Power sub-module, power module and method for manufacturing a power module

Abstract

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

Description

[0001] The present disclosure relates to a power submodule, a power module, and a method for manufacturing a power module. Furthermore, the disclosure relates to a method for manufacturing a power submodule.

[0002] There is a need for an improved power submodule, e.g., a power submodule with improved cooling properties. Furthermore, there is a need for an improved power module comprising at least one such power submodule. Furthermore, there is a need for a method for manufacturing such a power submodule and such a power module.

[0003] Embodiments of the disclosure relate to an improved power submodule and an improved power module. Further embodiments relate to a method for manufacturing such a power submodule and for manufacturing such a power module.

[0004] First, the power submodule is described in detail.

[0005] According to one embodiment, the power submodule comprises a power semiconductor device having a top side and a bottom side, and an electrically insulating body surrounding the power semiconductor device. The power submodule further comprises an upper contact element having a connection region on the top side of the power semiconductor device and an electrically conductive cooling element having a connection region on the bottom side of the power semiconductor device. The upper contact element and the cooling element are in electrical contact with the power semiconductor device. The connection regions of the upper contact element and the cooling element point away from the power semiconductor device and in opposite directions so that at least two such power submodules can be stacked on top of one another for a serial electrical connection. The cooling element comprises a cooling structure for cooling the power semiconductor device.

[0006] Typically, power modules for high-voltage direct current (HVDC) applications are stacked with multiple stacked submodules using spring contact elements on top of a power semiconductor device. This is intended to ensure that a series electrical connection is maintained even if the power semiconductor device is destroyed, as the spring contact element forms a short circuit with the contact element on the bottom of the power semiconductor device.

[0007] The present invention is based, among other things, on the finding that the spring contact elements limit heat conduction across the top side of a semiconductor device to the next cooling element in the stacking direction. Furthermore, the power module comprising one or more spring contact elements is a mechanically complex arrangement that requires numerous manufacturing steps and high material costs.

[0008] With the present invention, the spring contacts can be omitted. This is due, among other things, to the electrically insulating body surrounding the power semiconductor device. Even if the device were to be destroyed, the semiconductor material cannot escape laterally, so that electrical contact between the upper contact element on the top side and the cooling element on the bottom is always maintained. When these types of submodules are stacked on top of each other, it is possible to bring the upper 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.

[0009] The terms "upper" and "lower" should not be construed as being limited to directions along the gravitational direction. Instead, they can be used to indicate opposite sides, opposite directions, or the like.

[0010] The power semiconductor device is, for example, a power semiconductor chip. It can be a power semiconductor switch. The power submodule can comprise exactly one power semiconductor device or several power semiconductor devices that are, for example, electrically connected to one another. The power semiconductor device comprises at least one, for example, exactly one, semiconductor body. The semiconductor body can be made of Si or SiC or diamond or GaN.

[0011] Each power semiconductor device can be assigned an individual electrically insulating body, or all power semiconductor devices can be assigned the same electrically insulating body. The electrically insulating body can be an encapsulation. The insulating body is produced, for example, by transfer molding, such as film-assisted transfer molding, compression molding, or injection molding. The insulating body can comprise or consist of a thermoplastic or thermosetting plastic. For example, the insulating body is a resin, e.g., with additional fillers. The insulating body can be formed in one piece.

[0012] The insulating body surrounds the power semiconductor device at least in the lateral direction. In the lateral direction, the power semiconductor device can be completely surrounded by the insulating body. The insulating body can thus be in direct contact with the power semiconductor device and can surround the power semiconductor device in a form-fitting or conformal manner. In other words, the power semiconductor device can be embedded in the electrically insulating body.

[0013] A lateral direction is defined here as a direction that runs parallel to the top and / or bottom of the power semiconductor device. A main extension plane of the cooling element and / or a top side of the cooling element can run parallel to the top / bottom of the power semiconductor device.

[0014] The top and bottom sides of the power semiconductor device are main sides of the device, which run, for example, parallel to a main extension plane of the power semiconductor device. The upper contact element, also referred to here as the first contact element, can be in electrical contact with the top side. The cooling element can be in electrical contact with the bottom side. The bottom side of the power semiconductor device is located opposite the top side. The thickness of the power semiconductor device, measured as the distance between the top side and the bottom side, can be smaller than the lateral extensions of the top and bottom sides, measured along the top side or bottom side. The top and bottom sides of the power semiconductor device are, for example, partially formed by the semiconductor body of the power semiconductor device.

[0015] The upper contact element and the cooling element each comprise a connection region which is provided for the external electrical contacting of the upper contact element and the cooling element and thus of the power submodule. The submodule is configured, for example, to be operated with the upper contact element and the cooling element at different electrical potentials. The connection regions are not covered by the electrically insulating body. When the power submodule is not mounted or assembled, the connection regions can be exposed, i.e., freely accessible. The connection regions are, for example, surfaces of the respective elements. The upper contact element and / or the cooling element can each be formed in one piece or can each be formed in multiple pieces. Each of the upper contact element and the cooling element is made, for example, of metal, such as Al or Cu.The upper contact element, for example, is a solid metal block.

[0016] The oppositely facing connection areas of the upper contact element and the cooling element can each be flat and / or parallel to each other. This makes electrical contact between the upper contact element of one of the stacked power submodules and the connection area of ​​the next stacked power submodule particularly easy.

[0017] The cooling structure may be or include a cooling channel and / or an arrangement of multiple cooling fins and / or an arrangement of multiple cooling pin fins.

[0018] The cooling element may be a busbar. The cooling element may be a support of the power submodule and may support the power semiconductor device. The cooling element may be a continuous body. The cooling element may have a greater lateral extension, measured parallel to the main extension plane of the cooling element, than the power semiconductor device.

[0019] According to a further embodiment, the cooling structure comprises one or more cooling channels for guiding a cooling fluid through the cooling element in order to cool the power semiconductor device.

[0020] The cooling channel can have multiple windings. For example, the cooling channel can be S-shaped or meander-shaped. The cooling channel can extend from one lateral end of the cooling element to another lateral end.

[0021] The cooling channel can be a microchannel, e.g., with a channel diameter of less than 1 mm. Alternatively, the channel diameter can be greater than 1 mm. The cooling fluid can be a liquid or a gas.

[0022] An inlet and / or an outlet of the cooling channel can each be arranged on a lateral side of the cooling element. For example, the inlet and outlet are arranged so that two power submodules can be fluidically connected in series, so that the outlet of one submodule is 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 can be fluidically connected in parallel, so that the inlets can be supplied with cooling fluid of the same temperature.

[0023] According to a further embodiment, the power submodule also has a further contact element, hereinafter also referred to as the second contact element, which is in electrical contact with the power semiconductor device. The further contact element has a connection area for external electrical contacting of the power submodule. The power submodule is configured to operate with the further contact element, which is at a different electrical potential than the upper contact element and / or the cooling element.

[0024] The additional contact element can be in electrical contact with the top surface of the power semiconductor device. The terminal area of ​​the additional contact element is not covered by the electrically insulating body. In an unmounted or unassembled state of the power submodule, the terminal area of ​​the additional contact element may be exposed, i.e., freely accessible. The terminal area of ​​the additional contact element may, for example, be a surface of the element. The additional contact element is formed in one piece or in multiple pieces. It may be made of metal such as aluminum or copper.

[0025] The other contact element can be a solid metal block.

[0026] According to a further embodiment, the connection 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 with respect to the top side of the power semiconductor device.

[0027] This means that, in a vertical direction pointing from the underside to the top of the power semiconductor device, the connection areas of the upper contact element and the other contact element are either both located in front of or behind the power semiconductor device. For example, both connection areas are located on the top side, i.e., vertically behind the power semiconductor device.

[0028] Two elements positioned at the same height with respect to a flat surface, such as the top of a power semiconductor device, mean, for example, that a plane parallel to the surface passes through both elements. Conversely, two elements positioned at different heights mean, for example, that each plane is parallel to the surface and passes through one of the elements, but not the other.

[0029] Regarding the top surface, the connection areas of the upper contact element and the other contact element are arranged at different heights. For example, the height difference is at least 50 µm, at least 100 µm, or at least 300 µm. The connection area of ​​the upper contact element can be positioned at a greater height than the connection area of ​​the other contact element.

[0030] Such a configuration further simplifies stacking of the power submodules without spring contacts, as complicated routing of the upper contact element and the further contact element is avoided.

[0031] According to a further embodiment, the upper contact element and / or the further contact element are embedded in the electrically insulating body. The electrically insulating body can electrically insulate the upper and further contact elements from each other.

[0032] According to a further embodiment, a lower contact element is arranged between the cooling element and the power semiconductor device. The lower contact element is electrically connected to the power semiconductor device.

[0033] The lower contact element can be made of metal such as aluminum or copper. For example, the lower contact element can be a conductor frame. The lower contact element can be formed in one piece or in multiple pieces. The lower contact element, also referred to herein as the third contact element, can be, for example, a substrate with upper and lower metallization and an insulating layer, e.g., of polymer or ceramic, between the upper and lower metallization. The lower contact element can contact the power semiconductor device and / or its semiconductor body on the underside.

[0034] According to a further embodiment, the lower contact element and the cooling element are bonded to each other, e.g., sintered, soldered, welded, or glued. For example, a bonding layer, e.g., a sintered layer, soldered layer, welded layer, or adhesive layer, is formed between the lower contact element and the cooling element. The bonding layer can be in direct contact with both the cooling element and the lower contact element.

[0035] According to a further embodiment, the power semiconductor device is an electrical switch, e.g., a transistor.

[0036] According to a further embodiment, the upper contact element and the cooling element are electrically connected to the main electrodes of the power semiconductor device. The main electrodes are, for example, a cathode and an anode of the power semiconductor device.

[0037] According to a further embodiment, the further contact element is connected to an auxiliary electrode of the power semiconductor device. The auxiliary electrode is, for example, a gate electrode.

[0038] According to a further embodiment, the power semiconductor device is one of a MOSFET, MISFET, IGBT, BIGT or thyristor.

[0039] According to a further embodiment, the upper contact element is connected to a source electrode or emitter electrode of the power semiconductor device. The further contact element can be connected to a gate electrode of the power semiconductor device. The cooling element can be connected to a drain electrode or collector electrode of the power semiconductor device. For example, the source / emitter electrode and the gate electrode are located on the top side of the power semiconductor device, and the drain / collector electrode are located on the bottom side of the power semiconductor device.

[0040] According to another embodiment, the power submodule 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 submodule.

[0041] According to at least one embodiment, each of the at least two power semiconductor devices is assigned an individual upper contact element and / or an individual further contact element and / or an individual lower contact element.

[0042] According to a further embodiment, the same cooling element is assigned to the at least two power semiconductor devices. 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 same cooling element. The cooling element thus extends over the at least two power semiconductor devices. The at least two power semiconductor devices are arranged, for example, on an upper side of the cooling element and are laterally spaced from one another. The underside of the cooling element, opposite its upper side, can form a common connection region for the at least two power semiconductor devices.

[0043] According to at least one embodiment, the power submodule further comprises at least two electrically insulating bodies. All features disclosed in connection with one electrically insulating body are also disclosed for all other electrically insulating bodies.

[0044] According to a further embodiment, each of the at least two power semiconductor devices is assigned an individual insulating body that surrounds the associated power semiconductor device. For example, the insulating bodies of two adjacent power semiconductor devices are laterally spaced from one another.

[0045] The power semiconductor devices with the individual insulating bodies can 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 the power semiconductor device thereof. The footprint of the power semiconductor device is, for example, primarily determined by the footprint of the semiconductor body thereof. For example, at least 90% of the footprint of the power semiconductor device is allocated to the semiconductor body thereof.

[0046] According to a further embodiment, the at least two power semiconductor devices, each with an individual insulating body, are embedded in a common encapsulation. For example, the common encapsulation can be a thermoplastic or a thermoset, e.g., a resin. The common encapsulation can be manufactured by molding, e.g., by injection molding, transfer molding, or compression molding.

[0047] The common encapsulation differs from the electrically insulating body described in detail above. Each power semiconductor device is assigned an individual electrically insulating body, while the common encapsulation is assigned to multiple power semiconductor devices. The common encapsulation can be in direct contact with the electrically insulating bodies. However, an interface then forms between the electrically insulating bodies and the common encapsulation, indicating that the electrically insulating bodies and the common encapsulation were manufactured independently of each other.

[0048] According to a further embodiment, the at least two power semiconductor devices are each assigned a further individual contact element.

[0049] According to a further embodiment, the individual additional contact elements assigned to the at least two power semiconductor devices are electrically connected to one another. They are connected, for example, by a connecting element, which is also referred to here as the second connecting element. The second connecting element can be in direct mechanical contact with the connection areas of the additional contact elements. The second connecting element is, for example, a conductor frame or a rigid or flexible printed circuit board.

[0050] According to a further embodiment, the second connecting element is embedded in the common encapsulation. The second connecting element can be guided out of the common encapsulation, e.g., on a lateral side of the common encapsulation.

[0051] According to another embodiment, the common encapsulation, e.g., a top surface thereof, is flush with the connection areas of the upper contact elements.

[0052] Next, the power module will be described in detail.

[0053] According to one embodiment of the power module, the power module comprises a plurality of, i.e., two or more, power submodules according to any of the embodiments described herein. The power submodules are electrically connected to one another. For example, the power submodules are electrically connected in parallel and / or in series.

[0054] The power module can be designed for processing currents of more than 10 A. The power module can be a low-voltage module designed for processing voltages below 1 kV or a medium-voltage module designed for processing voltages between 1 kV and 30 kV.

[0055] According to a further embodiment, at least two power submodules are stacked one above the other. The stacked power submodules are connected in series, for example. For example, the connection area of ​​the upper contact element of at least one of the stacked power submodules points toward the connection area of ​​the cooling element of a next stacked power submodule and is electrically connected to it. Here and below, "next" means the next one in the stacking direction.

[0056] According to a further embodiment, a cooling element is arranged on and in electrical contact with the connection area of ​​an upper contact element of the last of the stacked power submodules. "Last" here means the last one in the stacking direction.

[0057] According to a further embodiment, at least two power submodules are stacked one above the other, wherein the submodules comprise at least two power semiconductor devices to which a common cooling element is assigned. These two power submodules are stacked, for example, directly above one another, i.e., without a power submodule in between. For example, the upper contact elements of at least one of these stacked power submodules are electrically connected to one another by the cooling element of a next stacked power submodule.

[0058] According to a further embodiment, the connection area of ​​an upper contact element of at least one of the stacked power submodules is in dry electrical contact with a connection area of ​​the cooling element of a next stacked power submodule. Dry electrical contact means that the connection areas are only pressed against each other, but not bonded to each other. The connection areas thus adjoin each other in dry electrical contact.

[0059] According to another embodiment, the power module comprises a pressure assembly that presses the stacked power submodules against each other to maintain dry electrical contact. The higher the pressure, the higher the thermal conductivity between the pressed-together connection areas. The pressure assembly is, for example, electrically insulated from the power submodules.

[0060] The compression assembly may comprise a pin extending in the stacking direction, e.g., through the submodules and their cooling elements. The compression assembly may comprise a compression element at each longitudinal end of the pin. The power submodules may be arranged between the compression elements. At least one of the compression elements may be threadedly connected to the pin, so that when the threaded connection is tightened, the power submodules are clamped between the compression elements and pressed against each other. One compression element threadedly connected to the pin may be a nut. The other of the compression elements may be a leaf spring.

[0061] According to a further embodiment, a terminal region of an upper contact element of at least one of the stacked power submodules is bonded to the terminal region of a next stacked power submodule. For example, the terminal regions are bonded directly to one another, e.g., soldered, welded, sintered, or glued. Accordingly, only a solder, sintered, welded, or adhesive layer is arranged between the bonded terminal regions. Ultrasonic welding or laser welding can be used, e.g., to bond the terminal regions.

[0062] According to another embodiment, the stacked power submodules are connected in a half-bridge configuration. For example, stacked power submodules belong to two different sides (high-side or low-side) of the half-bridge.

[0063] A half-bridge, for example, is an electrical circuit that includes two switch structures connected in series between two DC connection points, providing an AC connection point in between. The DC connection points and the AC connection point can be electrically connected to the terminals of the power module. Each switch structure can include one or more power semiconductor devices connected in parallel.

[0064] The power module can be used in an electrical inverter that, for example, rectifies a DC voltage to be supplied to a DC link or a battery, such as the battery of an electric vehicle. It is also possible for the inverter to generate an AC voltage to be supplied to an electric motor, such as the motor of an electric vehicle. The power module can be used in automotive applications, such as electric cars, motorcycles, buses, all-terrain construction vehicles, trucks, and charging stations. Applications in the power grid are also possible if the power module is part of an electrical inverter within an HVDC substation that converts high-voltage AC to high-voltage DC and / or vice versa.

[0065] For example, the power module comprises two or more power submodules, each power submodule comprising two or more power semiconductor devices connected in parallel. Two or more of the power submodules can be stacked on top of each other and connected in series.

[0066] Furthermore, a method for manufacturing a power sub-module is described in detail. This method is suitable, for example, for manufacturing a power sub-module as described here. All features disclosed in connection with the power sub-module are therefore also disclosed for the method, and vice versa.

[0067] According to one embodiment, the method comprises providing an arrangement with a cooling element and at least two power semiconductor devices. Each power semiconductor device has a top and a bottom. Each power semiconductor device is associated with an individual top contact element with a terminal area, the top contact element being located on the top and electrically connected to the respective power semiconductor device. The power semiconductor devices are arranged side by side on the cooling element, e.g., mounted, and are 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 to the cooling element such that the power semiconductor devices are at least laterally surrounded by the encapsulation.For example, at least parts of the upper contact elements are embedded in the encapsulation. In a further step, the upper contact elements and / or the encapsulation are partially separated, e.g., planarized, until the connection areas of the upper contact elements facing away from the cooling element are flush with the encapsulation and until the connection areas of the upper contact elements are at the same height with respect to the cooling element or an upper side thereof.

[0068] For example, the lower contact elements associated with the power semiconductor devices are electrically connected to the cooling element. The lower contact elements can be bonded to the cooling element.

[0069] Furthermore, a method for manufacturing a power module is described in detail. The method is suitable, for example, for manufacturing a power module according to one of the embodiments described here. Therefore, all features disclosed in connection with the power module are also disclosed for the method for manufacturing a power module, and vice versa.

[0070] According to one embodiment of the method for producing a power module, the method comprises a step of providing at least two power submodules according to one of the embodiments described here and electrically connecting the power submodules to one another.

[0071] 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 one above the other and electrically connecting an upper contact element of at least one of the stacked power submodules to the cooling element of a next power submodule. The resulting arrangement is also referred to herein as an assembly.

[0072] According to another embodiment, the method comprises manufacturing multiple assemblies of power submodules connected in series, as mentioned above. These assemblies are then connected in parallel.

[0073] The power submodule, the power module, the method for manufacturing a power submodule, and the method for manufacturing a power module are explained in more detail below with reference to the drawings using exemplary embodiments. The attached figures are included to provide a better understanding. In the figures, elements of the same structure and / or functionality may be designated by the same reference numerals. It is understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale. To the extent that elements or components in different figures correspond to one another in terms of their function, their description will not be repeated for each of the following figures. For reasons of clarity, elements may not appear with corresponding reference numerals in all figures. Fig. 1 and Fig. 2 show a first embodiment of the power submodule, Fig. 3 shows a second embodiment of the power submodule, Fig. 4 to 6 show embodiments of the power module, Fig. 7 shows a flowchart of an embodiment of the method for manufacturing a power submodule, Fig. 8 shows a flowchart of an embodiment of the method for manufacturing a power module.

[0074] Fig. 1 shows a first embodiment of the power submodule 200 in a cross-sectional view. The power submodule comprises a power component 100 mounted on a top side 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 here as the upper contact element. The second contact element 5 is also referred to here as the further contact element. The third contact element 5 is also referred to here as the lower contact element.

[0075] The power semiconductor device 1 is, for example, a transistor, such as an IGBT or a MOSFET, or a thyristor. The first 3 and second 4 contact elements are electrically connected to the top side 10 of the power semiconductor device 1, and the third contact element 5 is electrically connected to a bottom side 12 of the power semiconductor device 1. For example, the first contact element 3 is electrically connected to an emitter 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 or collector electrode of the power semiconductor device 1.

[0076] The power semiconductor device 1, ie a semiconductor body thereof, may be based on a wide band gap material such as SiC, GaN or diamond.

[0077] The power semiconductor device 1 and the first 3 and second 4 contact elements are enclosed and embedded in an electrically insulating body 2. The insulating body 2 is, for example, an encapsulation produced by injection molding or compression molding. For instance, the insulating body 2 is made of a resin. The contact elements 3, 4, 5 are electrically insulated from each other so that they can be at different electrical potentials during operation. The first 3 and the second 4 contact elements are partially electrically insulated from each other by the insulating body 2.

[0078] Each of the contact elements 3, 4, 5 and the cooling element 6 has a respective connection area 30, 40, 50, 60 in the form of a connection surface. Fig. In the unassembled configuration of the power submodule 200 shown in Figure 1, the connection areas 30, 40, 60 are exposed and freely accessible from the outside for external electrical connection.

[0079] In Fig. 1, the connection regions 30, 40 of the first 3 and second 4 contact elements are arranged on the same side of the power semiconductor device 1, but at different heights with respect to the top side 10 of the power semiconductor device 1. The connection regions 50, 60 of the third contact element 5 and of the cooling element 6 are arranged on a different side of the power semiconductor device 1 than the connection regions 30, 40. The first contact element 3 and the second contact element 4 both protrude from a top side 20 of the electrically insulating body 2, the top side 20 of which runs substantially parallel to the top side 10 of the power semiconductor device 1.

[0080] Since the connection areas 30 and 40 of the first 3 and second 4 contact elements are arranged at different heights, an electrical connection of several such power submodules 200 is simplified. Complicated routing is unnecessary.

[0081] The cooling element of Fig. 1 is formed, for example, from metal, such as Cu. The cooling element 6 comprises a cooling structure 7 in the form of a cooling channel, which is configured to conduct a cooling liquid through the cooling element 6. The cooling channel 7 may be a microchannel. For example, the cooling channel 7 extends in a meandering shape through the cooling element 6 (see also Fig. 6).

[0082] The connection region 50 of the third contact element 5 is bonded to a top side of the cooling element 6 and is thereby electrically connected 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 greater lateral extent than the power component 100.

[0083] The performance component 100 in Fig. 1 is, for example, a so-called chip-scale package in which the base area of ​​the entire component 100 is mainly determined by the base area of ​​the power semiconductor device 1 or its semiconductor body. Thus, for example, the base area of ​​the entire component 100 is at most 50% larger than the base area of ​​the power semiconductor device 1.

[0084] Fig. 2 shows the submodule 200 of Fig. 1. Top view of the top surface 20 of the insulating body. 2. The area of ​​the connection area 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.

[0085] Fig. Figure 3 shows another embodiment of the power submodule 200. In contrast to what is shown in Fig. As shown in Figure 1, the performance submodule 200 comprises Fig. 3 shows two power components 100, each with an individual power semiconductor device 1, an individual first 3, second 4, and third 5 contact element, and an individual insulating body 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. The second contact elements 4 are also electrically connected to one another via a connecting element 400, also referred to here as the second connecting element.

[0086] In Fig. 3, the power components 100 are both embedded in a common encapsulation 25, which is, for example, a resin. The second connecting element 400 is also embedded in the encapsulation 25 and protrudes from a lateral side of the common encapsulation 25. The connection areas 30 of the first contact elements 3 are flush with the encapsulation 25.

[0087] The power submodule of Fig. 3 can be produced as follows (see also flow chart in Fig. 7). In a step S1_1, two power components 100 are Fig. 1 is mounted on a cooling element 6, e.g., bonded to the cooling element 6. Subsequently, in a step S1_2, the power components 100 are encapsulated with a common encapsulation 25. This can be done, for example, by transfer molding or injection molding. Subsequently, in a step S1_3, planarization is performed, in which the first contact elements 3 and / or the common encapsulation 25 are planarized until the connection regions 30 of the first contact elements 3 are flush with the encapsulation 25 and are arranged at the same height relative to the top side of the cooling element 6.

[0088] Since the encapsulation 25 is formed after the insulating bodies 2 of the power components 100, an interface is formed between the encapsulation 25 and the insulating bodies 1. This applies both to the case where the encapsulation 25 is made of a different material than the insulating bodies 2 and to the case where it is made of the same material as the insulating bodies 2.

[0089] Fig. Figure 4 shows an embodiment of the power module 1000, in which two of the power submodules 200 are Fig. 3 are stacked one above the other, so that the first contact elements 3 of the lower power submodule 200 are 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 is electrically connected to its first contact elements 3. The cooling elements 6 thereby electrically connect the first contact elements 3 to one another. In this way, a configuration is achieved in which the power submodules 200 are electrically connected in series, wherein within each power submodule 200 the power components 100 or the power semiconductor devices 1 are electrically connected in parallel. Each power submodule 200 forms one side of a half-bridge. For example, the upper cooling element 6 forms a DC+ connection point, the lower cooling element 6 can form a DC- connection point, and the middle cooling element 6 forms an AC connection point.

[0090] In Fig. 4, the electrical connection between the first contact elements 3 and the respective adjacent cooling element 6 is a dry electrical connection, in which the contact elements 3 are adjacent to the respective cooling element 6 and pressed against it. For this purpose, a pressure arrangement 800 is used, which presses the cooling elements 6 against the adjacent first contact elements 3. The higher the pressure, the better the thermal connection between the cooling elements 6 and the first contact elements 3. Thus, the heat generated by the power semiconductor devices 1 can be efficiently dissipated by the pressure arrangement 800, the large surface area of ​​the first contact elements 3, and in particular the direct contact between the cooling elements 6 and the first contact elements 3 (without spring contact elements in between).

[0091] The printing arrangement 800 of Fig. 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 threadedly engaged with the pin 802. The pin 802 extends through the power submodules 200. Tightening the nut 802 forces the power submodules 200 against each other.

[0092] Fig. 5 shows a further embodiment of a power module 1000 with two power submodules 200, each comprising only one power component 100 or power semiconductor device 1, which are mounted on a cooling element 6 (see also Fig. 1). The power submodules 200 are stacked one above the other and thus electrically connected in series. Here, a cooling element 6 is also 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 elements 6 are not in dry contact with the adjacent first contact element 3, but are bonded to the adjacent first contact element 3, e.g., soldered, sintered, glued, or welded. A corresponding bonding layer 65 is formed between and in direct contact with the first contact elements 3 and the respective adjacent cooling elements 6. This bonded connection achieves good thermal conductivity between the first contact element 3 and the adjacent cooling element 6.

[0093] The power module 1000 from Fig. 5 already forms a half-bridge. To increase the rated power characteristics, several of these half-bridges can be connected in parallel to form a larger power module 1000, as shown in Fig. 6 is shown.

[0094] In Fig. 6 is a plan view of a cross-sectional plane defined by the dashed line in Fig. 5. The dashed line in Fig. 6 gives the cross-sectional plane for the view of Fig. 5. As can be seen, three smaller power modules 1000, also called assemblies, are Fig. 5 is connected in parallel with a larger power module 1000. As a result, the cooling elements 6 of each level are electrically connected to each other via a busbar 300 welded to the cooling elements 6. The second contact elements 4 of each level are electrically connected to each other by a PCB 400 that is pressed onto the respective second contact elements 4.

[0095] In Fig. 6, the cooling channels 7 of the cooling elements 6 are visible. The cooling channels 7 each have a meandering shape and extend laterally through the 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 different cooling elements 6 are aligned such that they are fluidically coupled and such that a continuous cooling channel 7 running through all three cooling elements 6 is realized.

[0096] A flowchart of an embodiment of a method for manufacturing the power module 1000 of Fig. 6 will be in Fig. 8. In step S2_1, two power submodules 200 are Fig. 1 are connected in series by stacking them one above the other and electrically connecting the first contact element 3 of the lower one to the cooling element 6 of the upper one, e.g., by soldering. This produces a small power module 1000 in a half-bridge configuration, which is also referred to here as an assembly (see, for example, Fig. 5). In step S2_1, several such assemblies are manufactured, e.g., three of them. Subsequently, in a step S2_2, the assemblies are connected in parallel by connecting the cooling elements 6 in each level via a first connecting element 300, e.g., the busbar 300, and by connecting the second contact elements 4 in each level via a second connecting element 400, namely, the PCB 400.

[0097] The Fig.The embodiments shown in Figures 1 to 8, as cited, represent exemplary embodiments; therefore, they do not constitute a complete list of all embodiments. Actual arrangements may differ from the embodiments shown, for example, with respect to arrangements, devices, and elements. Reference symbol 1 power semiconductor device 2 electrically insulating body 3 first / upper contact element 4 second / additional contact element 5 third / lower contact element 6 Cooling element 7 Cooling structure / cooling channel 10 Top side of power semiconductor device 1 12 Bottom of power semiconductor device 1 20 Top side of electrically insulating body 2 25 common encapsulation 30 Connection area of ​​first contact element 3 40 Connection area of ​​second contact element 4 50 Connection area of ​​third contact element 5 60 Connection area of ​​cooling element 6 65 bond layer 70 entrance 71 Outlet 100 performance components 200 power submodule 300 first connecting element 400 second connecting element 800 printing arrangement 801 leaf spring 802 pen 803 Mother 1000 power module S1_1 to S2_2 process steps

Claims

[1] Power submodule (200), comprising: - a power semiconductor device (1) having a top side (10) and a bottom side (12), - an electrically insulating body (2) surrounding the power semiconductor device (1), - an upper contact element (3) with a connection area (30) on the upper side (10) of the power semiconductor device (1), - an electrically conductive cooling element (6) with a connection area (60) on the underside (12) of the power semiconductor device (1), wherein - the upper contact element (3) and the cooling element (6) are in electrical contact with the power semiconductor device (1), - the connection areas (30, 60) of the upper contact element (3) and the cooling element (6) both point away from the power semiconductor device (1) and in opposite directions so that at least two such power submodules (200) can be stacked on top of each other for a serial electrical connection, - the cooling element (6) comprises a cooling structure (7) for cooling the power semiconductor device (1). [2] Power submodule (200) according to claim 1, wherein - the cooling structure (7) comprises a cooling channel (7) for guiding a cooling fluid through the cooling element (6) in order to cool the power semiconductor device (1). [3] The power submodule (200) of claim 1 or 2, further comprising: - a further contact element (4) which is in electrical contact with the power semiconductor device (1) and has a connection area (40) for external electrical contacting of the power submodule (200), wherein - the power submodule (200) is configured to be operated with the upper (3) and the further (4) contact element 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 side (10) of the power semiconductor device (1). [4] Power submodule (200) according to one of the preceding claims, further comprising - a lower contact element (5) arranged between the cooling element (6) and the power semiconductor device (1), wherein - the lower contact element (5) is electrically connected to the power semiconductor device (1), - the lower contact element (5) and the cooling element (6) are bonded together. [5] Power submodule (200) according to one of the preceding claims, comprising - at least two power semiconductor devices (1), - wherein each of the at least two power semiconductor devices (1) is assigned an individual upper contact element (3); - the same cooling element (6) is assigned to the at least two power semiconductor devices (1). [6] The power submodule (200) of claim 5, further comprising - at least two electrically insulating bodies (2), wherein - each power semiconductor device (1) is assigned an individual insulating body (1) which surrounds the assigned power semiconductor device (1), - the at least two power semiconductor devices (1), each with an individual insulating body (2), are embedded in a common encapsulation (25), - a further contact element (4) is assigned to each of the at least two power semiconductor devices (1); - the individual further contact elements (4) assigned to the at least two power semiconductor devices (1) are electrically connected to one another. [7] Power module (1000), comprising: - a plurality of power submodules (200) according to one of the preceding claims, wherein - the power submodules (200) are electrically connected to one another. [8] Power module (1000) according to one of the preceding claims, wherein - at least two power submodules (200) are stacked on top of each other, wherein - the connection region (30) of an upper contact element (3) of at least one of the stacked power submodules (200) points to the connection region (60) of the cooling element (6) of a next one of the stacked power submodules (200) and is electrically connected thereto. [9] Power module (1000) according to claim 8, wherein - a cooling element (6) is arranged on the connection region (30) of an upper contact element (3) of a last of the stacked power submodules (200) and is in electrical contact therewith. [10] Power module (1000) according to one of claims 7 to 9, wherein - at least two power submodules (200) stacked one above the other are those according to claim 5 or 6, - the upper contact elements (3) of at least one of the stacked power submodules (200) are electrically connected to one another by the cooling element (6) of a next one of the stacked submodules (200). [11] Power module (1000) according to one of claims 7 to 10, wherein - the connection area (30) of an upper contact element (3) of at least one of the stacked power submodules (200) is in dry electrical contact with the connection area (60) of the cooling element (6) of a next one of the stacked power submodules (200); - a pressure assembly (800) of the power module (1000) presses the stacked power submodules (200) against each other to maintain dry electrical contact. [12] Power module (1000) according to one of claims 7 to 11, wherein - a connection region (30) of an upper contact element (3) of at least one of the stacked power submodules (200) is bonded to the connection region (60) of the cooling element (6) of a next one of the stacked power submodules (200). [13] Power module (1000) according to one of claims 7 to 12, wherein - the stacked power submodules (200) are connected in a half-bridge configuration, - the stacked power submodules (200) belong to different sides of a half-bridge. [14] A method of manufacturing a power submodule (200), comprising: - Providing an arrangement with - a cooling element (6), - at least two power semiconductor devices (1), each having a top side (10) and a bottom side (12), - wherein each power semiconductor device (1) is assigned an individual upper contact element (3) with a connection region (30), wherein the upper contact element (3) is arranged on the upper side (10) and is electrically connected to the respective power semiconductor device (1), wherein - the power semiconductor devices (1) are arranged side by side on the cooling element (6) and are electrically connected thereto; - the connection areas (30) of the upper contact elements (3) point away from the cooling element (6); - applying an encapsulation (25) to the cooling element (6) such that the power semiconductor devices (1) are at least surrounded by the encapsulation (25); - partially separating the upper contact elements (3) and / or the encapsulation (25) until the connection areas (30) of the upper contact elements (3) pointing away from the cooling element (6) are flush with the common encapsulation (25) and until the connection areas (30) of the upper contact elements (3) are at the same height with respect to the cooling element (6). [15] Method for producing a power module (1000), comprising - Providing at least two power submodules (200) according to one of claims 1 to 6, - electrically connecting at least two power submodules (200) in series by - Stacking the power submodules to be connected in series (200), - electrically connecting an upper contact element (3) of at least one of the stacked power submodules (200) to the cooling element (6) of a next one of the stacked power submodules (200).

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