Liquid cooling power module, device and method for cooling high-power semiconductor device

Abstract

The invention discloses a liquid cooling power module, device and method for cooling a high-power semiconductor device. A semiconductor die supported by the directly bonded metal structure is attached to a cooling unit that circulates coolant from the inner chamber to the outer chamber through a spray nozzle such that the coolant impacts a metal surface in thermal contact with the directly bonded metal structure. The use of the cooling fluid provides more efficient and cost-effective cooling than relying on a solid metal heat sink. The disclosed liquid cooling power module can reduce the cost and weight of the heat dissipation assembly so as to be compatible with aerospace applications.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 510,714, filed on June 28, 2023, entitled “Power Module Housing,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to liquid-cooled power modules, devices and methods for cooling high-power semiconductor devices, and to semiconductor device modules, semiconductor device assemblies and semiconductor device assembly and packaging. More specifically, the present invention relates to cooling technology for high-power modules. Background Art

[0003] A semiconductor device assembly (e.g., a chip assembly including a power semiconductor device) can be implemented using multiple semiconductor dies, multiple substrates (e.g., a die attach pad (DAP)), multiple electrical interconnections, and molding compounds. Power transistors may include, for example, insulated-gate bipolar transistors (IGBTs), power metal-oxide-semiconductor field effect transistors (MOSFETs), and the like. Fast recovery diodes (FRDs) may be used in conjunction with power transistors. Electrical interconnections within a high-power semiconductor device module may include, for example, bonding wires, conductive pads, and conductive clips. Lead frames may be used to provide external electrical connections for high-power semiconductor device modules. Polymer molding compounds may be used as encapsulants to protect components in the device assembly. Some high-power chip assemblies may operate at voltages in the range of, for example, about 200V to about 800V. Such high-power chip components packaged as semiconductor device modules can be used as power converters in various applications, including: electric vehicles (EV) (e.g., electric cars, electric airplanes, or electric drones), hybrid electric vehicles (HEV), and industrial applications. Summary of the invention

[0004] In some aspects, the technology described herein relates to a liquid-cooled power module for cooling a high-power semiconductor device, comprising: a directly bonded metal structure, the directly bonded metal structure comprising a first conductive layer, a second conductive layer, and a non-conductive layer disposed between the first conductive layer and the second conductive layer; a semiconductor die coupled to the first conductive layer of the directly bonded metal structure; and a cooling unit coupled to the second conductive layer of the directly bonded metal structure, the cooling unit comprising a fluid path so that when the cooling fluid flows through the fluid path, the cooling fluid absorbs heat from at least a portion of the directly bonded metal structure.

[0005] In some aspects, the technology described herein relates to a liquid-cooled power module in which a cooling fluid impinges on surfaces in thermal contact with a directly bonded metal structure.

[0006] In some aspects, the technology described herein relates to a liquid-cooled power module in which a direct-bonded metal structure includes a dielectric layer disposed between a first conductive layer and a second conductive layer, and a cooling fluid impinges on a surface in thermal contact with the second conductive layer.

[0007] In some aspects, the technology described herein relates to a liquid-cooled power module in which a cooling unit includes a polymer-based material.

[0008] In some aspects, the technology described herein relates to a liquid-cooled power module, wherein a cooling unit includes an inlet chamber and an outlet chamber, which are separated from each other and connected by a cooling impingement nozzle.

[0009] In some aspects, the technology described herein relates to a liquid-cooled power module, wherein a cooling unit is configured to direct a flow of cooling fluid from a module inlet to a directly bonded metal structure through a nozzle formed in the cooling unit and then away from the directly bonded metal structure through an outlet chamber.

[0010] In some aspects, the technology described herein relates to a liquid-cooled power module in which some of the cooling fluid that has passed through the nozzle is discharged from the cooling unit through a module outlet of an outlet chamber.

[0011] In some aspects, the technology described herein relates to a liquid-cooled power module in which the cooling fluid rises in temperature by at most between 2 degrees Celsius and 8 degrees Celsius as it flows between a module inlet and a module outlet.

[0012] In some aspects, the technology described herein relates to a liquid-cooled power module in which a module inlet and a module outlet include O-ring seals.

[0013] In some aspects, the technology described herein relates to a liquid-cooled power module, further comprising: a polymer cap over the semiconductor die.

[0014] In some aspects, the technology described herein relates to a liquid-cooled power module, further comprising: an epoxy resin between the polymer cover and the semiconductor die.

[0015] In some aspects, the technology described herein relates to a liquid-cooled power module, wherein the cooling fluid includes ethylene glycol.

[0016] In some aspects, the technology described herein relates to an apparatus for cooling a high-power semiconductor device, comprising: an inner chamber having an inlet; an outer chamber having an outlet, the outer chamber at least partially surrounding the inner chamber; and a channel formed in the inner chamber to direct a flow of a cooling fluid to the outer chamber.

[0017] In some aspects, the technology described herein relates to a device in which the inner chamber and the outer chamber are formed from a polymer material by 3D printing.

[0018] In some aspects, the technology described herein relates to a device in which the inner chamber and the outer chamber are formed from a polymer material by injection molding.

[0019] In some aspects, the technology described herein relates to a device in which a channel pressurizes a cooling fluid to form an aerosol.

[0020] In some aspects, the technology described herein relates to a device wherein an inlet is disposed below an inner chamber and an outlet is disposed below an outer chamber.

[0021] In some aspects, the technology described herein relates to a method for cooling a high-power semiconductor device, comprising: directing a flow of a cooling fluid from an inlet into an inner chamber formed in a substrate supporting a semiconductor die so that heat is absorbed by the cooling fluid; directing the flow from the inner chamber through a plurality of openings to form a pressurized spray so that the cooling fluid impinges on a metal surface in thermal contact with a directly bonded metal structure; receiving the cooling fluid in an outer chamber formed in the substrate; and ejecting the cooling fluid from the outer chamber through an outlet isolated from the inlet.

[0022] In some aspects, the technology described herein relates to a method in which a cooling fluid is disposed beneath a directly bonded metal structure.

[0023] In some aspects, the technology described herein relates to a method in which a directly bonded metal structure includes a first conductive layer, a second conductive layer, and a non-conductive layer disposed between the first conductive layer and the second conductive layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a high-level schematic diagram of a liquid-cooled power module according to some embodiments of the present invention.

[0025] Figures 2 to 4 is a cross-sectional view of an isolated power module according to some embodiments of the present invention.

[0026] Figure 5A is a perspective view of an isolation module housing according to some embodiments of the present invention.

[0027] Figure 5B According to some embodiments of the present invention Figure 5A A bottom perspective view of the isolation module housing is shown.

[0028] Figure 5C According to some embodiments of the present invention Figure 5A An exploded view of the isolation module housing is shown.

[0029] Figure 6 is a perspective view of an interface between an isolation power module and a cooling jacket according to some embodiments of the present invention.

[0030] Figure 7 is a cross-sectional view of an isolation module housing according to some embodiments of the present invention.

[0031] Figure 8 is an exploded view of the interface between an isolated power module and a base manifold according to some embodiments of the present invention.

[0032] Fig. 9 is a flow chart of a method of cooling a power module according to some embodiments of the present invention.

[0033] When with Figure 1 When read together, various aspects of the present invention can be best understood by the following detailed description. Note that, according to industry practice, various features are not necessarily drawn to scale. For clear discussion, the sizes of various features can be increased or reduced arbitrarily. In the accompanying drawings, similar reference numerals can indicate similar and / or similar parts (elements, structures, etc.) in different views. The accompanying drawings generally describe various embodiments discussed in the present invention by way of example, rather than by way of limitation. The reference numerals shown in one drawing may not be repeated in the related views to indicate the same and / or similar elements. The reference numerals that repeat in multiple drawings may not be specifically discussed for each of the drawings in these drawings, but are provided as a background between the related views. In addition, when multiple instances of an element are shown, not all similar elements in the drawings are specifically referenced with reference numerals. DETAILED DESCRIPTION

[0034] A semiconductor device assembly (e.g., a chip assembly including a power semiconductor device) can be implemented using multiple semiconductor dies, multiple substrates (e.g., die attach pads (DAPs)), multiple electrical interconnects, and molding compounds. The power transistors described herein may include, for example, insulated-gate bipolar transistors (IGBTs), power metal-oxide-semiconductor field effect transistors (MOSFETs), and the like. Fast recovery diodes (FRDs) can be used in conjunction with power transistors. The electrical interconnects within a high-power semiconductor device module may include, for example, bonding wires, conductive pads, and conductive clips. A lead frame can be used to provide external electrical connections for a high-power semiconductor device module. A polymer molding compound can be used as an encapsulant to protect components in a device assembly. Some high-power chip assemblies described herein can operate at voltages in the range of, for example, about 200V to about 800V. Such high-power chip components packaged as semiconductor device modules can be used as power converters in various applications, including: electric vehicles (EV) (e.g., electric cars, electric airplanes, or electric drones), hybrid electric vehicles (HEV), and industrial applications.

[0035] In the power module described herein, it is important to dissipate the heat generated in the power semiconductor device to limit the adverse effects that may be caused by overheating, such as dimensional changes, variable operating characteristics, and uneven thermal expansion. Overheating can damage the reliability of the device and also waste electricity, thereby increasing operating costs. Ineffective cooling of semiconductor devices may impose restrictions on the design of power chip components by constraining the power density, circuit density, or system speed allowed. When heat is dissipated from a source (e.g., a power module) to a radiator (e.g., a heat sink) by conduction, successful heat transfer may depend on, for example, the direct contact area between the source and the radiator.

[0036] In some power modules, the chip assembly is supported by a multi-level substrate, such as a direct-bonded metal (DBM) structure (which may be a directed bonded copper (DBC) substrate). The DBM structure may be used in part to facilitate cooling of high-power semiconductor devices. The DBM structure may include a first conductive layer, a second conductive layer, and a non-conductive layer (e.g., a dielectric layer) disposed between the first conductive layer and the second conductive layer, the non-conductive layer being made of an insulating material (e.g., a ceramic material). The first conductive layer (and / or the second conductive layer) may include or may define one or more electrical traces and / or connections. The second conductive layer and / or the first conductive layer may be a heat sink or may be used as a heat sink. In some embodiments, the second conductive layer may be coupled to a heat sink for single-sided cooling.

[0037] In some embodiments, multiple DBMs (e.g., two DBMs) can be used for double-sided cooling, or for cooling multiple high-power chip arrays. The heat sink for attachment to the DBM can be configured as a metal substrate or metal fins, such as a "nail fin" type heat sink, which is used to accelerate heat dissipation by providing an increased metal surface area. However, at least one problem with such heat sinks is that they still cannot dissipate heat quickly enough. In addition, the metal substrate will add undesirable weight and cost to the power module. In some embodiments, the DBM structure can be referred to as a DBM substrate.

[0038] The present invention relates to an embodiment of a direct cooling method, in which a cooling unit of a liquid-cooled power module includes (e.g., is defined by, is formed with) a chamber to accommodate a cooling fluid (e.g., contains, promotes the flow of a cooling fluid). The cooling unit can be coupled to the DBM structure through an intermediate layer of a conductive adhesive. In some embodiments, the cooling fluid is contained in an inner chamber ("inlet chamber") having an inlet, and the cooling unit also includes an outer chamber ("outlet chamber") having an outlet, which is separated from the inlet so that the two chambers are independent of each other. In some embodiments, a channel connects the inlet to the outlet. In some embodiments, a nozzle formed in the inner chamber guides the fluid to flow to the outer chamber through the channel. In some embodiments, the fluid from the inner chamber can be pressurized to form a spray for cooling the lower surface of the DBM. In some embodiments, a cooler can be used to extract heat from the fluid at the outlet so that the fluid can be recirculated through the cooling unit.

[0039] Figure 1is a high-level external perspective view of a liquid-cooled power module 90 according to some embodiments of the present invention. The liquid-cooled power module 90 includes an isolated power module 100 mounted on (e.g., attached to, coupled to) a cooling jacket 102. In some embodiments, the isolated power module 100 is a high-power module that generates heat when powered, for example, during operation of one or more semiconductor chips within the isolated power module 100. In some embodiments, the cooling jacket 102 can be made of cast aluminum. In some embodiments, the cooling jacket 102 can be polymer-based. The cooling jacket 102 provides a container for a flow 103 of a cooling fluid, wherein the flow direction is indicated by an arrow. Figure 1 1 , an inlet 104 is shown at one end of the cooling jacket 102 , through which a cooling fluid may flow into the cooling jacket 102 and from the cooling jacket 102 into the isolated power module 100 during operation. Figure 1 Also shown in FIG. 1 is an outlet 106 located on the side of the cooling jacket 102 opposite to the inlet 104, through which the cooling fluid can be discharged from the cooling jacket 102 during operation. Figures 2 to 9 In some embodiments shown and described below, the cooling fluid interacts with a heat sink inside the isolated power module 100 .

[0040] Figure 2 is a cross-sectional view of a first example 100a of an isolated power module 100 according to some embodiments of the present invention. In the first example 100a, the isolated power module 100 includes a DBM assembly 200 or isolator coupled to a heat dissipation assembly 202 (e.g., a cooling unit) using a conductive adhesive 203 to effectively dissipate heat generated by the DBM assembly 200. The heat dissipation assembly 202 has a module inlet 204 and a module outlet 206 to direct a flow 103 of a cooling fluid from the cooling jacket 102 to the DBM assembly 200.

[0041] The DBM assembly 200 includes a multi-layer substrate (e.g., a DBM structure 201) supporting a single electronic component (e.g., a single chip or semiconductor die 214). The semiconductor die 214 can be attached to (e.g., mounted or coupled to) a top surface of the DBM structure 201 by a binder 216 (e.g., an epoxy, solder, a silver (Ag) sintering material, and / or an adhesive). During high power operation, the semiconductor die 214 may generate heat and may cause heat accumulation within the isolated power module 100. The DBM structure 201 can be used as a heat sink to provide single-sided cooling of the semiconductor die 214. In some embodiments, the DBM structure 201 can dissipate heat from both the back and front sides, acting as a double-sided heat sink to dissipate heat generated by the isolated power module 100.

[0042] In some embodiments, the semiconductor die 214 may include integrated circuits and / or discrete electronic components suitable for high-power applications. In some embodiments, the semiconductor die 214 may include, for example, a controller and / or an insulated gate bipolar transistor IGBT. An IGBT is a three-terminal device including an emitter, a gate, and a collector. In some embodiments including a plurality of semiconductor dies 214, such a die may include an IGBT and a controller configured to control the IGBT. The controller may also serve as a protection device for the IGBT. For example, the controller may provide temperature protection and / or overvoltage protection for the IGBT. The controller may also limit the amount of current delivered to the IGBT. In some embodiments, the controller may be configured to monitor the IGBT. In some embodiments, other types of semiconductor dies may be used, such as silicon MOSFETs, silicon carbide (SiC) MOSFETs, diodes, and the like. In some embodiments, SiC MOSFETs may replace IGBTs. In some embodiments, a fast recovery diode (FRD) may be used in conjunction with a power transistor.

[0043] The semiconductor die 214 may be fabricated on various types of semiconductor substrates, for example, semiconductor wafers such as silicon (Si), silicon carbide (SiC), gallium (Ga), gallium nitride (GaN), aluminum gallium nitride (AlGaN), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), indium phosphide (InP), glass substrates, sapphire substrates, etc. In general, any type of semiconductor die 214 may be fabricated on any type of substrate.

[0044] In some embodiments, different semiconductor dies 214 may be manufactured on different substrates in a hybrid configuration. For example, a first die may be manufactured using a SiC substrate, while a second die may be manufactured using a silicon substrate. As a specific example, an IGBT may be manufactured on a SiC substrate, while a controller may be manufactured on a silicon substrate. In some embodiments as described herein, multiple semiconductor dies 214 may be manufactured on the same substrate, for example, multiple semiconductor dies 214 may be manufactured on a SiC substrate suitable for high power applications.

[0045] In some embodiments, the DBM structure 201 may be a direct bond copper (DBC) type structure, a direct plating copper (DPC) type structure, or a direct bond aluminum (DBA) type structure. In some embodiments, the DBM structure 201 is designed as a three-layer DBM structure, which includes a non-conductive layer 222 disposed between a first conductive layer 220 and a second conductive layer 224 (e.g., sandwiched between the first conductive layer 220 and the second conductive layer 224). In some embodiments, the non-conductive layer 222 serves as a thermal mass disposed between the first conductive layer 220 and the second conductive layer 224 to absorb and absorb heat. The non-conductive layer 222 may also provide electrical insulation between the first conductive layer 220 and the second conductive layer 224 of the DBM structure 201.

[0046] In some embodiments, the first conductive layer 220 and / or the second conductive layer 224 may be or include a metal layer (e.g., a copper layer, a copper alloy layer) formed on the non-conductive layer 222 (e.g., bonded to, sputtered to, diffused to, thermally formed on the non-conductive layer 222). The first conductive layer 220 may be coupled to a first side of the non-conductive layer 222, and the second conductive layer 224 may be coupled to a second side of the non-conductive layer 222. Depending on the orientation of the device, the first conductive layer 220 or the second conductive layer 224 may be referred to as an upper conductive layer (e.g., a top layer) or a lower conductive layer (e.g., a bottom layer). In some embodiments, the non-conductive layer 222 may be a ceramic, such as silicon nitride (Si3N4) or aluminum oxide (Al2O3), Si3N4 being a ceramic material that is much more expensive than Al2O3. In some embodiments, the DBM structure 201 has a thickness ranging from about 0.5 millimeters (mm) to about 3.0 mm.

[0047] In some embodiments, the semiconductor die 214 can be mounted to (e.g., attached to, coupled to, adhered to) the DBM structure 201 by an adhesive 216. The adhesive 216 can include a solder or sintering layer, such as a conductive epoxy, a silver (Ag) or copper (Cu) sintering material and / or an adhesive, such as an epoxy, a glue or a tape (such as a polyimide tape), or other types of conductive adhesives. In some embodiments including multiple semiconductor dies 214, the first semiconductor die 214 can be coupled to the first conductive layer 220 by two different adhesives. For example, in some embodiments, the first semiconductor die 214 can be attached to the first conductive layer 220 by sintering, while the second semiconductor die 214 is attached to the first conductive layer 220 using a conductive polyimide tape.

[0048] In some embodiments, the first conductive layer 220 can be patterned, for example by etching, to form a die attach that provides support for the semiconductor die 214. In some embodiments, the first conductive layer 220 can be or include a metal redistribution layer (RDL) pattern on which the semiconductor die 214 is mounted (or coupled) using a die attach (DA). The DA can be integrated into or attached to the first conductive layer 220 of the DBM structure 201. In some embodiments, the non-conductive layer 222 and / or the second conductive layer 224 of the DBM structure 201 can have a larger footprint than the die attach.

[0049] The isolated power module 100 may also include one or more wire bonds 218 . The wire bonds 218 may electrically couple the semiconductor die 214 to the first conductive layer 220 .

[0050] Figure 2 Details of the heat dissipation assembly 202 according to some embodiments of the present invention are further shown. Specifically, the heat dissipation assembly 202 includes components for implementing an active cooling method (e.g., nozzle impingement cooling), in which the heat dissipation assembly 202 can be equipped with an inlet chamber 226, an outlet chamber 228, and a nozzle 230 (e.g., a cooling impingement nozzle, two of which are shown in the figure), and the nozzle 230 provides a fluid path between the inlet chamber 226 and the outlet chamber 228. In some embodiments, the outlet chamber 228 surrounds the inlet chamber 226. In some embodiments, the inlet chamber 226 can be disposed between a first portion (e.g., the top) of the outlet chamber 228 and a second portion (e.g., the bottom) of the outlet chamber 228. In some embodiments, both the inlet chamber 226 and the outlet chamber 228 are closed chambers, so that once the fluid moves from the inlet chamber 226 to the outlet chamber 228 via the nozzle 230, the fluid cannot (e.g., substantially cannot) return to the inlet chamber 226. In other words, the nozzle 230 acts as a one-way valve to prevent the hot fluid in the outlet chamber 228 from mixing with the cold fluid in the inlet chamber 226. In some embodiments, the module inlet 204 is disposed below the inlet chamber 226 , and the module outlet 206 is disposed below the outlet chamber 228 .

[0051] In some embodiments, one or more nozzles 230 may be or may include an opening. In some embodiments, one or more nozzles 230 may have a tapered shape. In some embodiments, one or more nozzles 230 may have a circular cross-sectional shape.

[0052] like Figure 2As shown, as indicated by a series of arrows and a linear path 232 connecting the arrows, a stream 103 of cooling fluid (e.g., 103a, 103b, 103c, 103d, and 103e) advances through the heat dissipation assembly 202. A constant flow of new fluid can be provided via the cooling jacket 102. The stream 103a of the fluid from the cooling jacket 102 enters the inlet chamber 226 of the heat dissipation assembly 202 through the module inlet 204 and advances toward the nozzle 230 as a stream 103b. In some embodiments, the inlet chamber 226 or a portion thereof (e.g., a horizontal portion of the inlet chamber) can form a channel for pressurizing the fluid. The nozzle 230 then sprays the pressurized cooling fluid onto the inner wall 229 of the outlet chamber 228 so that the cooling fluid impacts the surface in thermal contact with the lower side of the second conductive layer 224 of the DBM structure 201 via the conductive adhesive 203. The spray from the nozzle 230 is contained within the outlet chamber 228 as stream 103c and is directed to the module outlet 206 as stream 103d, where the cooling fluid is discharged from the outlet chamber 228 as stream 103e. In some embodiments, the structure of the inlet chamber 226 and / or the outlet chamber 228 can be formed from one or more polymer materials, reducing the weight, material cost, and manufacturing cost of the heat sink assembly 202 compared to previous structures using heavy metal (e.g., copper) substrates as the heat sink assembly 202. In some embodiments, the weight of the heat sink assembly 202 can be reduced by as much as 50% to 75% compared to the weight of embodiments of impingement-cooled metal or metal fins (e.g., "pin fins"). In some embodiments, the structure of the inlet chamber 226 and the outlet chamber 228 can be integrated into a housing (e.g., a casing), as described below and as shown in FIG. 5A to FIG. 5C , Figure 6 , Figure 7 and Figure 8 shown.

[0053] In some embodiments, any number of nozzles 230 may be provided along the path of the stream 103, depending on the volume of fluid and the fluid pressure required through the nozzles 230. In some embodiments, the nozzles 230 may take the form of holes through which the cooling fluid enters the outlet chamber 228. In some embodiments, the nozzles 230 may take the form of nozzles that allow for adjustment of the aperture size. In some embodiments, the nozzles 230 may automatically adjust the aperture size based on the fluid pressure. For example, when the fluid pressure in the inlet chamber 226 is high, the aperture may be made larger to adjust (e.g., expand or enlarge) the spray area that impacts the inner wall 229.

[0054] In some embodiments, the cooling fluid may include various concentrations of water and glycol, for example, a 60 / 40 mixture with 60% glycol and 40% water, or a 60 / 40 mixture with 60% water and 40% glycol, or a 50 / 50 mixture. Other examples of cooling fluids may include refrigerants, lubricating oils, or hydraulic fluids. In some embodiments, during operation of the isolated power module 100, the cooling fluid may be maintained at a temperature in the range of about -40°C to about 105°C before flowing through the module inlet 204. When the cooling fluid is transferred from the module inlet 204 to the module outlet 206, the fluid temperature may rise by as much as 2-8 degrees Celsius due to the heat absorbed by the cooling fluid from the DBM. In some embodiments, the flow rate of the flow 103 of the cooling fluid through the inlet chamber 226 may be as high as about 12 liters / minute. In some embodiments, the flow rate of the flow 103 of the cooling fluid in the outlet chamber 228 may be in the range of about 4 liters / minute to about 15 liters / minute. In some embodiments, the flow rate of cooling fluid through the module outlet 206 may be monitored and the flow rate of cooling fluid entering the module inlet 204 may be adjusted accordingly to maintain a desired volume of cooling fluid within the heat sink assembly 202 and / or within the cooling jacket 102 .

[0055] In some embodiments, the properties of the conductive adhesive 203 may significantly affect the effectiveness of the nozzle impingement cooling described above. For example, the thickness of the conductive adhesive 203 (e.g., solder) and / or the thermal conductivity of the conductive adhesive 203 may affect the heat transfer from the second conductive layer 224 to the cooling fluid contained in the outlet chamber 228. For example, in some embodiments, the thickness of the conductive adhesive 203 can be in the range of about 30 microns (μm) to about 100 μm, and the thermal conductivity of the conductive adhesive 203 can be in the range of about 30 watts per kilometer (W / Km) to about 200 W / Km. In some embodiments, the overall size of the isolated power module 100 is approximately 40×40 square millimeters (mm 2 ) to about 250mm x 100mm, or an area of ​​about 1600mm 2 To about 25,000mm 2 within the range.

[0056] Figure 3 is a cross-sectional view of a second example 100b of an isolated power module 100 according to some embodiments of the present invention. In the second example 100b, the isolated power module 100 includes a DBM structure 201 and a plurality of electronic components (eg, a plurality of chips or semiconductor dies 214, two of which are shown in the figure).

[0057] The second example 100b shows further details of the isolated power module 100, such as one or more external connectors 300, and a polymer housing 302 having a polymer cover 304 that provides protection for the isolated power module 100. Figure 3 In some embodiments shown, the polymer housing 302 may have curved sidewalls. The polymer housing 302 and the heat dissipation assembly 202 together surround the exterior of the isolated power module 100b to form an isolated module housing 310. In some embodiments, the polymer housing 302 and the polymer cover 304 may be injection molded parts. In some embodiments, the polymer housing 302 and the polymer cover 304 may be fused using a hot plate or laser welding process. The DBM assembly 200 may be attached to the polymer housing 302 and the polymer cover 304 using a sealing adhesive.

[0058] In some embodiments, polymer housing 302 may include encapsulant 306. In some embodiments, encapsulant 306 may include a molding material, such as a molding compound. For example, the molding compound may include a polymer material, such as an epoxy molding compound (EMC), or a gel, polymer, or other molding material for sealing and protecting various components of isolated power module 100, for example, by encapsulating semiconductor die 214 as a component of isolated power module 100. Encapsulation may be accomplished by, for example, an injection molding process or a transfer molding process.

[0059] In some embodiments, encapsulant 306 may expose DBM structure 201 through openings in encapsulant 306 and / or conductive adhesive 203 (not shown). For example, in some embodiments, Figure 3 As shown, DBM structure 201 can be disposed in an opening in encapsulant 306 and conductive adhesive 203 such that a portion of second conductive layer 224 is exposed at the bottom of isolated power module 100. In some embodiments, DBM structure 202 can be disposed in an opening in encapsulant 306 such that first conductive layer 220 serving as a DA is exposed at the top side of isolated power module 100.

[0060] In some embodiments, one or more external connectors 300 may be busbar connections, such as solid metal bars suitable for high current power distribution. External connectors 300 may be attached to DBM structure 201 by the same adhesive 216 used to attach semiconductor die 214 to DBM structure 201. External connectors 300 extend through polymer cap 304 to connect to external components such as power, ground, or other high power modules. In some embodiments, external connectors 300 may replace conventional lead frames.

[0061] Similar to the first example 100a, each semiconductor die 214 in the second example 100b can be attached to (e.g., mounted to or coupled to) the top surface of the DBM structure 201 by an adhesive 216 (e.g., epoxy, solder, silver (Ag) sintering material, and / or adhesive). In some embodiments including multiple semiconductor dies 214, different semiconductor dies 214 can be coupled to the DBM structure 201 by different adhesives 216. For example, in some embodiments including multiple semiconductor dies 214, a first chip component (e.g., an IGBT) can be attached to the non-conductive layer 222 by a first adhesive 216 (e.g., solder), while a second semiconductor die 214 (e.g., a controller) is attached to the non-conductive layer 222 by a second adhesive 216 (e.g., polyimide tape).

[0062] Similar to the first example 100a, the semiconductor die 214 in the second example 100b can be manufactured on various types of semiconductor substrates as described above. In some embodiments including multiple semiconductor dies 214, different semiconductor dies 214 can be manufactured on different substrates. For example, the IGBT semiconductor die 214 can be manufactured on a silicon substrate, while the controller semiconductor die 214 can be manufactured on a SiC substrate. In some embodiments, multiple semiconductor dies 214 can be manufactured on a common (same) substrate.

[0063] In the second example 100b, the conductive adhesive 203 can extend laterally outward to cover the bottom of the polymer housing 302. In some embodiments, the polymer housing 302 can be wider than the heat sink assembly 202 so that the underside of the polymer housing 302 and the conductive adhesive 203 can overhang the heat sink assembly 202.

[0064] Figure 4 1 is a cross-sectional view of a third example 100c of an isolated power module 100 according to some embodiments of the present invention. In the third example 100c, similar to the second example 100b, the isolated power module 100 includes a DBM structure 201 and a plurality of electronic components (e.g., a plurality of chips or semiconductor dies 214, two of which are shown in the figure), a plurality of external connectors 300 (two of which are shown in the figure), and a polymer housing 302. The third example 100c shows a different shape of the polymer housing 302 with vertical sidewalls.

[0065] The third example 100c further illustrates details of the isolated power module 100, such as an O-ring seal 400 and a mounting bracket 402 having a mounting hole 404. In some embodiments, the module inlet 204 and the module outlet 206 can be sealed using the O-ring seal 400 at the intersection of the inlet 104 and the outlet 106 with the outlet chamber 228 to prevent leakage. The isolated power module 100c can be mounted to a chassis, such as a vehicle chassis or a device chassis, using the mounting bracket 402 by securing hardware in and around the mounting hole 404.

[0066] Figure 5A , Figure 5B and Figure 5C Three different views of an isolated module housing 310 are shown according to some embodiments of the present invention. In some embodiments, the interior of the isolated module housing 310 may combine the module inlet 204, the module outlet 206, and the nozzle 230 to form an integrated nozzle impingement cooler.

[0067] Figure 5A is a top perspective view of an isolation module housing 310 according to some embodiments of the present invention. Figure 5A Shown are heat sink assembly 202, polymer cover 304, and multiple external connectors 300 (20 shown in the figure). In some embodiments, polymer cover 304 can be secured to cooling jacket 102 by corner posts 500 (4 shown in the figure), which can accommodate one or more sets of mounting screws.

[0068] Figure 5B is a bottom perspective view of an isolation module housing 310 according to some embodiments of the present invention. Figure 5B Protrusions of the module inlet 204 and the module outlet 206 extending from the bottom surface of the isolated power module 100 are shown.

[0069] Figure 5C is an exploded view of an isolation module housing 310 according to some embodiments of the present invention. Figure 5C It is shown how the isolated power module 100 including the DBM structure 201 and the external connector 300 is assembled into an isolated module housing 310 and secured by a polymer cover 304 .

[0070] Figure 6 is a top perspective view of an interface between a cooling jacket 102 and an isolated power module 100 according to some embodiments of the present invention. Figure 6 1 shows how an isolated power module 100 (eg, example 100a, example 100b, example 100c, etc.) is attached to a cooling jacket 102. Figure 6The cooling jacket 102 depicted in the illustrated example can accommodate three isolated power modules 100. In some embodiments, the top surface 602 of the cooling jacket 102 can be configured with openings, such as slots 604 (3 are shown in the figure) located on the same side of the cooling jacket 102 as the inlet 104 and slots 606 (3 are shown in the figure) located on the same side of the cooling jacket 102 as the outlet 106. The slots 604 are designed to be connected to the cooling jacket 102 as shown in FIG. Figure 5B The slot 606 is designed to mate with (eg, align with) the module entry 204 on the bottom surface of the isolated power module 100 shown and receive the placement of the module entry 204. Similarly, the slot 606 is designed to mate with the module entry 204 shown in FIG. Figure 5B The module outlet 206 on the bottom surface of the isolated power module 100 shown is docked (eg, aligned) and receives the placement of the module outlet 206. The groove 604 and / or the groove 606 may have different Figure 6 The depicted circular shape, for example, an oval, a square, or any other shape that holds the isolated power module 100 in place.

[0071] Figure 7 is a cross-sectional view of an isolation module housing 310 according to some embodiments of the present invention. Figure 7 The isolated module housing 310 is shown as an integral part of the cooling structure of the isolated power module 100. For example, the module inlet 204 and the module outlet 206 may be formed in the isolated module housing 310, and the inlet chamber 226, the outlet chamber 228, and the nozzle 230 may also be formed in the isolated module housing 310. The DBM structure 201 and the external connector 300 may then be installed in the isolated module housing 310. The polymer cover 304 may then be used to support the external connector 300, which extends upward in the z-direction and passes through a hole in the polymer cover 304.

[0072] Figure 8800 is an exploded view of a manifold 800 of an isolated power module 100 according to some embodiments of the present invention. The manifold 800 provides a structural base and a coolant interface for the isolated power module 100 (three are shown in the figure). In some embodiments, the manifold 800 can be used as an alternative to the cooling jacket 102. Similar to the cooling jacket 102, the manifold 800 can be made of aluminum or a polymer, and the manifold 800 is configured to guide the cooling fluid into the heat sink assembly 202 of the isolated power module 100. The manifold inlet 804 can be aligned with the module inlet 204 so as to dock with the module inlet 204 and guide the cooling fluid upward into the DBM structure 201 in the positive z direction. Similarly, the manifold outlet 806 can be aligned with the module outlet 206 so as to dock with the module outlet 206, thereby guiding the flow of the cooling fluid downward in the z direction away from the DBM structure 201. A first set of mounting screws (not shown) can be used to attach the isolated power module 100 to the manifold 800.

[0073] A printed circuit board assembly (PCBA) 808 may be added above the polymer cover 304 to receive a second set of mounting screws (e.g., mounting screws 810) into the screw holes 404 in the isolation module housing 310. Thus, the mounting screws 810 attach the PCBA 808 to the isolation module housing 310.

[0074] Fig. 9 4 is a flowchart illustrating a method 900 for cooling a power module (eg, isolating the power module 100) according to some embodiments of the present invention. Operations 902 to 910 of the method 400 may be performed according to some embodiments as described below, and with reference to the above Figures 1 to 8 Depending on the particular application, the operations of method 900 may be performed in a different order or not performed at all. It should be noted that method 900 may not completely cool the isolated power module 100. Therefore, it will be understood that additional processes may be provided before, during, or after method 900, and some of these additional processes may be briefly described herein.

[0075] At 902, the method 900 includes directing a flow of a cooling fluid from an inlet (e.g., the inlet 104 of the cooling jacket 102 and / or the module inlet 204) to an inner chamber (e.g., the inner chamber 226) of the isolated power module 100. In some embodiments, the inner chamber 226 forms a channel having a size that can affect the flow rate and / or pressure of the cooling fluid. The size of the channel that directs the flow of the fluid through the inner chamber 226 is a function of the surface area of ​​the DBM and the desired pressure difference between the inner chamber 226 and the outer chamber 228.

[0076] At 904, method 900 includes directing a flow of cooling fluid from inner chamber 226 to outer chamber 228 through an aperture (e.g., through nozzle 230). Nozzle 230 is formed on a wall of inner chamber 226. Cooling fluid can be directed from inner chamber 226 to through nozzle 230 to impact the metal surface of conductive adhesive 203, which is in thermal contact with the underside of second conductive layer 224. In some embodiments, when the cooling fluid flows through a small opening in nozzle 230, the cooling fluid can form a pressurized spray. In some embodiments, the pressurized spray of cooling fluid can become an aerosol, such as an aerosolized spray. In some embodiments, for example, when the fluid pressure difference between module inlet 204 and module outlet 206 exceeds the desired pressure difference, a portion of the cooling fluid can be directed to bypass nozzle 230 via a bypass valve or via a bypass flow nozzle.

[0077] At 906 , the method 900 includes receiving a cooling fluid in an external chamber (eg, the external chamber 228 of the isolated power module 100 ) that is isolated from the internal chamber 226 of the isolated power module 100 such that the cooling fluid does not flow back into the internal chamber 226 .

[0078] At 908, the method 900 includes ejecting a cooling fluid through an outlet (e.g., a module outlet 206 of the isolated power module 100) that is isolated from a module inlet 204 of the isolated power module 100. Isolation is provided by two different chambers, an outer chamber 228 and an inner chamber 226, which are separate and do not allow mixing of the cooling fluid between the two chambers.

[0079] At 910, method 900 includes extracting heat from the cooling fluid via a chiller so that the hot fluid is not recirculated, for example, reused as cooling fluid. Heat extraction enables the use of a closed loop system in which the fluid is recirculated, but only used after the fluid reaches a temperature below a cooling fluid set point. In some embodiments, the chiller can be disposed in the cooling jacket 102.

[0080] As described above, various embodiments of semiconductor device modules for high-power applications incorporate liquid cooling schemes designed to improve reliability and reduce the cost and weight of radiators. Fluid can be pumped from cooling jacket 102 through an inlet to a first reservoir, then sprayed onto a metal surface, and then captured in a second reservoir isolated from the first reservoir. The metal surface can be in thermal contact with the DBM structure of the high-power chip supporting cooling. Inlet, outlet, reservoir, and nozzle can be integrated into the module housing. A manifold can be used instead of a cooling jacket.

[0081] It should be understood that in the foregoing description, when an element such as a layer, region, or substrate is referred to as being located on, connected to, electrically connected to, coupled to, or electrically coupled to another element, it may be directly located on, connected to, or coupled to another element, or one or more intermediate elements may be present. In contrast, when an element is referred to as being directly located on, directly connected to, or directly coupled to another element or layer, there are no intermediate elements or layers. Although the terms directly on, directly connected to, or directly coupled to may not be used throughout the specific embodiments, an element shown as being directly on, directly connected to, or directly coupled to may be referred to as such meaning. The claims of the present application may be modified to reference exemplary relationships described in the specification or shown in the accompanying drawings.

[0082] As used in this specification, the singular may include the plural, unless the context clearly indicates a particular situation. In addition to the orientations depicted in the drawings, spatially relative terms (e.g., above, on, above, below, below, below, lower, top, bottom, etc.) are intended to cover different orientations of the device in use or operation. In some embodiments, the relative terms above and below may include vertically above and vertically below, respectively. In some embodiments, the term adjacent may include lateral adjacent or horizontal adjacent.

[0083] Some embodiments may be implemented using various semiconductor processing and / or packaging techniques. Some embodiments may be implemented using various types of semiconductor device processing techniques associated with semiconductor substrates, including but not limited to, for example, silicon (Si), silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), etc.

[0084] Although certain features of the described embodiments have been shown as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. For example, where appropriate, features shown with respect to one embodiment may also be included in other embodiments. Therefore, it should be understood that the appended claims are intended to cover all such modifications and changes that fall within the scope of the embodiments. It should be understood that they are presented only by way of example and not limitation, and that various changes may be made in form and detail. In addition to mutually exclusive combinations, any part of the apparatus and / or method described herein may be combined in any combination. The embodiments described herein may include various combinations and / or sub-combinations of the functions, components and / or features of the different embodiments described.

Claims

1. A liquid-cooled power module for cooling high-power semiconductor devices, characterized in that: include: A directly bonded metal structure, the directly bonded metal structure comprising a first conductive layer, a second conductive layer, and a non-conductive layer disposed between the first conductive layer and the second conductive layer; a semiconductor die coupled to the first conductive layer of the direct-bonded metal structure; as well as A cooling unit is coupled to the second conductive layer of the directly bonded metal structure, the cooling unit comprising a fluid path such that when a cooling fluid flows through the fluid path, the cooling fluid absorbs heat from at least a portion of the directly bonded metal structure.

2. The liquid-cooled power module according to claim 1, wherein: The cooling fluid impinges upon a surface in thermal contact with the directly bonded metal structure.

3. The liquid-cooled power module according to claim 1, wherein: The directly bonded metal structure includes a dielectric layer disposed between the first conductive layer and the second conductive layer, and the cooling fluid impinges on a surface in thermal contact with the second conductive layer.

4. The liquid-cooled power module according to claim 1, wherein: The cooling unit comprises a polymer-based material.

5. The liquid-cooled power module according to claim 1, wherein: The cooling unit includes an inlet chamber and an outlet chamber which are separated from each other and connected by a cooling impingement nozzle.

6. The liquid-cooled power module according to claim 5, wherein: The cooling unit is configured to direct a flow of cooling fluid from a module inlet to the directly bonded metal structure through a nozzle formed in the cooling unit and then away from the directly bonded metal structure via the outlet chamber.

7. The liquid-cooled power module according to claim 6, wherein: Some of the cooling fluid that has passed through the nozzle is discharged from the cooling unit through a module outlet of the outlet chamber.

8. The liquid-cooled power module according to claim 7, wherein: When the cooling fluid flows between the module inlet and the module outlet, the temperature of the cooling fluid rises by at most between 2 degrees Celsius and 8 degrees Celsius.

9. The liquid-cooled power module according to claim 7, wherein: The module inlet and the module outlet include O-ring seals.

10. The liquid-cooled power module according to claim 1, further comprising: A polymer cap is positioned over the semiconductor die.

11. The liquid-cooled power module according to claim 10, further comprising: An epoxy resin is located between the polymer cap and the semiconductor die.

12. The liquid-cooled power module according to claim 1, wherein: The cooling fluid includes ethylene glycol.

13. A device for cooling a high-power semiconductor device, characterized in that: include: an inner chamber having an inlet; an outer chamber having an outlet, the outer chamber at least partially surrounding the inner chamber; as well as A channel is formed in the inner chamber to direct a flow of a cooling fluid to the outer chamber.

14. The device according to claim 13, wherein: The inner chamber and the outer chamber are formed of polymer material by 3D printing.

15. The device according to claim 13, wherein: The inner chamber and the outer chamber are formed of a polymer material by injection molding.

16. The device according to claim 13, wherein: The channel pressurizes the cooling fluid to form an aerosol.

17. The device according to claim 13, wherein: The inlet is arranged below the inner chamber, and the outlet is arranged below the outer chamber.

18. A method for cooling a high power semiconductor device, characterized in that: include: directing a flow of a cooling fluid from an inlet into an internal chamber formed in a substrate supporting a semiconductor die so that heat is absorbed by the cooling fluid; directing the flow from the inner chamber through a plurality of openings to form a pressurized spray such that the cooling fluid impinges on a metal surface in thermal contact with a directly bonded metal structure; receiving the cooling fluid in an external chamber formed in the base plate; as well as The cooling fluid is ejected from the outer chamber through an outlet, the outlet being isolated from the inlet.

19. The method according to claim 18, wherein: The cooling fluid is disposed beneath the directly bonded metal structure.

20. The method according to claim 18, wherein: The directly bonded metal structure includes a first conductive layer, a second conductive layer, and a non-conductive layer disposed between the first conductive layer and the second conductive layer.

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