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] TECHNICAL FIELD 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] 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 comprising 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 DISCLOSURE Embodiments of the present disclosure relate to an improved power sub-module and an improved power module. Further embodiments relate to a method for manufacturing such a power sub-module and a method for manufacturing such a power module. Summary of the Invention [Means for solving the problem]

[0004] First, the power submodule is specified. According to one embodiment, a power submodule comprises 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 comprises a top contact element having a terminal area on the top surface of the power semiconductor device, and an electrically 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 in opposite directions 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 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 when a power semiconductor device is destroyed, the electrical series connection is maintained due to the spring contact elements forming a short circuit with the contact elements on the bottom surface of the power semiconductor device.

[0006] The invention is based, inter alia, on the recognition that the spring contact elements limit the heat conduction through the top surface of the semiconductor device to the next cooling element in the stacking direction. Moreover, a power module with one or more spring contact elements is a mechanically complex device 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 should be destroyed, the semiconductor material cannot escape laterally, so that the electrical contact between the upper top contact element on the upper side and the cooling element on the lower side is always maintained. If these kinds of submodules are stacked on top of each other, it is possible to bring the top contact element of one power submodule into direct electrical and thermal contact with the cooling element of the next power submodule. This significantly improves the thermal properties of the entire power module.

[0008] The terms "top" and "bottom" should not be understood to be limited to an orientation 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. The power submodule may comprise only one power semiconductor device or, for example, a plurality of 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 a 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-formally 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 surface 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 surface of the power semiconductor device.

[0013] The top and bottom surfaces of the power semiconductor device are the main surfaces of the device, e.g., parallel to the main extension surface of the power semiconductor device. The top contact element, also referred to herein as the first contact element, may be in electrical contact with the top surface. The 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 are, e.g., partially formed by the semiconductor body of the power semiconductor device.

[0014] The top contact element and the cooling element each comprise a terminal area intended to electrically contact the top contact element and the cooling element with the power submodule from the outside. The submodule is configured, for example, to operate with the top 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 top contact element and / or the cooling element may each be integrally formed or each may be formed from several parts. Each of the top contact element and the cooling element is, for example, formed from a metal such as Al or Cu. For example, the top contact element is a solid metal block.

[0015] The terminal areas of the top contact element and the cooling element facing in opposite directions can each be flat and / or parallel to each other. In this way, it is particularly easy to electrically contact the top 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 of a power submodule and may carry the power semiconductor device. The cooling element may be a continuous body. 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 device.

[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 is 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 such that two power submodules can be fluidly connected in series, such that the outlet of one submodule is aligned with the inlet of the other submodule to form a fluid connection between the respective cooling channels. Alternatively, the cooling elements of the two power submodules may be fluidly connected in parallel, such that the inlets can provide 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 electrical potential than the top contact element and / or the cooling element.

[0023] The further contact element may be in electrical connection with the top side 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 be, for example, a surface of the element. The further contact element is 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 regions 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 side to the top side 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 at the rear of the power semiconductor device, for example both terminal areas are located at the top side, i.e. in the vertical direction at the rear of the power semiconductor device.

[0026] Two elements being located at the same height relative to a flat surface such as the top surface of a power semiconductor device means in this specification, 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 each plane parallel to the surface and intersecting one of the two elements does not intersect the other one of the two elements.

[0027] Relative to the upper surface, the terminal areas of the upper contact element and the further contact element are arranged at different heights. 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 top contact element and the further contact elements 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 disposed between the cooling element and the power semiconductor device. The bottom contact element is electrically connected to the power semiconductor device.

[0031] The bottom contact element may be formed of 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 of 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 each other, for example, sintered, soldered, welded, or glued. For example, a bonding layer, for example, a sintered layer or a solder layer or 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 a power semiconductor device, for example the cathode and the 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 or 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 or 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. All features disclosed in connection with 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, the 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 onto the cooling element. The cooling element thus extends above the at least two power semiconductor devices. The at least two power semiconductor devices are, for example, arranged on a top surface of the cooling element and laterally spaced apart from one another. A bottom surface of the cooling element opposite to the top surface can constitute 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, for example the insulators of two adjacent power semiconductor devices being 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 is, for example, at most 50% or at most 30% larger than the footprint of its power semiconductor device. The footprint of a power semiconductor device is, 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, e.g., a resin. The common encapsulant may be manufactured by molding, e.g., injection molding or transfer molding or compression molding.

[0045] The common encapsulation is different from the electrical insulator specified above. Each power semiconductor device is assigned an individual electrical insulator, but a common encapsulation is assigned to several power semiconductor devices. The common encapsulation may be in direct contact with the electrical insulator. However, an interface is then formed between the electrical insulator and the common encapsulation, which indicates that the electrical insulator and the common encapsulation were 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 individual further contact elements assigned to the at least two power semiconductor devices are electrically connected to one another. For example, they are connected by a connection element, also referred to herein as a second connection element. The second connection element can be in direct mechanical contact with the terminal areas of the further contact elements. For example, the second connection 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 out of the common enclosure, for example at a side of the common enclosure.

[0049] According to a further embodiment, the common enclosure, 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, a terminal area of ​​a top contact element of at least one of the stacked power submodules faces and is electrically connected to a terminal area of ​​a cooling element of a 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, said submodules comprising at least two power semiconductor devices to which a common cooling element is assigned. 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 these 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 top 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 and are not joined to each other. The terminal areas are therefore 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 terminal areas pressed together. The pressure device is, for example, electrically insulated from the power sub-modules.

[0057] The pressure device may comprise, for example, a pin extending in the stacking direction through the submodule and its cooling element. The pressure device may comprise a pressure element at each longitudinal end of the pin. The power submodule may be arranged between the pressure elements. At least one of the pressure elements may have a threaded connection with the pin, so that upon tightening of the threaded connection the power submodule is clamped between the pressure elements and pressed against each other. One pressure element having a threaded connection with 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 top contact element of at least one of the stacked power submodules is joined to the terminal area of ​​the next one of the stacked power submodules. For example, the terminal areas are directly joined to each other, such as by soldering, welding, sintering or gluing. Thus, only a solder or sintered or welded or adhesive layer is arranged between the terminal areas joined to each other. For example, ultrasonic welding or laser welding may be used to join the terminal areas.

[0059] According to a further embodiment, the stacked power submodules are connected in a half-bridge configuration, for example the power submodules stacked on top of each other belong to two different sides (high side or low side) of a 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] The power module may be used, for example, in an electrical converter that can rectify a DC voltage supplied to a DC link or a battery, such as the battery of an electric vehicle. It may also be possible for an inverter to generate an AC voltage supplied to an electric motor, such as the motor of an electric vehicle. The power module 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 the power module is part of an electrical converter in an HVDC station that converts 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 the power submodules, for example, as described herein. Thus, 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 comprises providing an apparatus having a cooling element and at least two power semiconductor devices. Each power semiconductor device has a top side and a bottom side. Each power semiconductor device is assigned an individual top contact element with a terminal area, said top contact element being arranged on the top side and electrically connected to the respective power semiconductor device. The power semiconductor devices are arranged, e.g. mounted, adjacent to one another on the cooling element and electrically connected to the cooling element, with the terminal areas of the top contact elements facing away from the cooling element. In a further step, an encapsulation is applied onto the cooling element such that the power semiconductor devices are at least laterally surrounded by the encapsulation. For example, at least a part of the top contact elements is thereby integrated into the encapsulation. In a further step, the top contact elements and / or the encapsulation are partially peeled off, e.g. planarized, until the terminal areas of the top contact elements facing away from the cooling element end up flush with the encapsulation and until the terminal areas of the top contact elements are respectively flush with the cooling element or its top side.

[0065] For example, the bottom contact element assigned to the power semiconductor device may be electrically connected to the cooling element. The bottom contact element 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 a top contact element of at least one of the stacked power submodules to a cooling element of a 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. These assemblies are then connected in parallel.

[0070] Hereinafter, the power submodule, the power module, the method for manufacturing the power submodule, and the method for manufacturing the power module will be described in more detail with reference to the drawings based on exemplary embodiments. The attached figures are included to provide 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. Insofar as elements or components correspond to each other in terms of their functions in different figures, the description thereof will not be repeated for each of the following figures. For clarity, elements may not appear with corresponding reference symbols in all figures. [Brief description of the drawings]

[0071] [Figure 1] FIG. 2 illustrates a first exemplary embodiment of a power sub-module. [Diagram 2] FIG. 2 illustrates a first exemplary embodiment of a power sub-module. [Diagram 3] FIG. 2 illustrates a second exemplary embodiment of a power sub-module. [Figure 4] FIG. 1 illustrates an exemplary embodiment of a power module. [Diagram 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 flow chart of an exemplary embodiment of a method for manufacturing a power sub-module. [Figure 8] 1 is a flow chart of an exemplary embodiment of a method for manufacturing a power module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072] 1 illustrates a first exemplary embodiment of a power submodule 200 in a cross-sectional view. The power submodule comprises a power component 100 mounted on the top surface 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, i.e. 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, 4 are surrounded and embedded in an electrical insulator 2. The insulator 2 is an encapsulation produced, for example, by transfer molding or injection molding. For example, the insulator 2 is made of resin. The contact elements 3, 4, 5 are electrically insulated from each other so that they may be at different potentials during operation. The first and second contact elements 3, 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 side 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 than the terminal areas 30, 40. The first contact element 3 and the second contact element 4 both protrude from the top side 20 of the electrical insulator 2, which top side 20 extends essentially parallel to the top side 10 of the power semiconductor device 1.

[0078] Due to the terminal areas 30, 40 of the first contact element 3 and the second contact element 4 being arranged at different heights, the electrical connection of several such power submodules 200 is simplified: complex unravelling can be omitted.

[0079] The cooling element of Fig. 1 is formed from a metal, such as, for example, Cu. The cooling element 6 comprises 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 Fig. 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 or 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 larger lateral extension than 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 regions 30 of the first contact elements 3 is at least 50% of the area of ​​the top surface 10 of the power semiconductor device 1.

[0083] Fig. 3 shows a further exemplary embodiment of a power submodule 200. In contrast to the one shown in Fig. 1, the power submodule 200 in Fig. 3 comprises two power components 100, each having an individual power semiconductor device 1, an individual first contact element 3, a second contact element 4, and a third contact element 5, and an individual insulator 2. Both power components 100 are mounted laterally adjacent to each other 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 each other. The second contact elements 4 are also electrically connected to each other via a connection element 400, also referred to herein as the second connection element.

[0084] In Fig. 3, both power components 100 are embedded in a common encapsulation 25, for example a resin. The second connection element 400 is also embedded 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 flow chart 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 encapsulation body 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 encapsulation body 25 are planarized until the terminal areas 30 of the first contact elements 3 end up flush with the encapsulation body 25 and are located at the same height relative to the upper surface of the cooling element 6.

[0086] Since 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, so 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. A further cooling element 6 is arranged on the upper power submodule 200 and electrically connected to its first contact element 3. Thereby, the cooling element 6 electrically connects with the first contact element 3 and with each other. In this way, a configuration is achieved in which the power submodules 200 are electrically connected in series, and in each power submodule 200, the power components 100 or power semiconductor devices 1, respectively, are electrically connected in parallel. 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] In Fig. 4, the electrical connection between the first contact element 3 and the respective adjacent cooling element 6 is a dry electrical connection, in which the contact element 3 is adjacent to the respective cooling element 6 and pressed against it. 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. Thus, 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 with two power submodules 200, each of which comprises only one power component 100 or power semiconductor device 1, respectively, attached to a cooling element 6 (see also FIG. 1). The power submodules 200 are stacked on top of each other and are thereby electrically connected in series. Also here, a cooling element 6 is arranged on the upper power submodule 200, so that the first contact element 3 of this upper power submodule 200 is electrically and thermally connected to the cooling element 6. In contrast to FIG. 4, the cooling element 6 is not in dry contact with the adjacent first contact element 3, but is bonded to the adjacent first contact element 3, for example soldered or sintered or glued or welded. A corresponding bonding layer 65 is formed between the first contact element 3 and the respective adjacent cooling element 6 and is in direct contact with them. Due to this bonding connection, a good thermal conductivity is achieved between the first contact element 3 and the adjacent cooling element 6.

[0091] The power module 1000 of Fig. 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 Fig. 6.

[0092] In Fig. 6, a plan view is shown on the section plane indicated by the dashed line in Fig. 5. The dashed line in Fig. 6 indicates the section plane of the view in Fig. 5. According to Fig. 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 a busbar 300 welded to the cooling elements 6. The second contact elements 4 of each plane are electrically connected to each other by a PCB 400 that is 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 such that one continuous cooling channel 7 extending through all three cooling elements 6 is achieved.

[0094] A flow chart 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. Thereby, a compact power module 1000 in a half-bridge configuration, also called an assembly in this specification, is manufactured (see, for example, FIG. 5). In step S2_1, several such assemblies are manufactured, for example three of them. Then, in step S2_2, the assemblies are connected in parallel by connecting, in each plane, the cooling element 6 via a first connection element 300, for example a busbar 300, and by connecting, in each plane, the second contact element 4 via a second connection element 400, i.e. a PCB 400.

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

[0096] Reference sign 1. Power Semiconductor Devices 2. Electrical insulators 3 First / Top Contact Element 4 Second / 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 Inclusion Bodies 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 Parts 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 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 said upper surface (10) of said power semiconductor device (1); - an electrically conductive cooling element (6) having a terminal area (60) on said bottom surface (12) of said power semiconductor device (1); A power submodule (200) comprising: - said upper contact element (3) and said cooling element (6) are in electrical contact with said power semiconductor device (1); - said terminal areas (30, 60) of said upper contact element (3) and said cooling element (6) both face away from said 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 cooling element (6) comprises a cooling structure (7) for cooling said power semiconductor device (1); A power sub-module (200).

2. - said cooling structure (7) comprises a cooling channel (7) for directing a cooling fluid through said cooling element (6) to cool said power semiconductor device (1); The power submodule (200) of claim 1.

3. - a further contact element (4) which is in electrical contact with said power semiconductor device (1) and has a terminal area (40) for externally electrically contacting said power submodule (200); Further equipped with - said power submodule (200) is configured to operate with said upper (3) and said further (4) contact elements 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); A power submodule (200) according to claim 1 or 2.

4. a bottom contact element (5) arranged between said cooling element (6) and said power semiconductor device (1); Further equipped with - said bottom contact element (5) is electrically connected to said power semiconductor device (1); - said bottom contact element (5) and said cooling element (6) are joined to each other; A power submodule (200) according to any one of the preceding claims.

5. 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 cooling element (6); A power submodule (200) according to any one of the preceding claims.

6. - at least two electrical insulators (2) Further equipped with - each power semiconductor device (1) is assigned an individual insulation body (1) surrounding said assigned power semiconductor device (1); at least two of said power semiconductor devices (1), each with its own insulator (2), are integrated in 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 submodule (200) of claim 5.

7. - several power sub-modules (200) according to any one of the preceding claims Equipped with - said power sub-modules (200) are electrically connected to each other; Power module (1000).

8. 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 submodules (200) faces and is electrically connected to the terminal area (60) of the cooling element (6) of the next one of the stacked power submodules (200); A power module (1000) according to any one of the preceding claims.

9. a cooling element (6) is arranged 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); The power module (1000) of claim 8.

10. at least two power submodules (200) stacked on top of each other are power submodules (200) according to claim 5 or 6, the upper contact element (3) of at least one of the stacked power submodules (200) is electrically connected to one another by the cooling element (6) of the next one of the stacked power submodules (200); A power module (1000) according to any one of claims 7 to 9.

11. - said terminal area (30) of the upper contact element (3) of at least one of said stacked power submodules (200) is in dry electrical contact with said terminal area (60) of the cooling element (6) of a next one of said stacked power submodules (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 one of claims 7 to 10.

12. the terminal area (30) of the upper contact element (3) of at least one of the stacked power submodules (200) is joined to the terminal area (60) of the cooling element (6) of a next one of the stacked power submodules (200), A power module (1000) according to any one of claims 7 to 11.

13. - 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 7 to 12.

14. A method for manufacturing a power sub-module (200), comprising the steps of: a cooling element (6), at least two power semiconductor devices (1) each having a top surface (10) and a bottom surface (12); - providing an apparatus having - each power semiconductor device (1) is assigned an individual upper contact element (3) having a terminal area (30), said upper contact element (3) being arranged on said top side (10) and electrically connected to said respective power semiconductor device (1); - said power semiconductor devices (1) are arranged adjacent to one another on said cooling element (6) and are electrically connected thereto; - the terminal area (30) of the upper contact element (3) faces away from the cooling element (6); To provide, - applying an encapsulation (25) onto the cooling element (6) such that the power semiconductor device (1) is at least surrounded by the encapsulation (25); - partially peeling off the upper contact element (3) and / or the encapsulation (25) until the terminal area (30) of the upper contact element (3) facing away from the cooling element (6) ends flush with the common encapsulation (25) and until the terminal area (30) of the upper contact element (3) is at the same height relative to the cooling element (6); A method comprising:

15. A method for manufacturing a power module (1000), comprising the steps of: - providing at least two power submodules (200) according to any one of claims 1 to 6, - stacking on top of each other the power sub-modules (200) to be connected in series; - electrically connecting the upper contact element (3) of at least one of the stacked power submodules (200) to the cooling element (6) of the next one of the stacked power submodules (200); - electrically connecting at least two power sub-modules (200) in series; A method comprising:

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