METHOD FOR MANUFACTURING AN ELECTRONICS MODULE

Description

[0001] The present invention relates to a method for manufacturing an electronic module.

[0002] Electronic modules are well known from the prior art, for example as power electronics modules. Such electronic modules typically use switchable electronic components that are interconnected via conductive traces on a common substrate. Essential components of the substrate are an insulating layer, which, for example, in the case of a metal-ceramic substrate, is made of a material comprising a ceramic, and a metallization layer, which is preferably structured and formed on one side of the substrate to create conductive traces.

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

[0004] Examples of prior art include the publications DE 10 2008 029 829 B4, DE 10 2009 042 399 A1, US 7 589 412 B2 and DE 10 2014 117 086 A1, in which electrical components for forming an electronic module are arranged on a substrate and embedded in an encapsulation. Another example of an electronic module is the component designated "LTM4636" distributed by Analog Devices.

[0005] From US 2017 200 666 A1 and US 2012 0 056 312 A1, an electronic module with encapsulation is known.

[0006] In particular, US 2017 200 666 A1 discloses a method for manufacturing an electronic module, comprising: Providing a carrier substrate equipped with a first electronic component, at least partially encapsulating the equipped carrier substrate with an encapsulation, realizing a second recess in the encapsulation and forming a via to provide an electrical connection between a second electronic component on an outside of the encapsulation and a metallic layer.

[0007] Starting from this prior art, the present invention aims to provide an electronic module that is improved compared to those of the prior art, particularly with regard to a simplified manufacturing process.

[0008] The problem is solved according to the invention by a method for manufacturing an electronic module according to claim 1. Preferred embodiments of the invention are specified in the dependent claims and the following description, particularly in conjunction with the accompanying figures. According to the invention, a method for manufacturing an electronic module is provided, comprising: Providing a carrier substrate equipped with a first electronic component, wherein the carrier substrate comprises 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, and wherein the primary layer has a first recess, at least partially encapsulating the equipped carrier substrate with an encapsulation, realizing a second recess in the encapsulation, and forming a via to provide an electrical connection between a second electronic component on an outside of the encapsulation and the metallic intermediate layer, wherein the first recess in the primary layer and the second recess in the encapsulation are jointly filled with an electrically conductive material and / or electrically contacted with each other in a single step.

[0009] In particular, it is advantageously possible to dispense with the requirement that the substrate be provided with a via inherent to the substrate. Such vias would otherwise be created during the substrate manufacturing process, i.e., during the bonding of the primary layer to the intermediate layer, for example, using a brazing or AMB process. Such soldered vias inherent to the substrate restrict the process sequence in the substrate manufacturing process and must be produced via a dispensing process. The inventive method avoids these problems because the formation of the vias inherent to the substrate can be dispensed with, and instead, the first recess in the primary layer is filled during the filling of the second recess in the encapsulation.Furthermore, it is possible to eliminate the need for the special material required for soldering. This allows for greater flexibility in the choice of material for the vias, thereby optimizing both the cost and properties of the vias. Additionally, it is advantageously possible to better control the manufacturing process of the via, which runs from the outer surface to the intermediate layer. This positively impacts the quality of the manufactured vias and reduces the number of electronic module failures during via formation.

[0010] It is also conceivable that the vias could be produced using a DCB process, particularly with the use of copper beads or pastes. For example, the DCB process can be used to create cavities or recesses that can later be filled with a paste or similar material to form a via.

[0011] In an advantageous embodiment of the invention, the simultaneous filling of the first and second recesses creates a one-piece, and in particular, material-uniform, through-hole plating that extends from the outside of the encapsulation to the intermediate layer. This through-hole plating comprises a section within the encapsulation and a section that extends through the primary layer and the first metallization layer. The through-hole plating advantageously enables a direct electrical connection from the outside of the encapsulation to the metallic intermediate layer between the primary and secondary layers. It is provided that the encapsulation at least partially surrounds the substrate, e.g., in the form of a casting material, or that the substrate is embedded within the encapsulation.

[0012] Furthermore, a method is preferably provided in which the primary layer, the intermediate layer and the secondary layer are arranged one above the other in a stacking direction and the first recess and the second recess are arranged one above the other, at least partially aligned, when viewed in the stacking direction.

[0013] According to the invention, the metallic intermediate layer arranged between the primary layer and the secondary layer extends over a first surface in a plane parallel to the main extension plane, and the primary layer and / or the second secondary layer extend over a second surface, wherein the ratio of the first surface to the second surface is greater than 0.5, preferably greater than 0.75, and particularly preferably greater than 0.9. In particular, the ratio between the first surface and the second surface is substantially 1, i.e., the metallic intermediate layer extends over the entire surface beneath the primary layer. According to the invention, the metallic intermediate layer separates the primary layer from the secondary layer. According to the invention, the primary layer, the metallic intermediate layer, and the secondary layer form a sandwich structure.Furthermore, it is provided that the primary layer separates the first electrical component from the metallic intermediate layer, i.e., the primary layer is arranged between the first electrical component and the metallic intermediate layer.

[0014] Furthermore, it is preferably provided that the primary layer has a thickness in the stacking direction that is greater than 100 µm, preferably greater than 200 µm, and particularly preferably greater than 250 µm. It is further preferably provided that the primary layer or the support substrate is silicone-free, i.e., the silicone content of the support substrate is less than 1 wt.%, preferably less than 0.5 wt.%, and particularly preferably less than 0.1 wt.%. Furthermore, the primary layer and / or the secondary layer preferably extend in a single plane, i.e., the primary layer and / or the secondary layer do not form any valleys or ridges, or any waves or protrusions. For example, the primary layer and the secondary layer run parallel to each other.

[0015] Furthermore, it is conceivable that the metallic interlayer projects towards the main extension plane beyond an outermost edge of the primary layer, and that an electrically conductive connection is established with the projecting, particularly laterally projecting, section of the metallic interlayer by means of the via. In this case, the exposed edge region of the primary layer forms the first recess. This allows for a relatively simple implementation of a first recess. It is also conceivable that the metallic interlayer is flush with the primary layer in the main extension plane, and that the via passes through the primary layer laterally, contacting the metallic interlayer from the side, i.e., parallel to the main extension plane.

[0016] Furthermore, it is preferably provided that the substrate has a first metallization layer on which at least one first electronic component is arranged, wherein a third recess in the encapsulation and a further through-hole for electrically connecting a second metallization layer on the outside of the encapsulation to the first metallization layer and / or the first electronic component are realized, wherein the third recess is filled with an electrically conductive material, in particular simultaneously with filling the first and second recesses. The further through-hole provides a means for a direct electrical connection, i.e., without passing through the intermediate layer, between the first and second electronic components.The further through-hole plating 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 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 and the second electronic components on the outside. The invention is particularly characterized by the second metallization layer, which allows for direct connection to the outside of the encapsulation. The simultaneous formation of the through-hole plating extending to the intermediate layer and the further through-hole plating extending to the first electronic component advantageously optimizes manufacturing time.

[0017] Preferably, the distance between the first and second metallization layers, measured perpendicular to the main plane of extension, is less than 5 mm, preferably less than 2.5 mm, and most preferably less than 1 mm down to less than 400 µm, for example, approximately 300 µm – i.e., as small as possible. It is particularly preferred that the distance be less than 200 µm or 100 µm. It is especially preferred that the distance be between 100 and 200 µm. Accordingly, a very short distance is established between the first electrical component and the second electrical component in a direction perpendicular to the main plane of extension.

[0018] Furthermore, it is preferably provided that the first metallization layer and the second metallization layer are structured such that, in the assembled state, the first component and the second component are offset from each other by a lateral distance in a direction parallel to the main extension plane. This advantageously prevents the heat generation of the first and second components from influencing or impairing each other. To ensure effective control of the first component by the second component, it is preferably provided that the lateral distance is less than 35 mm, more preferably less than 15 mm, and most preferably less than 5 mm.

[0019] The term "embedding" or "being embedded" refers specifically to the encapsulation being directly adjacent to an outer surface of the substrate. This means that the encapsulation is in direct contact with the substrate, at least in some areas, and no open space or cavity is formed between the substrate containing the electronic component and the encapsulation. The substrate does not need to be completely enclosed or surrounded by the encapsulation on all sides. Furthermore, the encapsulation is intended to be solid, i.e., free of cavities.

[0020] Furthermore, it is preferably provided that the via and / or the further via each has a cross-section of less than 5 mm² in a dimension parallel to the main extension plane, preferably less than 1.5 mm², and particularly preferably less than 0.5 mm², especially if the further via is directly connected to the first component, in particular to a top surface of the first component. If the further via is connected to the first metallization layer, the cross-section is preferably less than 3.5 mm², more preferably less than 2.5 mm², and particularly preferably less than 1.5 mm². Since the cross-section changes in the stacking direction for manufacturing reasons, and may taper in the direction of the substrate, the cross-section is preferably understood to be its average cross-section along its extension in the stacking direction.

[0021] Furthermore, it is provided that the via and / or the subsequent via is flush with the outer surface of the encapsulation. The portion of the second metallization layer that is flush with, and in particular directly adjacent to, the via or subsequent via also has a contact area dimensioned parallel to the main plane. The ratio between the cross-section of the via, dimensioned parallel to the main plane, and the contact area of ​​the portion of the second metallization layer adjacent to the via is preferably less than 0.25, more preferably less than 0.15, and most preferably less than 0.1. In other words, the via is designed to be relatively narrow. Furthermore, it is conceivable that several vias orfurther vias are connected to a common electronic component and the sum of the cross-sectional areas of all vias is smaller than the contact area of ​​the second metallization layer.

[0022] The additional vias are preferably characterized by being arranged above the first metallization layer or between the first and second electronic components when viewed in the stacking direction. It is conceivable that a first proportion of all the additional vias directly contact the first components and a second proportion directly contact the first metallization layer. Preferably, the second proportion is larger than the first, or the first proportion is larger than the second.

[0023] The contacting of the first and second components via the subsequent via can be direct or indirect. For example, the first component itself can be integrated into a pre-assembly, or the subsequent via can contact the first metallization layer to establish an electrical connection between the first and second components.

[0024] Preferably, at least one outer surface of the substrate remains free of the encapsulation. In particular, it is provided that at least the component side of the substrate is completely encapsulated, i.e., covered or enclosed by the encapsulation. Furthermore, it is conceivable that an outer surface or perimeter is covered by the encapsulation to more than 40%, preferably more than 50%, and particularly preferably more than 60%. The direct connection to the substrate or the embedding of the substrate within the encapsulation advantageously improves the stability of the electronic module, and additional stabilization measures, e.g., between the encapsulation and the substrate, can be dispensed with. It is also conceivable that a protective layer is provided between the first electronic components and the encapsulation, which covers or encloses the first electronic components.protects and through which the vias and / or further vias run.

[0025] The first electronic components are preferably switchable or active components. Preferably, at least one first electronic component is a wide bandgap semiconductor (WBG), such as a silicon carbide, gallium nitride, and / or indium gallium nitride semiconductor, or a silicon semiconductor element. Examples of electronic components are MOSFETs (metal-oxide-semiconductor field-effect transistors) or IGBTs (insulated-gate bipolar transistors). The first electronic components can also be combined as a pre-assembly or prepackaging. In such a pre-assembly, one or more first electronic components are, for example, arranged on a printed circuit board and embedded in a matrix.

[0026] An example of a pre-assembled structure can be found in German patent application 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-assembled structure or the redistribution structure. Further examples of pre-assembled structures to which explicit reference is made can be found in the articles "Development of Embedded Power Electronics Modules for Automotive Applications" and "Embedding of Power Semiconductors for Innovative Packages and Modules" by L. Boettcher et al.

[0027] Second electronic components and / or contact elements are preferably Drivers or control elements, in particular "gate drivers", and / or connection devices that serve, for example, as a load connection for an input signal or for power supply, and / or capacitors, for example, intermediate capacitors. These components are provided and are contacted directly onto the second metallization layer, which serves as the connection, e.g., by soldering or sintering. A "gate driver," such as a MOSFET driver, IGBT driver, or half-bridge driver, is understood to be a discrete or integrated electronic circuit that controls power switches, such as MOSFETs or IGBTs. In the case of control elements as the second electronic components, this allows for improved control of the first electronic components on the component side, since long transmission paths for the control signal from the control element on the outside to the first electronic component to be controlled can be advantageously avoided.Another advantage resulting from the comparatively short conductor tracks is a reduction in parasitic inductances, which would otherwise be expected if no encapsulation and no via for the electrical connection between the outside of the encapsulation and the component side of the substrate were provided.

[0028] A via, or further via, is an electrical conduction path that penetrates the encapsulation or electrically connects two opposite or adjacent sides of the encapsulation. The via or further via can be made of the same metal or material as the first metallization layer, the second metallization layer, and / or the metallic intermediate layer, or it can be made of a different material. Furthermore, the via and / or further via can be completely or partially filled with a conductive material. The via preferably extends in a straight line. It can run parallel or obliquely to a direction perpendicular to the main plane of the substrate.The additional through-hole plating also allows for contacting the first electronic component via a side facing away from the substrate or a side facing the outside of the encapsulation; that is, electrical connections can also be routed "upwards" out of the encapsulation. In the case of pre-assembly or "prepacking," it is advantageously possible to create a pre-assembly-side contact surface on a side of the pre-assembly that faces the outside in the assembled state. It is advantageous to enlarge the pre-assembly-side contact surface to facilitate connection to the further through-hole plating within the encapsulation. For example, a ratio between the diameter of the through-hole measured parallel to the main plane of extension and the...The further through-connection to the pre-composite-side contacting surface measured parallel to the main extension plane yields a value between 0.1 and 1, preferably between 0.15 and 0.8 and preferably between 0.3 and 0.6.

[0029] Preferably, the first electronic components in the electronic module have a contact on one side facing the outside of the encapsulation, in particular the second metallization layer, and are connected to the further via via this contact.

[0030] In particular, the encapsulation is provided to be a cast part, preferably made of a plastic by casting, e.g., injection molding. The encapsulation interacts with the substrate in the assembled electronic module in a form-fit, force-fit, and / or material-fit manner. For example, the encapsulation includes an undercut or a protrusion-like projection through which it can interact with the substrate containing the components in a form-fit manner. In particular, the encapsulation can be clipped to the substrate or is clipped to the substrate, preferably on the side opposite the component, which is often used for cooling purposes. Suitable casting materials, also called molding compounds, are casting resins such as synthetic thermosets. Preferably, the encapsulation is made of an epoxy potting compound as the encapsulation material.The potting compound preferably has a comparatively high glass transition temperature, for example above 200 °C, a flexural strength between 10 and 15 kg / mm², and is particularly curable. For example, the material is Hysol® MG 15F-MOD2. Furthermore, it is preferably provided that the encapsulation material includes a filler material, for example comprising SiO₂ and / or an aluminum oxide.

[0031] Suitable materials for the first metallization layer, the second metallization layer, and / or the metallic intermediate 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 the grain size in the first copper layer differs from that in the second copper layer. Furthermore, it is preferably provided that the first metallization layer and / or the second metallization layer are surface-modified. Surface modification could include, for example, sealing with a precious metal, in particular silver and / or gold, or ENIG ("electroless nickel immersion gold"), or edge sealing of the first or second metallization layer to suppress crack formation or propagation.

[0032] Preferably, the second metallization layer is structured and / or the first electronic components can be controlled via the through-hole plating and / or further through-hole plating by several second electronic components.

[0033] According to a preferred embodiment of the present invention, the support substrate is a metal-ceramic substrate, wherein the metal-ceramic substrate has a structured first metallization layer on its component side, and wherein the metal-ceramic substrate is preferably configured as a multilayer substrate. Essential components of the metal-ceramic substrate are a primary layer made of ceramic and the metallization layer bonded to the primary layer. Due to their comparatively high insulating properties, ceramic primary layers have proven particularly advantageous. By structuring the first metallization layer, conductive traces and / or contact surfaces for the first electrical components can then be realized. In particular, the metal-ceramic substrate is configured as a three- or five-layer substrate.The multi-layered design advantageously allows for the use of comparatively thick metallic intermediate layers, while several ceramic layers serve for stabilization. Consequently, the thermal resistance can be reduced and a controlled heat spread can be achieved. In particular, the thickness of the ceramic primary layer is adapted to the required insulation strength. It is conceivable that the first metallization layer, the second metallization layer, and / or the intermediate layer are each composed of several metallic sub-layers or partial layers, which are, for example, bonded to each other with a solder material.

[0034] The primary layer, especially as an insulating layer, is preferably a ceramic layer.

[0035] Preferably, the insulating layer comprises Al₂O₃, Si₃N₄, AIN, an HPSX ceramic (i.e., a ceramic with an Al₂O₃ matrix containing an x ​​percent ZrO₂, for example, Al₂O₃ with 9% ZrO₂ = HPS9 or Al₂O₃ with 25% ZrO₂ = HPS25), SiC, BeO, MgO, high-density MgO (> 90% of the theoretical density), TSZ (tetragonally stabilized zirconia), or ZTA as the ceramic material. It is also conceivable that the insulating layer is designed as a composite or hybrid ceramic, in which several ceramic layers, each differing in their material composition, are arranged one above the other and joined together to form an insulating layer in order to combine various desired properties. Preferably, a highly thermally conductive ceramic is used to achieve the lowest possible thermal resistance.

[0036] Furthermore, it is preferably provided that the support substrate, comprising the primary layer, the secondary layer, and the metallic interlayer, is composed of five or more layers. In particular, for the five-layer structure, two metallic interlayers are provided between the primary and secondary layers, with a tertiary layer arranged between these two metallic interlayers. Preferably, at least two layers have a comparatively high modulus of elasticity. This further reduces the tendency to twist under operational and environmental temperature fluctuations. Preferably, the primary layer, the secondary layer, and / or the tertiary layer are made of a ceramic-based material, for example, one of the ceramics mentioned above. This advantageously allows the desired insulation strength requirements to be met.However, it is also conceivable that the secondary and / or tertiary layers are not made of a ceramic material, since these primarily serve to stiffen the substrate and do not contribute to insulation. For example, the use of molybdenum and / or tungsten instead of a ceramic would be possible.

[0037] According to a preferred embodiment, the primary layer, the intermediate layer, and the secondary layer are arranged one above the other in the stacking direction, and the first and second recesses are arranged one above the other, particularly aligned with each other, when viewed in the stacking direction. This alignment in the stacking direction makes it possible to fill the first recess by approaching the second recess. It is particularly preferred that the cross-section of the first recess, dimensioned parallel to the main extension plane, is larger than the cross-section of the second recess, also dimensioned parallel to the main extension plane. This advantageously increases the probability that the second recess will open above the first recess when formed.A lateral offset does not result in a cross-sectional narrowing in the transition area between the first recess and the second recess that impairs conductivity.

[0038] It is particularly preferred that the second recess is created after the encapsulation and / or the first recess is created before the encapsulation. That is, the carrier substrate with the first recess in the primary layer is encapsulated first, and only then is the second recess formed. This proves advantageous for creating a stable encapsulation. For example, the first and / or second recess can be formed by means of a bore. It is also conceivable that the second recess is created during the injection molding or injection molding process. This eliminates the need to create the second recess after encapsulation. Alternatively, it is conceivable that the first recess is created after encapsulation, for example, by first creating the second recess and then providing the portion of the primary layer exposed by the second recess with the first recess.

[0039] In a particularly preferred embodiment of the present invention, the second recess is created during the encapsulation process, particularly using a first tool half and a second tool half. In a closed state, the first and second tool halves form a cavity that at least partially surrounds the substrate. The second recess is created during filling by means of a portion of a punch element located within the cavity. By creating the second recess simultaneously, it is advantageously unnecessary to form it after the encapsulation process. A further advantage is that the use of laser drilling is eliminated.It has proven particularly advantageous to use a slidably mounted punch element that can compensate for manufacturing tolerance-related unevenness in the substrate, thus enabling the reliable creation of the second recesses. The punch element is preferably positioned above and / or within the first recess during the filling process. For example, the punch element rests on the primary layer and covers the first recess, or more specifically, completely covers it. In an alternative embodiment, the punch element projects into the first recess and preferably comes to rest against the intermediate layer. This ensures that direct through-hole plating to the intermediate layer can be achieved after encapsulation.

[0040] In a further embodiment of the present invention, the second and / or third recess is created using laser light, in particular by laser cutting. This allows the second and third recesses to be created with positional accuracy and precision. The second and / or third recess produced by laser light is characterized by its cross-section tapering towards the substrate, in particular by a conical profile. It is also conceivable that the first recess is also created using laser light. Preferably, a different light, for example, light differing in wavelength, intensity, and / or beam profile, is used for forming the first recess compared to the production of the second and third recesses.To correctly position the through-encapsulation, an edge of the encapsulation or a marking on the encapsulation can be used as a reference.

[0041] Preferably, the filling of the first recess, the second recess, and / or the third recess is achieved by means of an electroplating process. Alternatively, it is conceivable that the through-hole plating and / or further through-hole plating is achieved using wet chemical processes, a paste, a vapor deposition process, a screen printing process, a 3D printing process, and / or mechanical methods.

[0042] In particular, it is provided that the first metallization layer has a fourth recess, wherein, to form the via for providing an electrical connection between a second electronic component on an outer surface of the encapsulation and the metallic intermediate layer, the first recess in the primary layer, the second recess in the encapsulation, and the fourth recess in the first metallization layer are filled together with an electrically conductive material in a single step. It is evident to those skilled in the art that the fourth recess is necessary if the via is to be made over a portion of the primary layer that is covered by the first metallization layer. However, it is also conceivable that the via could be made in a portion of the primary layer that is free of a metallization layer.Preferably, the fourth recess is created using an etching process and / or a milling process. It is conceivable that the formation of the fourth recess takes place before and / or after encapsulation.

[0043] According to a preferred embodiment of the present invention, it is provided that the intermediate layer thicker than the primary layer and / or the secondary layer and / or thicker than 1 mm, preferably thicker than 1.5 mm and particularly preferably thicker than 2.5 mm.

[0044] Such thick metallic intermediate layers advantageously act as temporary storage and thus improve the thermal impedance Zth. The thickness particularly supports heat spreading during heat dissipation, whereby heat is conducted from the component side via the substrate to a side of the substrate opposite the component side. It is particularly desirable for the intermediate layer to be single-layered or monolithic. The intermediate layer can preferably serve as an electrical return conductor by incorporating an additional via in the primary layer, so that not only the first metallization layer but also the metallic intermediate layer can be used for current conduction.

[0045] Furthermore, it is preferably provided that the via extends to the cooling structure. The via extending to the cooling structure proves particularly advantageous because it allows for grounding, which can be provided, in particular, on the outside of the encapsulation. It is expediently provided that the intermediate layer is pre-structured or structured in such a way that, during the via installation, a portion of the intermediate layer remains insulated from the via to prevent a short circuit and to continue using the intermediate layer, especially the portion of the intermediate layer through which the via does not extend to the cooling structure, as a return conductor. The cooling structure can comprise fins or be designed as a solid metal block.

[0046] In a preferred embodiment of the present invention, the electronic module and / or the support substrate is designed to be thermomechanically symmetrical, particularly along a stacking direction that is perpendicular to a principal extension plane of the support substrate. Thermomechanical symmetry means, in particular, that the thermomechanical coefficients of expansion are symmetrical when viewed in the stacking direction. The thermomechanical coefficient of expansion is a measure of the expansion of the respective layer during a temperature change. Preferably, the electronic module can 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 exhibits comparatively low torsional rigidity under operational or environmental temperature fluctuations. Consequently, defects or cracks that would otherwise be caused by thermally induced mechanical stresses can be avoided. In particular, when combined with a substrate featuring a relatively thick metallic interlayer, especially one over 1 mm, it is possible to achieve a comparatively high coefficient of thermal expansion for the entire substrate. This simplifies the adjustment of the coefficient of thermal expansion for encapsulating the electronic module, as the effort required to reduce the typically high coefficient of thermal expansion of the encapsulation itself can be minimized.To reduce the coefficient of thermal expansion, a filler material is embedded in the encapsulation material. The increased expansion coefficient of the substrate allows for a reduction in the amount of filler material required, which in turn reduces the manufacturing costs of the electronic module.

[0047] In a further embodiment of the present invention, a contact plane is provided in the encapsulation between the outer surface of the encapsulation and the component side of the substrate. This contact plane extends obliquely and / or transversely to the direction of extension / direction of the vias or further vias for connecting at least two vias and / or further vias. This allows several vias within the encapsulation 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 contact plane.Preferably, the contact planes extend parallel to the main extension plane of the substrate and are designed as an additional structured metallization layer. For the production of such contact planes, it is conceivable, for example, that the encapsulation can be assembled in multiple parts or realized in several successive injection molding and / or compression molding processes. Furthermore, the contact planes allow for a simple lateral offset between the first and second components, particularly without vias running obliquely to the stacking direction.

[0048] According to the invention, the support substrate has a cooling structure on its side opposite the component side, and the electronic module preferably has a sealing element and / or sealing material, e.g., silicone, for a fluid-tight connection to a fluid cooling device. In particular, the cooling structure is advantageously integrated into the support substrate and is not enclosed by the encapsulation, i.e., it is exposed. This integration allows for less effort when installing the electronic module, since it advantageously eliminates the need for an additional working layer in which a base plate and / or a cooler is connected to the support substrate, for example, by soldering, sintering, and / or clamping. The fluid cooling device serves in particular to supply and remove a cooling fluid, especially a coolant.Preferably, the cooling structure comprises fins that project into a channel formed by the cooling structure and the fluid cooling device. To seal the channel formed between the cooling structure on the substrate side and the fluid cooling device, a sealing element is preferably provided, which is integrated into the electronic module and preferably arranged substantially in the stacking direction at the level of the cooling structure. Preferably, the sealing element is ring-shaped or bead-shaped and preferably surrounds the cooling structure, in particular the fins of the cooling structure. Preferably, the sealing element is arranged on the encapsulation, for example, in a groove provided for this purpose.

[0049] Another advantage of integrating the cooling structure directly onto the substrate is that it eliminates the need for material between the cooling structure and the substrate or secondary layer. Such a TIM (thermal interface material) typically exhibits lower thermal conductivity compared to other materials used in the substrate. Eliminating the TIM material and avoiding interfaces significantly improves the thermal resistance of the substrate and the electronic module.

[0050] In a further embodiment of the present invention, the via and / or the subsequent 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, and the control of the first electronic component by the second electronic component is thus improved.

[0051] To provide the substrate, a primary layer, a secondary layer, an intermediate layer, a first metallization layer, and / or a cooling structure are joined together using a common bonding process. Different bonding methods can also be used. Examples of bonding methods include DCB (direct copper bonding) or DAB (direct aluminum bonding), or bonding using an active brazing alloy, i.e., an AMB (active metal brazing) process. In this case, the substrate is provided with a primary layer that has a recess.

[0052] Preferably, the first electronic components are prepared or provided such that they have a contact surface which, when mounted on the substrate, faces the outside or the subsequent vias. It is conceivable that contact holes are embedded in the first electronic component and the connection is established by physical vapor deposition. Subsequently, the connection is reinforced by chemical deposition, for example, by electroplating. Preferably, the first electronic components or groups of first electronic components are provided with the desired contact surfaces.

[0053] Preferably, the encapsulation is formed using an injection molding and / or compression molding process, in particular around the equipped carrier substrate. Specifically, the encapsulation is formed within an injection molded and / or compression molded part. The equipped carrier substrate is preferably covered with the injection molded and / or compression molded material, particularly on the component side, after it has been inserted into the injection molded and / or compression molded part. Possible injection molding and / or compression molding processes include, for example, transfer molding, compression molding, and / or liquid casting.If one or more contacting levels are provided, it is conceivable that the encapsulation is realized in several successive injection molding and / or compression molding processes, whereby a contacting level with or without further components is realized between each of these injection molding and / or compression molding processes by applying a structured metallization layer to the last cast section of the encapsulation.

[0054] In a further embodiment of the present invention, it is provided that the second metallization layer is located on the outside of the encapsulation. by a metal foil inserted into an injection mold and / or injection mold during the injection molding and / or injection pressing process, by physical vapor deposition and / or electrochemical deposition This is achieved through various methods. In particular, electrochemical deposition, for example using electroplating, serves to reinforce the structure already begun or initiated by the metal foil or physical vapor deposition. For instance, the structure provided by vapor deposition or the metal foil is reinforced by electroplated copper, especially before or after structuring. In vapor deposition, a stencil is used, for example. If a metal foil is intended for 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, particularly a 3D printing process. It is also conceivable that the second metallization layer is post-processed after it has been applied. For example, the second metallization layer could be sealed (with gold, silver, or ENIG) and / or made solderable.

[0055] It is primarily about the production of an electronic module, comprehensive an encapsulation, and a support substrate embedded at least partially in the encapsulation with a component side having 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 outside of the encapsulation, wherein the support 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 a via is provided for electronic connection of the intermediate layer with the second electronic component, wherein the via passes through the encapsulation and the primary layer.

[0056] All features and advantages described for the inventive method can also be applied analogously to the inventive method and vice versa.

[0057] Further advantages and features will become apparent from the following description of preferred embodiments of the invention with reference to the accompanying figures. Individual features of the individual embodiments can be combined with one another within the scope of the invention.

[0058] It shows: Fig. 1: an electronic module according to a first exemplary embodiment of the present invention before the formation of the through-hole, Fig. 2: the electronic module according to the first exemplary embodiment of the present invention after formation of the through-hole, Fig. 3: schematically a method for manufacturing an electronic module according to an exemplary embodiment of the present invention, Fig. 4. an example of the production of a pre-composite Fig. 5 an electronic module according to a second exemplary embodiment of the present invention before the formation of the through-hole, Fig. 6 an electronic module according to a third exemplary embodiment of the present invention before the formation of the through-hole and Fig. 7a / 7b Electrical modules manufactured using a method according to a fourth and a fifth exemplary embodiment of the present invention.

[0059] In the Figure 1 and 2An electronic module 1 according to a first exemplary embodiment of the present invention is shown. 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 of the carrier substrate 10, which are preferably interconnected to form at least part of an electronic circuit. For example, the first electronic components 30 comprise semiconductors, in particular wide bandgap semiconductors (WBG semiconductors), such as...a semiconductor made of silicon carbide, gallium nitride, and / or indium gallium nitride, whose band gap between a valence band and the conduction band lies between 2 eV and 4 eV or higher. In particular, electronic module 1 is a power electronics module and serves, for example, to convert electrical energy using switching electronic components. It is conceivable, for example, that the electronic module could be used as a DC-DC converter, inverter, and / or frequency converter in the field of electronic drive technology, especially 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 switched-mode power supply or DC-DC converter.

[0060] To control the first electronic components 30 on component side 25, a second metallization layer 35, serving in particular as a connection for at least one second electronic component 31 or contact element, is provided on the outer surface 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 power supply connection, or the like.

[0061] Preferably, the substrate 10 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 principal extension plane HSE and are arranged one above the other along a stacking direction S perpendicular to the principal extension plane HSE. The metallic intermediate layer 16 preferably serves as an electrical return conductor, thereby advantageously reducing parasitic inductances. While the primary layer 11 and / or the secondary layer 12 primarily serve to stiffen the substrate 10, the intermediate layer 16, in addition to its optional function as an electrical return conductor (if a via through the primary layer is present), serves in particular as a heat sink.A temporary heat storage layer in which (additional) heat spreading occurs. As a temporary heat storage layer, the intermediate layer 16 improves the thermal impedance Zth of the support substrate 10. The heat spreading advantageously leads to a homogeneous temperature distribution on one side of the support substrate 10 opposite the component side 25, via which the heat generated by the first electronic components 30 is to be dissipated via a cooling structure 60 or another cooling device. Preferably, the intermediate layer 16 is thicker than the primary layer 11 and / or the secondary layer 12 and / or thicker than 1 mm, more preferably thicker than 1.5 mm, and particularly preferably thicker than 2.5 mm.

[0062] Preferably, the coefficients of thermal expansion, or the expansion of the individual components of the electronic module 1, are selected such that the coefficient of thermal expansion is essentially symmetrical, or as symmetrical as possible, when viewed in the stacking direction S. When using the metallic intermediate layer 16 with a thickness greater than 1 mm and thinner primary layers 11 or secondary layers 12, particularly made of ceramic, it is advantageously possible to achieve a comparatively high coefficient of thermal expansion (CTE) for the support substrate 10. This comparatively high coefficient of thermal expansion simplifies the adjustment of the coefficient of thermal expansion of the encapsulation 20, which would otherwise have to be reduced by means of a suitable filler material. Consequently, the material costs for the filler material can be advantageously reduced.

[0063] The encapsulation 20 ensures a particularly compact design. Specifically, the encapsulation 20 is designed such that it interacts with the support substrate 10 in the assembled state in a form-fit, force-fit, and / or positive-locking manner. Preferably, the support substrate 10 is embedded in the encapsulation 20 at least on its component side 25, i.e., the encapsulation 20 completely encloses the component side 25. In the Figure 1In the illustrated embodiment, the cooling structure 60 is provided on one side opposite the component side 25. In particular, the cooling structure 60 comprises fins. Furthermore, the cooling structure 60 is not enclosed by the encapsulation 20, i.e., the cooling structure 60 and 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 60. A sealing element 61 is provided for sealing a fluid channel formed between the fluid cooling structure or device and the cooling structure 60 on the substrate side. Preferably, the sealing element 61 is designed circumferentially in a plane running parallel to the main extension plane HSE.

[0064] In particular, at least one via 5 is provided, extending from the outer surface A of the encapsulation 20 through the encapsulation 20 and through the primary layer 11 of the substrate 10 to the intermediate layer 16 of the substrate 10. For this purpose, it is provided that, during the manufacture of the electronic module 1, the substrate 10 is supplied such that its primary layer 11 has a first recess 41. It is conceivable that, in a preceding step, the first recess 41 in the primary layer 11 is created, for example, by drilling a hole using milling or by laser light. The supplied substrate 10 is then provided with electrical or electronic components 30 via the first metallization layer 15 and subsequently with an encapsulation 20.A second recess 42 is in turn inserted into this encapsulation 20, for example by means of laser light or by a casting process with a movable stamping element (see . Figures 5 and 6 The second recess 42 is preferably located above the first recess 41 when viewed in the stacking direction S, and in particular is congruent with or aligned with the first recess 41. It is conceivable that the first recess 41 and the second recess 42 have substantially comparable cross-sections in a plane perpendicular to the stacking direction S. However, it is also conceivable that the cross-section of the first recess 41 is smaller and / or larger than the cross-section of the second recess 42.

[0065] Furthermore, it is provided that third recesses 43 are created in the encapsulation 20, for example by means of laser light or mechanical drilling, with the third recesses 43 extending from the outer surface A of the encapsulation 20 to the first metallization layer 15 or to the first electronic component 30. The third recess 43 is used to form a further via 5', which directly connects the outer surface A, in particular the second metallization layer 35 on the outer surface A, to the first metallization layer 15 or to the first electronic component 30, i.e., without using an electrical conductor via the intermediate layer 16. In addition to the via 5 and the further via 5', it is conceivable that the electronic module 10 has its own substrate vias 7 in the manufactured state.These substrate-integrated vias 7 are already implemented in the provided substrate 10. For example, the substrate-integrated via 7 differs from the via 5 and / or the further via 5', for example with regard to the manufacturing process or the material. It would be conceivable, for example, that the substrate-integrated via 7 is produced during the manufacturing process of the substrate 10 using a soldering process, in particular a hard soldering process, before the substrate 10 is provided for encapsulation 102.

[0066] In the Figure 1In the depicted state, in addition to the first recess 41 in the primary layer 11, the second recess 42, and the third recess 43 in the encapsulation 20, a fourth recess 44 is provided, which is realized in the first metallization layer 15. Preferably, the support substrate 10 with the first recess 41 and the fourth recess 44 is provided before encapsulation 102 takes place.

[0067] To simplify the manufacturing process, the via 5, which extends from the outer surface A to the intermediate layer 16, is realized in a single step by filling the first recess 41, the second recess 42, and the fourth recess 44 with an electrically conductive material. It is apparent to those skilled in the art that a fourth recess 44 can be omitted if the via 5 extends to the intermediate layer 16 in an area where the substrate 10 is free of metal on its component side 25, i.e., the first metallization layer 15 has a corresponding interruption. Furthermore, it is preferably provided that the via 5 is realized by an electroplating process, whereby the first recess 41, the second recess 42, and the fourth recess 44 are filled with the electrically conductive material, preferably copper.

[0068] To provide a direct electrical connection between the first electrical components 30 and the second electronic components 31, at least one further via 5' is provided in the encapsulation 20. This further via 5' extends from the outer surface A of the encapsulation 20 to the component side 25 of the substrate 10. Preferably, the further via 5' creates a distance between the first electrical component 30 at component side 25 and the second electrical component 31 at outer surface A of less than 10 mm, preferably 5 mm, particularly preferably 2.5 mm, and especially 1 mm down to less than 300 µm, i.e., as small as possible. The length L of the further via 5' preferably corresponds to the distance between the first component 30 and the second component 31.

[0069] In Figure 3A schematic representation of a process for manufacturing an electronic module 1 is shown. It is provided that a carrier substrate 10 is first provided. In particular, to provide the carrier substrate 10, the metallic intermediate layer 16 and / or a cooling structure 60 for the carrier substrate 10 are prepared. Subsequently, the primary layer 11, the secondary layer 12, the metallic intermediate layer 16, and / or the cooling structure 60 are joined together in one or more separate bonding processes. The bonding process is preferably a DCB or DAB process or joining using an active solder. To provide conductive traces and connection pads, the first metallization layer 15 on the component side 25 is structured, for example, by an etching process.Preferably, the component side 25 is subsequently surface-modified by nickel plating, silver plating, edge potting, or a similar process. In particular, it is provided that the support substrate 10 for providing 101 is provided with at least one first recess 41 in the primary layer 11 and / or a fourth recess 44 in the first metallization layer 15. It is also conceivable that the provided support substrate 10 has, in addition to the first recess 41, a through-hole 7 inherent to the support substrate.

[0070] Furthermore, it is planned that the first electronic components 30 are prepared for connection to the component side 25 for the electronic module 10 and are provided, for example, as a pre-assembly 50. In particular, contacts are implemented on the first electronic components 30 such that, when installed in the electronic module 1, the contacts face the outer surface A of the encapsulation 20. For this purpose, contact holes are provided in the pre-assembly 50. The provided contacts can be copper-plated by physical vapor deposition and subsequently electroplated for reinforcement.

[0071] After the carrier substrate 10 has been completed, the pre-composite 50 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, now equipped with the pre-composite 50, is then encapsulated. Preferably, an injection molding and / or compression molding process 102 is used for encapsulation. For this purpose, the equipped carrier substrate 10 is placed in an injection mold. Preferably, the injection mold is designed such that the cooling structure 60 faces away from any cavity to be filled during injection molding. Thus, the cooling structure 60 is not covered by the plastic used in the injection molding and / or compression molding process.

[0072] Furthermore, it is provided that a second recess 42 of the encapsulation 20 is formed, for example, by using laser light to create a second recess 42, in particular a hole or bore, in the encapsulation 20. The holes and bores are essentially conical in shape. This conical shape typically results from focusing a laser beam with which the second recess 42 is created. It is specifically provided that, viewed in the stacking direction S, the second recess 42 is created above the first recess 41 and / or the fourth recess 44, thereby creating an exposed channel from the outer surface A of the encapsulation 20 to the intermediate layer 16. Subsequently, the first recess 41, the second recess 42, and / or the fourth recess 44, i.e., the hole or bore, are closed.The bore for forming the via 103 is filled with an electrically conductive material, in particular a metal, for example using a paste or by electroplating. For orientation on the outer surface A when creating the second recess 42, markings are preferably provided. Preferably, the markings are holes milled into the encapsulation 20, which can also serve, for example, to align the encapsulation 20 before creating the holes.

[0073] Furthermore, it is conceivable that a metal foil is inserted into a die used to form the encapsulation, which, after injection molding and / or compression molding, forms the second metallization layer 35 for the second electronic components 31. Additionally or alternatively, it is conceivable that the second metallization layer 35 is produced on the die-cast encapsulation 20 after injection molding and / or compression molding using a physical vapor deposition process or a 3D printing process. Preferably, the second metallization layer 35 is reinforced by a metal applied by electroplating, for example, by electroplated copper.

[0074] Forming a structured second metallization layer 104 preferably involves structuring the second metallization layer 35 on the outer surface A. It is also conceivable to use a solder mask and / or to post-treat the second metallization layer 35 on the outer surface A. For example, a surface modification 105 in the form of sealing with ENIG (electroless nickel immersion gold), silver, or gold is conceivable as a post-treatment. Preferably, the second electronic component 31 is then mounted on the second metallization layer 35 provided for this purpose on the outer surface A. Furthermore, it is provided that a cover element is attached to the electronic module 1 and the provided electronic module 1 undergoes a final inspection.

[0075] In Figure 4A schematic and exemplary method for manufacturing a pre-composite 50 is shown. In this method, a first electronic 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 component-side electrical connections 54. These recesses 53 are filled with a conductive material, which also covers the outer surface of the dielectric matrix 52. The conductive material is then structured on the outer surface to provide the pre-composite-side contact surfaces 55.These pre-assembled contact surfaces 55 represent the contact surfaces of the first components 30 within the encapsulation 20 and are in contact with the further vias 5' of the encapsulation 20. One advantage of using the pre-assembled surface 50 is the realization of pre-assembled contact surfaces 55 that are larger than the component-side connections 54. This prevents, for example, a manufacturing-related misalignment of the vias 5 subsequently embedded in the encapsulation 20 from resulting in insufficient contact with the first component 30 or the pre-assembled surface 50.

[0076] In Figure 5An electronic module 1 according to a second exemplary embodiment of the present invention is shown before the formation of the via 5. In particular, it is provided here that the second recess 42 in the encapsulation 20 is formed during the encapsulation 102. For this purpose, the carrier substrate 10 is first arranged between a first tool half 71 and a second tool half 72. Preferably, the carrier substrate 10 is clamped by the first tool half 71 and / or the second tool half 72 and / or fixed to the first tool half 71 and / or the second tool half 72.After positioning the support substrate 10 between the first tool half 71 and the second tool half 72, the first tool half 71 and the second tool half 72 are brought into a closed state in which they form a cavity 75 that at least partially surrounds the support substrate 10. By filling this cavity 75 with a suitable material and subsequently curing it, it is advantageously possible to form the encapsulation 20.

[0077] Furthermore, it is provided that an inner side of the cavity 75 is lined with a film or foil, which simplifies the removal of the electronic module 1 during demolding. It is particularly preferred that a slidably mounted punch element 73 is inserted into the first tool half 71 and / or the second tool half 72 before filling the cavity 75. The portion of the punch element 73 inserted into the cavity 75 then advantageously ensures, during filling, that the area within the cavity 75 into which it was inserted is freed. In particular, it is provided that the portion of the punch element 73 inserted into the cavity 75 is arranged above the first recess 41. During filling, the area occupied by this portion of the punch element 73 is then freed to form the second recess 42. Figure 5In the illustrated embodiment, the punch element 73, particularly at its end projecting into the cavity 75, abuts the primary layer 11, especially a top surface of the primary layer 11, i.e., when the cavity 75 is filled, it covers, and in particular completely covers, the first recess 41. This advantageously allows the second recess 42 to be formed during the encapsulation 102, which is then filled together with the first recess 41 with an electrically conductive material to form the via 5. Furthermore, it is preferably provided that the first tool half 71, the second tool half 72, and the punch element 73 have draft angles that advantageously facilitate the demolding of the encapsulated carrier substrate 10 after filling and curing.

[0078] In the Figure 6In the illustrated embodiment, an electronic module 1 according to a second exemplary embodiment of the present invention is shown before the formation of the through-hole 5. The manufacturing process differs from that described in the Figure 5The modification essentially consists only in that the end of the punch element 73 projecting into the cavity 75, i.e., the end face of the punch element 73 projecting into the cavity 75, is arranged within the first recess 41 during filling. For example, the end of the punch element 73 projecting into the cavity 75 rests against the intermediate layer 16. Preferably, the end face projecting into the cavity 75 is smaller than a lateral extension of the first recess 41, i.e., than an extension of the first recess 41 in a direction parallel to the principal extension plane HSE. It is also conceivable that the punch element 73 has a deformable element, for example, a rubber element, at its end projecting into the cavity 75, which is inserted into the first recess 41 to form a seal during filling.

[0079] In the Figures 7a and 7bare electrical modules 1, manufactured using a method according to the invention for forming a fourth exemplary embodiment (Figure 7a) and a fifth exemplary embodiment ( Figure 7b ), shown. The electrical modules 1 differ from the Figures 7a and 7bdiffers from the preceding figures in that it provides an electrically conductive connection between the outer surface A of the encapsulation 20 and the cooling structure 60 on the support substrate 10. The cooling structure 60 is preferably formed on the side of the support substrate 10 opposite the outer surface A of the encapsulation 20 and may, for example, have fins or be designed as a solid metal element or solid metal block. This electrically conductive connection advantageously allows for grounding via the cooling structure 60 on the outer surface A of the encapsulation 20. The electrically conductive connection can be configured as a via 5 across the support substrate 10, as is the case for vias 5 in [reference missing]. Figure 7ashown on the right-hand side, or through the support substrate 10. For a via 5 extending through the support substrate 10, it is preferably provided that the intermediate layer 16 is structured, or has been pre-structured, in such a way that no short circuit is caused. For example, sections of the intermediate layer 16 are separated from each other by at least one free space 81. The [unclear] on the left-hand side of the electrical module 1 from Figure 7a The illustrated via 5 is designed such that it extends through the primary layer 11, the intermediate layer 16, and the secondary layer 12. For sufficiently deep recesses that would need to be filled to form the via 5, the method described in the [reference] is advantageously used. Figures 5 and 6to use instead of laser light formation, since laser drilling is particularly unsuitable for such long recesses. Furthermore, it is provided that the first metallization layer 15 is structured in such a way that no short circuit occurs due to the via 5 extending through the substrate 10.

[0080] In the Figure 7b It is provided that the via 5 extends to the portion of the intermediate layer 16 delimited by the free space 81, and that a bottom-side via 5" is implemented in the secondary layer 12 to form the electrically conductive connection. Such a double-sided implementation of the via 5 on the one hand and the bottom-side via 5" on the other proves, for example, to be advantageously simplifying for filling the corresponding recesses to be filled. In particular, the embodiment of Figure 7bprovides a particularly advantageous thermal path. Reference symbol list:

[0081] 1 Electronic module 5 Via 5' Further via 5" Bottom-side via 7 Carrier substrate-specific via 10 Carrier substrate 11 Primary layer 12 Secondary layer 15 First metallization layer 16 Intermediate layer 20 Encapsulation 25 Component side 30 First electronic component 31 Second electronic component 35 Second metallization layer 41 First recess 42 Second recess 43 Third recess 44 Fourth recess 50 Pre-assembly 51 Printed circuit board 52 Matrix 53 Recess 54 Component-side connections 55 Composite-side connections 60 Cooling structure 61 Sealing element 71 First tool half 72 Second tool half 73 Punching element 75 Cavity 81 Free space 101 Providing a carrier substrate 102 Encapsulation 103 Forming a through-hole 104 Forming a structured second metallization layer 105 Surface modification A Outer side L Length S Stack direction H S Main extent plane

Claims

1. A method for the production of an electronic module (1), comprising: - providing (101) a carrier substrate (10) equipped with a first electronic component (30), wherein the carrier substrate (10) 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), wherein in order to form a sandwich structure, the metallic intermediate layer (16) spaces the primary layer (11) from the secondary layer (12), wherein the primary layer (11) has at least one first recess (41), - at least partially encapsulating (102) the assembled carrier substrate (10) with an encapsulation (20), - realising a second recess (42) in the encapsulation (20) and - forming (103) a via (5) for providing an electrical connection between a second electronic component (31) on an outer side (A) of the encapsulation (20) and the metallic intermediate layer (16), wherein the first recess (41) in the primary layer (11) and the second recess (42) in the encapsulation (20) are filled together with an electrically conductive material in a single step, wherein the metallic intermediate layer (16) arranged between the primary layer (11) and the secondary layer (12) extends over a first area in a plane running parallel to the main extension plane (HSE) and the primary layer (11) and / or the second secondary layer (12) extends over a second area, wherein a ratio of the first area to the second area is greater than 0.5, preferably greater than 0.75 and most preferably greater than 0.9.

2. The method according to claim 1, wherein the primary layer (11), the intermediate layer (16) and the secondary layer (12) are arranged on top of one another in a stacking direction (S) and the first recess (41) and the second recess (42) are arranged on top of one another, at least partially aligned, as viewed in stacking direction (S).

3. The method according to any one of the preceding claims, wherein the second recess (42) is realised after the encapsulation (20) and / or the first recess (41) is realised before the encapsulation (20).

4. The method according to any one of the preceding claims, wherein the second recess (42) is realised during the encapsulation (102), in particular with the use of a first tool half (71) and a second tool half (72), wherein the first tool half (71) and the second tool half (72) in an enclosed state form a cavity (75) which at least partially surrounds the carrier substrate (10), wherein the second recess (42) is realised by leaving it free by means of a part of a stamping element (73) arranged within the cavity (75) when filling.

5. The method according to any one of the preceding claims, wherein the carrier substrate (10) has a first metallisation layer (15), on which at least one first electronic component (30) is arranged, wherein a third recess (43) is realised in the encapsulation (20) and wherein the third recess (43) is filled with an electrically conductive material, in particular at the same time as the filling of the first recess (41) and second recess (42), in order to form a further via (5') which electrically joins a second metallisation layer (35) on the outer side (A) of the encapsulation (20) to the first metallisation layer (15) and / or the first electronic component (30).

6. The method according to claim 5, wherein the first metallisation layer (15) has a fourth recess (44), wherein, for forming (103) the via (5) for providing an electrical connection between a second electronic component (31) on an outer side (A) of the encapsulation (20) and the metallic intermediate layer (16), the first recess (41) in the primary layer (11), the second recess (42) in the encapsulation (20) and the fourth recess (44) in the first metallisation layer (15) are filled together with an electrically conductive material in a single step.

7. The method according to any one of the preceding claims, wherein the via (5) extends to a cooling structure (60) on the carrier substrate (10).

8. The method according to any one of the preceding claims, wherein the intermediate layer (16) - is thicker than the primary layer (11) and / or the secondary layer (12) and / or - is thicker than 1 mm, more preferably thicker than 1.5 mm and most preferably thicker than 2.5 mm.

9. The method according to any one of the preceding claims, wherein the encapsulation (20) is formed by means of an injection moulding process and / or transfer moulding process, in particular formed around the equipped carrier substrate (10).

10. The method according to any one of the preceding claims, wherein the primary layer (11) is a ceramic layer.

11. The method according to any one of the preceding claims, wherein the primary layer (11) has a thickness, measured in stacking direction (S), which is greater than 100 µm, more preferably greater than 200 µm and most preferably greater than 250 µm.

12. The method according to any one of the preceding claims, wherein a cross-section of the first recess (41), measured parallel to the main extension plane (HSE), is larger than a cross-section of the second recess (42), measured parallel to the main extension plane (HSE).