Electronics module and method for producing such an electronics module

Abstract

Proposed is an electronics module (100), in particular a power electronics module, comprising - a metal-ceramic substrate (1) which serves as a carrier and has a ceramic element (10) and a primary component metallization (21) and preferably a cooling side metallization (20), - an insulation layer (40) which is directly or indirectly connected to the primary component metallization (21), and - a secondary component metallization (22), said secondary component metallization being connected to the side of the insulation layer (40) which faces away from the ceramic element (10) and in particular being insulated with respect to the primary component metallization (21) by the insulation layer (40), wherein the ceramic element (10) has a first size (L, D) and the insulation layer (40) has a second size (L1, D1), and wherein, to form an island-like insulation layer (40) on the primary component metallization (21), a ratio of the second size (L1, ID1) to the first size (L, D) has a value that is less than 0.4, preferably less than 0.22 and particularly preferably less than 0.15 or even less than 0.1, and wherein, as viewed in a direction running perpendicularly to the main plane of extent (HSE), an outer side (A) of the secondary component metallization (22) and an outer side (A) of the first component metallization (21) end substantially at a common height.

Description

[0001] Electronic module and method for producing such an electronic module

[0002] The present invention relates to an electronic module and a method for producing an electronic module.

[0003] Electronic modules, particularly in power electronics, in which metal-ceramic substrates serve as circuit boards are known from the prior art. Metal-ceramic substrates are well known, for example, as printed circuit boards or circuit boards, for example from DE 10 2013 104 739 A1, DE 19 927 046 B4, and DE 10 2009 033 029 A1. Typically, connection surfaces for electrical components and conductor tracks are arranged on one component side of the metal-ceramic substrate, wherein the electrical components and the conductor tracks can be interconnected to form electrical circuits. Essential components of the metal-ceramic substrates are an insulating layer, preferably made of a ceramic, and at least one metal layer bonded to the insulating layer.Due to their comparatively high insulation strength, ceramic insulation layers have proven particularly advantageous in power electronics. Structuring the metal layer can then create conductor tracks and / or connection pads for the electrical components.

[0004] DE 102 27 658 A1 discloses an electronic module having an additional insulation layer made of a glass-containing material. The metal sections connected to the additional insulation layer protrude from the remaining metal sections. An example of the island-like use of an additional insulation layer is also known from WO 2021 180 639 A1. EP 3 252 810 A1 and DE 10 2012 206 276 A1 disclose further electronic modules in which vertically offset insulation layers are provided. Here, the two insulation layers extend almost completely over the entire electronic module.

[0005] In the above examples, substrate compactness, thermal resistance, and low-inductance current conduction can only be improved at the expense of one of the mentioned variables.

[0006] Based on this, the present invention sets itself the object of providing an electronic module that allows compactness, thermal resistance and current conduction to be optimized without significantly deteriorating any of the dimensions.

[0007] The object is achieved by an electronic module according to claim 1 and by a method according to claim 10. Further advantages and properties emerge from the subclaims as well as the description and the attached figures.

[0008] According to a first aspect, an electronic module, in particular a power electronic module, is provided, comprising

[0009] - a metal-ceramic substrate serving as a carrier with a ceramic element and a primary component metallization and preferably with a cooling side metallization,

[0010] - an insulation layer that is directly or indirectly connected to the primary component metallization, and

[0011] - a secondary component metallization, which is connected to the side of the insulation layer facing away from the ceramic element and is in particular insulated from the primary component metallization by the insulation layer, wherein the ceramic element has a first size and the insulation layer has a second size, and wherein, in order to form an island-like insulation layer on the primary component metallization, a ratio of the second size to the first size assumes a value which is less than 0.4, preferably less than 0.22 and particularly preferably less than 0.15 or even less than 0.1, wherein, viewed in a direction perpendicular to the main extension plane, an outer side of the secondary component metallization and an outer side of the first component metallization essentially terminate at a common height, wherein the primary component metallization essentially serves to connect electronic components,in particular of power electronic components and particularly preferably of active electrical components, and the secondary component metallization essentially serves as a conductor track for signal transmission and / or for carrying a load current.

[0012] In contrast to the prior art, the present invention provides that the secondary component metallization arranged on the insulation layer is used essentially for signal transmission or for carrying a load current, while the electrical components, in particular high-performance components, are arranged or connected on the primary component metallization. This proves to be particularly advantageous because it ensures that no insulation layer is arranged between the electronic component and the ceramic element, which would otherwise increase the thermal resistance. This would, however, be the case if the insulation layer extended over the entire surface, in particular also beneath the electrical component, since the heat emanating from the electrical component would have to pass through both the insulation layer and the ceramic element.

[0013] Therefore, by using the secondary component metallization for signals, the thermal resistance of the entire electronic module is optimized, which also allows maximum system output power to be utilized. At the same time, the compactness of the electronic module is increased, as the secondary component metallizations for signal routing and / or for carrying a load current are provided in the area where the primary component metallization is already arranged. This makes it possible to introduce an additional wiring level, which can increase the functionality per unit area of ​​the electronic module. At the same time, the common termination of the outer side at the common height ensures that the assembly of semiconductors is favored and, in particular, there are no protruding levels or metallizations that would conflict with the compactness of the electronic module.

[0014] In particular, the secondary component metallization serves as a conductor track for signal transmission and / or for carrying a load current. In particular, the secondary component metallization is free of power electronics components or high-performance electronics components. Particularly preferably, the secondary component metallization is free of active electrical components. A power electronics component and / or a high-performance electronics component is to be understood in particular as one that comprises at least one active component and / or is part of a load circuit. In particular, these are electrical components whose power dissipation is greater than 20 W, preferably greater than 50 W, and particularly preferably greater than 100 W. Examples of such power electronics components are transistors and diodes, FETs, semiconductor components, and / or high-current diodes.In particular, "essentially" in this context means that the primary component metallization is not intended exclusively for connecting electronic components. However, if electrical components, especially high-performance components, are intended, they are arranged on a part of the primary component metallization. The same applies to the secondary component metallization. Here, it is intended that the secondary component metallization is essentially free of power electronics and / or high-performance electronics.

[0015] If the secondary component metallization is a conductor track that serves to carry a load current, it proves to be particularly advantageous to have the currents in the first component metallization and the second component metallization run anti-parallel, since in this way, corresponding compensation through oppositely directed inductive effects is particularly effective. In this case, the second component metallization carries a current of at least 20 A, preferably at least 50 A, and particularly preferably greater than 100 A, for carrying a load current. Furthermore, it is conceivable that a distance between the first component metallization and the second component metallization is less than 10 mm, preferably less than 5 mm, and particularly preferably less than 2.5 mm, in particular measured along a direction running parallel to the main extension plane.

[0016] The first and / or second dimensions refer to the respective volumes of the insulation layer and / or the ceramic element. This first and / or second dimension therefore includes both the areal extent of the island-like insulation layer or the ceramic element, measured in a plane parallel to the main extension plane, and its thickness, measured along a direction perpendicular to the main extension plane. The island-like design of the insulation layer thus allows for large areas of the island-like insulation layer to remain free, which can be used to connect primary component metallizations of electronic components to the primary component metallization. This advantageously prevents the thermal resistance in the local areas of the electronic components from increasing accordingly.However, this regularly occurs when the insulation layer extends over large parts of the primary component metallization.

[0017] It is preferably provided that the secondary component metallization is used to carry the load current, in particular to implement DC+ and / or DC- lines. Furthermore, it is preferably provided that the secondary component metallization is used as gate lines. In particular, when using the secondary component metallization as a signal carrying line or to carry a load current, it is possible to dimension it smaller, in particular thinner, than the primary component metallization, which is additionally provided to conduct the thermal energy emanating from the electrical components and is subject to heat spreading. This nevertheless makes it possible to design a common outer side that ends at a common height. At the same time, the region of the primary component metallization that is arranged beneath the electrical component is thicker, in particular thicker than the secondary component metallization.The electronic module, in particular the secondary component metallization, is appropriately contacted to form signal routing or to guide a load current or provides corresponding areas or connection surfaces so that signal currents can flow through the secondary component metallization.

[0018] Preferably, an island-like insulation layer is provided, which, in particular, provides electrical insulation between the primary component metallization and the secondary component metallization. This eliminates the need to form electrical lines or conductor paths as part of structuring the primary component metallization. Instead, the insulation layer can be used to arrange various electrical components in an electrically insulating manner, or to establish specific connections, without necessarily requiring structuring of the primary component metallization. The insulation layer is preferably directly bonded to the primary component metallization.

[0019] Alternatively, it is conceivable that, for example, the insulation layer is part of a further, in particular smaller, metal-ceramic substrate, which in turn is placed on the larger metal-ceramic substrate serving as the carrier and is bonded to the metal-ceramic substrate using a DCB or active soldering process or by means of an adhesive. In particular, the insulation layer is a comparatively thin insulation layer made of ceramic, which contributes to the electrical insulation of the secondary component metallization from the primary component metallization. In this case, it is particularly provided that the electronic module or the arrangement of the primary component metallization and the secondary component metallization is not completely embedded in an encapsulation or a housing. Preferably, the insulation layer is surrounded on all sides by the primary component metallization in a plane running parallel to the main extension plane.Alternatively, it is also conceivable that the insulation layer is arranged at the edge of the primary component metallization, so that the insulation layer is surrounded by the primary component metallization on a plane running parallel to the main extension plane on at most three or two sides.

[0020] Furthermore, it is provided that the primary or secondary component metallization and / or the cooling side metallization is immediately and directly bonded to the insulation layer or the ceramic element, for example bonded by means of a DCB process, an AM B process, hot isostatic pressing, a diffusion bonding process, by means of thick-film technology or by means of thin-film technology. Furthermore, the metal-ceramic substrate or the further metal-ceramic substrate comprises at least one metal layer, for example as part of the cooling side metallization or the primary or secondary component metallization, which is materially bonded to an outer side of the ceramic element or the insulation layer, wherein the metal layer and the ceramic element extend along a main extension plane and are arranged one above the other in a stacking direction running perpendicular to the main extension plane. The materials for the metallizations orthe metal sections, i.e. for the primary component metallization, the secondary component metallization, the cooling side metallization and / or a back side metallization, copper, aluminum, molybdenum and / or their alloys, as well as laminates such as CuW, CuMo, CuAl, AlCu and / or CuCu are conceivable, 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 at least one metallization, i.e. the primary component metallization or secondary component metallization, is surface modified. As a surface modification, for example, a sealing with a precious metal, in particular silver and / or gold, or ENIG (“electroless nickel immersion gold”) or edge casting on the first or second metallization layer to suppress crack formation or widening is conceivable.

[0021] Preferably, the ceramic element and / or the insulation layer comprises at least one ceramic layer, wherein the ceramic layer is Al2O3, Si3N4, AlN, an HPSX ceramic (i.e. a ceramic with an Al2O3 matrix comprising an x ​​percent ZrCh content, for example Al2O3 with 9% ZrCh = HPS9 or Al2O3 with 25% ZrO2 = HPS25), SiC, BeO, MgO, high-density MgO (> 90% of the theoretical density), TSZ (tetragonally stabilized zirconium oxide) or ZTA. It is also conceivable for the insulation layer or the ceramic element to be designed as a composite or hybrid ceramic, in which, in order to combine various desired properties, several ceramic layers, each differing in terms of their material composition, are arranged one above the other and joined together to form an insulation layer. Preferably, a ceramic that is as thermally conductive as possible is used for the lowest possible thermal resistance.It is also conceivable that a metallic intermediate layer is arranged in the ceramic element or in the insulation layer between two ceramic layers.

[0022] The electrical component is preferably a switchable component, or an active or passive component. This is preferably 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).

[0023] According to an advantageous embodiment, it is provided that the primary component metallization is structured to form a first metal section and a second metal section such that the first metal section and the second metal section are electrically insulated from one another, wherein, viewed in a direction perpendicular to the main extension plane, the outer side of the secondary component metallization in the first metal section and the outer side of the primary component metallization in the second metal section essentially terminate at a common height.

[0024] Preferably, the entire outer surface on the component side terminates at a common height, regardless of whether it is the first or second metal section, but in particular also regardless of whether it is the primary component metallization or the secondary component metallization. Due to the electrical insulation between the first metal section and the second metal section, the first and second metal sections can be used completely independently of one another, thereby advantageously increasing the complexity of the printed circuit board, particularly with regard to the compactness of the functionality per unit area of ​​the electronic module.

[0025] In particular, it is provided that the outer side of the primary component metallization in the first metal section terminates at a common height with the outer side of the secondary component metallization in the first metal section. This advantageously makes it possible to realize a direct connection between the primary component metallization and the secondary component metallization in the first metal section, in particular by using corresponding cross-conductors. The common height at which the primary component metallization and the secondary component metallization terminate simplifies the implementation of such connections, in particular the possibility of connection via wire bonding processes.

[0026] Furthermore, it is preferably provided that the primary component metallization, in particular a maximum thickness assigned to the primary component metallization, essentially corresponds to the thickness assigned to the cooling-side metallization. Furthermore, it is preferably provided that the insulation layer is arranged in a recess and / or a recessed profile of the primary component metallization. In other words, the insulation layer with the secondary component metallization is recessed into the primary component metallization to provide a correspondingly compact design.

[0027] Alternatively or additionally, it is conceivable for the primary component metallization to form a base-like projection on which an insulating layer is arranged, which protrudes, in particular, relative to the base-like projection in a direction parallel to the main extension plane. This allows the corresponding secondary component metallizations and primary component metallizations to be optimally adapted to the respective application, particularly taking into account the electrical insulation between the primary component metallization and the secondary component metallization.

[0028] Preferably, the primary component metallization contacts the insulation layer on at least two sides, preferably at least three sides, particularly preferably at least four sides. A materially bonded connection is preferably created. In particular, the primary component metallization contacts the insulation layer on the first side, the second side, the third side, and the fourth side. The first side and the fourth side are substantially parallel to the main extension plane and are arranged opposite one another along a direction perpendicular to the main extension plane.

[0029] The third side and second side run essentially perpendicular to the main extension plane and connect the first and fourth sides of the insulation layer. By covering or contacting the first, second, third and fourth sides, it is advantageously possible to embed the insulation layer in the primary component metallization, thereby forming an additional positive connection between the primary component metallization and the insulation layer, which has proven advantageous for the longevity and electrical insulation in the electronic component. It is preferably provided that the first and / or fourth side of the insulation layer is at least partially free of contact with the primary component metallization. This allows the electrical insulation between the secondary component metallization and the primary component metallization to be adapted to the requirements, in particular a required pullback.

[0030] Preferably, the electronic module comprises an additional insulation layer. This advantageously makes it possible to integrate additional wiring levels into the electronic module in a space-saving manner, thereby further increasing the functionality per unit area of ​​the electronic module. In particular, the insulation layer and the additional insulation layer are arranged vertically offset from one another in a direction perpendicular to the main extension plane.Considering that the outer side of the secondary component metallization is flush with the outer side of the primary component metallization, the formation of the insulation layer and the further insulation layer at different heights has the advantage that the first thickness and second thickness of the secondary component metallization and / or the further secondary component metallization can be adapted to the respective needs and space requirements. For example, this makes it possible to realize larger first thicknesses of the secondary component metallization by using a smaller first height, whereby the width of these lines, in particular of the secondary component metallization, can be kept smaller along a direction running parallel to the main extension direction, i.e., can be made narrower, while maintaining the same current-carrying capacity.This further optimizes flexibility with regard to the respective application and further increases design freedom when designing the circuit board.

[0031] Furthermore, it is preferably provided that the insulation layer has a first insulation layer thickness and the further insulation layer has a second insulation layer thickness, wherein the first insulation layer thickness and the second insulation layer thickness are different. This advantageously makes it possible to adapt the insulation capacity of the insulation layer to the respective requirements and, in particular, to increase or reduce it as needed. In principle, it is preferably provided that the first insulation layer thickness and / or the second insulation layer thickness is smaller than the insulation layer thickness of the ceramic element.

[0032] Furthermore, it is preferably provided that the secondary component metallization has a first thickness, measured perpendicular to the main extension plane, that is greater than 150 μm. A correspondingly comparatively large first thickness of the secondary component metallization advantageously makes it possible to conduct even high currents via the secondary component metallization for signal transmission or for conducting a load current. This is generally not possible if the first thickness is less than 150 μm.

[0033] Preferably, the insulation layer has a cross-section that deviates from a rectangle in a plane running parallel to the main extension plane. The insulation layer can be strip-shaped or have an elliptical, circular, diamond-shaped, and / or square cross-section. In particular, by allowing appropriate design freedom for the insulation layer, it is possible to position the insulation behavior and / or the free areas of the insulation layer in such a way that they are adapted, for example, to the intended location for the power electronics component and / or the high-performance electronics component.

[0034] Preferably, the secondary component metallization is structured. It is particularly preferred if the secondary component metallization is structured to form conductor tracks that run parallel to one another at least in sections. In particular, this makes it possible to induce currents to flow in opposite directions through the correspondingly parallel conductor tracks, which result in inductive effects being mutually compensated. This advantageously makes it possible to reduce or eliminate parasitic inductive effects, at least in partial sections.

[0035] Preferably, the primary component metallization, secondary component metallization, and the insulating element or ceramic element extend along a main extension plane and are arranged one above the other along a stacking direction running perpendicular to the main extension plane, wherein a bonding layer is formed in the manufactured carrier substrate between the primary component metallization or the secondary component metallization and the insulating element or ceramic element, wherein an adhesion promoter layer of the bonding layer has a sheet resistance that is greater than 5 ohms / sq, preferably greater than 10 ohms / sq, and particularly preferably greater than 20 ohms / sq. It has been found that with an increasing proportion of active metal, the formation of brittle, intermetallic phases is favored, which in turn is disadvantageous for the peel strength of the metal layer on the insulating layer.In other words, the claimed sheet resistances describe bonding layers whose peel strength is improved, i.e., increased, due to the reduced formation of brittle intermetallic phases. By specifically adjusting the claimed sheet resistances, particularly strong bonds between the at least one metal layer and the ceramic element can be achieved. Such increased bond strength has a beneficial effect on the service life of the carrier substrate.

[0036] To determine the sheet resistance, the metal layer and, if present, a solder base layer are first removed from the manufactured carrier substrate, for example by etching. Using a four-point measurement, a sheet resistance is then measured on the top or bottom side of the carrier substrate, which has been freed of at least one metal layer and the solder base layer. In particular, the sheet resistance of a material sample is understood as its resistance relative to a square surface area. It is customary to designate the surface resistance with the unit OhmZsq(square). The physical unit of sheet resistance is Ohm.

[0037] A further aspect of the present invention is a method for producing the electronic module according to the invention, wherein a metal layer or metal layer is bonded to the ceramic element to form the primary component metallization, and a further metal layer or metal layer is bonded to the insulation layer to form the secondary component metallization, preferably in a common process step, in particular by hot isostatic pressing. For this purpose, it is preferably provided that the individual components are first stacked and then joined in a common bonding step. The manufactured metal-ceramic substrate is then further processed, for example, separated, structured, and / or surface-finished. Alternatively, it is also conceivable for the metal-ceramic substrate to be joined together successively.All properties and advantages described in connection with the electronic module apply analogously to the process and vice versa.

[0038] In particular, it is provided that the metal layer / metal layer or the further metal layer / metal layer is bonded to the insulation element / insulation layer or ceramic element by means of an active soldering process and / or hot isostatic pressing and / or a DC B process.

[0039] For example, it is provided that a method for producing a metal-ceramic substrate is provided, comprising:

[0040] - Providing a soldering layer, in particular in the form of at least one soldering foil or brazing foil,

[0041] - Coating the insulation element, which forms the ceramic element in the manufactured electronic module, and / or the at least one metal layer and / or the at least one solder layer with at least one active metal layer, preferably a separate active metal layer, for example in the form of a foil,

[0042] - Arranging the at least one solder layer between the insulation element and the at least one metal layer along a stacking direction to form a solder system comprising the at least one solder layer and the at least one active metal layer, wherein a solder material of the at least one solder layer is preferably free of a melting point-lowering material or of a phosphorus-free material, and

[0043] - Bonding the at least one metal layer to the at least one ceramic layer via the soldering system using an active soldering process. The at least one metal layer then forms the primary component metallization. Preferably, a further metal layer is arranged on an insulating layer and bonded using the described soldering process. The further metal layer then forms the secondary component metallization. Preferably, the ceramic element, the metal layer, the insulating layer, and the further metal layer are stacked, wherein, after stacking, the desired bond between the layers to form the electronic module is realized in a joint bonding process.It is preferably provided that titanium (Ti), zirconium (Zr), hafnium (Hf), chromium (Cr), niobium (Nb), cerium (Ce), tantalum (Ta), magnesium (Mg), lanthanum (La) and vanadium (V), molybdenum (Mo) or tungsten (W) is used as the active metal, and preferably the solder material is a solder base material, wherein the solder base material has a proportion of active metal of less than 1.5 wt.%, preferably less than 1.0 wt.% and particularly preferably less than 0.5 wt.%.

[0044] In particular, a multi-layer soldering system comprising at least one solder layer, preferably free of melting point-lowering elements, particularly preferably a phosphorus-free solder layer, and at least one active metal layer is provided. The separation of the at least one active metal layer and the at least one solder layer proves to be particularly advantageous because it enables comparatively thin solder layers to be realized, especially when the solder layer is a foil. For solder materials containing active metals, comparatively large solder layer thicknesses must otherwise be realized due to the brittle intermetallic phases or the high modulus of elasticity and high yield strength of common active metals and their intermetallic phases, which hinder the forming of the solder paste or solder layer, whereby the minimum layer thickness is limited by the manufacturing properties of the solder material containing active metal.Accordingly, for solder layers containing active metals, the minimum solder layer thickness is not determined by the minimum thickness required for the joining process, but rather by the minimum technically feasible solder layer thickness. As a result, this thicker, active-metal-containing solder layer is more expensive than thinner layers. The term "phosphorus-free" is understood by those skilled in the art to mean, in particular, that the phosphorus content in the solder layer is less than 150 ppm, less than 100 ppm, and particularly preferably less than 50 ppm.

[0045] The solder layer, in particular the phosphorus-free solder layer, preferably comprises several materials in addition to the pure metal. For example, indium is a component of the solder material used in the solder layer. Furthermore, it is conceivable that the solder material for forming the solder layer is applied to the active metal layer and / or the at least one metal layer by physical and / or chemical vapor deposition and / or galvanically. This advantageously makes it possible to realize comparatively thin solder layers in the soldering system, in particular with a homogeneous distribution.

[0046] Particularly preferably, in the production of the electronic module, in particular the metal-ceramic substrate, the following steps are provided for the bonding process, comprising:

[0047] - Providing the ceramic element and a metal layer that serves as the primary component metallization in the later electronic module,

[0048] - providing a gas-tight container enclosing the ceramic element, wherein the container is preferably formed from the metal layer or comprises the metal layer,

[0049] - Forming the metal-ceramic substrate by bonding the metal layer to the ceramic element by means of hot isostatic pressing, wherein, to form the metal-ceramic substrate, an active metal layer or a contact layer comprising an active metal is arranged at least in sections between the metal layer and the ceramic element to support the bonding of the metal layer to the ceramic element. The container is preferably formed as a metal container made of a metal layer and / or a further metal layer. Alternatively, it is also conceivable to use a glass container. In this case, the metal layer advantageously forms the subsequent primary component metallization. Preferably, a further metal layer is provided to realize the subsequent secondary component metallization, wherein the further metal layer is arranged on an insulation layer, which in turn is arranged on the metal layer.

[0050] The use of hot isostatic pressing is advantageous because several metal layers, especially with different thicknesses, are joined together to form an electronic module. Layers such as the metal layer or metal layer are preferably provided as a form-etched part or stamped part. For example, it is possible to create a metal layer with a recess by then introducing the insulation layer for connecting the further metal layer or metal layer. The individual layers, in particular the further metal layer or metal layer, are then arranged and positioned. It is particularly advantageous that the outer sides end at the same height. This is particularly suitable for the application of hot isostatic pressing, as it ensures uniform pressure during production.

[0051] A further advantage is that there are no solder or joining materials between the individual metal layers. This advantageously simplifies the etching process for layout production. Furthermore, the lack of solder or joining materials cannot act as thermal barriers, which would otherwise adversely affect the thermal properties of the electronic module.

[0052] Preferably, a proportion of active metal in the adhesion promoter layer comprising an active metal or the active metal layer is greater than 15% by weight, preferably greater than 20% by weight.

[0053] In hot isostatic pressing, it is particularly intended that the bonding takes place by heating under pressure, during which the first and / or second metal layer of the metal container, in particular the subsequent metal layer of the metal-ceramic substrate and any eutectic layer present there, does not enter the melting phase. Accordingly, lower temperatures are required for hot isostatic pressing than for a direct metal bonding process, in particular a DCB process.

[0054] In comparison to the bonding of a metal layer to a ceramic layer by means of a solder material, which usually uses temperatures below the melting temperature of the at least one metal layer, the present procedure advantageously makes it possible to dispense with a solder base material and only requires an active metal. The use or utilization of pressure during hot isostatic pressing also proves advantageous because it can reduce air inclusions or cavities between the first metal layer and / or the second metal layer on the one hand and the ceramic element on the other, whereby the frequency of voids forming in the formed or manufactured metal-ceramic substrate can be reduced or even avoided. This has a beneficial effect on the quality of the bond between the metal layer or the first and / or second metal layer of the metal container and the ceramic element.In addition, it is advantageously possible to simplify the “second etching” and avoid solder residues and silver migration.

[0055] It is also conceivable that during hot isostatic pressing an additional solder material is introduced between the ceramic element and the at least one metal layer, wherein a melting temperature of the additional solder material can be lower than the temperature at which the hot isostatic pressing is carried out, ie lower than the melting temperature of the at least one metal layer.

[0056] It is preferably provided that during hot isostatic pressing, the metal container is exposed in a heating and pressing device to a gas pressure of between 100 and 2000 bar, preferably between 150 and 1200 bar, and particularly preferably between 300 and 1000 bar, and a process temperature of 300°C up to a melting temperature of the at least one metal layer, in particular up to a temperature below the melting temperature. It has been advantageously found that it is thus possible to bond a metal layer, i.e. a first and / or second metal layer of the metal container, to the ceramic element without the required temperatures of a direct metal bonding process, for example a DCB or a DAB process, and / or without a solder base material that is used in active soldering. In addition, the use or application of an appropriate gas pressure allows the possibility of producing a bond that is as void-free as possible, i.e.to produce a metal-ceramic substrate without gas inclusions between the metal layer and the ceramic element. In particular, process parameters mentioned in DE 2013 113 734 A1 are used, and are hereby explicitly incorporated by reference. Following the bonding, structuring is preferably carried out, for example, by etching and / or laser light, and / or separation, for example, by separation and / or via a predetermined breaking line.

[0057] Further advantages and features will become apparent from the following description of preferred embodiments of the subject matter according to 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:

[0059] Fig. 1 : schematically shows an electronic module according to a first exemplary embodiment of the present invention

[0060] Fig. 2: schematically an electronic module according to a second exemplary embodiment of the present invention

[0061] Fig. 3: schematically an electronic module according to a third exemplary embodiment of the present invention

[0062] Fig. 4: schematically shows an electronic module according to a fourth exemplary embodiment of the present invention

[0063] Fig. 5: schematically shows an electronic module according to a fifth exemplary embodiment of the present invention and

[0064] Fig. 6: schematically shows an electronic module according to a sixth exemplary embodiment of the present invention

[0065] Figure 1 schematically shows an electronic module 100 according to a first exemplary embodiment of the present invention. Such electronic modules 100, in particular power electronic modules, comprise a metal-ceramic substrate 1 as a carrier for at least one electrical component (not shown). The metal-ceramic substrate 1 serving as a carrier comprises a ceramic element 10, to which a primary component metallization 21 and a cooling-side metallization 20 are bonded on opposite sides. The primary component metallization 21 and the cooling-side metallization 20 are preferably bonded to the ceramic element 10 using a DAB or DCB process, i.e., a direct bonding process, or using an active soldering process, a diffusion bonding process, or hot isostatic pressing.

[0066] It is preferably provided that the primary component metallization 21 and the cooling-side metallization 20 are selected to be of equal thickness during the bonding process, in particular to avoid deflection effects that would otherwise occur. This takes advantage of the fact that the forces occurring due to the symmetrical arrangement of the primary component metallization 21 and the cooling-side metallization 20 compensate for each other and thus counteract deflection.

[0067] In the exemplary embodiment illustrated in Figure 1, the primary component metallization 21 is structured. As a result of the structuring, the primary component metallization 21 has a first metal section 31 and a second metal section 32 that are electrically insulated from one another. Structuring is understood to mean that a free area extending to the ceramic element 10 is formed between the first metal section 31 and the second metal section 32. Such a free area is also known as an isolation trench 5.

[0068] To increase the compactness of the electronic module 100, it is provided that a secondary component metallization 22 is formed alongside the primary component metallization 21. The secondary component metallization 22 is separated, in particular electronically insulated, from the primary component metallization 22 by an insulation layer 40. By using the secondary component metallization 22, it is advantageously possible to introduce a further wiring level or line level, for example, in the first metal section 31 or in the second metal section 32, whereby the functionality per unit area of ​​the electronic module 100 can be advantageously increased, since both the primary component metallization 21 and the secondary component metallization 22 can be used in this area.Otherwise, it would be necessary to arrange the secondary component metallization 22 in a plane running parallel to the main extension plane HSE, laterally offset from the primary component metallization 21, or to introduce a further metal section for this purpose.

[0069] To further increase compactness, it is further provided that an outer side A of the primary component metallization 21 terminates at or with a common height H with an outer side A of the secondary component metallization 22. The outer side A is understood in particular to be the outer surface of the metallizations 21, 22 or metal sections 31, 32, which faces away from the ceramic element 10 and extends essentially parallel to the main extension plane HSE. The common height H is measured in particular along a stacking direction S running perpendicular to the main extension plane HSE.In order to ensure that the outer side A ends at the common height H, the exemplary embodiment of Figure 1 provides that the secondary component metallization 22 is arranged in a recess of the primary component metallization 21 and in particular the secondary component metallization 22 has a first thickness D1 and the first insulation layer 40 has a first insulation layer thickness ID1, wherein the outer sides A of the primary component metallization 21 and the secondary component metallization 22 end at the common height H. Furthermore, the embodiment shown in Figure 1 provides that the outer side A of the primary component metallization 21 and the outer side A of the secondary component metallization 22 belong to the first metal section 31.

[0070] The secondary component metallization 22 is electrically insulated from the primary component metallization 21 by the insulation layer 40. In particular, it is provided that the insulation layer 40 is designed in an island-like manner. To form a correspondingly island-like insulation layer 40, it is provided that a first size (L, D), which is assigned to the ceramic element 10, is many times larger than a second size (D1, L1), which is assigned to the island-like insulation layer 40. The first size (D, L) is determined by the volume of the ceramic element 10, and the second size (D1, L1) is determined by the volume of the island-like insulation layer 40. In the embodiment shown in Figure 1, the first insulation thickness ID1 and the first length L1 are shown for the insulation layer 40, wherein the first length L1 is to be understood as representative of a areal extent in a plane running parallel to the main extension plane.In particular, it is provided that a ratio of the second variable D1, L1 to the first variable D, L assumes a value which is less than 0.4, preferably less than 0.22 and particularly preferably less than 0.15 or even less than 0.1.

[0071] The advantage resulting from corresponding island-like insulation layers 40 is, in particular, that full-surface insulation layers 40 are avoided. This is particularly advantageous because heat emanating from electrical components would otherwise have to pass through both the insulation layer 40 and the ceramic element 10. This is particularly disadvantageous because the corresponding passing through the insulation layer 40 and the ceramic element 10 increases the thermal resistance, as a result of which the maximum output power of the electronic module 100 with its electrical components cannot be used. Furthermore, it is preferably provided that the secondary component metallization 22 essentially serves as a conductor track for signal routing or for conducting a load current, and the primary component metallization 21 essentially serves to connect electronic components, in particular power electronics components orHigh-performance electronic components. This has the decisive advantage that the secondary component metallizations 22 are preferably free of high-performance electronic components or power components or active electrical or electronic components, particularly with increased power dissipation. This fulfills the requirements for the dissipation of thermal energy or

[0072] Heat in the area of ​​the secondary component metallization 22 is lower, and the thermal resistance, which is increased due to the insulating layer 40 and the ceramic element 10 that must be passed through, plays a subordinate role. In contrast, electronic components, or in particular high-performance electronic components, are arranged on the outer side A of the primary component metallization 21. In this area, it is advantageous that essentially only metal and not the insulating layer 40 is arranged beneath the components. Thus, the thermal resistance here is not increased compared to the areas in which the insulating layer 40 is arranged.Furthermore, the portion of the primary component metallization 21 located beneath the insulation layer 40 can be used to dissipate thermal energy, particularly considering heat spreading beneath the component, which is connected to the outer side A of the primary component metallization 21 and can also extend into the region beneath the insulation layer 40. This optimizes the thermal resistance as a whole in the entire electronic module 100.

[0073] Preferably, the insulation layer 40 has a first insulation layer thickness ID1 and is arranged at a first height H1 relative to the ceramic element 10 in a direction perpendicular to the main extension plane HSE. In particular, the first insulation layer thickness ID1 and / or the first height H1 are adjusted in such a way that optimal current conduction or signal conduction and / or for conducting a load current in the secondary component metallization 22 is enabled.

[0074] In addition to the insulation layer 10 and the secondary component metallization 22, the electronic module 100 of the first exemplary embodiment also comprises a further insulation layer 41 and a further secondary component metallization 23. The further insulation layer 41 and the further secondary component metallization 22 are arranged in the second metal section 32. The insulation layer 40 and the secondary component metallization 22 of the first section differ from the further insulation layer 41 and the further secondary component metallization 23 of the second metal section 32 in that the further secondary component metallization 23 is structured, i.e., preferably has two conductor tracks. In particular, it is provided that the conductor tracks of the further secondary component metallization 22 shown here, which are electrically insulated from one another, are intended or designed to carry antiparallel electrical currents.This advantageously reduces an inductive effect, as this has a compensating effect due to the opposing currents.

[0075] Furthermore, it is provided that the further insulation layer 41 is arranged at a second height H2 relative to the ceramic element 10 in a direction perpendicular to the main extension plane HSE, wherein the first height H1 differs from the second height H2. Consequently, it is provided that a second thickness D2 of the further secondary component metallization 23 is less than a first thickness D1 of the secondary component metallization 22. In particular, it is provided that the outer side A of the further secondary component metallization 22 also terminates at the common height H. In particular, it is provided that all outer sides A terminate at a common height H relative to the ceramic element 10 in order to ensure a common flush termination towards the component side. This applies to the primary component metallization 21, the secondary component metallization 22, and the further secondary component metallization 23.

[0076] Furthermore, it is advantageously provided that the further insulation layer 41 has a second insulation layer thickness ID2 that is greater than the insulation layer thickness ID1. In particular, it is provided that the first insulation layer thickness ID1 and / or second insulation layer thickness ID2 are selected such that they satisfy the electrical insulation requirements of the conductor tracks of the secondary component metallization 22 or the further secondary component metallization 23. This can be adapted to the respective application. In particular, it is also conceivable that the height-staggered arrangement or the different first heights H1 and second heights H2 can be used to dimension the first thicknesses D1 and second thickness D2, whereby the magnitude of the currents that can flow through the secondary component metallization 22 or the further secondary component metallization 23 can be advantageously controlled.Therefore, the design freedom allows the first height H1 and second height H2 to be adapted to the respective application.

[0077] In addition to the insulation layer 10 and the further insulation layer 41, the first metal section 31 also comprises a second further insulation layer 42 with a second further secondary component metallization 24. In analogy to the secondary component metallization 22 or insulation layer 40 and the further secondary component metallization 23 and the further insulation layer 41, the same applies here analogously to the third thickness D3 of the second further secondary component metallization, the third insulation layer thickness ID3 and the third height H3.

[0078] Furthermore, it is provided that the insulation layer 10, the further insulation layer 40 and / or the second further insulation layer 41 contact the primary component metallization 21 at least on a first side S1 and on a second side S2. In the case of the insulation layer of Figure 1, it is further provided that a third side S3 is contacted by the primary component metallization 21. It is provided that the first side S1 runs essentially parallel to the main extension plane HSE, while the second side S2 and third side S3 of the insulation layer 40 run essentially perpendicular to the main extension plane HSE.

[0079] In particular, it is provided that the secondary component metallization 21 is provided for load current conduction.

[0080] Figure 2 shows an electronic module 100 according to a second exemplary embodiment of the present invention. In the exemplary embodiment shown here, the electronic module 100 comprises, by way of example, only a first metal section 31. However, it is also conceivable for a second metal section 32 to be formed in addition to the first metal section 31 shown here. In particular, the exemplary embodiment in Figure 2 differs from that in Figure 1 in that the insulation layer 40 is contacted by the primary component metallization 21 on the first side S1, the second side S2, the third side S3 and a fourth side S4. The fourth side S4 runs essentially parallel to the main extension plane HSE and is arranged opposite the first side S1 in a direction running perpendicular to the main extension plane HSE.In other words, the primary component metallization 21 encompasses the insulation layer 40 at preferably opposite ends, whereby the insulation layer 40 and the primary component metallization 21 interact in a form-fitting manner, in particular in both directions perpendicular to the main extension plane HSE. As a result, the insulation layer 40 is advantageously integrated into the primary component metallization 21 in such a way that a permanent and secure connection between the primary component metallization 21 and the insulation layer 40 is ensured. Furthermore, it is possible to influence the insulation behavior of the secondary component metallization 22 relative to the primary component metallization 21 by appropriately dimensioning the first length L1 and / or the first area of ​​the insulation layer 40.

[0081] Figure 3 shows an electronic module 100 according to a third exemplary embodiment of the present invention. The embodiment shown in Figure 3 comprises a first metal section 31 and a second metal section 32. In the exemplary embodiment shown here, it is provided that the outer side A of the secondary component metallization 22 of the first metal section 31 terminates at the common height H with the outer side A of the primary component metallization 21 in the second metal section 32. In the exemplary embodiment shown here, it is provided that the insulation layer 40 is not formed in a recess of the primary component metallization 21. Instead, it is provided that the insulation layer is arranged or formed in particular on a base-like projection of the primary component metallization 21.Preferably, it is provided that the insulation layer 40 protrudes in a direction parallel to the main extension plane HSE relative to the base-like section in the primary component metallization 21 in the first metal section 31. This advantageously realizes a pullback, which in particular effectively prevents electrical interaction between the secondary component metallization 22 and the primary component metallization 21. In the embodiment of the electronic module 100 illustrated in Figure 4 according to an exemplary fourth embodiment of the present invention, it is provided that the insulation layer 40 contacts the primary component metallization 21 on the first side S1 and the second side S2. In contrast to the exemplary embodiment in Figure 1, it is thus provided that the third side S3 and the fourth side S4 of the insulation layer 40 are free of the primary component metallization 21.In particular, in the exemplary embodiment illustrated here, it is provided that the insulation layer 40 protrudes into a recess in the primary component metallization 21, whereby at least a partial region of the first side S1 of the insulation layer 40 is also exposed. This further improves the electrical insulation between the secondary component metallization 22 and the primary component metallization 21. In particular, it should be noted that the free region illustrated here, into which the insulation layer 40 protrudes, does not extend as far as the ceramic element 10, so that this is not an insulation trench 5, so that Figure 4 essentially represents a first metal section 31. As already mentioned, this can also be part of a primary component metallization with a first metal section 31 and a second metal section 32.

[0082] Figure 5 shows an electronic module 100 according to a fifth exemplary embodiment. In particular, it is provided that the first metal section 31 has an insulation layer 40 with a secondary component metallization 22, and the second metal section 32 has a further insulation layer 41 with a further secondary component metallization 23. The same properties that were already discussed in connection with Figure 1 apply to the insulation layer 40 and the further insulation layer 41, as well as to the secondary component metallization 22 and the further secondary component metallization 23.In embodiment 5, it is merely additionally provided that both the insulation layer 40 and the further insulation layer 41 are contacted on the first side S1, the second side S2, the third side S3, and the fourth side S4 by the primary component metallization, in particular in the respective first metal section 31 and second metal section 32. Figure 6 shows a plan view of an electronic module 100 according to an exemplary embodiment of the present invention. For clarity, the island-like insulation layers 40, the secondary component metallizations 22, and the primary component metallizations 21 are indicated in dashed lines in the plan view.In the exemplary embodiment illustrated here, the insulation layers 40 protrude into the primary component metallization 21, so that the first side S1, the second side S2, the third side S3, and the fourth side S4 are contacted by the primary component metallization 21. In particular, it is provided that, for example, the insulation layer 40 has an L-shaped profile. In principle, it is conceivable for the insulation layer 40 to assume any desired geometric shape, in particular with regard to a surface that runs parallel to the main extension plane HSE. The geometric shape of the insulation layer is preferably adapted to the requirements of the individual case.

[0083] List of reference symbols:

[0084] 1 metal-ceramic element

[0085] 5 Isolation trench

[0086] 10 ceramic elements

[0087] 20 Cooling side metallization

[0088] 21 primary component metallization

[0089] 22 secondary component metallization

[0090] 23 additional secondary component metallization

[0091] 24 second further secondary component metallization

[0092] 31 first metal section

[0093] 32 second metal section

[0094] 40 insulation layer

[0095] 41 additional insulation layer

[0096] 42 second additional insulation layer 100 electronic module

[0097] D Thickness

[0098] D1 first thickness

[0099] D2 second thickness

[0100] D3 third thickness

[0101] H1 first height

[0102] H2 second height

[0103] H Height

[0104] 151 first insulation layer thickness

[0105] 152 second insulation layer thickness

[0106] 153 third insulation layer thickness

[0107] A outside

[0108] HSE main extension level

[0109] 51 first page

[0110] 52 second page

[0111] 53 third page

[0112] 54 fourth page

[0113] L length

[0114] L1 first length

Claims

Claims Electronic module (100), in particular power electronic module, comprising - a metal-ceramic substrate (1) serving as a carrier with a ceramic element (10) and a primary component metallization (21) and preferably with a cooling side metallization (20), - an insulation layer (40) which is directly or indirectly connected to the primary component metallization (21), and - a secondary component metallization (22) which is connected to the side of the insulation layer (40) facing away from the ceramic element (10) and is in particular insulated from the primary component metallization (21) by the insulation layer (40), wherein the ceramic element (10) has a first size (L, D) and the insulation layer (40) has a second size (L1, D1), and wherein, in order to form an island-like insulation layer (40) on the primary component metallization (21), a ratio of the second size (L1, D1) to the first size (L, D) assumes a value which is less than 0.4, preferably less than 0.22, and particularly preferably less than 0.15 or even less than 0.1, wherein, viewed in a direction perpendicular to the main extension plane (HSE), an outer side (A) of the secondary component metallization (22) and an outer side (A) of the first component metallization (21) are substantially on a common height,and wherein the primary component metallization (21) serves essentially for connecting electronic components, in particular power electronic components, and the secondary component metallization serves essentially as a conductor track for signal routing and / or for conducting a load current. The electronic module (100) according to claim 1, wherein the primary component metallization (21) is structured to form a first metal section (31) and a second metal section (32) such that the first metal section (31) and the second metal section (32) are electrically insulated, wherein, viewed in a direction perpendicular to the main extension plane (HSE), the outer side (A) of the secondary component metallization (22) in the first metal section (31) and the outer side (A) of the primary component metallization (21) in the second metal section (32) terminate essentially at a common height. Electronic module (100) according to one of the preceding claims, wherein the primary component metallization (21) contacts the insulation layer (40) on at least two sides (S1, S2), preferably at least three sides (S1, S2, S3) and particularly preferably on at least four sides (S1, S2, S3, S4). Electronic module (100) according to one of the preceding claims, wherein the electronic module (100) has a further insulation layer (41). Electronic module (100) according to claim 4, wherein the insulation layer (40) and the further insulation layer (41) are arranged offset in height from one another in a direction perpendicular to the main extension plane (HSE).Electronic module (100) according to claim 4 or 5, wherein the insulation layer. (40) a first insulation layer thickness (IS1 ) and the further insulation layer (41) has a second insulation layer thickness (ID2), wherein the first insulation layer thickness (IDS1) and the second insulation layer thickness (IDS2) are different. Electronic module (100) according to one of the preceding claims, wherein the secondary component metallization (22) has a first thickness (D1) measured perpendicular to the main extension plane (HSE) that is greater than 150 pm. Electronic module (100) according to one of the preceding claims, wherein the insulation layer (40) is in a plane parallel to the main extension plane (HSE) extending plane has a cross-section that deviates from a rectangle. Electronic module (100) according to one of the preceding claims, wherein the secondary component metallization (22) is structured. Method for producing an electronic module (100) according to one of the preceding claims, wherein to form the primary component metallization (21) a metal layer or metal layer is bonded to the ceramic element (10) and to form the secondary component metallization (22) a further metal layer or further metal layer is bonded to the insulation layer (40), preferably in a common method step, in particular by hot isostatic pressing.

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