavity 1111 of the electrical connectors 1100a-l and 1100a-2, respectively, to contact corresponding electrical contacts 1130 disposed therein.

[0074] In some implementations, the electrical connectors 1300-1 and 1300-2 may each include one or more openings 1320 that function similar to the openings 1120 on the electrical connector 1100a. In other words, the openings 1320 may allow coolant liquid to enter the housing cavity 1111 through the housing 1310 and / or coolant vapor to escape the housing cavity 1111 through the housing 1310. For example, FIG. 3A shows the electrical connectors 1300-1 and 1300-2 may each include at least one opening 1320 disposed on the side of the housing 1310. This opening 1320 may provide a pathway directly into the housing cavity 1111 through the portion of the housing 1310 supporting the electrical contacts 1330.

[0075] In this example, the electrical connectors 1300-1 and 1300-2 in the computing system 1200 do not include a heater or a boiling plate, thus simplifying the electrical interface. Thus, bubbles of coolant vapor are generated at each electrical interface formed by the pairs of the electrical connectors 1100a-l and 1300-1 and the electrical connectors 1100a-2 and 1300-2 by the combination of the heaters 1152 and the boiling plates 1150. However, it should be appreciated that, in some implementations, the connectors 1300-1 and 1300-2 may each include a heater and / or a boiling plate or, more generally, a surface with microstructures formed thereon to augment the boiling of coolant liquid and / or the generation of bubbles by the connectors 1100a- 1 and 1100a-2.

[0076] FIG. 3B shows an example two-phase immersion cooling system 1400 that includes the computing system 1200 of FIG. 3 A. As shown, the system 1400 includes a tank 1411 defining a tank volume 1412 to contain coolant liquid 1420. The computing system 1200 includes PCBs 1210-1 and 1210-2 with electrical connectors 1100a- 1 and 1100a-2, respectively, which are shown submerged in the coolant liquid 1420. The PCBs 1210-1 and 1210-2 are further connected together via a cable 1340 with electrical connectors 1300-1 and 1300-2. The system 1400 further includes a cooling distribution unit 1413 with a condenser coil 1414 that carries a secondary coolant. The cooling distribution unit 1413 is a non-limiting example of a heat exchanger used to extract heat from the coolant vapor within the tank 1411. The condenser coil 1414 is partially disposed in the tank volume 1412 above the coolant liquid 1420. During operation, the electronic components of the PCBs 1210-1 and 1210-2, including the heaters 1152 in the connectors 1100a-l and 1100a-2, generate heat, which is dissipated to the coolant liquid. When the coolant liquid is sufficiently heated, the coolant liquid vaporizes producing coolant vapor 1421, which rises above into a gas space 1424 within the tank volume 1412 containing a mixture 1423 of air and coolant vapor. As the coolant vapor 1421 physically contacts the condenser coil 1414, heat from the coolant vapor 1421 is transferred to the secondary coolant carried by the condenser coil 1414, thus causing the coolant vapor 1421 to condense to liquid droplets 1422 that falls back into the coolant liquid 1420 below. The secondary coolant is circulated to the cooling distribution unit 1413 where the heat is thereafter dissipated from the secondary coolant.1.2 An Example Demonstration of Using Bubbles to Improve Signal Integrity

[0077] To evaluate the feasibility of the inventive concepts disclosed herein, particularly with respect to the electrical connector 1100a described in Section 1.1, a proof-of-concept experiment was performed, which demonstrated boiling coolant liquid and, in turn, generating bubbles ofcoolant vapor can improve the signal integrity at an electrical interface. For this experiment, an electrical connector assembly was coupled to a pair of electrical cables carrying an RF signal and partially submerged in coolant liquid. The coolant liquid was then boiled and the effect of generating bubbles of coolant vapor around the electrical connector assembly on the signal integrity was evaluated by measuring the attenuation of the RF signal.

[0078] FIG. 4A shows the setup 1500 used for this experiment. As shown, a beaker 1510 containing a small volume of coolant liquid was placed on a hot plate 1520. The hot plate 1520 provided a way to controllably adjust the temperature of the coolant liquid in the beaker (e g., by increasing or decreasing the amount of heat provided). A thermocouple 1530 was placed into the beaker 1510 and coupled to a thermocouple reader (not shown) to monitor the temperature of the coolant liquid. The setup 1500 further included electrical cables 1532 and 1533, which were each coupled to a vector network analyzer 1540 and to each together via an electrical connector assembly 1534. The electrical connector assembly 1534 included a pair of mating SubMiniature version A (SMA) connectors. The electrical connector assembly 1534 was partially submerged in the coolant liquid contained in the beaker 1510. Additionally, the electrical connector assembly 1534 was not sealed, thus coolant liquid was allowed to infiltrate the electrical interface formed by the mating SMA connectors.

[0079] In this experiment, the vector network analyzer 1540 was used, in part, to generate an RF signal, which was transmitted from a first port of the vector network analyzer 1540 coupled to the electrical cable 1532 to a second port of the vector network analyzer 1540 coupled to the electrical cable 1533 via the electrical cables 1532 and 1533 and the electrical connector assembly 1534. If an impedance mismatch was present between the electrical connector assembly 1534 and the electrical cables 1532 and 1533, the RF signal transmitted across the electrical connector assembly 1534 and received at the second port of the vector network analyzer 1540 was attenuated. As described above, an impedance mismatch may occur if the characteristic impedance of the electrical connector assembly 1534 is different from the characteristic impedances of the electrical cables 1532 and 1533. Further, the characteristic impedance of the electrical connector assembly 1534 depends, in part, on the dielectric constant of the medium surrounding the electrical connector assembly 1534.

[0080] Thus, any alterations to the medium surrounding the electrical connector assembly 1534 is detected in the setup 1500 by measuring variations in the attenuation of the RF signal using thevector network analyzer 1540. In this manner, the setup 1500 provided a way to evaluate whether generating bubbles of coolant vapor around the electrical connector assembly 1534 is a feasible way of improving signal integrity.100811 FIG. 4B shows the attenuation of the measured RF signal as a function of frequency with different lines corresponding to different temperatures of coolant liquid. For this experiment, the coolant liquid was fluoroketone, which has a liquid-to-gas transition temperature of 49°C. As shown, the attenuation of the RF signal decreased slightly across all measured frequencies as the temperature of the coolant liquid increased from 28°C to 42°C. However, when the temperature of the coolant liquid reached 49° and boiling of the coolant liquid was observed, the attenuation exhibited an appreciable decrease across the measured range of frequencies. This includes the frequency of 24 GHz, which is the frequency at which the electrical connector 1100a may be designed to operate at, as described in Section 1. These results clearly show boiling coolant liquid and generating bubbles appreciably affect the characteristic impedance of an electrical interface and may be used to improve the signal integrity of RF signals transmitted across the electrical interface by altering the medium surrounding the electrical interface such that it’s dielectric constant is more similar to air.2. An Example Sealed Connector Assembly

[0082] FIG. 5 A shows a computing system 2100 with an example sealed connector assembly 2140. As shown, the computing system 2100 may include a computing device 2120 with a processor 2122 mounted to an interposer 2124. The processor 2122 may be a chip with an integrated circuit. For example, the processor 2122 may include, but is not limited to, a computer processor unit (CPU), a graphics processor unit (GPU), a data processing unit (DPU), a field- programmable gate array (FPGA), an application-specific integrated circuit (ASIC), and memory (e.g., rapid access memory).

[0083] The interposer 2124 provides an electrical interface to communicatively couple the processor 2122 to a substrate 2110. The interposer 2124 may be a printed circuit board (PCB) that is mechanically and electrically coupled to the processor 2122. The processor 2122 may be electrically coupled to the interposer 2124 via a plurality of electrical interconnects (not shown) that includes, but is not limited to, a pin grid array, a land grid array, and a ball grid array. The substrate 2110 may also be a PCB, such as a motherboard or, more generally, a PCB assembly (PCBA). As shown in FIG. 5A, the interposer 2124 may be coupled to the substrate 2110 via aball grid array (BGA) 2126 where each ball in the BGA 2126 provides an electrical connection to transmit an electrical signal to and from the computing device 2120. It should be appreciated, however, that the BGA 2126 is a non-limiting example and that the computing device 2120 may be electrically coupled to the substrate 2110 via other types of electrical interconnects, such as a pin grid array, or a land grid array.

[0084] The sealed connector assembly 2140 (also referred to herein as the “connector assembly 2140”) may be co-packaged with the computing device 2120. In one example, FIG. 5A shows the connector assembly 2140 may be directly mounted to the interposer 2124. Thus, the connector assembly 2140 may provide one or more electrical connections that are separate from the electrical connections of the BGA 2126. For instance, the connector assembly 2140 may include one or more cables 2154 to facilitate connection to one or more devices, e.g., device(s) that form part of the computing system 2100 and / or device(s) that are external to the computing system 2100. These devices may include, but are not limited to, a network switch and a graphics processor unit (GPU). The cable(s) 2154 may include a copper wire cable configured to carry an electrical signal and / or a fiber optic cable configured to carry an optical signal.

[0085] By incorporating the connector assembly 2140 directly into the package of the computing device 2120, the connector assembly 2140 may provide higher-speed and / or lower latency electrical connections compared to the electrical connections of the BGA 2126. Accordingly, in some implementations, the computing system 2100 may be configured to transmit electrical power and / or low-speed signals (e.g., telemetry signals) to and from the processor 2122 using the BGA 2126 and high-speed signals to and from the processor 2122 using the connector assembly 2140. In some implementations, a low-speed signal is a signal transmitted at a frequency less than 10 GHz. In some implementations, a high-speed signal is a signal transmitted at a data rate greater than or equal to 10 GHz.

[0086] It should be appreciated that the connector assembly 2140 in FIG. 5A is a non-limiting example. In some implementations, the connector assemblies disclosed herein may be mounted directly onto the processor 2122. For example, the connector assembly may include one or more electrical interconnects that directly couple to the processor 2122. In other words, the connector assembly may transmit signals to and from the processor 2122 without going through an interposer 2124 and / or electrical interconnects that couple the processor 2122 to the interposer 2124. In someimplementations, the connector assembly may be integrated onto the processor 2122 as an inpackage connector.10087J FIG. 5B shows a magnified view of the connector assembly 2140. As shown, the connector assembly 2140 may include a housing 2142 that defines a cavity 2143. The connector assembly 2140 further includes a connector 2146 disposed within the cavity 2143 and mounted to the housing 2142. The connector 2146 communicatively couples the connector assembly 2140 to the interposer 2124. For example, the interposer 2124 may include a corresponding connector (not shown) that mates with the connector 2146. Additionally, the cable(s) 2154 may be mounted to the housing 2142 and coupled to the connector 2146 to facilitate the transmission of signal(s) to and from the interposer 2124 via the connector 2146.

[0088] The housing 2142 may be formed from various materials including, but not limited to, aluminum, stainless steel, polybutylene terephthalate (PBT), Nylon 66, polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polycyclohexylenedimethylene terephthalate (PCT), liquid crystalline polymer (LCP), FR-4, and polyimide. In some implementations, the material for the housing 2142 may be selected based on its chemical compatibility with a coolant liquid of a two-phase immersion cooling system. The material may also be selected based on the manner in which the housing 2142 is mechanically coupled and sealed to the computing device 2120, which is discussed in further detail below.[0089| In one non-limiting example, the connector 2146 may be a differential pair connector, such as a mezzanine connector. More generally, the connector 2146 may be any standardized or nonstandardized electrical connector with one or more electrical pins and / or sockets. In some implementations, the connector 2146 may be electrically coupled to one or more copper wires in the cable(s) 2154 to facilitate the transmission of electrical signal(s) to and from the computing device 2120 via the connector assembly 2140. In some implementations, the connector 2146 may be electrically coupled to one or more fiber optic cables in the cable(s) 2154 to facilitate the transmission of optical signal(s) to and from the computing device 2120 via the connector assembly 2140. This may be accomplished, for example, by the connector assembly 2140 including various electronic components to facilitate the conversion of an electrical signal to an optical signal and / or an optical signal to an electrical signal, such as a light source (e.g., a light emitting diode), and / or a photodetector.[0090J The cavity 2143 is sealed when the connector assembly 2140 is coupled to the interposer 2124, thus reducing or, in some instances, preventing the infdtration of external fluids into the cavity 2143. For example, if the computing system 2100 is submerged in a coolant liquid (see, for example, FIG. 6), the cavity 2143 may be sufficiently sealed to prevent the infiltration of coolant liquid into the cavity 2143. The coupling between the connector 2146 and the cables 2154 may also be encapsulated within the housing 2142 (e.g., within the cavity 2143 or another cavity of the housing 2142) to limit or, in some instances, prevent the exposure of the electrical and / or optical communication interfaces formed between the connector 2146 and the cables 2154 to external fluid, such as the coolant liquid. In this manner, any undesirable changes to the characteristic impedance of the connector 2146 and / or the coupling between the connector 2146 and the cable(s) 2154 that may otherwise arise due to the exposure to coolant liquid is appreciably mitigated, thus preserving the signal integrity of signals transmitted by the connector assembly 2140.] 00911 In some implementations, the seal may be formed using a compliant gasket. For example, FIG. 5B shows the connector assembly 2140 includes a gasket 2144 disposed near the periphery of the cavity 2143. When the connector assembly 2140 is coupled to the interposer 2124, the gasket 2144 may be compressed between the connector housing 2142 and the interposer 2124 to form a seal around the cavity 2143.[00921 The compression of the gasket 2144 may be accomplished in several ways. In one example, FIG. 5B shows the connector assembly 2140 may include one or more locking tabs 2148 to securely couple the connector assembly 2140 to the interposer 2124. The locking tab(s) 2148 may form, for example, a snap-fit mechanism where the locking tab(s) 2148 are inserted into corresponding receptacles formed on the interposer 2124 and include structural features to retain the locking tab(s) 2148 in the respective receptacles. The locking tab(s) 2148 may generate a retaining force when coupled to the receptacles of the interposer 2124. The retaining force, in turn, may cause a surface of the housing 2142 to press the gasket 2144 against a surface of the interposer 2124 when the connector assembly 2140 is coupled to the interposer 2124. In another example, one or more threaded fasteners (e.g., screw fasteners, bolt fasteners) may be used to securely couple the housing 2142 to the interposer 2124. The fasteners may be arranged such that, when tightened, a compressive force is similarly generated that causes a surface of the housing 2142 to press the gasket 2144 against a surface of the interposer 2124.

[0093] In both of the above examples, the connector assembly 2140 may be removably coupled to the interposer 2124. This, in turn, may allow the connector assembly 2140 and, more generally, the computing system 2100 to be more easily serviced and / or maintained. For example, the connector assembly 2140 may be readily removed and / or replaced with another connector assembly 2140 by actuating the locking tab(s) 2148 and / or loosening the fastener(s).

[0094] The gasket 2144 may be formed of a material that is chemically compatible with the coolant liquid of a two-phase immersion cooling system, such as fluoroketone. The gasket 2144 may be formed from various materials including, but not limited to, ethylene propylene diene terpolymer (EDPM), polytetrafluoroethylene (PTFE), and silicon-free polymers. It should be appreciated that the connector assembly 2140 is not limited to a single gasket 2144. In some implementations, the connector assembly 2140 may include multiple gaskets to further reduce the likelihood of any external fluid infiltrating the cavity 2143. For example, the gaskets may be arranged in a concentric manner, so that each gasket forms a barrier that separates the cavity 2143 from any external fluids around the connector assembly 2140, thus further reducing the likelihood of an external fluid infiltrating the cavity 2143 during operation.

[0095] It should be appreciated that the formation of a seal using a gasket is a non-limiting example. In some implementations, the seal may be formed by joining the connector assembly 2140 to the interposer 2124 in a semi -permanent or, in some instances, permanent manner. For example, the housing 2142 may be attached to the interposer 2124 via epoxy. The epoxy may be applied along the periphery of the housing 2142 to join the housing 2142 to the interposer 2124. In another example, the housing 2142 may be attached to the interposer 2124 via a solder joint, a brazing joint, and / or a weld joint. In this example, at least a portion of the interposer 2124 and at least the portion of the housing 2142 that physically contacts the portion of the interposer 2124 may be formed of metal to improve adhesion with the solder joint, the brazing joint, and / or the weld joint. In yet another example, the housing 2142 may be attached to the interposer 2124 via a cold weld. For instance, the housing 2142 may include one or more metallic plugs that are inserted into corresponding metallic receptacles on the interposer 2124 when connecting the connector assembly 2140 to the interposer 2124. When the plugs are inserted into the receptacles, the plugs may be plastically deformed and forced into physical contact with the receptacles, resulting in a cold weld.]0096] The cavity 2143 may contain a fluid that does not appreciably affect the characteristic impedance of the connections formed by the connector 2146 with the interposer and / or the cable(s) 2154. For example, the cavity 2143 may be configured to contain air, an inert gas (e.g., argon, nitrogen), or a mixture of air and an inert gas. The composition of the fluid within the cavity 2143 may be controlled, in part, by attaching the connector assembly 2140 to the interposer 2124 in an environment containing the desired fluid. For example, the connector assembly 2140 may be attached to the interposer 2124 in an air environment to form a sealed cavity 2143 containing air. Thereafter, the computing system 2100 may be submerged in coolant liquid with air remaining in the cavity 2143.

[0097] The cavity 2143 may be depressurized to create a low vacuum environment, i.e., the pressure within the cavity 2143 may be decreased with respect to the ambient pressure of the environment. A low vacuum environment within the cavity 2143 may provide several benefits including, but not limited to, a lower dielectric permittivity and a lower dissipation factor, and a compression seal due to the pressure difference between the cavity 2143 and the ambient environment. The cavity 2143 may be configured to have a pressure that is less than the ambient pressure of the environment where the difference between the pressure in the cavity 2143 and the ambient pressure ranges from about 5 pounds per square inch (psi) to about 10 psi. The pressure in the cavity 2143 may be controlled, in part, using a port 2152 mounted to the housing 2142. After the connector assembly 2140 is coupled to the interposer 2124, the port 2152 may facilitate the removal of fluid from the cavity 2143. For example, the port 2152 may include a one-way valve that is arranged to only allow fluid to flow out of the cavity 2143 (and not into the cavity 2143). A pump (not shown) may be inserted into the port 2152 and activated to withdraw fluid from the cavity 2143, thus decreasing the pressure. The port 2152 may be sufficiently small to be mounted directly to the housing 2142. For example, the port 2152 may have a diameter less than or equal to 1 centimeter.

[0098] In some implementations, the port 2152 may also provide a way to evaluate the quality of the seal formed between the connector assembly 2140 and the interposer 2124. For example, the connector assembly 2140 may be mounted to the interposer 2124 in an air environment as described above. Thereafter, the port 2152 may be used to withdraw air from the cavity 2143 to create a low vacuum environment within the cavity 2143. A helium leak test may then be performed. A helium gas detector (e.g., a mass spectrometer) may be coupled to the port 2152 todetect the presence of helium within the cavity 2143. The computing system 2100 may then be placed within an environment containing primarily helium gas. This may be accomplished, for example, using a hermetically sealed chamber or a glove box. The detector may thereafter measure a flow rate of helium from the cavity 2143 to the detector for a predetermined period of time (e.g., hours, days). If, during this period of time, the detector is unable to measure a flow rate of helium above a predetermined threshold flow rate, the connector assembly 2140 may be considered sufficiently sealed. Otherwise, if the detector measures a flow rate of helium above the predetermined threshold flow rate, this may indicate the seal was not properly formed. Accordingly, the connector assembly 2140 may be removed and reattached to establish a better seal and / or replaced with another connector assembly 2140. The predetermined threshold flow rate may be defined to be IO-8cubic centimeters (cc) per sec per atmosphere (atm).

[0099] For the connector assemblies disclosed herein, the seal formed when the connector assembly is mounted to the interposer 2124 may be of sufficient quality to maintain the desired composition of fluid and / or pressure within the cavity 2143 for a desired period of time. In some implementations, this period of time may range from about 5 years to about 10 years.

[0100] FIG. 6 shows an example two-phase immersion cooling system 2200 that includes the computing system 2100 of FIG. 5 A. As shown, the system 2200 includes a tank 2211 defining a tank volume 2212 to contain coolant liquid 2220. The substrate 2110, the interposer 2124, the processor 2122, and the connector assembly 2140 are further shown submerged in the coolant liquid 2220 (e g., fluoroketone). The system 2200 further includes a cooling distribution unit 2213 with a condenser coil 2214 that carries a secondary coolant. The condenser coil 2214 is partially disposed in the tank volume 2212 above the coolant liquid 2220. During operation, the electronic components of the computing system 2100 generates heat, which is dissipated to the coolant liquid 2220. When the coolant liquid 2220 is sufficiently heated, the coolant liquid 2220 vaporizes producing coolant vapor 2221, which rises above into a gas space 2224 within the tank volume 2212 containing a mixture 2223 of air and coolant vapor 2221. As the coolant vapor 2221 physically contacts the condenser coil 2214, heat from the coolant vapor 2221 is transferred to the secondary coolant carried by the condenser coil 2214, thus causing the coolant vapor 2221 to condense to liquid droplets 2222 that falls back into the coolant liquid 2220 below. The secondary coolant is circulated to the cooling distribution unit 2213 where the heat is thereafter dissipated from the secondary coolant.3. Conclusion[0101 J All parameters, dimensions, materials, and configurations described herein are meant to be example and the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the inventive teachings is / are used. It is to be understood that the foregoing embodiments are presented primarily by way of example 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.[(IIO2| 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. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of respective elements of the example implementations without departing from the scope of the present disclosure. The use of a numerical range does not preclude equivalents that fall outside the range that fulfill the same function, in the same way, to produce the same result.

[0103] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0104] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety.

[0105] 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.

[0106] 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.”

[0107] 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 areconjunctively 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.[0108} 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.

[0109] 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 than one, B, with no A present (and optionally including elements other than A); in yet anotherembodiment, 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.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, comprising: a two-phase immersion cooling system, comprising: a tank defining a tank volume configured to contain a coolant liquid; and a computing system disposed within the tank volume and configured for submersion in the coolant liquid, the computing system comprising: a printed circuit board assembly (PCBA); and an electrical connector electrically coupled to the PCBA, the electrical connector comprising: a housing defining a housing cavity and having an opening configured for the coolant liquid to enter the housing cavity; a plurality of electrical contacts coupled to the housing; and a heater, at least partially disposed within the housing cavity, configured to boil the coolant liquid and generate a plurality of bubbles of coolant vapor such that: the plurality of bubbles forms a mixture with the coolant liquid near the plurality of electrical contacts; and the mixture has an effective dielectric constant less than a dielectric constant of the coolant liquid.

2. The system of claim 1, further comprising: the coolant liquid disposed in the tank volume of the tank.

3. The system of claim 2, wherein the coolant liquid has a liquid-to-gas transition temperature ranging from about 45°C to about 60°C.

4. The system of claim 2, wherein the coolant liquid is fluoroketone.

5. The system of claim 1, wherein the heater is configured to generate the mixture with a volume fraction of bubbles ranging from about 30 vol% to about 70 vol%.

6. The system of claim 1 , wherein the heater is configured to generate the mixture with the effective dielectric constant ranging from about 1.3 to about 1.7.

7. The system of claim 1, wherein the heater receives electrical power from the PCBA.

8. The system of claim 1, wherein the electrical connector does not include another heater.

9. The system of claim 1, wherein: the heater is a first heater configured to boil the coolant liquid in a first portion of the housing cavity; and the electrical connector further comprises: a second heater, at least partially disposed within the housing cavity, configured to boil the coolant liquid in second portion of the housing cavity, the first and second heaters together generating the plurality of bubbles of coolant vapor.

10. The system of claim 1, wherein the heater is disposed below the plurality of electrical contacts such that the plurality of bubbles, when generated, rises up and surrounds the plurality of electrical contacts.

11. The system of claim 1, wherein: the opening is a first opening; and the housing has a second opening configured for the plurality of bubbles to escape the housing cavity.

12. The system of claim 1, wherein: the housing has a plurality of interior surfaces defining the housing cavity; and at least one interior surface of the plurality of interior surfaces has a plurality of microstructures providing a plurality of nucleation sites to promote boiling of the coolant liquid.

13. The system of claim 1 , wherein the heater includes at least one surface having a plurality of microstructures providing a plurality of nucleation sites to promote boiling of the coolant liquid.

14. The system of claim 1, wherein the electrical connector further comprises: a boiling plate directly coupled to the heater and configured to be in direct contact with the coolant liquid, the boiling plate including at least one surface having a plurality of microstructures providing a plurality of nucleation sites to promote boiling of the coolant liquid.

15. The system of claim as in one of claims 12-14, wherein the plurality of microstructures is at least one of a plurality of grooves, a microporous structure, a mesh screen, or a plurality of particulates.

16. The system of claim as in one of claims 12-14, wherein each microstructure of the plurality of microstructures has a characteristic length less than or equal to about 500 pm.

17. The system of claim as in one of claims 12-14, wherein each microstructure of the plurality of microstructures has a characteristic length less than or equal to about 100 pm.

18. The system of claim 1, wherein the housing is formed of a polymer.

19. The system of claim 1, wherein the housing is formed of at least one of polybutylene terephthalate (PBT), acrylonitrile butadiene styrene (ABS), polyimide, or liquid-crystal polymer.

20. The system of claim 1, wherein the plurality of electrical contacts comprises either electrical pins or electrical sockets.

21. The system of claim 1, wherein the electrical connector is configured to operate at a frequency band ranging from about 3 GHz to about 30 GHz.

22. The system of claim 1, wherein the electrical connector is configured to support a data transmission rate having an upper limit ranging from about 5 gigabits per second to about 50 gigabits per second.

23. The system of claim 1, wherein the electrical connector is one of a pin header, a mezzanine connector, an edge card connector, or a backplane connector.

24. The system of claim 1, wherein the electrical connector satisfies at least one of a VMEbus International Trade Association (VITA) standard, a Peripheral Component Interconnect Special Interest Group (PCI-SIG) standard, an Institute of Electrical and Electronics Engineers (IEEE) standard, a Joint Test Action Group (JTAG) standard, or a PC / 104 standard.

25. The system of claim 1, wherein the electrical connector is directly mounted to the PCBA.

26. The system of claim 1, wherein: the computing system further comprises a cable to transmit a signal to or from the PCBA; and the electrical connector is directly coupled to the cable.

27. The system of claim 1, wherein the electrical connector is a male connector.

28. The system of claim 1, wherein the electrical connector is a female connector.

29. The system of claim 1, wherein: the electrical connector is a first electrical connector, the housing is a first housing, and the plurality of electrical contacts is a first plurality of electrical contacts; and the computing system further comprises: a second electrical connector directly coupled to the first electrical connector, the first electrical connector and the second electrical connector forming an electrical interface, the second electrical connector comprising: a second housing; anda second plurality of electrical contacts coupled to the second housing, each electrical contact of the second plurality of electrical contacts being electrically coupled to a corresponding electrical contact of the first plurality of electrical contacts.

30. The system of claim 29, wherein the second electrical connector does not include a heater.

31. The system of claim 29, wherein: the opening is a first opening; and the second housing includes a second opening configured for the plurality of bubbles to escape the housing cavity.

32. The system of claim 1, wherein the computing system further comprises: a computing device, comprising: an interposer; a processor mounted to the interposer; and a connector assembly mounted to the interposer, the connector assembly comprising: a housing mechanically coupled to the interposer and defining a cavity, the housing being sealed to prevent infiltration of the coolant liquid into the cavity; an electrical connector, coupled to the housing and disposed within the cavity, to communicatively couple the connector assembly to the interposer and the processor; and one or more cables, coupled to the housing, configured to communicatively couple the connector assembly to another device.

33. A method for operating a computing system immersed in a coolant liquid of a two-phase immersion cooling system, the computing system comprising: a printed circuit board assembly (PCBA); and an electrical connector coupled to the PCBA, the electrical connector comprising:a housing defining a housing cavity containing the coolant liquid; one or more electrical contacts coupled to the housing; and a heater disposed within the housing cavity and electrically coupled to at least one electrical contact of the one or more electrical contacts, the method comprising: generating, by the heater, heat to increase a temperature of the coolant liquid within the housing cavity; in response to the heat increasing a temperature of the coolant liquid above a liquid-to-gas phase transition temperature associated with the coolant liquid, boiling the coolant liquid; and while boiling the coolant liquid, generating a plurality of bubbles of coolant vapor to form a mixture with the coolant liquid near the one or more electrical contacts of the electrical connector, wherein the plurality of bubbles of the coolant vapor has a first dielectric constant less than a second dielectric constant of the coolant liquid.

34. An electrical connector configured for a computing system disposed in a coolant liquid of a two-phase immersion cooling system, the electrical connector comprising: a housing defining a housing cavity and having at least one opening to allow the coolant liquid to at least enter the housing cavity; one or more electrical contacts coupled to the housing; and a heater, disposed within the housing cavity and electrically coupled to at least one electrical contact of the one or more electrical contacts, to generate heat so as to boil the coolant liquid within the housing cavity.

35. The electrical connector of claim 34, wherein: the housing has a plurality of interior surfaces defining the housing cavity; and at least one interior surface of the plurality of interior surfaces has a plurality of microstructures and is sufficiently close to the heater such that, during operation, the coolant liquid boils at the plurality of microstructures.

36. The electrical connector of claim 34, wherein the heater includes at least one surface having a plurality of microstructures such that, during operation, the coolant liquid boils at the plurality of microstructures.

37. The electrical connector of claim 34, further comprising: a boiling plate, coupled to the housing, having a plurality of microstructures, the boiling plate being positioned sufficiently close to the heater such that, during operation, the coolant liquid boils at the plurality of microstructures.

38. The electrical connector as in one of claims 35-37, wherein the plurality of microstructures is at least one of a plurality of grooves, a microporous structure, a mesh screen, or a plurality of particulates.

39. The electrical connector as in one of claims 35-37, wherein each microstructure of the plurality of microstructures has a characteristic length less than or equal to about 500 pm.

40. The electrical connector as in one of claims 35-37, wherein each microstructure of the plurality of microstructures has a characteristic length less than or equal to about 100 pm.

41. The electrical connector of claim 34, wherein the housing is formed of a polymer.

42. The electrical connector of claim 34, wherein the housing is formed of at least one of polybutylene terephthalate (PBT), acrylonitrile butadiene styrene (ABS), polyimide, or liquidcrystal polymer.

43. The electrical connector of claim 34, wherein the one or more electrical contacts are either one or more electrical pins or one or more electrical sockets.

44. A computing system, comprising: a printed circuit board assembly (PCBA) having one or more electronic circuit elements and a first electrical connector; anda cable having a second electrical connector coupled to the first electrical connector, wherein the first electrical connector is the electrical connector of claim 34.

45. A system, comprising: a two-phase immersion cooling system, comprising: a tank defining a tank volume; a coolant liquid disposed within the tank volume; and a heat exchanger partially disposed in the tank volume above the coolant liquid; and the computing system of claim 44 immersed in the coolant liquid within the tank volume.

46. The system of claim 45, wherein: during operation, the heater of the first electrical connector generates heat to boil the coolant liquid and thereby form a plurality of bubbles; and the plurality of bubbles forms a mixture with the coolant liquid near the one or more electrical contacts of the first electrical connector.

47. The system of claim 46, wherein a volume fraction of bubbles in the mixture ranges from about 30 vol% to about 70 vol%.

48. The system of claim 45, wherein the heater of the first electrical connector is located below the one or more electrical contacts of the first electrical connector.

49. A system, comprising: a two-phase immersion cooling system, comprising: a tank defining a tank volume configured to contain a coolant liquid; and a computing system disposed within the tank volume and configured for submersion in the coolant liquid, the computing system comprising: a computing device, comprising: an interposer; a processor mounted to the interposer; anda connector assembly mounted to the interposer, the connector assembly comprising: a housing mechanically coupled to the interposer and defining a cavity; a seal, disposed between the housing and the interposer, to prevent infiltration of the coolant liquid into the cavity; an electrical connector, coupled to the housing and disposed within the cavity, to communicatively couple the connector assembly to the interposer and the processor; and one or more cables, coupled to the housing, configured to communicatively couple the connector assembly to another device.

50. The system of claim 49, further comprising: the coolant liquid disposed in the tank volume of the tank.

51. The system of claim 50, wherein the coolant liquid is fluoroketone.

52. The system of claim 49, wherein the cavity of the housing is at a pressure lower than an ambient pressure of an environment surrounding the system.

53. The system of claim 52, wherein a difference between the pressure and the ambient pressure ranges between about 5 pounds per square inch (psi) to about 10 psi.

54. The system of claim 52, wherein the seal is sufficient to maintain the pressure for 5 or more years.

55. The system of claim 49, wherein the cavity of the housing contains at least one of air or an inert gas.

56. The system of claim 49, wherein the seal is formed using at least one of an epoxy, a solder joint, or a cold weld.

57. The system of claim 49, wherein: the seal comprises a gasket disposed between the housing and the interposer; and the connector assembly further comprises a threaded fastener, to securely couple the connector assembly to the interposer and apply a force to compress the gasket.

58. The system of claim 49, wherein the connector assembly further comprises: one or more locking tabs to securely couple the connector assembly to the interposer.

59. The system of claim 49, wherein the one or more cables comprises at least one of a cable with a copper wire or a fiber optic cable.

60. The system of claim 49, wherein the connector assembly further comprises: a port to facilitate removal of a fluid from the cavity.

61. The system of claim 60, wherein the port comprises a one-way valve.

62. The system of claim 60, wherein the port has a diameter less than or equal to 1 centimeter.

63. The system of claim 49, further comprising: a plurality of electrical interconnects, coupled to the interposer, configured to electrically couple the computing device to a substrate, wherein during operation of the computing device: one or more high-speed signals are transmitted via the one or more cables; and one or more low-speed signals and / or power are transmitted via the plurality of electrical interconnects.

64. The system of claim 63, wherein the plurality of electrical interconnects comprises a ball grid array.

65. The system of claim 63, wherein: the one or more high-speed signals are transmitted at a first frequency greater than or equal to 10 GHz; and the one or more low-speed signals are transmitted at a second frequency less than 10 GHz.

66. A computing device, comprising: an interposer; a processor mounted to the interposer; and a connector assembly mounted to the interposer, the connector assembly comprising: a housing mechanically coupled to the interposer and defining a cavity; a seal, disposed between the housing and the interposer, to mitigate infiltration of a fluid in an environment surrounding the computing device into the cavity; an electrical connector, coupled to the housing and disposed within the cavity, to communicatively couple the connector assembly to the interposer and the processor; and one or more cables, coupled to the housing, configured to communicatively couple the connector assembly to another device.

67. The computing device of claim 66, wherein the cavity of the housing is at a pressure lower than an ambient pressure of the environment.

68. The computing device of claim 67, wherein a difference between the pressure and the ambient pressure ranges between about 5 pounds per square inch (psi) to about 10 psi.

69. The computing device of claim 67, wherein the seal is sufficient to maintain the pressure for 5 or more years.

70. The computing device of claim 66, wherein the cavity of the housing contains at least one of air or an inert gas.71 . The computing device of claim 66, wherein the seal is formed using at least one of an epoxy, a solder joint, or a cold weld.

72. The computing device of claim 66, wherein: the seal comprises a gasket disposed between the housing and the interposer; and the connector assembly further comprises a threaded fastener, to securely couple the connector assembly to the interposer and apply a force to compress the gasket.

73. The computing device of claim 66, wherein the connector assembly further comprises: one or more locking tabs to securely couple the connector assembly to the interposer.

74. The computing device of claim 66, wherein the one or more cables comprises at least one of a cable with a copper wire or a fiber optic cable.

75. The computing device of claim 66, wherein the connector assembly further comprises: a port to facilitate removal of a fluid from the cavity.

76. The computing device of claim 66, further comprising: a plurality of electrical interconnects, coupled to the interposer, configured to electrically couple the computing device to a substrate, wherein during operation of the computing device: one or more high-speed signals are transmitted via the one or more cables; and one or more low-speed signals and / or power are transmitted via the plurality of electrical interconnects.

77. The computing device of claim 76, wherein the plurality of electrical interconnects comprises a ball grid array.

78. The computing device of claim 76, wherein: the one or more high-speed signals are transmitted at a first frequency greater than or equal to 10 GHz; andthe one or more low-speed signals are transmitted at a second frequency less than 10GHz.

79. A system, comprising: a two-phase immersion cooling system, comprising: a tank defining a tank volume; coolant liquid disposed within the tank volume; and a heat exchanger partially disposed in the tank volume above the coolant liquid; and the computing device of claim 66 immersed in the coolant liquid within the tank volume.

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