Semiconductor power module and method for manufacturing a semiconductor power module

Abstract

A semiconductor power module comprising one or more semiconductors arranged on a substrate having a conductive layer, a housing made of casting compound surrounding at least the substrate and the semiconductor, at least one receptacle with a socket base mounted on the substrate and configured to receive and hold a connector in a substantially upright position perpendicular to the substrate by means of a cavity in the socket shaft defining the upright direction, and at least one sealing ring arranged around the socket shaft and resting on the socket base. The sealing ring is elastically deformed by the casting compound in a direction perpendicular to the base and pressed against the socket base, sealing the socket shaft against the ingress of casting compound into the cavity during the casting of the housing, such that the cavity provides an opening on the outside of the housing.

Description

[0001] The present invention relates to a semiconductor power module and a method for manufacturing a semiconductor power module.

[0002] In power electronics, framed and shaped power modules are common. These semiconductor power modules contain semiconductor components such as semiconductor diodes, transistors, thyristors, rectifiers, and switches, for example, in the form of IGBTs or MOSFETs. These components can be silicon-based semiconductors or, increasingly common, wide-bandgap semiconductors such as silicon carbide (SiC) or gallium nitride (GaN). Power modules typically use load terminals and control pins that protrude from a package.

[0003] For power modules operating at high switching frequencies, especially when using wide-bandgap semiconductor technologies, it is crucial that the contact pins are as short as possible when connecting components, control electronics, or the load. However, molded power modules with protruding contact pins are rare due to the complexity of the necessary manufacturing processes.

[0004] These contact pins are attached to the substrate before forming. To carry out the forming step or process, it is necessary to attach sealing elements that are permanently or semi-permanently connected to the contact pins. These sealing elements must be attached to the contact pins before the pins are fixed to the substrate to ensure they can reliably perform their sealing function.

[0005] A known solution is shown in DE 10 2021 120 935 A1, which discloses a semiconductor power module with one or more semiconductors arranged on a substrate. The power module includes a contact formed by a contact pin enclosed by a plastic sleeve, the sleeve being continuous from its distal region to its proximal region, with the proximal region being in direct contact with the substrate.

[0006] One of the disadvantages of prior art solutions is that the sealing elements must be connected to the contact pins before they can be attached to the substrate. Accordingly, ultrasonic welding of contact pins is difficult and requires complex tooling. Therefore, methods for attaching contact pins to substrates, such as soldering or gluing, are rarely used because they are complex and expensive. If the sealing elements are mounted only after the contact pins have been attached (when using prior art solutions), the sealing elements do not exert pressure on the pin shaft and the sealing contour of the opening in the upper mold half. This has the undesirable consequence that the casting compound can penetrate the opening in the upper mold part or the upper mold half, which can lead to an overflow of casting compound during the casting process and thus to contamination of the mold and / or the contact pin.

[0007] Furthermore, in order to form reliable contact pins and prevent an overflow of the casting material during a casting process, as required by the state of the art, manufacturing costs increase and the process becomes less flexible, as special contact pins and special molds are required.

[0008] Therefore, there is a need for a semiconductor power module that does not have the aforementioned disadvantages of the state of the art.

[0009] It is therefore an objective of the present invention to provide a method for the improved fabrication of semiconductor power modules, in which a sufficiently tight seal of the opening in the upper mold or the upper mold half can be created to prevent overflow of casting material and / or contamination of the contact pin, while increasing the versatility of the contact pin configuration without increasing manufacturing costs. The improved fabrication method is intended to enable a simple, flexible, robust, and cost-effective manufacturing process for semiconductor power modules with high reproducibility. A further objective is to provide a semiconductor power module that can be fabricated without the aforementioned disadvantages.

[0010] The object of the present invention is achieved according to independent claim 1 by a semiconductor power module and by a method according to parallel independent claim 13. Preferred embodiments are defined in the dependent claims, explained in the following description, and illustrated in the accompanying drawings.

[0011] The semiconductor power module according to the invention comprises one or more semiconductors arranged on a substrate with a conductive layer, a housing made of cast material that encapsulates at least the substrate and the semiconductor, at least one receptacle with a receptacle base mounted on the substrate and configured to receive and hold a connector in a position substantially perpendicular to the substrate by means of a cavity in the receptacle shaft that defines the upright direction, and at least one sealing ring arranged around the receptacle shaft and resting on the receptacle base.The sealing ring is pressed firmly against the connector socket base by the casting compound in a vertically deformed elastic state and seals the connector socket shaft against the ingress of casting compound into the hollow area during the casting step of the housing in such a way that the hollow area provides an opening on the outer surface of the housing.

[0012] The substrate of the power module according to the invention, on which the one or more semiconductors are arranged, can be a direct copper bonding (DCB) substrate, such as a silicon dioxide (SiC) or aluminum nitride (AlN) ceramic, or the like. The use of a DCB ceramic can be advantageous due to its good thermal conductivity. As is known in the art, various types of semiconductor devices, such as semiconductor diodes, transistors, thyristors, or switches, can be mounted on such a semiconductor DCB ceramic.

[0013] Both the DCB substrate and the semiconductor components can be electrically contacted laterally on the outside of the power module, i.e., essentially parallel to the main extension directions of the substrate, by means of electrical contact pins or terminals. According to the invention, at least one further connector socket extends essentially vertically, i.e., at right angles or at an angle of approximately 90° to the substrate, and is open to the outside of the power module or protrudes from the power module with a terminal on a side parallel to the substrate. The vertical connector socket is electrically connected to the substrate or at least to a semiconductor arranged on the substrate.In the further course of the description of the invention, any orientation or shape of a connector socket falls under the term vertical connector socket, as long as a connection area of ​​the connector socket is exposed on the top or bottom of the power module from the potting compound or the housing of the power module, even if the connector socket has an S-shape or similar.

[0014] The vertical connector socket can be attached to the substrate via its socket base by soldering, ultrasonic welding, laser welding, gluing, sintering, or press-fitting. In one embodiment, the connector socket is a press-fit socket that can be inserted into bores in the substrate, e.g., in a printed circuit board (PCB), another example of a DCB substrate according to the invention. In another embodiment, the connector socket can have bores or threaded holes in the socket base that are connected to the substrate by a screw connection to electrically connect the connector socket and fix it to the substrate.

[0015] Preferably, after the vertical connector socket is attached to the substrate or semiconductor, a sealing ring and a washer are fitted to the connector socket shaft, so that the sealing ring deforms elastically when the mold is closed, at least partially enclosing the one or more semiconductors, the substrate, and the connector socket. A mold typically consists of two mold halves, with the substrate, the one or more semiconductors, and the connector socket initially arranged in the first (lower) mold half. In this state, the vertical connector socket does not protrude beyond the parting line of the mold with its terminal end. The arrangement of the sealing ring and washer protrudes slightly beyond the parting line, so that the sealing ring deforms elastically when the second mold half is placed onto the first mold half to seal the cavity at the parting line.The sealing ring and washer are arranged in such a way that they are securely held on the connector socket. In this state, the remaining cavity of the mold is prepared to be filled with casting compound in order to at least partially surround and encapsulate the substrate, the semiconductor(s), and the connector socket.

[0016] In the area of ​​the end of the connector socket furthest from the substrate, the mold can have a flat surface that contacts and rests flush against the sealing ring or washer to seal the area above the connector socket. In such a case, the connector socket shaft does not protrude above the potting compound. Otherwise, the socket shaft would be compressed or crushed by the mold. However, it is also possible for the connector socket shaft to be flush with the potting compound, so that the mold does contact the socket shaft. In this case, however, the contact force must be low. Otherwise, the connector socket shaft and / or the circuit board, the semiconductors, and / or even the substrate could be damaged or affected.

[0017] Since the mold seals the area above the connector socket shaft, the casting compound does not reach the top of the socket shaft, and the end face of the socket shaft is not embedded in the casting compound but lies outside of it. Therefore, the end face of the socket shaft is exposed after the encased power module is removed from the mold. During manufacturing, the mold is pressed against the washer, and a compressive force is exerted by the washer to elastically deform the sealing ring in the direction of the connector socket axis when the upper mold half is placed onto the parting line of the lower mold half to close the cavity. In this closed state of the mold, casting compound can be poured into the mold cavity while the sealing ring remains deformed according to the invention.

[0018] Due to the axial elastic deformation of the sealing ring, restoring forces of the sealing ring create a good sealing force in the axial direction. This force presses the washer against the inner surface of the upper mold half, and the sealing ring seals against the underside of the washer and against the connector base on the underside, or against a second washer if the connector base does not provide a suitable sealing surface. These elastic restoring forces of the sealing ring must be maintained at least until the casting compound / sealant has cured. Once the casting compound has cured, the washer is surrounded and fixed by the casting compound / sealant. In this state, the cured casting compound is solid and can no longer flow, meaning it cannot contaminate the terminal end, i.e., the end face of the connector socket shaft.Furthermore, the hollow area formed in the connector socket shaft is also open to the outside of the casting compound. This hollow area can have a round, oval, or rectangular cross-section.

[0019] It is also possible that the upper mold does not have a flat surface. In this case, it is only necessary that the lower surface of the upper mold comes into contact with the washer or sealing ring. With such contact, one end face of the connector socket shaft is protected against the ingress of the casting compound. Furthermore, in such a case, the connector socket shaft may protrude from the potting compound. The protruding connector socket shaft could, for example, be accommodated in a recess formed in the mold.

[0020] According to the invention, the sealing ring is also fixed on its radial outer surface by the casting material during the casting process of the semiconductor(s), substrate, and connector socket. Once the casting has hardened, the washer and the sealing ring can no longer move or expand in the direction of the connector socket axis. Therefore, the sealing ring remains in its elastically deformed state once the casting material has hardened.

[0021] In one embodiment of the invention, the sealing ring, which is elastically deformed / compressed in the direction of the connector axis, seals against the washer and, on its inner side, also against the connector axis, so that when the mold is filled, no casting compound can flow along the connector axis and penetrate the connector shaft. This means that no casting compound can contaminate the end of the vertical connector; in other words, the end face of the connector shaft and the hollow area formed in the connector shaft are essentially free of casting compound. In the compressed / deformed state, the sealing ring is flattened in its axial direction while expanding in the radial direction.Although in this embodiment the sealing ring also seals with the plug socket shaft due to the radial extension of the sealing ring, this feature is not essential for the invention, since the sealing contact of the sealing ring in the axial direction on both the top and bottom sides is already sufficient to prevent the ingress of casting compound onto the end surface of the plug socket shaft and the hollow area.

[0022] Since the sealing ring is elastically deformed and seals against the socket base, against the washer, or against two washers in the case of a sandwich-like socket arrangement, and since the upper washer is pressed downwards towards the socket shaft by closing the second mold half, all radial paths for the penetration of casting compound to the socket shaft are tightly sealed, so that no casting compound can reach the socket shaft and rise up the socket shaft to contaminate the terminal end.

[0023] In a preferred embodiment, the sealing ring rests on the connector base, requiring only one washer resting on the sealing ring. When the mold is closed, the washer is pressed downwards, elastically deforming the sealing ring against the connector base. If the cross-section of the connector base is smaller than the radial extent of the required diameter of the sealing ring's support, or even smaller than the opening in the sealing ring, the sealing ring would rest on the substrate, the semiconductor, or another component of the power module.Although this is not a preferred embodiment, it is covered by the idea of ​​the invention, since this solution could be feasible as long as the substrate or the other components of the power module are not damaged by the force that elastically deforms the sealing ring and as long as no short circuit, leakage current, impedance or other parasitic current occurs through the direct contact of the sealing ring with the adjacent components.

[0024] Those skilled in the art will recognize that, according to the invention, the sealing ring and the washer can also be applied to the connector socket in the opposite direction, i.e., such that the washer contacts the base of the connector socket and the sealing ring contacts the lower inner surface of the upper mold half. In this embodiment, the upper mold half elastically deforms the sealing ring directly when the mold is closed. In this case, the sealing ring would be visible on the top surface of the finished power module. However, the casting compound is hardened in this state, and no contamination of the connector socket shaft by the casting compound can occur, so that a power module according to the invention is obtained here as well.

[0025] In a further preferred embodiment of the invention, the sealing ring is arranged sandwich-like between two washers in order to be fixed in a deformed state in the closed mold and furthermore in the power module, thereby sealing with both washers and optionally with the connector socket shaft. This embodiment is preferred when the connector socket base has insufficient radial extension or a support that is too small for direct sealing with the sealing ring, i.e., when the support of the connector socket base is too small to ensure reliable elastic deformation of the sealing ring without damaging the sealing ring or the components of the power module arranged on the substrate, or damaging the applied / printed circuit.If there is a risk that the sealing ring or washer will touch the applied circuit on the substrate, it is preferred that the lower washer, which touches the circuit and / or the plug socket base, is made of an electrically non-conductive material to prevent short circuits, leakage current, impedance, inductance or other parasitic currents.

[0026] The sealing ring preferably consists of a natural or synthetic elastomer or silicone material that is elastically deformable, such that the sealing ring is able to maintain a sealing contact against the washer and / or the second mold half, at least during the casting / sealing step in which the substrate, the one or more semiconductors, and the connector socket are at least partially surrounded / encapsulated, due to internal restoring forces. Since, according to the invention, the sealing ring does not have to perform any function other than sealing with the washer(s), the connector socket base, and / or the underside of the mold, the sealing ring is preferably a standard component, i.e., a standardized component that can be acquired easily and inexpensively.Since the washer(s) according to the invention need not fulfill any function other than providing axial surfaces that can seal under pressure with another flat surface or with the sealing ring, the washer(s) can also be selected as standardized components that can be purchased. Standardized washers are available in a huge variety of diameters and thicknesses. Thicker washers are also known as spacers or simply as standoffs. All these variants of washers can thus be used according to the invention to bridge the gap between the connector socket base or the substrate and the upper outer surface of the power module housing, together with the deformed sealing ring.In other words, the washer(s) should be selected in height such that the length of the sealing ring assembly with one or two washers, when placed on the connector base, is greater by the amount by which the sealing ring elastically deforms when the two mold halves are joined. The elastic deformation of the sealing ring should be sufficient to ensure a good sealing pressure that prevents molten casting material from penetrating radially between the connector base and the sealing ring or washer, or between the sealing ring and the washer, or between the washer and the lower inner surface of the upper mold half.

[0027] Furthermore, according to the invention, at least one washer or both washers are made of metal, plastic, reinforced plastic, ceramic, or elastic material, depending on economic or technical reasons / requirements, in order to avoid short circuits, leakage currents, inductance, or other parasitic currents. It should be noted that the washers can be electrically conductive or electrically insulating, and the material can be metallic, organic, inorganic, or a combination of these materials.

[0028] According to the invention, the cross-section of the connector socket and the socket shaft, which extends perpendicular or substantially perpendicular to the substrate, can have any shape, preferably round, oval, or rectangular. Corresponding to the cross-section of the connector socket, the sealing ring or the opening in the sealing ring has a suitable shape to surround the connector socket shaft. The washer(s) need not necessarily have the same outer or inner shape as the sealing ring, since the sealing ring seals with the washer(s) primarily in the axial direction, i.e., in the direction of the connector socket axis.

[0029] In a further embodiment of the invention, more than one upper contact or one lower contact can be brought to the outside by means of a connector socket which is connected perpendicular to the substrate to an electrical element of the power module. In all these cases, according to the invention, each connector socket can be brought to the outside separately, i.e., a sealing ring and at least one washer can be arranged on each connector socket, so that when the power module is potted, no liquid potting compound runs / flows along the connector socket and contaminates the terminal end of the connector socket.

[0030] In the event that a power module is designed such that a lower contact runs parallel to an upper contact, the idea according to the invention is applicable analogously, with the difference that the substrate in the first mold half is pushed into its final vertical position when the second mold half is positioned on the parting plane.

[0031] In a further embodiment of the power module according to the invention, several connector sockets arranged vertically on the substrate can be sealed in such a way that their terminal ends are not contaminated by the potting compound. Each connector socket can separately accommodate a sealing ring and at least one washer, or a possibly oval sealing ring and at least one washer can enclose all the shafts of the connector socket. This works particularly well when two or more connector sockets have the same electrical potential and can reduce the number of parts required for assembling the power module. A person skilled in the art would likely use a solution in which the (possibly oval or rectangular) sealing ring is sandwiched between two (possibly oval or rectangular) washers.A person skilled in the art will also find other ways to reduce the number of parts in order to complete power modules according to the invention with more than one upper or lower contact. All these solutions are therefore encompassed by the invention.

[0032] Furthermore, the connector socket can be designed in a press-fit configuration. This means that the connector socket provides a press-fit connection to the outside. According to the invention, the connector socket is open to the outside of the potting compound. A press-fit connection is provided on this exposed part of the connector socket. On the exposed part of the connector socket, for example, a recess or an opening, both referred to as a cavity, is located axially along the connector socket or connector socket shaft and centered on the axial direction. Therefore, a cross-section along the axial direction can have a U-shape or resemble an inverted "pi". The cavity can have any shape and does not necessarily have to be aligned parallel to the central axis of the connector socket. The cross-section in the radial direction of this cavity can be circular, rectangular, oval, or another shape.Accordingly, a counterpart can be inserted into this cavity of the connector socket and pressed in. The counterpart can have a different cross-sectional shape to improve the press-fit connection.

[0033] The connector socket according to the invention allows for flexible external connection via a press-fit connection suitable for the respective application. If the connector socket shaft does not protrude from the potting compound, the mold can be the same for different connection configurations. If, for example, the connector socket were to protrude from the potting compound, the mold would require a recess to accommodate the connector socket and prevent it from being crushed or bent when the two molds come into contact. However, the mold according to one embodiment of the present invention can have a flat surface. Therefore, different connector socket arrangements can be realized while always using the same mold. This leads to a reduction in manufacturing costs, since individual molds are not required for the production of the power modules.

[0034] Furthermore, a flat surface allows for better stacking and packaging of power modules, as it prevents damage to connectors that protrude from at least one surface. This applies both to transport and to the use of numerous power modules stacked together. For example, two power modules could potentially be connected using pins with two press-fit terminals.

[0035] Furthermore, the connector configuration can be easily modified and varied across different power modules. This increases flexibility and customization for both the manufacturer and the customer. In addition, specific connections can be provided without compromising manufacturing reliability.

[0036] It is noted that the power modules are connected to a higher-level system by connecting their externally open terminals. The prior art and the present invention differ in that the prior art provides at least one protruding terminal, while the present invention provides at least one press-fit terminal. The use of the press-fit terminal allows a press-fit pin or a contact pin of the press-fit design to be inserted into the cavity of the connector socket after the casting process, thus creating a protruding terminal. As a result, the press-fit connection is transformed into a protruding connection after the casting process, so that the customer receives a power module with the same connections as in the prior art.

[0037] Furthermore, the present invention provides a method for manufacturing a semiconductor power module with one or more semiconductors arranged on a substrate with a conductive layer, wherein the substrate and the semiconductors are at least partially covered by a housing formed from a potting compound, and wherein at least one opening is provided in the housing for electrical contacting the conductive layer. The method comprises the steps of providing a substrate with a conductive layer and one or more semiconductors arranged thereon, attaching at least one connector socket with a socket base to the conductive layer such that the socket shaft extends perpendicular to the substrate, and placing a sealing ring over the socket shaft so that the sealing ring rests on the socket base.Positioning the substrate with the connector socket and the sealing ring in a first mold half, closing the first mold half in an upright direction parallel to the connector socket shaft using a second mold half, thereby elastically deforming the sealing ring by pressing it onto the connector socket by means of the second mold half, so that the second mold half closes a cavity of the connector socket, the sealing ring sealing the connector socket shaft against the ingress of molding compound into the cavity, filling the cavity of the mold with potting compound, opening the mold after the potting compound has hardened and removing the semiconductor power module from the mold.

[0038] With reference to the accompanying figures, preferred embodiments of a power module according to the invention are explained in more detail to improve understanding of the basic idea of ​​the invention. The present embodiments do not limit the scope of the concept according to the invention, but merely represent possible alternative embodiments to which modifications can be made with the knowledge of a person skilled in the art in the relevant field, without deviating from the scope of the invention. Therefore, all such modifications and changes are covered by the claimed invention. The figures show: Fig. 1 a first embodiment of the power module according to the invention before the closing of the mold tool; Fig. 2 the power module from Fig. 1 with closed forming tool; Fig. the power module from Fig. after removal from the mold; Fig. 4 a second embodiment of the power module according to the invention; Fig. 5 a third embodiment of the power module according to the invention; Fig. 6 a fourth embodiment of the power module according to the invention; Fig. 7 a fifth embodiment of the power module according to the invention; Fig. 8a & 8b show a possible embodiment for the plug socket and cross-sections of the plug socket and a corresponding contact pin; Fig. 9a & 9b a possible embodiment for the plug socket; Fig. 10 a power module in which a contact pin is mounted in a plug socket; and Fig. 11 a schematic flowchart for a method for manufacturing a power module according to the invention.

[0039] To improve the traceability and readability of the detailed description, the same reference numbers are used throughout the illustrations to identify identical parts or elements with the same function.

[0040] Even when information is given regarding the upper and lower directions and positions, it refers only to the orientation of the elements as shown in the figures and does not necessarily correspond to the orientations and positions in the usual use of a power module according to the invention. For example, an upper contact shown in the figures may be oriented downwards or to the side in the usual use of the power module according to the invention. The information regarding the upper or lower side serves only to improve the understanding and legibility of the figures and their description and results from the usual positioning of the casting mold and the mold halves used.

[0041] Fig. Figure 1 shows a first embodiment of a non-encapsulated semiconductor power module 1 (also referred to as power module 1) according to the invention, which is arranged in an open mold or potting mold 20, i.e., the situation immediately before closing the potting mold 20 to carry out the potting process, in which at least partially a substrate 7 with a bonded or conductive layer 9 applied thereto, one or more semiconductors 4 connected to the bonded / conductive layer 9, and a connector socket 60 projecting substantially perpendicular to the substrate 7 are encapsulated with potting compound, also called encapsulation compound or potting material. The perpendicularly oriented connector socket 60 is attached to the conductive layer 9, for example, via a connector base 61, by any known fastening method such as soldering, ultrasonic welding, laser welding, gluing, sintering, or press-fitting.The invention also includes the arrangement and attachment of the connector socket 60 with its connector base 61 to any other component arranged in the power module 1, e.g. to a connector socket 60 which is connected to the semiconductor 4 via its connector base 61.

[0042] According to the invention and the in Fig. In the exemplary embodiment shown in Figure 1, after a connector socket 60 has been attached to the substrate, the bonded or conductive layer 9, or the semiconductor 4, a washer 8 and a sealing ring 5 are received by the connector socket shaft 62 of the connector socket 60 such that the sealing ring 5 contacts the connector socket base 61. This (pre-)assembly, consisting of the substrate 7 with the bonded or conductive layer 9, the semiconductor 4, and the connector socket 60 with the washer 8 and the sealing ring 5, is placed into a first, lower mold half 21 such that the connector socket shaft 62 with its connector socket end 65 is oriented upright.

[0043] The connector socket shaft 62 is a projection extending from the connector socket base 61 and includes a cavity 63 along the connector socket axis 64. A cross-section along the axial direction of the connector socket shaft 62 shows two parallel projections enclosing an empty area. This empty area is the cavity 63, which can have a tubular 3D shape. The cavity 63 is recessed from the shaft end 65 of the connector socket towards the base 61. The direction towards the connector socket base 62 is downward, and the opposite direction is upward. Therefore, the cavity 63 is formed from the connector socket base 61 in the upward direction. The cavity 63 can penetrate the connector socket shaft 62 completely or partially. In a cross-section along the radial direction of the connector socket shaft 62, the cavity 63 can have any shape and can be circular, rectangular, or oval.The cavity 63 can be aligned with the central axis of the shaft of the connector socket 62, but this is not necessary. After casting the housing 15, the cavity 63 is exposed on the outside of the housing 15. Therefore, the cavity 63 forms an opening on the outside of the housing 15.

[0044] As in Fig. As can be seen in Figure 1, the first, lower mold half 21 has a mold parting line or parting plane 24 at its upper end, where the first, lower mold half and the second, upper mold half 22 can be joined to tightly seal a cavity 23 of the mold 20. When the mold 20 is closed, the encapsulation or potting compound 10 (see Figure 1) can be applied. Fig. The casting compound 10 is filled into the cavity 23 via a mold inlet 25. After the casting compound 10 has hardened, the finished power module 1 can be removed from the lower mold half 21 after the second, upper mold half 22 has been removed. Fig. 3 shows the power module according to the Fig. 1 and Fig. 2 after removal from the potting mold 20, wherein the potting compound or potting material 10 forms a housing 15 of the power module 1. Therefore, the housing 15 also corresponds to an encapsulation of the power module 1. However, it is possible that an additional cover is provided alongside the cover 15.

[0045] Out of Fig. Figure 1 further shows that, in the open state of the potting mold 20, the shaft end 65 of the connector socket 60 does not project vertically beyond the parting line 24, while at least a portion of the washer 8, which is mounted on the connector socket shaft 62 and supported by the sealing ring 5, projects vertically beyond the parting line 24, and the sealing ring 5 is in an undeformed state in which its cross-section has a round, substantially circular shape. According to the invention, the upper mold half 22 has a substantially flat surface 3 on the side facing the cavity 23, which is designed to contact at least the portion of the washer 8 projecting from the parting line 24 when the second, upper mold half 22 is brought into direct contact with the first, lower mold half 21, i.e., when the potting mold 20 is closed and prepared for the potting process (see also Figure 1). Fig. 2).

[0046] When placing the second, upper half of the mold 22 - as indicated by the arrow 26 in Fig. As shown in Figure 1, the washer 8 is pushed downwards into the cavity 23 of the mold 20 along the axis of the shaft of the connector socket 62, i.e., in the longitudinal direction of the connector socket 62, onto the lower mold half 21. This causes the sealing ring 5, which rests stationary on the connector socket base 61, to deform elastically in the axial direction and expand radially, according to the invention. In this state, the sealing ring 5 has a more or less oval cross-section, as shown in Figure 1. Fig. 2 can be seen. Fig. Figure 2 shows the final deformation state of the sealing ring 5 in the (fully) closed potting mold 20. According to the invention, at this point the cavity 23 of the mold 20 can be filled with potting compound 10 via the mold inlet 25 in order to at least partially encapsulate the substrate 7, the semiconductor(s) 4 and the vertical connector socket 60 together with the elastically deformed sealing ring 5 and the undeformed washer 8.

[0047] In the with Fig. In the situation shown in Figure 2, the sealing ring 5 is forced into an elastically deformed state in the direction of a shaft axis 64 of the connector socket. The elastic restoring forces of the sealing ring material provide sealing forces in the axial direction of the sealing ring 5 upwards onto the washer 8 and downwards onto the connector base 61. The washer 8 is pushed upwards by the elastic restoring forces of the deformed sealing ring 5 and pressed against the lower mold surface, the cavity boundary surface 27 of the second upper mold half 22. This upward elastic force creates a sealing effect between the washer 8 and the cavity boundary surface 27, preventing potting compound 10 from flowing towards the shaft of the connector socket 62 or the upper end surface of the connector socket 62 during the molding process. Such an undesired material flow would lead to contamination of the shaft of the connector socket 65 of the connector socket 60.The elastic restoring forces of the sealing ring 5 in the axial direction, i.e., towards the connector socket 62, actively seal this access point and all other possible access points for potting compound 10 in the radial direction, in order to reach and rise up the connector socket 62, through the elastic restoring forces of the deformed sealing ring 5. These elastic restoring forces ensure sealed contact points between the disk 8 and the form 20, the disk 8 and the sealing ring 5, and the sealing ring 5 and the connector socket base 61, at least in the axial / vertical directions.

[0048] In the first exemplary embodiment, as described in the Fig. 1, Fig. 2 to Fig. As shown in Figure 3, the sealing ring 5 is elastically deformed, so that its cross-section becomes oval due to compression in the axial direction and expands in the radial directions (away from and towards the connector socket shaft 62). This expansion effect towards the shaft of the connector socket 62 can be used to achieve a further sealing contact between the deformed sealing ring 5 and the connector socket shaft 62. As described above, the axially aligned seals are generally sufficient to prevent liquid potting compound from flowing to the connector socket shaft 62 and upwards along the connector socket 62, thus preventing contamination of the end of the connector socket 65 during potting.

[0049] Fig. Figure 3 shows an encapsulated power module 1 according to the invention with an upper contact point, i.e., the shaft end of the connector socket 65 with the cavity 63 free of potting compound 10 and encapsulated by the potting compound 10, which forms the housing 15 of the power module 1. The power module 1 shown can be contacted on any side that is substantially parallel to the substrate 7. The electrical connections can be made by inserting a contact pin 70 into the cavity 63 and / or by connecting a contact pin 70 to the end face of the shaft of the connector socket 62. As a person skilled in the art will recognize from the prior art, this can be any side of the power module when using it and does not have to be, as shown in Figure 3, the end face of the power module. Fig. Figure 3 shows the top side. The person skilled in the art will also recognize that the illustrated embodiment of a power module may have at least one or more other contact terminals, which, for example, project towards the plane of the substrate 7, in Fig. 3 also in a lateral direction. In this respect, the one with the Fig. 1, Fig. 2 to Fig. Figure 3 shows only a simplified representation to illustrate the idea underlying the invention.

[0050] As in the Fig. 1, Fig. 2 to Fig. As can be seen in Figure 3, the power module 1 according to the invention can be manufactured using a variant of a mold. However, as can be seen in the figures, the same mold can be used if the connector socket 60 is arranged in a different position, since the connector socket 60 does not protrude beyond the parting line 24. The electrical contact to the outside of the power module is made via the cavity 63 in the connector socket shaft 62. This reduces manufacturing costs, as the mold can be used for several configurations of the connector socket 60.

[0051] Even if the connector socket 60 crosses the parting line 24, the present invention is still feasible, although in such cases the mold must be modified for different configurations. In such a case, a contact pin 70 can still be connected to the connector socket 60 by inserting the contact pin 70 into the cavity 63.

[0052] In Fig. Figure 4 shows a further embodiment of the idea according to the invention. The embodiment of a power module 1 of the Fig. 4 deviates from the one in the Fig. 1, Fig. 2 to Fig. The embodiment shown in Figure 3 differs in that the sealing ring 5 is inserted between two washers 8. This option is particularly preferred when the bearing surface of the connector socket 61 for supporting the sealing ring 5 during deformation by closing the mold 20 is not large enough to ensure adequate deformation of the sealing ring 5, as this would prevent sufficiently high elastic restoring forces from being achieved to provide tight contact points in the radial direction and thus prevent potting material from penetrating between the cavity boundary surface 27, the washer 8, the sealing ring 5, and the connector socket base 61. Fig. As can be seen in Figure 2, the sealing ring 5 would slip over the connector socket 61 if it were pressed downwards, were it not for the second lower washer 8. Therefore, the height of the connector socket 61 would limit the elastic deformation of the sealing ring 5 and the restoring forces to ensure a good seal between the cavity boundary surface 27, the washer 8, the sealing ring 5, and the connector socket 61. Therefore, a second, lower washer 8 is provided, which rests on the connector socket 61 and provides support against deformation of the sealing ring 5 when the potting mold is closed for the potting process.

[0053] The in Fig. Solution 4 shown is therefore particularly preferred if the radial extent of the connector socket 61 is small or, for example, a press-fit pin is used. The person skilled in the art will recognize from Fig. 4, that washers covering or surrounding the connector socket base, e.g. in the form of a sleeve or the like, and providing a bearing surface for the sealing ring 5, also belong to the scope of the invention, even if they are not shown in the figures. The person skilled in the art will understand from Fig. It can be seen from Figure 4 that washers covering or surrounding the connector socket base, e.g., in the form of a sleeve or the like, and providing a bearing surface for the sealing ring 5, also fall within the scope of the invention, even if they are not shown in the figures. Furthermore, it is according to the invention that, regardless of the embodiments shown, the washers 8 can have a circumferential sealing groove – similar to sealing grooves known from the prior art – at least on the side facing the sealing ring 5. The invention also includes the use of three or more washers, for example, to adapt the height of the washer / sealing ring assembly to the height of the connector socket shaft. In this context, the use of two sealing rings 5 ​​and three washers 8 arranged alternately one above the other is also conceivable, so that each sealing ring 5 is embedded between two washers 8.Here, a person skilled in the art will find many possibilities for arriving at a package that fills the space between the socket base 61 and the shaft end 65 of the socket 60 in such a way that at least one sealing ring 5 is elastically deformed when the potting mold 20 is closed. Since all these embodiments of the invention are known to those skilled in the art, a description of these possibilities is omitted.

[0054] Another embodiment of the invention is described in Fig. Figure 5 shows that the invention also includes power modules 1 having more than one connector socket 60, which protrude substantially perpendicularly to the substrate 7. In the embodiment of Fig. Figure 5 shows an embodiment with two connector sockets 60, which is representative of all power modules 1 according to the invention with more than one connector socket 60 projecting perpendicularly to the substrate 7. Those skilled in the art will recognize that it is merely a matter of design to arrange and secure two or even more perpendicularly oriented connector sockets 60 on a substrate 7 or on one or more semiconductors 4. Depending on the number of perpendicular connector sockets 60, the upper mold half 22 still has a flat surface if all connector sockets 60 do not project beyond the parting line 24 of the potting mold. Otherwise, the upper mold half 22 must have a recess at a corresponding location for each connector socket 60 that projects beyond the parting line 24, so that these connector sockets 60 are not damaged when the mold is closed.

[0055] With Fig. Figure 6 shows another way of implementing the inventive concept, in which two washers 8 are designed as a type of perforated sheet with a number of holes corresponding to the number of connector sockets 60. These holes are intended to be free of potting compound and face the outside of the power module 1, or to be exposed on the outside of the power module 1. A sealing ring 5 is clamped between the two washers 8 and deforms elastically when the potting mold 20 is closed. The sealing ring can be shaped like an O-ring, having a circular, oval, or rectangular shape that can replicate the outer shape of the connector socket shaft 62. Furthermore, the upper washer 8 is not necessarily a perforated sheet but can, for example, also have an elongated hole through which more than one connector socket shaft 62 can pass.According to the invention, the ingress of potting compound into an area between two shafts of the connector socket 62 must be prevented. This is achieved, as in the embodiment of the . Fig. As shown in Figure 6, this is already achieved by pressing the lower washer 8 onto the connector socket base 61 through elastic deformation of the sealing ring 5. As is readily apparent to a person skilled in the art, the sealing ring 5 can also be a type of disc that is elastically deformable in order to transmit a sealing force in the longitudinal direction of the axis of the connector socket shaft. Furthermore, it is easily conceivable to a person skilled in the art that the two washers 8, together with the sealing ring 5 between them, can accommodate / enclose more than two connector sockets 60 or their shafts 62, as shown in Figure 6. Fig. 6 indicated by the dashed shafts 62.

[0056] Fig. Figure 7 shows a further embodiment of a power module 1 according to the invention with connector sockets 60 that protrude perpendicularly on both sides of the substrate 7, i.e., on both the top and the bottom, as shown in Fig. Figure 7 illustrates this. It should be noted that if the connector sockets 60 project beyond the parting lines 24, or if one or more connector sockets 60, whose socket shafts 62 are to be accessible, are flush with or protrude from the cured potting compound, a corresponding recess in the lower mold half 21 is required. However, here the connector sockets 60 are designed so that they do not project beyond the parting line 24, thus eliminating the need for recesses in the mold. Furthermore, it must be considered that the unencapsulated power module 1 must be pressed downwards to elastically compress the sealing ring 5, which sits on the downward-facing connector socket 60. For this purpose, a plurality of support ribs can be arranged in the lower mold half 21 of the potting mold 20 to limit the deformation of the sealing ring 5 and prevent damage to the substrate 7 and the components located on it.The downward movement of the substrate 7 with the components attached to it can occur, similarly to the previously mentioned embodiments, when the upper mold half 22 is placed onto the parting line 24, thereby deforming all sealing rings 5 ​​simultaneously. Of course, this is only one of several possible solutions that are within the knowledge of a person skilled in the art. The embodiment of... Fig. Figure 7 is merely intended to show that the invention is not limited to providing power modules 1 and their manufacturing method according to the invention, which have one or more shafts of the connector sockets 65 that protrude perpendicularly to the substrate 7 only on one side, since it is shown that the arrangement according to the invention of an elastically deformable sealing ring 5 and at least one washer 8 received on the respective connector socket shaft 62 is also applicable to embodiments of power modules 1 with more than one connector socket shaft 62, regardless of whether the shaft end 65 of the connector socket is exposed to the outside of the power module 1 only on one side or on two opposite sides, e.g. the top and the bottom.

[0057] In Fig. Figure 8a shows a plug socket 60 as an example of a variety of plug sockets that can be used in the implementation of the invention. Fig. Figure 8a shows the connector socket 60, which is rotationally symmetrical about the axis of the shaft of the connector socket 64 and has a round cross-section. The round connector socket base 61 is preferably suitable for being welded to the bonded or conductive layer 9 on a substrate 7, e.g., by ultrasound or laser. The geometric shapes of the Fig. Figure 8b shows examples of cross-sections of the hollow body 63 and the contact pin 70. The left shape is an example of a circular cross-section of the cavity 63, and the right shape is an example of a rectangular cross-section of the contact pin 70. When the rectangular contact pin 70 is inserted into the circular cavity 63 to provide an electrical connection to the outside of the power module 1, these two components are press-fitted due to their different shapes. Of course, a person skilled in the art will determine the shape of the connector 60 and the shapes of the cavity 63 and the contact 70 according to the specific application, thus providing a suitable configuration.

[0058] Fig. Figure 9a shows an embodiment of the present invention in which the plug socket 60 projects beyond the separating plane 24. As in Fig. As can be seen in Figure 9, the upper mold half has the aforementioned recess. The connector socket 60, which protrudes beyond the parting line 24, is received in the recess so that the connector socket 60 is not damaged when the upper mold half 22 is placed onto the lower mold half 21. Fig. 9b shows the power module 1 from Fig. 9a after the casting process with housing 15 and protruding plug socket 60 with cavity 63.

[0059] Fig. Figure 10 shows a power module 1 with a connector socket 60 into which the contact pin 70 is inserted, e.g., by press-fitting. The contact pin 70 is an electrical pin to which further electrical components, connections, wires, or plugs can be attached, thus providing an electrical connection to the interior of the power module 1. The contact pin 70 is adapted to the connector socket 60—or vice versa—and, in particular, to the cavity 63 of the connector socket 60 to establish a secure and stable connection. However, it is also possible to provide a detachable connection, e.g., with a threaded hole as the cavity 63 and a screw thread as the outer circumference of the contact pin 70.

[0060] Fig.Figure 11 illustrates a method and the corresponding process steps for manufacturing the power module 1. In step S0, the substrate 7 is provided, wherein the substrate contains electronic components such as the conductive layer 9 and the semiconductor 4 (or at least one semiconductor 4). The conductive layer 9 and the semiconductor 4 are arranged on the substrate 7 and fixed to the substrate 7.

[0061] In step S1, the connector socket 60 (or at least one connector socket 60) is attached to the conductive layer 9 with the connector socket base 61, the connector socket shaft 62 and the cavity 63. The connector socket 60 is attached such that the connector socket shaft 62 runs perpendicular to the substrate 7.

[0062] In step S2, a sealing ring 5 is placed over the connector socket shaft 62 so that the sealing ring 5 rests on the connector socket base 61. Optionally, at least one washer 8 can also be placed on the connector socket shaft 62, as explained in some embodiments. It is important to note that the height of the sealing ring 5 and / or the washers 8 must be adjusted so that a stack formed by the sealing ring 5 and the attached washers 8 slightly crosses or extends beyond the parting line 24, allowing an axial force to be applied when the mold 20 is closed (see step S4).

[0063] In step S3, the substrate 7 with the electronic components and the connector socket 60 is placed into the first mold half 21. This is the first step for the encapsulation or casting process.

[0064] In step S4, the mold 20 is closed to form a cavity 23. The first mold half 21 is closed with the second mold half 61 in the vertical direction 11, parallel to the connector socket shaft 62. The sealing ring 5 is elastically deformed by pressing the second mold half 22 onto the connector socket base 61 (by crossing or protruding the parting line 24 of the sealing ring 5 or the disc 8), so that the second mold half 22 closes the cavity 63 of the connector socket 60, with the sealing ring 5 sealing the connector socket shaft 62 against the ingress of potting compound 10 into the cavity 63. The cavity limiting surface 27 is the surface that presses the sealing ring 5 and / or the washers 8 against the connector socket base 61, whereby the sealing of the shaft end of the connector socket and the cavity 63 is ensured by the pressing force between the cavity limiting surface 27 and the sealing ring 5 and / or the washers 8.

[0065] In step S5, the cavity 23 formed in mold 20 is filled with the potting or molding compound 10. The potting compound 10 can, for example, be a suitable resin with insulating properties.

[0066] In step S6, after the potting compound 10 has cured, the mold 20 is opened so that the power module 1 can be removed from the mold 20. After curing, the potting compound 10 forms the housing 15 of the power module 1, which encapsulates the substrate 7, the electronic units, and the connector socket 60 completely or partially. However, the cavity 63 and at least part or an end face of the shaft of the connector socket 62 (the connector socket end 65) are accessible from the outside of the power module 1.

[0067] Therefore, providing the connector socket 60 and the method according to the invention improves the ease of manufacturing the power module 1, ensures the reliability of the electrical connections, facilitates the flexibility of the circuit configuration and reduces manufacturing costs.

[0068] From the above description and the attached figures and claims, it is evident that the power module according to the invention and the method for manufacturing such a power module offer many possibilities and advantages compared to the prior art. Reference symbol list 1 semiconductor power module 3 Flat surface 4 semiconductors 5 sealing ring 7 Substrat 8 Washers 9 Management Layer 10 mold / potting compound / potting material 15 cases 20 Mold / Molding Tool 21 First, lower half of the mold 22 Second, upper half of the mold 23 Cavity of the mold 24 Form parting line / parting plane 25 Mold inlet 26 Closing direction of the mold 27 Boundary surface of the cavity 60 plug socket 61 plug sockets 62 plug socket shaft 63 Cavity in the plug socket shaft 64 Axis of the connector socket 65 End of the plug socket

Claims

[1] comprising a semiconductor power module (1): - one or more semiconductors (4) arranged on a substrate (7) with a conductive layer (9); - a housing (15) made of potting compound (10) that encapsulates at least the substrate (7) and the semiconductor (4); - at least one socket (60) with a socket base (61) mounted on the substrate (7) and configured to receive and hold a connector in a substantially upright position perpendicular to the substrate (7) by means of a cavity (63) in the socket shaft (62) which defines the upright direction (11), - at least one sealing ring (5) arranged around the connector socket shaft (62) and resting on the connector socket base (61); wherein the sealing ring (5) is fixed by the potting compound (10) in an elastically deformed state in the upright direction (11) against the connector socket base (61) and seals the connector socket shaft (62) against the ingress of potting compound (10) into the cavity (63) during the potting step of the housing (15), so that the cavity (63) provides an opening on the outer surface of the housing (15). [2] Semiconductor power module (1) according to claim 1, wherein the connector socket shaft (62) and / or the cavity (63) have a round, oval or rectangular cross-section. [3] Semiconductor power module (1) according to claim 1 or 2, wherein the sealing ring (5) has a circular, oval or rectangular shape which copies the outer shape of the connector socket shaft (62), and wherein the cross-section of the sealing ring (5) is circular, oval, rectangular or of any other shape. [4] Semiconductor power module (1) according to one of the preceding claims, wherein the sealing ring (5) is pressed in an upright direction (11) into an elastically deformed state against the connector socket base (61) by means of a washer (8) fixed around the connector socket shaft (62) by the potting compound (10) of the housing (15). [5] Semiconductor power module (1) according to claim 4, wherein the washer (8) has a circular, oval or rectangular circumferential shape and a substantially rectangular cross-section. [6] Semiconductor power module (1) according to claim 4 or 5, wherein the sealing ring (5) is inserted between two washers (8), one of which rests on the connector socket base (61). [7] Semiconductor power module (1) according to any one of claims 4 to 6, wherein at least one washer (8) or both washers (8) are made of metal, plastic, reinforced plastic, ceramic or elastic material. [8] Semiconductor power module (1) according to any of the preceding claims, wherein the sealing ring (5) is made of an elastomer or silicone material. [9] Semiconductor power module (1) according to any of the preceding claims, wherein the connector socket (61) is attached to the substrate (7) by ultrasonic welding, laser welding, soldering, gluing, sintering or press-fitting. [10] Semiconductor power module (1) according to one of the preceding claims, wherein two or more connector socket shafts (62) are mounted side by side on the substrate (7), wherein a washer (8) rests on the at least one connector socket base (61) and a sealing ring (5) is held elastically deformed in an upright direction by a second washer (8) in a sandwich-like manner, wherein each of the washers (8) and the sealing ring (5) surrounds all connector socket shafts (62). [11] Semiconductor power module (1) according to one of the preceding claims, wherein the cavity (63) is configured to hold and accommodate the pin connector, which is a contact pin (70) of press-fit design, so that the contact pin (70) can be inserted into the cavity (63) of the connector socket (60) and secured. [12] Semiconductor power module (1) according to one of the preceding claims, wherein in a semiconductor power module (1) according to one of the preceding claims at least one second connector socket (60) with at least one sealing ring (5) and a washer (8) received thereon is arranged in an analogous manner, but with its cavity (63) facing the opposite side of the substrate (7). [13] Method for manufacturing a semiconductor power module comprising one or more semiconductors (4) arranged on a substrate (7) having a conductive layer (9), wherein the substrate (7) and the semiconductors (4) are at least partially covered by a housing (15) formed from a potting compound (10), wherein at least one opening is provided in the housing (15) for electrical contacting the conductive layer (9), and the method comprises the following steps: a) Providing (S0) a substrate (7) with a conductive layer (9) and one or more semiconductors (4) arranged on it, b) Attaching (S1) at least one socket (60) with a socket base (61) to the conductive layer (9) such that a socket shaft (62) extends perpendicular to the substrate (7), c) Attaching (S2) a sealing ring (5) over the plug socket shaft (62) so that the sealing ring (5) rests on the plug socket base (61), d) Arranging (S3) the substrate (7) with the connector socket (60) and the sealing ring (5) in a first mold half (21), e) Closing (S4) the first mold half (21) in an upright direction (11) parallel to the connector socket shaft (62) by means of a second mold half (22), whereby the sealing ring (5) is elastically deformed by being pressed onto the connector socket shaft (62) by means of the second mold half (22), so that the second mold half closes a cavity (63) of the connector socket (60), and the sealing ring (5) seals the connector socket shaft (62) against the entry of potting compound (10) into the cavity (63), f) Filling (S5) a cavity (23) of the mold (20) with casting compound (10), g) Opening (S6) the mold (20) after the casting compound (10) has hardened, and h) Removing the semiconductor power module (1) from the mold (20).

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