Power submodule, power module, and method for manufacturing a power module

Abstract

The power submodule (200) comprises a power semiconductor device (1) having a top surface (10) and a bottom surface (12), and an electrical insulator (2) surrounding the power semiconductor device. The power submodule further comprises a top contact element (3) having a terminal area (30) on the top surface of the power semiconductor device, and an electrically conductive cooling element (6) having a terminal area (60) on the bottom surface of the power semiconductor device. The top contact element and the cooling element are in electrical contact with the power semiconductor device. The terminal areas of the top contact element and the cooling element face away from the power semiconductor device to allow at least two such power submodules to be stacked on top of each other for series electrical connection. The cooling element comprises a cooling structure (7) for cooling the power semiconductor device.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to a power sub-module, a power module, and a method for manufacturing a power module.Furthermore, the present disclosure relates to a method for manufacturing a power sub-module. [Background technology]

[0002] WO 2020 / 250405 relates to a component-embedded substrate and a method for manufacturing a component-embedded substrate. EP 3716321 A1 relates to a component carrier with embedded semiconductor components and embedded highly conductive blocks that are bonded to each other. US Patent Application Publication No. 2007 / 0108560 relates to a stackable power semiconductor packaging system. There is a need for improved power submodules, for example, power submodules having improved cooling characteristics. There is also a need for improved power modules including at least one such power submodule. There is also a need for such power submodules and methods of manufacturing such power modules.

[0003] SUMMARY OF THE INVENTION Embodiments of the present disclosure relate to improved power sub-modules and improved power modules. Further embodiments relate to methods for manufacturing such power sub-modules and methods for manufacturing such power modules. Summary of the Invention [Means for solving the problem]

[0004] First, the power sub-module is specified. According to one embodiment, a power submodule includes a power semiconductor device having a top surface and a bottom surface, and an electrical insulator surrounding the power semiconductor device. The power submodule further includes a top contact element having a terminal area on the top surface of the power semiconductor device and a conductive cooling element having a terminal area on the bottom surface of the power semiconductor device. The top contact element and the cooling element are in electrical contact with the power semiconductor device. The terminal areas of the top contact element and the cooling element face away from the power semiconductor device to enable at least two such power submodules to be stacked on top of each other for series electrical connection. The cooling element includes a cooling structure for cooling the power semiconductor device.

[0005] Typically, power modules for HVDC applications with several stacked sub-modules are stacked on top of each other by using spring contact elements on the top surface of the power semiconductor devices, which ensures that even if a power semiconductor device is destroyed, the electrical series connection is maintained because the spring contact elements form a short circuit with the contact elements on the bottom surface of the power semiconductor device.

[0006] The present invention is based, inter alia, on the recognition that the spring contact elements limit heat conduction through the top surface of the semiconductor device to the next cooling element in the stacking direction. Furthermore, power modules comprising one or more spring contact elements are mechanically complex devices requiring many manufacturing steps and high material costs.

[0007] In the present invention, spring contacts can be omitted. This is due, among other things, to the electrical insulator surrounding the power semiconductor device. Even if the device were to be destroyed, the semiconductor material cannot escape laterally, so electrical contact between the upper top contact element and the lower cooling element is always maintained. When these types of submodules are stacked on top of each other, it is possible to place the top contact element of one power submodule in direct electrical and thermal contact with the cooling element of the next power submodule. This significantly improves the thermal characteristics of the entire power module.

[0008] The terms "top" and "bottom" should not be understood to be limited to directions along the direction of gravity. Instead, they may be used to characterize opposite sides or opposite directions, etc.

[0009] The power semiconductor device is, for example, a power semiconductor chip. It may also be a power semiconductor switch. A power submodule may comprise only one power semiconductor device or, for example, multiple power semiconductor devices electrically connected to each other. The power semiconductor device comprises at least one, for example only one, semiconductor body. The semiconductor body may be made of Si or SiC or diamond or GaN.

[0010] Each power semiconductor device may be assigned an individual electrical insulator, or all power semiconductor devices may be assigned the same electrical insulator. The electrical insulator may be an encapsulant. For example, the insulator is manufactured by transfer molding, such as film-assisted transfer molding, compression molding, or injection molding. The insulator may include or consist of a thermoplastic or thermosetting plastic. For example, the insulator is a resin with, for example, additional filler material. The insulator may be integrally formed.

[0011] The insulator surrounds the power semiconductor device at least laterally. In the laterally direction, the power semiconductor device may be completely surrounded by the insulator. The insulator may thereby be in direct contact with the power semiconductor device or may mold- or conformally surround the power semiconductor device, respectively. In other words, the power semiconductor device may be embedded in the electrical insulator.

[0012] A lateral direction is defined herein as a direction parallel to the top and / or bottom surfaces of the power semiconductor device. The main extension plane of the cooling element and / or the top surface of the cooling element may extend parallel to the top / bottom surfaces of the power semiconductor device.

[0013] The top and bottom surfaces of the power semiconductor device are main surfaces of the device, e.g., parallel to the main extension surface of the power semiconductor device. An upper contact element, also referred to herein as a first contact element, may be in electrical contact with the top surface. A cooling element may be in electrical contact with the bottom surface. The bottom surface of the power semiconductor device is opposite the top surface. The thickness of the power semiconductor device, measured as the distance between the top and bottom surfaces, may be less than the lateral extension of the top and bottom surfaces measured along the top or bottom surfaces. The top and bottom surfaces of the power semiconductor device may be, for example, partially formed by a semiconductor body of the power semiconductor device.

[0014] The upper contact element and the cooling element each have a terminal area intended to electrically connect the upper contact element and the cooling element to the power submodule from the outside. The submodule is configured, for example, to operate with the upper contact element and the cooling element at different electrical potentials. The terminal area is not covered by an electrical insulator. In the unmounted or unassembled state of the power submodule, the terminal area may be exposed, i.e., freely accessible. The terminal area is, for example, a surface of the respective element. The upper contact element and / or the cooling element may each be integrally formed or may each be formed from several parts. Each of the upper contact element and the cooling element is, for example, formed from a metal such as Al or Cu. For example, the upper contact element is a solid metal block.

[0015] The terminal areas of the upper contact element and the cooling element facing in opposite directions can each be flat and / or parallel to each other, making it particularly easy to electrically contact the upper contact element of one of the stacked power submodules with the terminal area of ​​the next one of the stacked power submodules.

[0016] The cooling structure may be or comprise a cooling channel and / or an arrangement of several cooling ribs and / or an arrangement of several cooling pin fins.

[0017] The cooling element may be a busbar. The cooling element may be a carrier for a power submodule and may carry the power semiconductor devices. The cooling element may be continuous. The cooling element may have a lateral extension, measured parallel to a main extension plane of the cooling element, that is greater than the power semiconductor devices.

[0018] According to a further embodiment, the cooling structure comprises a cooling channel or several cooling channels for directing a cooling fluid through the cooling element to cool the power semiconductor device.

[0019] The cooling channel may have several windings. For example, the cooling channel may be S-shaped or serpentine-shaped. The cooling channel may extend from one side end of the cooling element to another side end thereof.

[0020] The cooling channels can be microchannels, for example, having a channel diameter of less than 1 mm. Alternatively, the channel diameter is greater than 1 mm. The cooling fluid can be a liquid or a gas.

[0021] The inlets and / or outlets of the cooling channels may each be located on a side of the cooling element. For example, the inlets and outlets may be arranged so that two power submodules can be fluidly connected in series, with the outlet of one submodule aligned with the inlet of the other submodule to form a fluid connection between the individual cooling channels. Alternatively, the cooling elements of two power submodules may be fluidly connected in parallel, with the inlets capable of supplying cooling fluid at the same temperature.

[0022] According to a further embodiment, the power submodule further comprises a further contact element, also referred to herein as a second contact element, in electrical contact with the power semiconductor device. The further contact element has a terminal area for externally electrically contacting the power submodule. The power submodule is configured to operate with the further contact element at a different potential than the top contact element and / or the cooling element.

[0023] The further contact element may be electrically connected to the top surface of the power semiconductor device. The terminal area of ​​the further contact element is not covered by an electrical insulator. In the unmounted or unassembled state of the power submodule, the terminal area of ​​the further contact element may be exposed, i.e., freely accessible. The terminal area of ​​the further contact element may, for example, be a surface of the element. The further contact element may be formed in one piece or in several pieces. It may be formed from a metal such as Al or Cu. The further contact element may be a solid metal block.

[0024] According to a further embodiment, the terminal areas of the upper contact element and the further contact element are arranged on the same side of the power semiconductor device but at different heights relative to the top surface of the power semiconductor device.

[0025] This means that in the vertical direction pointing from the bottom surface to the top surface of the power semiconductor device, the terminal areas of the upper contact element and the further contact element are both located at the front or rear of the power semiconductor device, for example both terminal areas are located at the top surface, i.e. in the vertical direction at the rear of the power semiconductor device.

[0026] In this specification, two elements being arranged at the same height relative to a flat surface such as the top surface of a power semiconductor device means, for example, that a plane extending parallel to the surface intersects both elements, whereas two elements being located at different heights means, for example, that a plane parallel to the surface and intersecting one of the two elements does not intersect the other one of the two elements.

[0027] The terminal areas of the upper contact element and the further contact element are arranged at different heights relative to the upper surface. For example, the height difference is at least 50 μm, or at least 100 μm, or at least 300 μm. The terminal area of ​​the upper contact element may be arranged at a higher height than the terminal area of ​​the further contact element.

[0028] Such an arrangement further simplifies stacking of power sub-modules without spring contacts, since complex unwinding of the upper contact element and the further contact element is avoided.

[0029] According to a further embodiment, the top contact element and / or the further contact element are incorporated in an electrical insulator, which can electrically insulate the top contact element and the further contact element from each other.

[0030] According to a further embodiment, a bottom contact element is arranged between the cooling element and the power semiconductor device, the bottom contact element being electrically connected to the power semiconductor device.

[0031] The bottom contact element may be formed from a metal such as Al or Cu. For example, the bottom contact element is a lead frame. The bottom contact element may be formed of one piece or several pieces. The bottom contact element, also referred to herein as the third contact element, may be, for example, a substrate having a top metallization and a bottom metallization and an insulating layer, for example, a polymer or ceramic, between the top and bottom metallizations. The bottom contact element may contact the power semiconductor device and / or its semiconductor body at the bottom surface.

[0032] According to further embodiments, the bottom contact element and the cooling element are bonded to one another, for example, by sintering, soldering, welding, or gluing. For example, a bonding layer, such as a sintered layer, a solder layer, a welded layer, or an adhesive layer, is formed between the bottom contact element and the cooling element. The bonding layer can be in direct contact with both the cooling element and the bottom contact element.

[0033] According to a further embodiment, the power semiconductor device is an electrical switch, for example a transistor.

[0034] According to a further embodiment, the top contact element and the cooling element are electrically connected to main electrodes of the power semiconductor device, for example the cathode and anode of the power semiconductor device.

[0035] According to a further embodiment, the further contact element is connected to an auxiliary electrode of the power semiconductor device, the auxiliary electrode being, for example, a gate electrode.

[0036] According to a further embodiment, the power semiconductor device is one of a MOSFET, a MISFET, an IGBT, a BIGT, or a thyristor.

[0037] According to a further embodiment, the top contact element is connected to a source electrode or an emitter electrode of the power semiconductor device. The further contact element may be connected to a gate electrode of the power semiconductor device. The cooling element may be connected to a drain electrode or a collector electrode of the power semiconductor device. For example, the source / emitter and gate electrodes are located on a top surface of the power semiconductor device, and the drain / collector electrodes are located on a bottom surface of the power semiconductor device.

[0038] According to a further embodiment, the power sub-module comprises at least two power semiconductor devices, and all features disclosed in relation to one power semiconductor device are also disclosed for all other semiconductor devices of the sub-module.

[0039] According to at least one embodiment, each of the at least two power semiconductor devices is assigned a respective top contact element and / or a respective further contact element and / or a respective bottom contact element.

[0040] According to a further embodiment, at least two power semiconductor devices are assigned the same cooling element. In other words, the at least two power semiconductor devices share the same cooling element. For example, the at least two power semiconductor devices are bonded to the cooling element. Thus, the cooling element extends over the at least two power semiconductor devices. For example, the at least two power semiconductor devices are arranged on the top surface of the cooling element and laterally spaced apart from each other. The bottom surface of the cooling element opposite the top surface can form a common terminal area for the at least two power semiconductor devices.

[0041] According to at least one embodiment, the power sub-module further comprises at least two electrical insulators. All features disclosed in relation to one electrical insulator are also disclosed for all other electrical insulators.

[0042] According to a further embodiment, each of the at least two power semiconductor devices is assigned a respective insulator surrounding the assigned power semiconductor device, e.g., the insulators of two adjacent power semiconductor devices are laterally spaced apart from each other.

[0043] The power semiconductor devices with individual insulators may each be a so-called chip-scale-package (CSP) component. The footprint of each CSP component may be, for example, at most 50% or at most 30% larger than the footprint of the power semiconductor device. The footprint of a power semiconductor device may be, for example, primarily determined by the footprint of its semiconductor body. For example, at least 90% of the footprint of a power semiconductor device is attributable to its semiconductor body.

[0044] According to a further embodiment, at least two power semiconductor devices, each having a separate insulator, are integrated into a common encapsulant. For example, the common encapsulant may be a thermoplastic or thermosetting plastic, such as a resin. The common encapsulant may be manufactured by molding, for example, injection molding, transfer molding, or compression molding.

[0045] The common encapsulant differs from the electrical insulator specified above. Each power semiconductor device is assigned its own electrical insulator, but a common encapsulant is assigned to several power semiconductor devices. The common encapsulant may be in direct contact with the electrical insulator. However, an interface is then formed between the electrical insulator and the common encapsulant, indicating that the electrical insulator and the common encapsulant are manufactured independently of each other.

[0046] According to a further embodiment, the at least two power semiconductor devices are each assigned a further individual contact element.

[0047] According to a further embodiment, the respective additional contact elements assigned to at least two power semiconductor devices are electrically connected to one another. For example, they are connected by a connecting element, also referred to herein as a second connecting element. The second connecting element can be in direct mechanical contact with the terminal areas of the additional contact elements. For example, the second connecting element is a lead frame or a rigid or flexible circuit board.

[0048] According to a further embodiment, the second connecting element is integrated into the common enclosure. The second connecting element may be guided outside the common enclosure, for example at a side of the common enclosure.

[0049] According to a further embodiment, the common encapsulation, for example its upper surface, terminates flush with the terminal area of ​​the upper contact element.

[0050] Next, the power module is specified. According to one embodiment of the power module, the power module comprises several, i.e., two or more, power sub-modules according to any one of the embodiments described herein. The power sub-modules are electrically connected to each other. For example, the power sub-modules are electrically connected in parallel and / or in series.

[0051] The power module may be adapted to handle currents in excess of 10 A. The power module may be a low voltage module adapted to handle voltages below 1 kV, or may be a medium voltage module adapted to handle voltages between 1 kV and 30 kV.

[0052] According to a further embodiment, at least two power submodules are stacked on top of each other. The stacked power submodules are, for example, connected in series. For example, the terminal area of ​​the upper contact element of at least one of the stacked power submodules faces and is electrically connected to the terminal area of ​​the cooling element of the next one of the stacked power submodules. Hereinafter, "next one" means the next one in the stacking direction.

[0053] According to a further embodiment, the cooling element is arranged on and in electrical contact with the terminal area of ​​the upper contact element of the last one of the stacked power sub-modules, where "last one" here means the last one in the stacking direction.

[0054] According to a further embodiment, at least two power submodules are stacked on top of each other, the submodules comprising at least two power semiconductor devices that are assigned a common cooling element. These two power submodules are, for example, stacked directly on top of each other, i.e., there is no power submodule between them. For example, the top contact elements of at least one of the stacked power submodules are electrically connected to each other by the cooling element of the next one of the stacked power submodules.

[0055] According to a further embodiment, the terminal area of ​​the upper contact element of at least one of the stacked power submodules is in dry electrical contact with the terminal area of ​​the cooling element of the next one of the stacked power submodules. Dry electrical contact means that the terminal areas are only pressed against each other, but are not joined together. Thus, the terminal areas are adjacent to each other in dry electrical contact.

[0056] According to a further embodiment, the power module comprises a pressure device for pressing the stacked power sub-modules together to maintain a dry electrical contact, the higher the pressure, the higher the thermal conductivity between the pressed-together terminal areas, and the pressure device is, for example, electrically insulated from the power sub-modules.

[0057] The pressure device may, for example, comprise a pin extending through the sub-module and its cooling element in the stacking direction. The pressure device may comprise a pressure element at each longitudinal end of the pin. The power sub-module may be disposed between the pressure elements. At least one of the pressure elements may have a threaded connection with the pin, so that when the threaded connection is tightened, the power sub-module is clamped between the pressure elements and pressed against each other. One pressure element threadedly connected to the pin may be a nut. The other pressure element may be a leaf spring.

[0058] According to a further embodiment, the terminal area of ​​the upper contact element of at least one of the stacked power submodules is bonded to the terminal area of ​​the next one of the stacked power submodules. For example, the terminal areas are directly bonded to each other, such as by soldering, welding, sintering, or gluing. Thus, only a solder layer, a sintered layer, a welded layer, or an adhesive layer is disposed between the bonded terminal areas. For example, ultrasonic welding or laser welding may be used to bond the terminal areas.

[0059] According to a further embodiment, the stacked power sub-modules are connected in a half-bridge configuration, for example, the power sub-modules stacked on top of each other belong to two different sides (high side or low side) of the half-bridge.

[0060] A half-bridge is, for example, an electrical circuit comprising two switch structures connected in series between two DC nodes and providing an AC node therebetween. The DC and AC nodes may be electrically connected to terminals of a power module. Each switch structure may comprise one or more power semiconductor devices connected in parallel.

[0061] Power modules may be used, for example, in electrical converters that can rectify DC voltages supplied to a DC link or a battery, such as the battery in an electric vehicle. Inverters may also be capable of generating AC voltages supplied to electric motors, such as the motors in electric vehicles. Power modules may be used in automotive applications, such as electric cars, motorcycles, buses, off-road construction vehicles, trucks, and charging stations. Applications in power grids are also possible, where power modules are part of the electrical converters in HVDC stations that convert high-voltage AC to high-voltage DC and / or vice versa.

[0062] For example, a power module may include two or more power sub-modules, each of which includes two or more power semiconductor devices connected in parallel. Two or more power sub-modules may be stacked on top of each other and connected in series.

[0063] Next, a method for manufacturing a power submodule is specified. The method is suitable for manufacturing, for example, the power submodules described herein. Accordingly, all features disclosed in relation to the power submodule are also disclosed in relation to the method, and vice versa.

[0064] According to one embodiment, the method includes providing an apparatus having a cooling element and at least two power semiconductor devices. Each power semiconductor device has a top surface and a bottom surface. Each power semiconductor device is assigned a separate upper contact element having a terminal area, the upper contact element being disposed on the top surface and electrically connected to the respective power semiconductor device. The power semiconductor devices are disposed adjacent to one another on the cooling element, e.g., mounted and electrically connected to the cooling element, with the terminal areas of the upper contact elements facing away from the cooling element. In a further step, an encapsulant is applied onto the cooling element so that the power semiconductor devices are at least laterally surrounded by the encapsulant. For example, at least a portion of the upper contact elements is thereby embedded in the encapsulant. In a further step, the upper contact elements and / or the encapsulant are partially peeled off, e.g., planarized, until the terminal areas of the upper contact elements facing away from the cooling element terminate flush with the encapsulant and are respectively flush with the cooling element or its top surface.

[0065] For example, the bottom contact elements assigned to the power semiconductor devices may be electrically connected to the cooling element, or the bottom contact elements may be bonded to the cooling element.

[0066] Next, a method for manufacturing a power module is specified. The method is suitable for manufacturing a power module, for example, according to any of the embodiments described herein. Thus, all features disclosed in relation to a power module are also disclosed in relation to a method for manufacturing a power module, and vice versa.

[0067] According to one embodiment of a method for manufacturing a power module, the method includes providing at least two power sub-modules according to any of the embodiments described herein and electrically connecting the power sub-modules to each other.

[0068] According to a further embodiment, at least two power submodules are electrically connected in series by stacking the power submodules to be connected in series on top of each other and electrically connecting the top contact element of at least one of the stacked power submodules to the cooling element of the next one of the power submodules, the resulting device also being referred to herein as an assembly.

[0069] According to a further embodiment, the method comprises manufacturing several assemblies of power sub-modules connected in series as described above, which are then connected in parallel.

[0070] Hereinafter, a power submodule, a power module, a method for manufacturing a power submodule, and a method for manufacturing a power module will be described in more detail with reference to the drawings based on exemplary embodiments. The accompanying figures are included to provide a further understanding. In the figures, elements of the same structure and / or function may be referred to by the same reference symbols. It should be understood that the embodiments shown in the figures are exemplary representations and are not necessarily drawn to scale. To the extent that elements or components correspond to each other in terms of their function in different figures, their description will not be repeated for each of the following figures. For clarity, elements may not appear with corresponding reference symbols in all figures. [Brief explanation of the drawings]

[0071] [Figure 1] FIG. 1 illustrates a first exemplary embodiment of a power sub-module. [Figure 2] FIG. 1 illustrates a first exemplary embodiment of a power sub-module. [Figure 3] FIG. 10 illustrates a second exemplary embodiment of a power sub-module. [Figure 4] FIG. 1 illustrates an exemplary embodiment of a power module. [Figure 5]FIG. 1 illustrates an exemplary embodiment of a power module. [Figure 6] FIG. 1 illustrates an exemplary embodiment of a power module. [Figure 7] 1 is a flowchart of an exemplary embodiment of a method for manufacturing a power sub-module. [Figure 8] 1 is a flowchart of an exemplary embodiment of a method for manufacturing a power module. DETAILED DESCRIPTION OF THE INVENTION

[0072] 1 illustrates, in cross-section, a first exemplary embodiment of a power submodule 200. The power submodule comprises a power component 100 mounted on top of an electrically conductive cooling element 6. The power component 100 comprises a power semiconductor device 1, and a first contact element 3, a second contact element 4, and a third contact element 5. The first contact element 4 is also referred to herein as a top contact element. The second contact element 5 is also referred to herein as a further contact element. The third contact element 5 is also referred to herein as a bottom contact element.

[0073] The power semiconductor device 1 is, for example, a transistor such as an IGBT or a MOSFET, or a thyristor. The first contact element 3 and the second contact element 4 are electrically connected to a top surface 10 of the power semiconductor device 1, and the third contact element 5 is electrically connected to a bottom surface 12 of the power semiconductor device 1. For example, the first contact element 3 is electrically connected to an emitter electrode or a source electrode of the power semiconductor device 1, the second contact element 4 is electrically connected to a gate electrode of the power semiconductor device 1, and the third contact element 5 is electrically connected to a drain electrode or a collector electrode of the power semiconductor device 1.

[0074] The power semiconductor device 1, ie its semiconductor body, may be based on a large bandgap material such as SiC or GaN or diamond.

[0075] The power semiconductor device 1 and the first and second contact elements 3 and 4 are enclosed in an electrical insulator 2. The insulator 2 is an encapsulant manufactured by, for example, transfer molding or injection molding. For example, the insulator 2 is made of resin. The contact elements 3, 4, and 5 are electrically insulated from each other so that they may be at different potentials during operation. The first and second contact elements 3 and 4 are partially electrically insulated from each other via the insulator 2.

[0076] Each of the contact elements 3, 4, 5 and the cooling element 6 comprises a respective terminal area 30, 40, 50, 60 in the form of a terminal surface. In the unmounted configuration of the power submodule 200 shown in Figure 1, the terminal areas 30, 40, 60 are exposed and freely accessible from the outside for external electrical connection.

[0077] 1 , the terminal areas 30, 40 of the first contact element 3 and the second contact element 4 are arranged on the same side of the power semiconductor device 1 but at different heights relative to the top surface 10 of the power semiconductor device 1. The terminal areas 50, 60 of the third contact element 5 and the cooling element 6 are arranged on different sides of the power semiconductor device 1 from the terminal areas 30, 40. The first contact element 3 and the second contact element 4 both protrude from the top surface 20 of the electrical insulator 2, which top surface 20 extends essentially parallel to the top surface 10 of the power semiconductor device 1.

[0078] Due to the fact that the terminal areas 30, 40 of the first contact element 3 and the second contact element 4 are arranged at different heights, the electrical connection of several such power sub-modules 200 is simplified: complex unwinding can be omitted.

[0079] The cooling element of Figure 1 is formed from a metal such as Cu. The cooling element 6 includes a cooling structure 7 in the form of a cooling channel configured to direct a coolant through the cooling element 6. The cooling channel 7 may be a microchannel. For example, the cooling channel 7 extends in a serpentine shape through the cooling element 6 (see also Figure 6).

[0080] The terminal area 50 of the third contact element 5 is bonded to the top surface of the cooling element 6, thereby electrically connecting to the cooling element 6. For example, a solder layer, a sintered layer, or an adhesive layer 65 is formed between the third contact element 5 and the cooling element 6. The cooling element 6 has a lateral extension greater than that of the power component 100.

[0081] 1 is, for example, a so-called chip-scale package in which the footprint of the entire component 100 is determined primarily by the footprint of the power semiconductor device 1 or its semiconductor body. For example, the footprint of the entire component 100 is up to 50% larger than the footprint of the power semiconductor device 1.

[0082] 2 shows in plan view the submodule 200 of FIG. 1 on the top surface 20 of the insulator 2. The area of ​​the terminal region 30 of the first contact element 3 is at least 50% of the area of ​​the top surface 10 of the power semiconductor device 1.

[0083] Figure 3 shows a further exemplary embodiment of a power submodule 200. In contrast to that shown in Figure 1, the power submodule 200 of Figure 3 comprises two power components 100, each having an individual power semiconductor device 1, individual first, second, and third contact elements 3, 4, and 5, and an individual insulator 2. Both power components 100 are mounted laterally adjacent to one another on the same cooling element 6 and are each electrically connected to the cooling element 6 via a bonding layer 65. The cooling element 6 electrically connects the third contact elements 5 of both power components 100 to one another. The second contact elements 4 are also electrically connected to one another via a connecting element 400, also referred to herein as a second connecting element.

[0084] 3, both power components 100 are mounted in a common encapsulation 25, for example a resin. A second connection element 400 is also mounted in the encapsulation 25 and protrudes from a side of the common encapsulation 25. The terminal area 30 of the first contact element 3 terminates flush with the encapsulation 25.

[0085] The power submodule of FIG. 3 may be manufactured as follows (see also the flowchart of FIG. 7): In step S1_1, two power components 100 according to FIG. 1 are attached to the cooling element 6, for example bonded to the cooling element 6. Then, in step S1_2, the power components 100 are encapsulated by a common encapsulant 25. This may be done, for example, by transfer molding or injection molding. Afterwards, in step S1_3, a planarization is performed in which the first contact elements 3 and / or the common encapsulant 25 are flattened until the terminal areas 30 of the first contact elements 3 end up flush with the encapsulant 25 and are located at the same height relative to the upper surface of the cooling element 6.

[0086] Because the encapsulant 25 is formed after the insulator 2 of the power component 100, an interface is formed between the encapsulant 25 and the insulator 1. This is true both when the encapsulant 25 is made of a different material than the insulator 2 or when it is made of the same material as the insulator 2.

[0087] FIG. 4 shows an exemplary embodiment of a power module 1000 in which two power submodules 200 of FIG. 3 are stacked on top of each other, such that the first contact element 3 of the lower power submodule 200 is electrically connected to the cooling element 6 of the upper power submodule 200. An additional cooling element 6 is disposed on the upper power submodule 200 and electrically connected to its first contact element 3. The cooling element 6 is thereby electrically connected to the first contact element 3 and to each other. In this manner, a configuration in which the power submodules 200 are electrically connected in series is achieved, and within each power submodule 200, the power components 100 or power semiconductor devices 1 are electrically connected in parallel, respectively. Each power submodule 200 constitutes one side of a half-bridge. For example, the upper cooling element 6 can constitute a DC+ connection point, the lower cooling element 6 can constitute a DC- connection point, and the middle cooling element 6 constitutes an AC connection point.

[0088] 4, the electrical connection between the first contact element 3 and each adjacent cooling element 6 is a dry electrical connection, in which the contact element 3 is adjacent to and pressed against the respective cooling element 6. For this purpose, a pressure device 800 is used, which presses the cooling element 6 against the adjacent first contact element 3. The higher the pressure, the better the thermal connection between the cooling element 6 and the first contact element 3. Therefore, due to the pressure device 800, the large area of ​​the first contact element 3, and in particular the direct contact between the cooling element 6 and the first contact element 3 (without a spring contact element between them), the heat generated by the power semiconductor device 1 can be efficiently carried away.

[0089] 4 includes a leaf spring 802 connected to one longitudinal end of a pin 802 and a nut 803 connected to the other longitudinal end of the pin 802. The nut 803 is in threaded engagement with the pin 802. The pin 802 extends through the power sub-modules 200. Tightening the nut 802 presses the power sub-modules 200 together.

[0090] FIG. 5 shows a further exemplary embodiment of a power module 1000 (see also FIG. 1 ) having two power submodules 200, each of which comprises only one power component 100 or power semiconductor device 1 mounted on a cooling element 6. The power submodules 200 are stacked on top of each other and are thereby electrically connected in series. Here, the cooling element 6 is also arranged on the upper power submodule 200, so that the first contact elements 3 of this upper power submodule 200 are electrically and thermally connected to the cooling element 6. In contrast to FIG. 4 , the cooling elements 6 are not in dry contact with the adjacent first contact elements 3, but are instead bonded to the adjacent first contact elements 3, for example, by soldering, sintering, gluing, or welding. A corresponding bonding layer 65 is formed between the first contact elements 3 and the respective adjacent cooling elements 6 and is in direct contact with them. Due to this bonding connection, good thermal conductivity is achieved between the first contact elements 3 and the adjacent cooling elements 6.

[0091] The power module 1000 of Figure 5 already comprises half bridges. To increase the power rating characteristics, several of these half bridges can be connected in parallel to form a larger power module 1000, as shown in Figure 6.

[0092] In Figure 6, a plan view is shown on the plane indicated by the dashed line in Figure 5. The dashed line in Figure 6 indicates the plane of the view in Figure 5. According to Figure 5, it can be seen that three smaller power modules 1000, also called assemblies, are connected in parallel with a larger power module 1000. Thereby, the cooling elements 6 of each plane are electrically connected to each other via bus bars 300 welded to the cooling elements 6. The second contact elements 4 of each plane are electrically connected to each other by PCBs 400 press-fitted into the respective second contact elements 4.

[0093] In Figure 6, the cooling channels 7 of the cooling elements 6 are visible. The cooling channels 7 each have a serpentine shape and extend laterally through a respective cooling element 6. Each cooling channel 7 begins at an inlet 70 of the cooling element 6 and ends at an outlet 71 of the cooling element 6. The cooling elements 6 are arranged such that the inlets 70 and outlets 71 of the different cooling elements 6 are fluidly coupled and are aligned to achieve one continuous cooling channel 7 that extends through all three cooling elements 6.

[0094] A flowchart of an exemplary embodiment of a method for manufacturing the power module 1000 of FIG. 6 is shown in FIG. 8. In step S2_1, two power submodules 200 according to FIG. 1 are connected in series by stacking them on top of each other and electrically connecting the first contact element 3 of the lower one with the cooling element 6 of the upper one, for example by soldering. This results in a compact power module 1000 in a half-bridge configuration, also referred to herein as an assembly (see, for example, FIG. 5). In step S2_1, several such assemblies, for example three of them, are manufactured. Then, in step S2_2, the assemblies are connected in parallel by connecting the cooling element 6 via a first connection element 300, for example a bus bar 300, in each plane, and by connecting the second contact element 4 via a second connection element 400, i.e., a PCB 400, in each plane.

[0095] The embodiments illustrated in Figures 1-8 above represent exemplary embodiments and, therefore, do not constitute an exhaustive list of all embodiments. Actual apparatus may differ from the illustrated embodiments, for example, with respect to apparatus, devices, and elements. [Explanation of symbols]

[0096] Reference sign 1. Power semiconductor devices 2 Electrical insulators 3 First / Top Contact Element 4 Secondary / Further Contact Elements 5 Third / Bottom Contact Element 6 cooling elements 7 Cooling structure / cooling channel 10 Top surface of power semiconductor device 1 12 Bottom surface of power semiconductor device 1 20 Upper surface of electrical insulator 2 25 Common Inclusions 30 terminal area of ​​first contact element 3 40 terminal area of ​​second contact element 4 50 terminal area of ​​third contact element 5 60 Terminal area of ​​cooling element 6 65 Bonding layer 70 Entrance 71 Exit 100 Power Components 200 Power Submodule 300 first connecting element 400 Second connecting element 800 Pressure Equipment 801 Leaf spring 802 pin 803 Nut 1000 Power Module S1_1~S2_2 Method steps

Claims

1. A power module (1000) having a plurality of power sub-modules (200), each of which comprises: a power semiconductor device (1) having a top surface (10) and a bottom surface (12); an electrical insulator (2) surrounding said power semiconductor device (1); an upper contact element (3) having a terminal area (30) on the upper surface (10) of the power semiconductor device (1); an electrically conductive cooling element (6) having a terminal area (60) on the bottom surface (12) of the power semiconductor device (1); A power sub-module (200) comprising: - said upper contact element (3) and said electrically conductive cooling element (6) are in electrical contact with said power semiconductor device (1); - the terminal areas (30, 60) of the upper contact element (3) and the electrically conductive cooling element (6) both face away from the power semiconductor device (1) in opposite directions to allow at least two such power sub-modules (200) to be stacked on top of each other for series electrical connection; - said electrically conductive cooling element (6) comprises a cooling structure (7) for cooling said power semiconductor device (1); - said cooling structure (7) comprises cooling channels (7) for directing a cooling fluid through said electrically conductive cooling element (6) to cool said power semiconductor device (1); - said power sub-modules (200) are electrically connected to each other, - at least two power sub-modules (200) are stacked on top of each other, the terminal area (30) of the upper contact element (3) of at least one of the stacked power sub-modules (200) faces and is electrically connected to the terminal area (60) of the conductive cooling element (6) of the next one of the stacked power sub-modules (200); Power module (1000).

2. The power sub-module (200) - further contact elements (4) which are in electrical contact with the power semiconductor device (1) and which have terminal areas (40) for externally electrically contacting the power sub-module (200); Furthermore, - said power sub-module (200) is configured to operate with said upper contact element (3) and said further contact element (4) at different electrical potentials; the upper contact element (3) and the further contact element (4) are located on the same side of the power semiconductor device (1) but at different heights relative to the top surface (10) of the power semiconductor device (1); The power module (1000) of claim 1.

3. The power sub-module (200) a bottom contact element (5) arranged between said electrically conductive cooling element (6) and said power semiconductor device (1); Furthermore, - said bottom contact element (5) is electrically connected to said power semiconductor device (1); - said bottom contact element (5) and said electrically conductive cooling element (6) are bonded to each other; A power module (1000) according to claim 1 or 2.

4. The power sub-module (200) - at least two power semiconductor devices (1) Equipped with - each of the at least two power semiconductor devices (1) is assigned a respective upper contact element (3), at least two of said power semiconductor devices (1) are assigned the same electrically conductive cooling element (6); A power module (1000) according to any one of claims 1 to 3.

5. The power sub-module (200) further comprises: - at least two electrical insulators (2) Furthermore, - each power semiconductor device (1) is assigned an individual insulator (2) surrounding said assigned power semiconductor device (1); - at least two of said power semiconductor devices (1), each with its own insulator (2), are integrated into a common encapsulation (25); at least two of said power semiconductor devices (1) are each assigned a respective further contact element (4), the respective further contact elements (4) assigned to at least two of the power semiconductor devices (1) are electrically connected to one another; The power module (1000) of claim 4.

6. - At least two power submodules (200) stacked on top of each other are power submodules (200) according to claim 4 or 5, the upper contact elements (3) of at least one of the stacked power sub-modules (200) are electrically connected to each other by the electrically conductive cooling element (6) of the next one of the stacked power sub-modules (200), A power module (1000) according to claim 4 or 5.

7. an electrically conductive cooling element (6) is placed on the terminal area (30) of the upper contact element (3) of the last one of the stacked power sub-modules (200) and is in electrical contact with said terminal area (30); A power module (1000) according to any one of claims 1 to 6.

8. the terminal area (30) of the upper contact element (3) of at least one of the stacked power sub-modules (200) is in dry electrical contact with the terminal area (60) of the conductive cooling element (6) of a next one of the stacked power sub-modules (200), - a pressure device (800) of the power module (1000) presses the stacked power sub-modules (200) together to maintain the dry electrical contact; A power module (1000) according to any one of claims 1 to 7.

9. the terminal area (30) of the upper contact element (3) of at least one of the stacked power sub-modules (200) is joined to the terminal area (60) of the electrically conductive cooling element (6) of the next one of the stacked power sub-modules (200), A power module (1000) according to any one of claims 1 to 8.

10. - the stacked power sub-modules (200) are connected in a half-bridge configuration, - the power sub-modules (200) stacked on top of each other belong to different sides of a half-bridge; A power module (1000) according to any one of claims 1 to 9.

11. A method for manufacturing a power module (1000), comprising: - providing at least two power sub-modules (200), Each power sub-module (200) comprises: a power semiconductor device (1) having a top surface (10) and a bottom surface (12); an electrical insulator (2) surrounding said power semiconductor device (1); an upper contact element (3) having a terminal area (30) on the upper surface (10) of the power semiconductor device (1); an electrically conductive cooling element (6) having a terminal area (60) on the bottom surface (12) of the power semiconductor device (1); A power sub-module (200) comprising: - said upper contact element (3) and said electrically conductive cooling element (6) are in electrical contact with said power semiconductor device (1); - the terminal areas (30, 60) of the upper contact element (3) and the electrically conductive cooling element (6) both face away from the power semiconductor device (1) in opposite directions to allow at least two such power sub-modules (200) to be stacked on top of each other for series electrical connection; - said electrically conductive cooling element (6) comprises a cooling structure (7) for cooling said power semiconductor device (1); - said cooling structure (7) comprises cooling channels (7) for directing a cooling fluid through said electrically conductive cooling element (6) to cool said power semiconductor device (1); The method for manufacturing the power module (1000) further comprises: - stacking the power sub-modules (200) to be connected in series on top of each other; - electrically connecting the upper contact element (3) of at least one of the stacked power sub-modules (200) to the conductive cooling element (6) of the next one of the stacked power sub-modules (200); - electrically connecting at least two power sub-modules (200) in series; A method comprising:

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