Patent ID: 12255124

DETAILED DESCRIPTION

As described in detail below, embodiments include a heat exchange assembly for performing jet impingement cooling of semiconductor power modules. Such jet impingement cooling may be used to improve a thermal performance of the semiconductor power modules, including, e.g., improving an output power in traction inverters of electric vehicles, as described in more detail, below.

In many scenarios, it is desirable to implement jet impingement cooling by leveraging an existing fluid flow. For example, in example automotive contexts just referenced, it may occur that various automotive components (e.g., a motor and/or a battery) require a fluid flow for one or more related cooling systems. Such a fluid flow may require one or more pumps and associated components, and may have a fluid volume and/or fluid pressure required to perform desired cooling of such automotive components.

In such contexts, it is often undesirable and/or infeasible to provide a separate fluid flow dedicated to jet impingement cooling. For example, cost and/or space constraints may prevent the addition of a separate set of fluid pump(s) and associated components.

In the context of semiconductor power modules, however, it may be necessary to cool a number and variety of relatively small semiconductor chips. Moreover, relevant thermal ranges may be different for different ones of the semiconductor chips, and/or different than those of the larger automotive components being cooled.

Further, fluid flow that is suitable for larger scale automotive components may not be suitable for cooling semiconductor power modules, even when jet impingement cooling is available. For example, a pressure or velocity of fluid being emitted by a jet nozzle onto the semiconductor power modules may be excessive, and may lead to undesired effects, such as an erosion of a metal or metal coating that may be on the semiconductor power module.

Additionally, inserting a jet impingement cooling system into an existing fluid-based cooling system may introduce an excessive and undesirable pressure drop into the system. Such a pressure drop may be problematic for other components being cooled, and/or may require compensatory components (e.g., a larger or more expensive fluid pump) to be included.

In example implementations, therefore, a fluid bypass is provided, in which an inlet fluid flow is partially diverted so that a first or jet fluid portion is directed to cool the semiconductor power module(s), while a second or bypass fluid portion flows essentially unimpeded through the heat exchange assembly. Accordingly, the fluid bypass may cause the jet fluid portion of the inlet fluid flow to have a reduced velocity when impinging upon the semiconductor power modules. Moreover, the fluid bypass may result in a lower pressure drop for a given level of thermal performance, as compared to conventional jet impingement cooling systems.

Thus, by providing the described fluid bypass, a lifetime of the semiconductor power modules and/or related packaging may be extended, a thermal performance of a jet impingement cooling system may be improved, and a reliability of the semiconductor power modules and the jet impingement cooling system may be improved. Moreover, the fluid bypass may be customized, so that desired ranges of cooling and associated thermal performance(s) may be achieved.

For example, conventional jet impingement cooling systems may include components (e.g., heat exchange assembly components) that are made primarily or entirely using metal. Semiconductor power modules may be fastened within such conventional jet impingement cooling systems using available o-rings, gaskets, and fasteners.

Such conventional jet impingement cooling systems may be complex and costly to manufacture, and may suffer from poor reliability. For example, the o-ring seals may result in points of failure for the fluid flow, particularly for the types of high-pressure, high-velocity fluid flows typically present in conventional cooling systems.

In example implementations, however, polymers may be used to construct heat exchange assembly components. For example, such polymer components may be provided using injection molding techniques, and/or 3D printing techniques.

Such approaches reduce a cost and complexity of manufacturing jet impingement cooling systems. In addition, use of such polymers enable use of adhesives as a seal(s) in the jet impingement cooling systems, because, e.g., such adhesives may be effective in bonding the polymer of a heat exchange assembly to an epoxy or other molding of semiconductor power modules. Thus, described techniques may be used to replace the costly, complex, and/or error-prone o-rings, gaskets, and fasteners of conventional systems, thereby reducing cost (including costs of material and assembly), simplifying manufacturability, improving reliability, and generally facilitating adoption and use of jet impingement cooling systems for semiconductor power modules.

FIG.1is an example cross-sectional side view of a jet impingement cooling assembly for high power semiconductor devices with a bypass fluid portion. InFIG.1, a heat exchange base102(which may be referred to, or include, a water jacket or cooling jacket) includes an inlet connection104, which may be in fluid contact with a fluid pump (not illustrated inFIG.1) to receive an inlet fluid flow114. The heat exchange base102also includes an outlet connection106, which may be part of a fluid loop that returns an outlet fluid flow115to the fluid pump. That is, as referenced above, the heat exchange base102for jet impingement cooling may be only part of a fluid loop used within a larger setting (e.g., within an automobile or other vehicle) to provide fluid-based heat dissipation to multiple components.

A jet plate108may be positioned within the heat exchange base102. Multiple jet nozzles110may be formed within the jet plate108. The jet plate108may be sealed to an inlet chamber112, e.g., using an adhesive, as described herein. In some examples, the jet plate108may be mounted to the inlet chamber112and interchangeable with other jet plates having different configurations. In other implementations, the jet plate108may be formed integrally with the inlet chamber (e.g., using injection molding or 3D printing techniques).

The inlet fluid flow114, such as a water flow, may be maintained through the inlet connection104and into the inlet chamber112. Within the inlet chamber112, the inlet fluid flow114is divided into a jet fluid portion116and a bypass fluid portion118.

As shown inFIG.1, the jet fluid portion116is directed through the jet nozzles110. For the sake of clarity of description, the jet fluid portion is referred to as jet fluid portion116within the inlet chamber112, and as jet fluid portion124after passing through the jet nozzles110and entering an outlet chamber126.

Meanwhile, the bypass fluid portion118is directed through at least one bypass nozzle120. Upon exiting the bypass nozzle120, the bypass fluid portion118rejoins the jet fluid portion124and forms a total outlet fluid flow115.

The jet nozzle110provides a vent, gap, or opening through which the pressurized inlet fluid flow114, flowing through the inlet connection104, is forced, to provide the high-speed fluid flow of the jet fluid portion124within the outlet chamber126. The jet nozzles110may be sized, spaced, and positioned in any suitable or desired fashion on the jet plate108. The jet nozzles110may be any desired and suitable shape, such as, e.g., circular, or ellipsoidal. The jet nozzles110may be formed within the jet plate108, as shown, or may be attached or otherwise positioned at least partially on the jet plate108, e.g., using a separate jet nozzle structure, which itself may have a desired and suitable width, length, and height.

Thus, the jet plate108forms a sealed connection with the inlet chamber112, so that the jet fluid portion116of the inlet fluid flow114received by way of the inlet connection104is forced through the jet nozzles110to provide jet fluid portion124. Accordingly, the jet fluid portion124may be impinged upon a semiconductor power module122, in order to dissipate heat generated by operations of the semiconductor power module122.

The semiconductor power module122may be mounted to the heat exchange base102using a mounting member134. For example, the semiconductor power module122may include at least one semiconductor device with a frontside facing away from the inlet chamber112and a backside facing the jet plate108.

In example implementations, as described and illustrated in more detail in various examples, below, the semiconductor power module122may be sealed using an appropriate adhesive136to the mounting member134, and the mounting member134may be sealed using the same or different adhesive to a surface of the heat exchange base102.

The semiconductor power module122may include a circuit board or other assembly of a plurality of semiconductor chips, or other devices. The various semiconductor power module devices may have heat signatures that range from high to negligible. Some semiconductor power module devices may be in close proximity to one another, which may exacerbate a need for heat dissipation, as compared to the need for heat dissipation of each of the individual semiconductor power module devices in isolation.

As referenced above, and illustrated inFIG.1, the heat exchange base102is configured to receive the semiconductor power module122, so that the jet nozzles110may be positioned to be directly below devices of the semiconductor power module122. Consequently, the inlet fluid flow114from the inlet connection104may be divided into the jet fluid portion116and the bypass fluid portion118, with the jet fluid portion116thereby being forced through the jet nozzles110to impinge directly onto corresponding backsides of devices of the semiconductor power module122. Such an approach provides highly-efficient and direct cooling of the devices of the semiconductor power module122.

Following this jet impingement onto the devices of the semiconductor power module122, the jet fluid portion124may flow directly into the outlet chamber126, or may proceed through included fluid-return channels (not visible inFIG.1, but with examples provided below in the context ofFIG.7). As illustrated inFIG.1, the jet fluid portion124may proceed into the outlet chamber126and rejoin with the bypass fluid portion118directed through the bypass nozzle120, to thereby provide a total outlet fluid flow115through the outlet connection106. In this way, the outlet fluid flow115may thereby be provided to other elements being cooled, and ultimately return to the fluid pump being used.

In described implementations, use of the bypass nozzle120and the bypass fluid portion may enable a degree of control over a velocity of the jet fluid portion116/124, as well as control over a pressure drop across the jet impingement cooling system. For example, the bypass fluid portion118may be virtually any desired percentage of the inlet fluid flow114(e.g., may be 5%-50% of the inlet fluid flow114). Consequently, the jet fluid portion116may include any remaining percentage of the inlet fluid flow not diverted to be included in the bypass fluid portion118.

As a result, a velocity of the jet fluid portion116/124may be reduced or increased by corresponding increases/reductions in the bypass fluid portion118. As noted above, the semiconductor power module122may have a metal, e.g., a metal coating (not shown inFIG.1) provided at an impingement surface facing the jet nozzles110, which may be eroded by high-velocity jet impingement fluid flows in conventional systems. Thus, the example ofFIG.1illustrates that described techniques may be used to obtain a desired trade-off between, e.g., fluid velocities, heat transfer, pressure drops, and metal coating erosion.

FIG.2is a flowchart illustrating an example manufacturing process for making a jet impingement cooling assembly, in accordance with example embodiments described herein. InFIG.2, operations202-210are illustrated as separate, ordered, sequential operations. However, it will be appreciated that in various example manufacturing processes, the operations202-210may be performed in a different order than that shown and/or may be executed partially or completely in parallel. Moreover, additional or alternative operations may be included, and/or one or more operations may be omitted.

In the example ofFIG.2, the inlet chamber112configured to receive the inlet fluid flow114may be formed (202). The jet plate108having a plurality of jet nozzles110formed therein and coupled to the inlet chamber112may be formed, and positioned to direct the jet fluid portion1116of the inlet fluid flow114from the inlet chamber112through the jet nozzles110(204). The outlet chamber126may be formed that is positioned to receive the jet fluid portion116(as the jet fluid portion124) once the jet fluid portion116has passed through the jet nozzles110(206). At least one bypass nozzle120may be formed in fluid connection with the inlet chamber112and configured to direct the bypass fluid portion118of the inlet fluid flow114into the outlet chamber126with the jet fluid portion124to thereby define an outlet fluid flow115.

At least one semiconductor power module122may be sealed to the heat exchange base102that contains the inlet chamber112, the outlet chamber126, the jet plate108, the at least one bypass nozzle120, and the jet nozzles110(210). For example, the adhesive136may be used to seal the at least one semiconductor power module122to the heat exchange base102. In example implementations, the separate mounting member134may additionally or alternatively sealed to the semiconductor power module122, and/or to the heat exchange base102.

As referenced herein, the process ofFIG.2may be performed using injection molding and/or 3D printing, e.g., using any suitable plastic or other polymer. The various components may thus be formed integrally to some extent, or may be formed separately and then attached using a suitable adhesive or other sealant, as described herein. The various configurations described herein, including any desired variation in size, position, or number of the jet nozzles110, may be manufactured inexpensively and quickly. Moreover, the various sealed components may be used reliably during subsequent jet impingement cooling, without a need for the types of o-rings, gaskets, and/or fasteners used in conventional systems.

Thus, the devices and methods ofFIGS.1and2provide, with desired levels of velocity and pressure, a cooling liquid with high accuracy and/or precision to identified hotspots of semiconductor power modules. For example, described jet impingement cooling assembly embodiments provide direct contact of a cooling fluid to a backside of a substrate (e.g., direct bonded copper (DBC) substrate (e.g., a substrate including a dielectric disposed between a pair of metal layers for traces and/or bonding)) being cooled.

The described jet impingement heat exchange (cooling) assembly embodiments may be configured to provide either uniform or customized pressure(s) at each of one or more jet nozzles110, to thereby provide uniform cooling to a corresponding plurality of hotspots. The jet impingement cooling assembly is efficient, in that jet impingement occurs at least at (e.g., only at) the desired and necessary hotspots.

For example,FIG.3Ais an exploded view of a first example embodiment of the jet impingement cooling assembly ofFIG.1. InFIG.3A, a heat exchange base302includes an inlet connection304, which may be in fluid contact with a fluid pump, as described above, to receive an inlet fluid flow314. The heat exchange base302also includes an outlet connection306. That is, as referenced above, the heat exchange base302for jet impingement cooling may be only part of a fluid loop used within a larger setting (e.g., within an automobile or other vehicle) to provide fluid-based heat dissipation to multiple components.

A jet plate308may be positioned within the heat exchange base302. Multiple jet nozzles310may be formed within the jet plate308. The jet plate308may be sealed to an inlet chamber312, e.g., may be formed integrally with the inlet chamber312(e.g., using injection molding or 3D printing techniques).

The inlet fluid flow314may be maintained through the inlet connection304and into the inlet chamber312. Within the inlet chamber312, the inlet fluid flow314is divided into a jet fluid portion and a bypass fluid portion (not shown inFIG.3A, but illustrated above inFIG.1), so that a jet fluid portion may be directed through the jet nozzles310into an outlet chamber326, while bypass fluid portion may be directed through at least one bypass nozzle320to the outlet chamber326. Upon exiting the bypass nozzle320, the bypass fluid portion may thus rejoin the jet fluid portion within the outlet chamber326and provide a total outlet fluid flow through the outlet connection306.

The jet nozzles310may be sized, spaced, and positioned to provide a substantially uniform pressure along a length of the jet plate308. For example, as shown, the jet nozzles310may include at least a subset of jet nozzles with diameters that decrease in a direction of the inlet fluid flow. For example, the jet nozzles310may include a first group of jet nozzles310a, a second group of jet nozzles310b, and a third group of jet nozzles310c. As also shown, the jet nozzles310bare smaller in diameter than the jet nozzles310a, while the jet nozzles310care smaller in diameter than the jet nozzles310b. Consequently, even though jet fluid portion through the inlet chamber312may decrease in pressure and velocity along a length of the jet plate308, the successively smaller groups of jet nozzles310a,310b,310cmay cause jet fluid portions emitted from the groups of jet nozzles310a,310b,310cto have substantially the same or similar velocities and pressures.

Further inFIG.3A, the jet plate308forms a sealed connection with the inlet chamber312, so that the jet fluid portion of the inlet fluid flow314received by way of the inlet connection304is forced through the jet nozzles310to provide jet fluid portion to be impinged upon semiconductor power modules322a,322b,322c, in order to dissipate heat generated by operations of the semiconductor power module322a,322b,322c.

The semiconductor power modules322a,322b,322cmay be mounted to the heat exchange base302using a mounting member334. The semiconductor power modules322a,322b,322cmay be sealed using an appropriate adhesive (not shown inFIG.3A) to the mounting member334, and the mounting member334may be sealed using the same or different adhesive to a surface of the heat exchange base302.

The semiconductor power modules322a,322b,322cmay include a circuit board(s) or other assembly of a plurality of semiconductor chips, or other devices. As referenced above, and illustrated inFIG.1, the heat exchange base302may be configured to receive the semiconductor power modules322a,322b,322c, so that the jet nozzles310may be positioned to be directly below devices of the semiconductor power modules322a,322b,322c. Consequently, the inlet fluid flow314from the inlet connection304may be divided into a jet fluid portion and bypass fluid portion, with the jet fluid portion thereby being forced through the jet nozzles310to impinge directly onto corresponding backsides of devices of the semiconductor power modules322a,322b,322c.

Following this jet impingement onto the devices of the semiconductor power modules322a,322b,322c, the jet fluid portion may flow directly into the outlet chamber326. The jet fluid portion may proceed into the outlet chamber326and rejoin with the bypass fluid portion directed through the bypass nozzle320, to thereby provide a total outlet fluid flow through the outlet connection306. In this way, the outlet fluid flow may thereby be provided to other elements being cooled, and ultimately return to the fluid pump being used.

FIG.3Billustrates an alternate example implementation of a jet plate ofFIG.3A. InFIG.3B, the jet nozzles310are customized to obtain desired results with respect to jet fluid portions through the jet nozzles310. As shown, the group of jet nozzles310amay be the same as inFIG.3A, but a group of jet nozzles310dincludes some jet nozzles having a smaller diameter than the jet nozzles310bofFIG.3A, or than other jet nozzles of the group of jet nozzles310d. Similarly, a group of jet nozzles310eincludes some jet nozzles having a larger diameter than the jet nozzles310cofFIG.3A, or than other jet nozzles of the group of jet nozzles310e.

In other words,FIG.3Aillustrates an example in which at least a first subset of nozzle sizes are generally reduced in a direction of flow in order to maintain (substantially) uniform jet velocity on all impinging surfaces. In contrast, inFIG.3B, nozzles sizes are customized so that desired levels of velocity/pressure (and associated extent(s) of cooling) at each group of nozzles may be obtained. In other words, at least a second subset of the jet nozzles may have diameters that increase in a direction of the inlet fluid flow.

For example, inFIG.3B, it may occur that two devices are positioned above the group of nozzles310d, of which a first device is positioned closer to the group of jet nozzles310aand happens to require a relatively high degree of cooling, while a second device is positioned farther from the group of jet nozzles310a(in a direction of the fluid flow) and happens to require a similar degree of cooling as a device(s) positioned above the group of jet nozzles310a. Consequently, as shown, a first group of jet nozzles of the jet nozzles310dare smaller in diameter to provide the desired increase in pressure/velocity/cooling, while a second group jet nozzles of the jet nozzles310dare larger than the first group, but smaller than the group of jet nozzles310aso as so maintain a similar velocity/pressure/cooling profile as that provided by the group of jet nozzles310a(as described above with respect toFIG.3A).

Also inFIG.3B, the at least one bypass nozzle320ofFIG.3is illustrated as including four bypass nozzles320a. More generally, the bypass nozzle320may be configured to include any desired and suitable number and arrangement of bypass nozzles. As with the jet nozzles310, diameters and other parameters of the bypass nozzles may be customized to obtain a desired outcome with respect to cooling the semiconductor power modules322a,322b,322c, or desired outcomes with respect to other system parameters (e.g., with respect to a permissible level of erosion over time that may occur with respect to a metal coating on an underside(s) of the semiconductor power modules322a,322b,322c).

FIG.4is an assembled view of the examples ofFIGS.3A and3B. As shown inFIG.4, described techniques enable a compact, secure, customizable, and reliable cooling assembly.

FIG.5is an exploded view of an alternate example implementation of the jet impingement cooling assembly ofFIG.1.FIG.6is a bottom view of a jet plate of the implementation ofFIG.5.FIG.7is a top view of the jet plate of the implementation ofFIG.6.

InFIG.5, a heat exchange base502includes an inlet connection504(indicated but not visible inFIG.5) and an outlet connection506. A jet plate508may be insertable into the heat exchange base502. Multiple jet nozzles510may be formed within the jet plate508. An inlet chamber512may be defined by insertion of the jet plate508into the heat exchange base502.

During operation, as described above, an inlet fluid flow may thus be maintained through the inlet connection504and into the inlet chamber512. As also described, the inlet fluid flow514may be divided into a jet fluid portion and a bypass fluid portion, so that a jet fluid portion may be directed through the jet nozzles510into an outlet chamber526, while bypass fluid portion may be directed through two bypass nozzles520to the outlet chamber526. Upon exiting the bypass nozzle520, the bypass fluid portion may thus rejoin the jet fluid portion within the outlet chamber526and provide a total outlet fluid flow through the outlet connection506.

In some implementations, the jet plate508may be adhered to the heat exchange base502to form a sealed connection that defines the inlet chamber512, so that the jet fluid portion of the inlet fluid flow received by way of the inlet connection504is forced through the jet nozzles510to provide jet fluid portion to be impinged upon semiconductor power modules522.

The semiconductor power modules522may be mounted to the jet plate508and/or the heat exchange base502using a mounting member534. For example, the semiconductor power modules522may be sealed using an appropriate adhesive736, as shown inFIG.7, between the jet plate508and the semiconductor power modules522and/or the mounting member534.

FIG.7further illustrates that the jet nozzles510may include, or be connected to, jet nozzles710. As shown, the jet nozzles710may be sized and positioned to define a fluid return path within part of the outlet chamber526that provides the outlet fluid flow that rejoins with the bypass fluid portion through the two bypass nozzles520, to thereby provide the total outlet fluid flow through the outlet connection506.

FIG.8illustrates a table demonstrating example pressures and thermal responses for various example implementations of the jet impingement cooling assembly ofFIG.1. In the table ofFIG.8, a column802includes example thermal resistance values, while a column804includes example pressure drops. Columns806include various bypass flow parameters, including a column808indicating a number of bypass nozzles included, column810indicating a diameter of each bypass nozzle, and a column812indicating an inlet flow rate.

InFIG.8, example values of thermal resistance in column802are shown as approximate ratios determined with respect to a base value shown as “Y”. Similarly, example values of pressure drop in column804are shown as approximate ratios determined with respect to a base value shown as “X”.

As shown in example row814, a low thermal resistance may be achieved in the example while retaining a suitably low pressure drop, by including 4 bypass nozzles, each having a diameter of 1.5 mm at a flow rate of 8 liters per minute. Of course,FIG.8is a non-limiting example, and actual implementation values will depend on many factors assumed (and held constant) for the example ofFIG.8, such as, e.g., a size, number, and/or positioning of jet nozzles.

More generally, all of the preceding examples are non-limiting, and many variations may be implemented. For example, a profile on a jet plate top surface may be parallel to a backside surface of a semiconductor power module being cooled, or may have a sloped surface, to produce either accelerating or decelerating fluid flow. In other examples, although the various inlet connections and outlet connections are illustrated as being located on opposed sides of a heat exchange base (e.g., to define a substantially linear fluid flow), other example implementations may provide inlet and outlet connections adjacent to one another on a single wall of a heat exchange base, or on adjacent sidewalls of a heat exchange base.

Described techniques reduce a complexity and cost of implementing jet impingement cooling systems, while increasing a reliability of such systems. Further, potential erosion/corrosion of metal coatings may be reduced or eliminated, e.g., by controlling a fluid jet velocity of impinging fluid flows. Additionally, pressure drops across a jet impingement cooling system may be reduced in an adjustable, configurable manner.

In specific examples, using polymers as described herein also simplifies manufacturability and lowers material costs of impingement cooling housing/components. Using adhesives as a seal(s) in impingement cooling systems eliminates o-rings, gaskets, and fasteners used in conventional systems.

In specific examples, the described jet impingement cooling assembly may be used for cooling in the context of automobile or other engine applications, including electric vehicles. Such applications often have high power requirements within high-heat environments, while also meeting safety mandates. In other implementations, described techniques can be used in, e.g., wind turbine electronics, rail, and industrial drives.

It will be understood that, in the foregoing description, when an element, such as a layer, a region, a substrate, or component is referred to as being on, connected to, electrically connected to, coupled to, or electrically coupled to another element, it may be directly on, connected or coupled to the other element, or one or more intervening elements may be present. In contrast, when an element is referred to as being directly on, directly connected to or directly coupled to another element or layer, there are no intervening elements or layers present. Although the terms directly on, directly connected to, or directly coupled to may not be used throughout the detailed description, elements that are shown as being directly on, directly connected or directly coupled can be referred to as such. The claims of the application, if any, may be amended to recite exemplary relationships described in the specification or shown in the figures.

As used in the specification and claims, a singular form may, unless definitely indicating a particular case in terms of the context, include a plural form. Spatially relative terms (e.g., over, above, upper, under, beneath, below, lower, and so forth) are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. In some implementations, the relative terms above and below can, respectively, include vertically above and vertically below. In some implementations, the term adjacent can include laterally adjacent to or horizontally adjacent to.

Some implementations may be implemented using various semiconductor processing and/or packaging techniques. Some implementations may be implemented using various types of semiconductor processing techniques associated with semiconductor substrates including, but not limited to, for example, Silicon (Si), Gallium Arsenide (GaAs), Gallium Nitride (GaN), Silicon Carbide (SiC) and/or so forth.

While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the scope of the implementations. It should be understood that they have been presented by way of example only, not limitation, and various changes in form and details may be made. Any portion of the apparatus and/or methods described herein may be combined in any combination, except mutually exclusive combinations. The implementations described herein can include various combinations and/or sub-combinations of the functions, components and/or features of the different implementations described.