ELECTRONIC MODULE AND METHOD FOR PRODUCING THE SAME

Description

[0001] The present invention relates to an electronic module and a method for its production.

[0002] Electronic modules are well known in the art, for example, as power electronics modules. Such electronic modules typically utilize switchable electronic components interconnected via conductor tracks on a common carrier substrate. Key components of the carrier substrate include an insulation layer, which, in the case of a metal-ceramic substrate, is made of a material comprising a ceramic, and a metallization layer, which is preferably structured to form conductor tracks and is formed on one component side of the carrier substrate.

[0003] Such electronic modules are typically designed for a long service life and high operational reliability, avoiding thermally induced mechanical stresses in the electronic module as much as possible and dissipating heat generated on the component side as optimally as possible, preferably using a dedicated cooling structure. The specifications of new electronic components, such as WBG semiconductors (wide bandgap semiconductors), particularly semiconductors made of silicon carbide, gallium nitride, and / or indium gallium nitride, pose new challenges for electronic modules, as do new areas of application, such as e-mobility.

[0004] Prior art documents include, for example, DE 10 2008 029 829 B4, DE 10 2009 042 399 A1, US Pat. No. 7,589,412 B2, and DE 10 2014 117 086 A1, in which electrical components are arranged on a carrier substrate and embedded in an encapsulation to form an electronic module. Another example of an electronic module is the component marketed by Anlog Devices with the designation "LTM4636."

[0005] Furthermore, the prior art discloses encapsulations for conductor tracks and their carriers from US 2018 0 053 745 A1, US 2011 128 707 A1, DE 10 2016 000 264 and US 20150 303 164 A1. US 2017 0 018 478 A1 discloses a multilayer arrangement of semiconductors that are interconnected via vias.

[0006] Based on this prior art, the present invention aims to provide an electronic module that is improved over those of the prior art, in particular with regard to its design, switching behavior and service life.

[0007] The object is achieved according to the invention by an electronic module according to claim 1 and a method for producing an electronic module according to claim 13. Preferred embodiments of the invention are specified in the dependent claims and the following description, in particular in connection with the accompanying figures.

[0008] According to the invention, an electronic module is provided which comprises an encapsulation and a carrier substrate which is at least partially embedded in the encapsulation and has a component side which has a first metallization layer and on which at least one first electronic component is arranged, wherein at least one second metallization layer for at least one second electronic component, in particular for controlling the first electronic component, is provided on an outer side of the encapsulation and wherein the encapsulation has at least one via for the electrical connection, in particular for the direct electrical connection, of the first electronic component and the second electronic component.

[0009] In contrast to the prior art, the invention provides that the encapsulation at least partially surrounds the carrier substrate, e.g. in the form of a cast material, or the carrier substrate is embedded in the encapsulation, and the through-hole provides a possibility for electrical connection between the first electrical component and the second electrical component. The through-hole extends from the outside, in particular from the second metallization layer serving as a connection for the second electronic components, to the first electronic component and / or to the first metallization layer on the component side of the carrier substrate. As a result, not only is a compact electronic module created, but a comparatively small distance is also provided between the first electronic component on the component side, on the one hand, and the second electronic components on the outside, on the other.In particular, the invention is characterized by the second metallization layer, which allows direct bonding to the outside of the encapsulation.

[0010] It is preferably provided that a distance measured perpendicular to the main extension plane between the first metallization layer and the second metallization layer is less than 5 mm, preferably less than 2.5 mm and particularly preferably less than 1 mm down to less than 400 µm, for example approximately 300 µm, i.e. is as small as possible. Accordingly, a very short distance is established between the first component and the second component in a direction running perpendicular to the main extension plane. Furthermore, the vias are embedded in the encapsulation, i.e. the vias are realized after encapsulation. The vias can be realized mechanically and / or galvanically using wet chemistry, a paste, a vapor deposition process, a screen printing process, a 3D printing process.Furthermore, it is preferably provided that the first metallization layer and the second metallization layer are structured such that the first component and the second component are offset from one another by a lateral distance in a direction running parallel to the main extension plane.

[0011] This advantageously prevents the heat development of the first and second components from influencing or impairing each other. To ensure effective control of the first component by the second component, the lateral distance is preferably less than 35 mm, preferably less than 15 mm, and particularly preferably less than 5 mm.

[0012] "Embedding" or "being embedded" refers, in particular, to the encapsulation being directly adjacent to an outer side of the carrier substrate, i.e., the encapsulation lies directly flat against the carrier substrate at least in certain areas, and no clear area or cavity is formed between the carrier substrate populated with the electronic component and the encapsulation. The carrier substrate does not have to be encased or surrounded by the encapsulation on all sides. Furthermore, the encapsulation is intended to be solid, i.e., free of cavities.

[0013] Furthermore, it is preferably provided that the via has a cross-section of less than 5 mm 2<, preferably less than 1.5 mm 2< and particularly preferably less than 0.5 mm 2< in a direction parallel to the main extension plane, in particular if the via is connected directly to the first component, in particular to an upper side of the first component. If the via is connected to the first metallization layer, the cross-section is preferably less than 1.5 mm 2<, preferably less than 2.5 mm 2< and particularly preferably less than 1.5 mm 2<. Since the cross-section can change, in particular taper, as seen in the stacking direction for manufacturing reasons, the cross-section is preferably to be understood as its average along its extension in the stacking direction.

[0014] Furthermore, it is provided that the via is flush with the outside of the encapsulation. The part of the second metallization layer that is flush with the via further has a contact area dimensioned parallel to the main extension plane. A ratio between a cross-section of the via, dimensioned parallel to the main extension plane, to the contact area of ​​the part of the second metallization layer that adjoins the via is preferably less than 0.25, preferably less than 0.15, and particularly preferably less than 0.1. In other words, the via is designed to be comparatively narrow. Furthermore, it is conceivable that several vias are connected to a common electronic component and the summed cross-section of all vias is smaller than the contact area of ​​the second metallization layer.

[0015] The vias are further preferably characterized in that at least some of all of the vias are arranged above the first electronic components or between the first electronic and the second electronic components, as viewed in the stacking direction. It is conceivable that a first part of all of the vias directly contacts the first components and a second part of all of the vias contacts the first metallization layer. Preferably, the second part is larger than the first part. The contacting of the first component and the second component via the via can be direct or indirect. For example, the first component itself can be integrated in a pre-assembly or the via contacts the first metallization layer in order to realize an electrical connection between the first component and the second component.

[0016] Preferably, at least one outer side of the carrier substrate remains free of the encapsulation. In particular, it is provided that at least the component side of the carrier substrate is completely encapsulated, i.e. covered or enclosed by the encapsulation. According to the invention, it is provided that an outer surface is covered by the encapsulation to more than 50% and preferably more than 60%. The direct connection to the carrier substrate or the embedding of the carrier substrate in the encapsulation advantageously also improves the stability of the electronic module and additional stabilization measures, e.g. between the encapsulation and the carrier substrate, can be dispensed with. It is also conceivable that a protective layer is provided between the first electronic components and the encapsulation, which protective layer covers or protects the first electronic components and through which the via and / or further vias run.

[0017] First electronic components are preferably switchable components or active components. Preferably, at least one first electrical component is one with a WBG semiconductor (wide bandgap semiconductor), such as a semiconductor made of silicon carbide, gallium nitride, and / or indium gallium nitride. Examples of electronic components are MOSFETs ("metal-oxide-semiconductor field-effect transistors") or IGBTs ("insulated-gate bipolar transistors"). The first components can also be combined as a pre-assembly or "prepackaging." In such a pre-assembly, one or more first electronic components are arranged, for example, on a printed circuit board and embedded in a matrix. An example of a pre-assembly can be found in the document DE 10 2014 117 086 A1 as a redistribution structure in which an electrical component is integrated into a dielectric matrix.Explicit reference is hereby made to the disclosure content of DE 10 2014 117 086 A1 regarding the pre-composite and the redistribution structure. Further examples of pre-composite to which explicit reference is made can be found in the articles "Development of Embedded Power Electronics Modules for Automotive Applications" by L. Boettcher et al. and "Embedding of Power Semiconductors for Innovative Packages and Modules" by L. Boettcher et al.

[0018] The second electronic components and / or contact elements are preferably Driver or control elements, in particular "gate drivers," and / or connection devices, which serve, for example, as a load connection for an input signal or for power supply, and / or capacitors, for example intermediate capacitors, are provided and are in particular directly contacted, e.g., soldered or sintered, to the second metallization layer serving as a connection. A "gate driver," e.g., a MOSFET driver, IGBT driver, or half-bridge driver, is understood in particular to be a discrete or integrated electronic circuit that controls power switches, such as MOSFETs or IGBTs. In the case of control elements as second electronic components, the first electronic components on the component side can be controlled more effectively, since long transmission paths for the control signal from the control element on the outside to the first electronic component to be controlled can advantageously be dispensed with.A further advantage resulting from the comparatively short conductor tracks is a reduction in parasitic inductances that would otherwise be expected if no encapsulation and no through-plating were provided for the electrical connection between the outside of the encapsulation and the component side of the carrier substrate.

[0019] A via is understood to be an electrical conduction path that penetrates the encapsulation or electrically connects two opposite sides of the encapsulation. The via can be made of the same metal or material as the first metallization layer and / or the second metallization layer or can be different from it. Furthermore, it is conceivable for the via to be completely or only partially filled with a conductive material. Furthermore, the via preferably runs in a straight line. The via can run parallel or obliquely to a direction extending perpendicular to the main extension plane of the carrier substrate. The via can also be used to contact the first electronic component via a side facing away from the carrier substrate or via a side facing the outside of the encapsulation, i.e.Electrical connections can also be routed upwards out of the encapsulation. In the case of a pre-assembly or "prepacking," it is advantageously possible to create a pre-assembly-side contacting area on a side of the pre-assembly facing the outside in the installed state. In this case, it is advantageous to enlarge the pre-assembly-side contacting area to facilitate connection to the through-connection in the encapsulation. For example, the ratio between a diameter of the through-connection measured parallel to the main extension plane and the pre-assembly-side contacting area measured parallel to the main extension plane assumes a value between 0.1 and 1, preferably between 0.15 and 0.8, and preferably between 0.3 and 0.6.

[0020] It is preferably provided that the first electronic components in the electronic module have a contact on a side facing the outside of the encapsulation, in particular the second metallization layer, and are connected to the through-plating via this contact.

[0021] In particular, it is provided that the encapsulation is a cast part and is preferably manufactured from a plastic by means of casting, e.g., injection molding. In this case, the encapsulation in the assembled electronic module interacts with the carrier substrate in a form-fitting, force-fitting, and / or material-fitting manner. For example, the encapsulation comprises an undercut or a nose-like projection via which the encapsulation can interact with the populated carrier substrate in a form-fitting manner. In particular, the encapsulation can be clipped to the carrier substrate or is clipped to the carrier substrate, preferably on the side opposite the component side, which is used for cooling purposes according to the invention. Suitable casting materials, also called molding compounds, are casting resins such as synthetic thermosets. The encapsulation is preferably manufactured from an epoxy casting component as the encapsulation material.The encapsulation component preferably has a comparatively high glass transition temperature, for example, above 200 °C, a flexural strength between 10 and 15 kg / mm ​​2 , and is particularly curable. For example, the material is Hysol ® MG 15F-MOD2. Furthermore, it is preferably provided that a filler material, for example, comprising SiO 2 and / or an aluminum oxide, is added to the encapsulation material.

[0022] Materials conceivable for the first metallization layer and the second metallization layer include copper, aluminum, molybdenum, and / or their alloys, as well as laminates such as CuW, CuMo, CuAl, AlCu, and / or CuCu, in particular a copper sandwich structure with a first copper layer and a second copper layer, wherein a grain size in the first copper layer differs from that of a second copper layer. Furthermore, it is preferably provided that the first metallization layer and / or the second metallization layer are surface-modified. A possible surface modification is, for example, sealing with a precious metal, in particular silver and / or gold, or ENIG ("electroless nickel immersion gold"), or edge encapsulation on the first or second metallization layer to suppress crack formation or crack widening.

[0023] Preferably, the second metallization layer is structured and / or the first electronic components can be controlled via the through-hole through a plurality of second electronic components.

[0024] According to the invention, the carrier substrate is a metal-ceramic substrate, wherein the metal-ceramic substrate has a structured first metallization layer on its component side, wherein the metal-ceramic substrate is preferably designed in multiple layers. Essential components of the metal-ceramic substrate are an insulating layer made of a ceramic and the metallization layer bonded to the insulating layer. Due to their comparatively high insulation strengths, insulating layers made of ceramic have proven particularly advantageous. By structuring the first metallization layer, conductor tracks and / or connection surfaces for the first electrical components can then be realized. In particular, the metal-ceramic substrate is designed in three or five layers.The multi-layer design advantageously makes it possible to use comparatively thick metallic intermediate layers, while several ceramic layers serve for stabilization. As a result, the thermal resistance can be reduced and heat spread can be specifically adjusted. In particular, it is provided that the layer thickness of the ceramic insulation layer is adapted to the required insulation strength. Preferably, the insulation layer has Al 2 O 3 , Si 3 N 4 , AIN, an HPSX ceramic (i.e. a ceramic with an Al 2 O 3 matrix which comprises an x ​​percent proportion of ZrO 2 , for example Al 2 O 3 with 9% ZrO 2 = HPS9 or Al 2 O 3 with 25% ZrO 2 = HPS25), SiC, BeO, MgO, high-density MgO (> 90% of the theoretical density), TSZ (tetragonally stabilized zirconium oxide) or ZTA as the material for the ceramic. It is also conceivable that the insulation layer is designed as a composite orA hybrid ceramic is used, in which several ceramic layers, each differing in their material composition, are arranged one above the other and combined to form an insulating layer to combine various desired properties. Preferably, a highly thermally conductive ceramic is used to achieve the lowest possible thermal resistance.

[0025] Preferably, the encapsulation is designed as a single piece, integrally or monolithically. "Single piece" is understood in particular to mean that the encapsulation cannot be disassembled into further individual parts without causing damage. This creates a particularly stable encapsulation that provides optimal protection for the encapsulated components. Furthermore, it is preferably provided that the second metallization is formed on the exterior of the electronic module in its manufactured state. In the manufactured state, the electronic module is not embedded in a further encapsulation that encapsulates, for example, the external second electronic components. This allows easy access to the second electronic components on the exterior of the manufactured electronic module.In a further embodiment of the present invention, the manufactured electrical module is surrounded by a removable casing, so that the second electronic components can be easily accessed by removing the casing.

[0026] It is preferably provided that the carrier substrate has a primary layer, a secondary layer and a metallic intermediate layer arranged between the primary layer and the secondary layer, in particular as an electronic return conductor, wherein the intermediate layer preferably thicker than the primary layer and / or the secondary layer and / or thicker than 1 mm, preferably thicker than 1.5 and particularly preferably thicker than 2.5 mm.

[0027] Such thick metallic intermediate layers advantageously act as temporary storage and thus improve the thermal impedance Z th . The thickness particularly supports heat spreading during heat dissipation, in which the heat is conducted from the component side via the carrier substrate to a side of the carrier substrate opposite the component side. In particular, it is provided that the intermediate layer is designed as a single layer or in one piece. The intermediate layer can preferably serve as an electrical return conductor by having an additional via in the primary layer, so that not only the first metallization layer but also the metallic intermediate layer can be used to conduct current.

[0028] Furthermore, it is preferably provided that the carrier substrate with the primary layer, the secondary layer and the metallic intermediate layer is composed of five or more layers. In particular, for the five-layer structure, two metallic intermediate layers are provided between the primary layer and the secondary layer, with a tertiary layer arranged between the two metallic intermediate layers. Preferably, at least two layers have a comparatively high modulus of elasticity. This further reduces the tendency to twist during operational and environmental temperature changes. Preferably, the primary layer, the secondary layer and / or the tertiary layer are made of a material comprising ceramic, for example from one of the ceramics mentioned above. This advantageously allows the desired requirements for insulation strength to be met.However, it is also conceivable that the secondary layer and / or tertiary layer are not made of a material that includes a ceramic, as these essentially serve to stiffen the carrier substrate and do not contribute to insulation. For example, the use of molybdenum and / or tungsten instead of a ceramic would be conceivable here.

[0029] InIn a preferred embodiment of the present invention, it is provided that the electronic module and / or the carrier substrate is designed to be thermomechanically symmetrical, in particular along a stacking direction that runs perpendicular to a main extension plane of the carrier substrate. A thermomechanically symmetrical design is to be understood in particular as meaning that thermomechanical expansion coefficients are symmetrical when viewed in the stacking direction. The thermomechanical expansion coefficient is a measure of the expansion of the respective layer during a temperature change or a temperature change. The electronic module can preferably be divided into virtual sub-substrates, in particular with a virtual primary substrate, a virtual secondary substrate and a virtual intermediate layer, and the thermal expansion coefficients of the virtual sub-substrates are distributed symmetrically in the stacking direction.The symmetrical design of the expansion coefficients advantageously provides an electronic module that is comparatively resistant to torsion due to operational or ambient temperature changes. As a result, defects or cracks that would otherwise be caused by thermally induced mechanical stresses can be avoided. In particular, when combined with a carrier substrate with a comparatively thick metallic intermediate layer, especially over 1 mm, it is possible to provide a comparatively high thermal expansion coefficient for the entire carrier substrate. This simplifies the adaptation of the thermal expansion coefficient for the encapsulation of the electronic module, as the effort required to reduce the typically high thermal expansion coefficient of the encapsulation can be reduced.Finally, to reduce the thermal expansion coefficient, a filler material is embedded in the encapsulation material. The increased expansion coefficient for the carrier substrate allows the amount of filler material to be reduced, which in turn reduces the cost of manufacturing the electronic module.

[0030] According to the invention, a further via is provided for the electrical connection of the intermediate layer to the second electronic component, wherein the further via runs through the encapsulation and the primary layer. The further via can run through the first metallization layer of the carrier substrate or comprise several partial sections. For example, the further via comprises a partial section in the encapsulation and a partial section that runs through the primary layer. By means of the further via, it is advantageously possible to realize a direct electrical connection from the outside of the encapsulation to the metallic intermediate layer between the primary layer and the secondary layer.

[0031] In a further embodiment of the present invention, it is provided that a contacting plane is provided in the encapsulation between the outer side of the encapsulation and the component side of the carrier substrate, which contacting plane runs obliquely and / or transversely to the extension direction / running direction of the vias for connecting at least two vias. This allows several vias to be electrically connected to one another, so that the area within the encapsulation can already be used as a distribution system, i.e. as a three-dimensional conductor system. Furthermore, it is conceivable to connect the further via to one or more vias by means of the contacting plane. The contacting planes preferably extend parallel to the main extension plane of the carrier substrate and are designed as an additional structured metallization layer.To manufacture such contact levels, it is conceivable, for example, for the encapsulation to be assembled in multiple parts or to be realized in several consecutive injection molding and / or transfer molding processes. Furthermore, the contact levels allow for a simple lateral offset between the first component and the second component, particularly without vias running at an angle to the stacking direction.

[0032] According to the invention, the carrier substrate has a cooling structure on its side opposite the component side, wherein the electronic module preferably has a sealing element and / or sealing material, e.g. a silicone, for fluid-tight connection to a fluid cooling device. According to the invention, the cooling structure is advantageously integrated into the carrier substrate and is not enclosed by the encapsulation, i.e. is exposed. The integration allows for low outlay when installing the electronic module, since an additional work step in which a base plate and / or a cooler is connected to the carrier substrate, for example by soldering, sintering and / or clamping, can advantageously be dispensed with. The fluid cooling device serves in particular for the supply and removal of a cooling fluid, in particular a cooling liquid.The cooling structure preferably comprises fins that protrude into a channel formed by the cooling structure and the fluid cooling device. To seal the channel formed between the carrier substrate-side cooling structure and the fluid cooling device, a sealing element is preferably provided, which is integrated into the electronic module and is preferably arranged substantially at the level of the cooling structure, as viewed in the stacking direction. The sealing element is preferably ring-shaped or beaded and preferably surrounds the cooling structure, in particular the fins of the cooling structure. The sealing element is preferably arranged on the encapsulation, for example in a groove provided for this purpose.

[0033] A further advantage of integrating the cooling structure directly onto the carrier substrate is that there is no need for material between the cooling structure and the carrier substrate or the secondary layer. TIM (thermal interface material) material generally has a reduced thermal conductivity compared to the other materials used in the carrier substrate. The omission of the TIM Material and the avoidance of interfaces significantly improves the thermal resistance of the carrier substrate or the electronic module.

[0034] In a further embodiment of the present invention, the via has a length between 0.1 and 15 mm, preferably between 0.15 and 8 mm, and particularly preferably between 0.2 and 5 mm. It has been advantageously found that with such short conductor paths or vias, the influence of parasitic inductances can be significantly reduced, thus improving the control of the first electronic component by the second electronic component.

[0035] A further subject of the present invention is a method for producing an electronic module, in particular an electronic module according to the invention, comprising: Providing a carrier substrate populated with a first electronic component, wherein the first electronic component is connected to a first metallization layer of the carrier substrate, at least partially encapsulating the populated carrier substrate with an encapsulation, forming a via in the encapsulation for providing an electrical connection between the first electronic component and a second electronic component on an outer side of the encapsulation, and forming a second metallization layer, in particular a structured second metallization layer, for the second electronic component on the outer side of the encapsulation.

[0036] All features and their advantages described for the metal-ceramic substrate according to the invention can be applied analogously to the method according to the invention, and vice versa. In particular, it is provided that the second metallization layer is connected to the first component and / or the first metallization layer via the through-hole.

[0037] To provide the carrier substrate, a primary layer, a secondary layer, an intermediate layer, a first metallization layer, and / or a cooling structure are bonded together in a common bonding process. Different bonding processes can also be used. Possible bonding processes include DCB (direct copper bonding) or DAB (direct aluminum bonding), or bonding using an active solder, i.e., an AMB (active metal brazing) process.

[0038] To form the through-hole plating, it is preferably provided that a recess, in particular a bore, is let into the manufactured encapsulation. This is preferably realized using laser light. However, it is also conceivable that the bore or, for the through-hole plating, a through-hole is milled into the encapsulation. If laser light is used, a recess is preferably formed that tapers towards the carrier substrate, for example a conical taper. To position the through-hole plating correctly, an edge of the encapsulation or a marking can be used as a reference. After the recess has been manufactured, the recess is fully or partially filled with a conductive material. For example, a paste made of a conductive material can be introduced into the through-hole plating and the paste is then cured.

[0039] Preferably, the first electronic components are prepared or provided such that they have a contact surface that, when installed on the carrier substrate, faces the outside or the through-hole. It is conceivable that contact holes are formed in the first electronic component and that the terminal contact is established by means of physical vapor deposition. The terminal contact is then reinforced by chemical deposition, for example, by means of electroplating. Preferably, the first electronic components or groups of first electronic components are provided with the desired contact surfaces.

[0040] Preferably, the encapsulation is formed by means of an injection molding and / or transfer molding process, in particular around the populated carrier substrate. In particular, the encapsulation is formed in an injection molding and / or transfer molding part. In this case, the populated carrier substrate is preferably covered, in particular on the component side, with the injection molding and / or transfer molding material after it has been inserted into the injection molding and / or transfer molding part. As an injection molding and / or transfer molding process, for example, a transfer molding, a compression molding and / or a liquid casting process is conceivable. If one or more contact levels are provided, it is conceivable that the encapsulation is realized in several successive injection molding and / or transfer molding processes, wherein between each of these injection molding -and / or transfer molding processes, a contact level with or without further components is realized by applying a structured metallization layer to the last molded section of the encapsulation.

[0041] In a further embodiment of the present invention, it is provided that the second metallization layer on the outside of the encapsulation by a during the injection molding and / or transfer molding process into an injection molding -and / or transfer press mold, is realized by physical vapor deposition and / or electrochemical deposition. In particular, the electrochemical deposition, for example by means of electroplating, serves to reinforce the structure that was already started or initiated by the metal foil or the physical vapor deposition. For example, the structure provided by vapor deposition or the metal foil is reinforced by galvanic copper, in particular after or before structuring. In this case, a stencil is used for vapor deposition, for example. If a metal foil is provided for the realization of the second metallization layer, it is conceivable that this metal foil is already structured. Alternatively or additionally, it is conceivable that the second metallization layer is structured after its production.Furthermore, it is also conceivable that the second metallization layer is bonded to the encapsulation. Furthermore, it is conceivable that the second metallization layer is applied using a printing process, in particular a 3D printing process. Furthermore, it is conceivable that after the second metallization layer has been provided, it is further processed. For example, the second metallization layer is sealed (with gold; silver, ENIG) and / or made solderable.

[0042] Further advantages and features will become apparent from the following description of preferred embodiments of the subject matter of the invention with reference to the accompanying figures. Individual features of the individual embodiments

[0043] can be combined within the scope of the invention. It shows: Fig.1: an electronic module according to a first exemplary embodiment of the present invention, Fig. 2:an electronic module according to a second exemplary embodiment of the present invention, Fig. 3: schematically shows a method for producing an electronic module according to an exemplary embodiment of the present invention and Fig. 4. an example of the production of a pre-composite.

[0044] In the Figure 11 shows an electronic module 1 according to a first exemplary embodiment of the present invention. Essential components of such an electronic module 1 are a carrier substrate 10 and an encapsulation 20, wherein the carrier substrate 10 is at least partially embedded in the encapsulation 20, i.e. the carrier substrate 10 is at least partially encapsulated in the encapsulation 20. The carrier substrate 10 has a component side 25 with a first metallization layer 15, wherein the first metallization layer 15 is structured to form conductor tracks or connection pads. First electronic components 30 are connected to the component side 25 and are preferably interconnected to form at least part of an electronic circuit. For example, the first electronic components comprise semiconductors, in particular WBG semiconductors (wide bandgap semiconductors), such as, for example,a semiconductor made of silicon carbide, gallium nitride, and / or indium gallium nitride, whose band gap between a valence band and the conduction band is between 2 eV and 4 eV or higher. In particular, the electronic module 1 is a power electronics module and is used, for example, to convert electrical energy using switching electronic components. It would be conceivable, for example, for the electronic module to be used as a DC-DC converter, inverter, and / or frequency converter in the field of electronic drive technology, particularly in the field of e-mobility, as a solar inverter and / or inverter for wind turbines for feeding renewable energy into the grid, or as a switching power supply or DC-DC converter.

[0045] To control the first electronic components 30 on the component side 25, a second metallization layer 35, serving in particular as a connection for at least one second electronic component or contact element 31, is provided on the outer side A of the encapsulation 20. Preferably, the second metallization layer 35 is also structured. For example, the second electronic component 31 is a control element, such as a gate driver, an intermediate capacitor, a load connection, a connection for the power supply, or the like. To provide a direct electrical connection between the first electrical components 30 and the second electronic components 31, at least one via 5 is provided in the encapsulation 20. The via 5 extends from the outer side A of the encapsulation 20 to the component side 25 of the carrier substrate 10.

[0046] Preferably, it is provided that, by means of the through-plating 5, a distance between the first electrical component 30 on the component side 25 and the second electrical component 31 on the outer side A is dimensioned to be less than 10 mm, preferably 5 mm, particularly preferably 2.5 mm, in particular 1 mm down to less than 300 µm, i.e., as small as possible. A length L of the through-plating 5 preferably corresponds to the distance between the first component 30 and the second component 31.

[0047] The carrier substrate 10 preferably comprises a primary layer 11, a secondary layer 12, and a metallic intermediate layer 16 arranged between the primary layer 11 and the secondary layer 12. The primary layer 11, the secondary layer 12, and the intermediate layer 16 extend along a main extension plane HSE and are arranged one above the other along a stacking direction S running perpendicular to the main extension plane HSE. The metallic intermediate layer 16 preferably serves as an electrical return conductor, which can advantageously reduce parasitic inductances. While the primary layer 11 and / or the secondary layer 12 are primarily provided to stiffen the carrier substrate 10, the intermediate layer 16, in addition to its optional function as an electrical return conductor (if there is a through-hole connection through the primary layer), serves in particular as a heat sink or temporary heat accumulator in which (additional) heat spreading takes place.As a temporary heat storage device, the intermediate layer improves a thermal impedance Z th of the carrier substrate. The heat spreading advantageously leads to a homogeneous temperature distribution on a side of the carrier substrate 10 opposite the component side 25 of the carrier substrate 10, via which side the heat developed by the first components is to be dissipated via a cooling structure 60 or another cooling device. For this purpose, the intermediate layer 16 is preferably thicker than the primary layer 11 and / or the secondary layer 12 and / or is thicker than 1 mm, preferably thicker than 1.5 mm, and particularly preferably thicker than 2.5 mm.

[0048] Preferably, the thermal expansion coefficients or the expansion of the individual components of the electronic module 10 are selected such that the thermal expansion coefficient, viewed in the stacking direction S, is essentially symmetrical or as symmetrical as possible. When using the metallic intermediate layer 16 with a thickness greater than 1 mm and using thinner primary layers 11 or secondary layers 12, in particular made of ceramic, it is then advantageously possible to realize a comparatively high thermal expansion coefficient CTE for the carrier substrate 10. This comparatively high thermal expansion coefficient simplifies the adaptation of the thermal expansion coefficient of the encapsulation 20, which would otherwise have to be reduced by means of a corresponding filler material. As a result, the material costs for the filler material can be advantageously reduced.

[0049] Encapsulation 20 in particular ensures the most compact design possible.

[0050] In particular, the encapsulation is designed such that the encapsulation interacts with the carrier substrate 10 in a form-fitting, force-fitting and / or positive-locking manner in the assembled state. Preferably, the carrier substrate 10 is embedded in the encapsulation 20 at least on its component side 25, ie the encapsulation completely encloses the component side 25. In the Figure 1In the embodiment shown, a cooling structure 60 is provided according to the invention on a side opposite the component side 25. In particular, the cooling structure 60 comprises fins. Furthermore, it is provided that the cooling structure 60 is not enclosed by the encapsulation 20, i.e. the cooling structure or its fins are exposed. Instead, the cooling structure 60 is provided for direct connection to a fluid cooling device, for example a corresponding channel that carries a cooling fluid to and from the cooling structure. A sealing element 61 is provided to seal a fluid channel that is formed between the fluid cooling structure and the carrier substrate-side cooling structure 60. The sealing element 61 is preferably designed to run circumferentially in a plane running parallel to the main extension plane HSE.

[0051] In Figure 2An electronic module 10 according to a second embodiment of the present invention is shown schematically. The embodiment from the Figure 2 differs essentially from that of Figure 1 only in the sense that a plurality of contacting planes 14 are provided in the encapsulation 20. These contacting planes 14 extend essentially obliquely or transversely to the direction of extension of the vias 5, wherein the direction of extension in the illustrated embodiment runs parallel to the stacking direction. However, it is also conceivable for the direction of extension of the vias to run obliquely to the stacking direction S. A plurality of vias 5 can be advantageously connected to one another via the contacting planes 14. Preferably, a plurality of the further contacting planes 14 run parallel to one another, in particular parallel to the main extension plane.

[0052] In Figure 3A method for producing an electronic module 10 is shown schematically. In this case, it is provided that a carrier substrate 10 is first provided. In particular, to provide 101 the carrier substrate 10, the metallic intermediate layer 16 and / or a cooling structure 60 for the carrier substrate are prepared. Subsequently, the primary layer 11, the secondary layer 12, the metallic intermediate layer 16 and / or the cooling structure 60 are connected to one another in a common or several individual bonding processes. The bonding process is preferably a DCB or DAB process or a bonding by means of an active solder. To provide conductor tracks and connection pads, the first metallization layer 15 is structured on the component side 25, for example by an etching process.Preferably, the component side 25 is subsequently surface modified by nickel plating, silver plating, edge casting or something similar.

[0053] Furthermore, it is provided that the first electronic components 20 are prepared for connection to the component side 25 for the electronic module 10 and are provided, for example, as a pre-assembly. In particular, contacts are implemented on the electronic components 30 such that, when installed in the electronic module 1, the contacts face the outer side A of the encapsulation 20. For this purpose, contact holes are introduced into the pre-assembly. The introduced contacts can be copper-plated using physical vapor deposition and subsequently electroplated for reinforcement.

[0054] After the carrier substrate 10 has been completed, the pre-composite is attached to the structured metallization layer 15 on the component side 25 of the carrier substrate 10, for example, by soldering or sintering. The carrier substrate 10 populated with the pre-composite is then encapsulated. Preferably, an injection molding and / or transfer molding process is used for encapsulation 102. For this purpose, the populated carrier substrate is placed in an injection mold. The injection mold is preferably designed such that the cooling structure 60 faces away from a cavity to be filled during injection molding. Thus, the cooling structure 60 is not covered by the plastic used during the injection molding and / or transfer molding process.

[0055] Furthermore, it is provided that a formation 103 of a through-plating of the encapsulation 20 takes place by, for example, creating a recess, in particular a hole or bore, in the encapsulation 5 using laser light. The holes and bores are essentially conical in shape. This conical shape typically results from focusing a laser beam with which the recess is created. Furthermore, it is provided that the hole or bore to form the through-plating 5 is filled with a metal, for example using a paste. Markings are preferably provided for orientation on the outer side A when creating the bores. The markings are preferably holes milled into the encapsulation 20, which can also be used, for example, to align the encapsulation 20 before the holes are created.

[0056] Furthermore, it is conceivable that a metal foil is inserted into an injection mold used to form the encapsulation, which metal foil provides the second metallization layer 35 for the second electronic components 31 after injection molding and / or transfer molding. Additionally or alternatively, it is conceivable that the second metallization layer 35 after injection molding - and / or transfer molding process on the injection-molded encapsulation 20 using a physical vapor deposition process or a 3D printing process. Preferably, the second metallization layer is reinforced by a metal applied by electroplating, for example, by electroplated copper.

[0057] Forming the metallization layer 104 preferably includes structuring the second metallization layer 35 on the outer side A. It is also conceivable that a solder resist is used and / or that the second metallization layer 35 on the outer side A is post-treated. As a post-treatment, for example, a surface modification 105 in the form of a sealing with ENIG (electroless nickel immersion gold), silver, or gold is conceivable. Preferably, the second electronic component 31 is finally mounted on the second metallization layer 35 provided for this purpose on the outer side A. Furthermore, it is provided that a cover element is attached to the electronic module 10 and that the provided electronic module is subjected to a final inspection.

[0058] In Figure 4A method for producing a pre-assembly 50 is shown schematically and by way of example. In this case, it is provided that a first component 30 with component-side connections 54 is applied to a printed circuit board 51. The printed circuit board 51 and the first component 30 are then laminated such that the first component 30 is arranged or embedded within a matrix 52, for example a dielectric matrix 52. To expose the component-side connections 54, the dielectric matrix 52 is structured. This results in recesses 53 that extend to the printed circuit board 51 or to the electrical connections 54. These recesses 53 are filled with a conductive material, whereby the outside of the dielectric matrix 52 is also covered.

[0059] The conductive material is then structured on the outside to provide the pre-bonded contact surfaces 55. These pre-bonded contact surfaces 55 represent the contact surfaces of the first components within the encapsulation 20 and are in contact with the via 5 of the encapsulation 20. The advantage of using the pre-bonded contact surface 50 is sometimes the realization of pre-bonded contact surfaces 55 that are larger than the component-side connections 53. This can prevent, for example, a situation where contact cannot be established with the first component 30 due to a manufacturing-related offset of the vias 5 subsequently embedded in the encapsulation 20. List of reference symbols:

[0060] 1Electronic module 5Through-hole plating 5'Further through-hole plating 10Carrier substrate 11Primary layer 12Secondary layer 15First metallization layer 16Intermediate layer 20Encapsulation 25Component side 30First electronic component 31Second electronic component 35Second metallization layer 50Pre-assembly 51Printed circuit board 52Matrix 53Recess 54Component-side connections 55Assembly-side connections 60Cooling structure 61Sealing element 101Providing a carrier substrate 102Encapsulation 103Forming a through-hole plating 104Forming a structured second metallization layer 105Surface modification AOutside LLength

Claims

1. An electronic module (1), comprising - an encapsulation (20) and - a carrier substrate (10) embedded in the encapsulation (20) and having a component side (25) which has a first metallisation layer (15) and on which at least a first electronic component (30) is arranged, wherein the first electronic component (30) is enclosed by the encapsulation (20) and wherein the carrier substrate (10) is a metal-ceramic substrate, wherein at least one second metallisation layer (35) is provided on an outer side (A) of the encapsulation (20) for at least one second electronic component (31), in particular for controlling the first electronic component (30), wherein the encapsulation (20) has at least one via (5) for the electrical connection, in particular for the direct electrical connection, of the first electronic component (30) and the second electronic component (31), wherein an outer surface of the carrier substrate (10) is covered by more than 50% by the encapsulation, characterised in that that the carrier substrate (10) has a cooling structure (60) on its side opposite the component side (25), wherein the cooling structure is integrated into the carrier substrate and is not enclosed by the encapsulation.

2. The electronic module (1) according to claim 1, wherein the second metallisation layer (35) is structured and / or wherein a distance between the first metallisation layer (15) and the second metallisation layer (35), measured perpendicular to the main extension plane, is less than 1 mm.

3. The electronic module (1) according to one of the preceding claims, wherein the carrier substrate has a primary layer (11), a secondary layer (12) and a metallic intermediate layer (16) arranged between the primary layer (11) and the secondary layer (12) as an electronic return, wherein the intermediate layer (16) is preferably - thicker than the primary layer (11) and / or the secondary layer (12) and / or - thicker than 1 mm.

4. The electronic module (1) according to claim 3, wherein a further via (5') is provided for the electrical connection of the intermediate layer (16) to the first and / or second electronic component (30, 31), wherein the further via (5') runs at least through the primary layer (11).

5. The electronic module (1) according to one of the preceding claims, wherein a contact plane (14) is provided in the encapsulation (20) between the outer side (A) of the encapsulation (20) and the component side (25) of the carrier substrate (10), which runs obliquely and / or transversely to the direction of extension of the vias (5) for joining at least two vias (5).

6. The electronic module (1) according to one of the preceding claims, wherein the electronic module (1) has a sealing element (61) for fluid-tight bonding to a fluid cooling device.

7. The electronic module (1) according to one of the preceding claims, wherein the via (5) has a length (L) between 0.2 and 5 mm.

8. The electronic module (1) according to one of the preceding claims, wherein the via (5) has a cross-section of less than 5 mm2 in a direction measured parallel to the main extension plane (HSE).

9. The electronic module (1) according to one of the preceding claims, wherein the encapsulation (20) is made of an epoxy casting component as encapsulation material.

10. The electronic module (1) according to one of the preceding claims, wherein the via (5) runs obliquely to a direction extending perpendicular to the main extension plane (HSE) of the carrier substrate (10).

11. A method for producing an electronic module (1) according to one of the preceding claims, comprising: - providing (101) a carrier substrate (10) equipped with a first electronic component (30), the first electronic component (30) being bonded to a first metallisation layer (15) of the carrier substrate (10), - encapsulating (102) of the equipped carrier substrate (10) with an encapsulation (20), wherein the first electronic component (30) is enclosed by the encapsulation (20), wherein the carrier substrate (10) is a metal-ceramic substrate and wherein an outer surface of the carrier substrate (10) is covered by more than 50% by the encapsulation, - forming (103) a via (5) in the encapsulation (20) for providing an electrical connection between the first electronic component (30) and a second electronic component (31) on an outer side (A) of the encapsulation, and - forming (104) a second metallisation layer (35) for the second electronic component (31) on the outer side (A) of the encapsulation (20), characterised in that the carrier substrate (10) has a cooling structure (60) on its side opposite the component side (25), wherein the cooling structure is integrated into the carrier substrate and is not enclosed by the encapsulation.

12. The method according to claim 11, wherein the encapsulation (20) is formed by means of an injection moulding process.

13. The method according to claim 11, wherein the second metallisation layer (35) is realized on the outer side (A) of the encapsulation (20) - by a metal foil inserted into an injection mould and / or injection press mould during an injection moulding and / or injection press process, - by physical vapour deposition and / or - electrochemical deposition.