Insulating metal substrate and method for manufacturing insulating metal substrate

Abstract

An insulated metal substrate (1) for a power semiconductor device is provided. The insulated metal substrate (1) includes a metal base (2), a dielectric layer (3) disposed on the metal base (2), a conductive layer (4) disposed on the dielectric layer (3), and a reinforcing structure (5), the reinforcing structure (5) being disposed in a peripheral region of the insulated metal substrate (1) at least partially surrounding a central region of the insulated metal substrate (1). A method for manufacturing the insulated metal substrate is also provided.

Description

[Technical Field]

[0001] This disclosure relates to an insulating metal substrate for power semiconductor devices and a method for manufacturing an insulating metal substrate. [Background technology]

[0002] Embodiments of this disclosure relate particularly to highly reliable and mechanically stable insulating metal substrates. Further embodiments of this disclosure relate to methods for manufacturing such insulating metal substrates. [Overview of the project] [Means for solving the problem]

[0003] This is achieved by the subject matter of the independent claim. Further embodiments are evident from the dependent claims in the following description.

[0004] This document describes insulating metal substrates for power semiconductor devices. The term “power” as used herein and below refers to power semiconductor devices, power semiconductor modules, and / or power semiconductor chips adapted to handle, for example, voltages and currents greater than 100V and / or greater than 10A, exemplary voltages up to 10kV and currents up to 5000A.

[0005] According to one embodiment, the insulating metal substrate includes a metal base. The metal base has a primary extending surface that extends laterally. The metal base has a back surface and an upper surface opposite to the back surface. The back surface and the upper surface are connected by at least one side surface. Both the back surface and the upper surface extend laterally, as an example, and at least one side surface extends longitudinally, perpendicular to the laterally. The metal base is formed in particular as a plate.

[0006] The metal base has a height of, for example, 0.5 mm to 10 mm in the vertical direction, and more particularly, 1 mm to 2 mm. Exemplarily, the metal base contains or consists of a conductive material. The metal base particularly contains or consists of a metal alloy or metal, such as aluminum and / or copper.

[0007] According to the embodiment, the insulating metal substrate includes a dielectric layer disposed on a metal base. The dielectric layer extends particularly in the transverse direction. The dielectric layer has, for example, a back surface and a top surface, both extending in the transverse direction.

[0008] For example, a dielectric layer, particularly its back surface, is placed directly on a metal base, especially on the top surface of the metal base. In particular, the dielectric layer is placed on the first side of the insulating metal substrate. The dielectric layer covers only, for example, at least 80% or 90% of the top surface of the metal base. Exemplarily, the dielectric layer completely covers the top layer of the metal base.

[0009] The vertical height of the dielectric layer is, for example, 50 μm to 500 μm, and particularly 100 μm to 200 μm. Exemplarily, the dielectric layer contains or consists of an electrical insulating material.

[0010] According to the embodiment, the insulating metal substrate includes a conductive layer disposed on a dielectric layer. The conductive layer extends particularly in the transverse direction. The conductive layer has, for example, a transversely extending back surface and a transversely extending top surface.

[0011] For example, a conductive layer, particularly the back surface of the conductive layer, is directly placed on the dielectric layer, particularly on the upper surface of the dielectric layer. In particular, the conductive layer is placed on the first side of the insulating metal substrate. The conductive layer covers the upper surface of the dielectric layer by, for example, at least 50% or 70% and / or up to 95% or 90%. In particular, the dielectric layer, particularly the upper surface of the dielectric layer, does not locally contain the conductive layer.

[0012] The vertical height of the conductive layer is, for example, 0.1 mm to 2.5 mm, and more particularly 0.5 mm to 1.0 mm. Exemplarily, the conductive layer contains or consists of a conductive material. In particular, the conductive layer contains or consists of a metal alloy or metal, such as aluminum and / or copper.

[0013] For example, the metal base, dielectric layer, and conductive layer are stacked on top of each other in the stacking direction, which is the vertical direction perpendicular to the lateral direction.

[0014] According to the embodiment, the insulating metal substrate includes a reinforcing structure. The reinforcing structure has a main extending surface that extends laterally. The reinforcing structure has a back surface and an upper surface opposite to the back surface. The back surface and the upper surface are connected by at least two sides, an inner surface and an outer surface. Both the back surface and the upper surface extend laterally, as an example, and each of the at least two sides extends longitudinally.

[0015] In particular, the reinforcing structure is positioned on the first side of the insulating metal substrate. In this case, the reinforcing structure layer faces the upper surface of the metal base.

[0016] The reinforcing structure has, for example, a vertical height of 0.5 mm to 8 mm or 5 mm. Exemplarily, the reinforcing structure includes or consists of a conductive material such as a metal or metal alloy.

[0017] According to the embodiment of the insulating metal substrate, the reinforcing structure is arranged in the peripheral region of the insulating metal substrate that at least partially surrounds the central region of the insulating metal substrate.

[0018] For example, the inner surface of the reinforcing structure faces the central region, while the outer surface of the reinforcing structure faces in the opposite direction from the central region. The central region is located in the center of the insulating metal substrate and extends laterally toward the edge of the insulating metal substrate. The peripheral region extends laterally along the edge of the insulating metal substrate that defines the central region.

[0019] The peripheral region completely encloses the central region in the lateral direction. The reinforcing structure is located at least locally or entirely within the peripheral region. For example, the reinforcing structure encloses the central region in a frame-like manner. The shape of the reinforcing structure should be understood as not being limited to "frame-like."

[0020] Exemplary, the reinforcing structure is provided to be connected to the metal base, dielectric layer, and conductive layer in a mechanically stable manner. In this case, the reinforcing structure mechanically and stably supports the metal base, dielectric layer, and conductive layer, thereby reducing or preventing concave bending of the insulating metal substrate. In particular, the back surface of the insulating metal substrate is convexly bent. In this specification and the following description, concave bending means that the insulating metal substrate is bent towards the upper surface, particularly in the central region. In other words, concave bending means that the back surface of the metal base is bent towards the conductive layer, particularly in the central region.

[0021] In embodiments of an insulating metal substrate, the reinforcing structure does not project laterally beyond the metal base. For example, the reinforcing structure does not project laterally beyond the dielectric layer and / or conductive layer. Exemplarily, the outer surface of the reinforcing structure terminates coplanar with the outer surface of the metal base, the outer surface of the dielectric layer, and / or the outer surface of the conductive layer. In particular, the outer surface of the reinforcing structure lies within a common area with the outer surface of the metal base, the outer surface of the dielectric layer, and / or the outer surface of the conductive layer.

[0022] For example, a metal base, dielectric layer, and conductive layer form a laminate, which may bend, particularly concave, during assembly processes that involve heating and cooling steps and expose the laminate to heat. In particular, if a reinforcing structure is not used, concave bending of the back surface of the metal base of a conventional insulating metal substrate results in several drawbacks. Such drawbacks include, for example, an unsuitable thermal interface between the metal base and the heat sink, or cracks in the dielectric layer.

[0023] In summary, an insulating metal substrate for a power semiconductor device having a reinforcing structure can provide, among other things, the following advantages. By preventing or at least reducing concave bending, a relatively cost-effective insulating metal substrate technology can be used for large power modules and power modules for high voltage classes. The mechanically rigid reinforcing structure can further reduce the risk of dielectric breakdown due to cracks in the dielectric layer caused by stress from strong bending. Furthermore, such an insulating metal substrate can reduce even concave or convex bending of the metal base, which is advantageous for the thermal interface between the power module and the cooler. In addition, such an insulating metal substrate has its long-term increase in thermal resistance suppressed, resulting in an extended lifespan. In addition, the bending behavior caused by thermal cycles during the operation of the power semiconductor device is reduced, thereby improving the long-term behavior of the thermal interface, and as a result, reliability is improved, for example, the discharge of the thermal interface material is reduced. Furthermore, such an insulating metal substrate is lightweight compared to the standard arrangement where the substrate is soldered onto the base plate. Such an insulating metal substrate also requires fewer process steps in the assembly process.

[0024] Such an insulating metal substrate can be used particularly for low-voltage industrial and automotive products.

[0025] According to a further embodiment of the insulating metal substrate, the dielectric layer is an electrically insulating resin layer. The insulating metal substrate illustratively includes or consists of an epoxy resin containing an inorganic filler. The inorganic filler includes or consists of a ceramic material such as aluminum nitride (AlN), silicon nitride (Si3N4), boron nitride (BN) and / or aluminum oxide (Al2O3).

[0026] According to a further embodiment of the insulating metal substrate, the conductive layer includes circuit metallization. The circuit metallization includes, for example, a plurality of portions. At least some of these portions are arranged spaced apart from each other in the lateral direction. In this case, at least some of these portions will be electrically insulated from each other.

[0027] The circuit metallization is configured to be connected to at least one power semiconductor device, for example, in a central region.

[0028] According to a further embodiment of the insulating metal substrate, the height of the reinforcement structure is greater than or equal to the height of the conductive layer. The height of the reinforcement structure is the range from the back surface to the front surface of the reinforcement layer in the longitudinal direction. Furthermore, the height of the conductive layer is the range from the back surface to the front surface of the conductive layer in the longitudinal direction. In particular, all portions have the same height.

[0029] Exemplarily, the upper surface of the reinforcement structure projects vertically above the upper surface of the conductive layer in a direction opposite to the metal base.

[0030] For example, the height of the reinforcement structure is at most 7.5 mm or 4.5 mm higher than the height of the conductive layer.

[0031] Alternatively, the height of the reinforcement structure is lower than the height of the conductive layer. The height of the reinforcement structure is determined in consideration of the physical properties of the material used for the reinforcement structure. The physical properties can be the Young's modulus, the coefficient of thermal expansion, and other physical properties related to the flexibility or hardness of the material and its behavior with temperature changes. The higher the value of the Young's modulus, the smaller the height or thickness required for the reinforcement structure determined for a material having a similar coefficient of thermal expansion (constant coefficient of thermal expansion, CTE value) can be.

[0032] According to a further embodiment of the insulating metal substrate, the reinforcement structure is formed continuously. In particular, the reinforcement structure completely surrounds the central region in the lateral direction. In this case, the reinforcement structure will be formed continuously connected. Exemplarily, the reinforcement structure is formed as an integral part.

[0033] Alternatively, a continuously formed reinforcing structure includes at least two parts made of different materials. Exemplarily, these parts are connected to each other.

[0034] According to further embodiments of the insulating metal substrate, the reinforcing structure is formed discontinuously. In this case, the reinforcing structure is formed discontinuously without connection. In particular, the reinforcing structure includes at least two regions. These regions are, exemplary, spaced laterally apart from one another. Exemplarily, the reinforcing structure is formed as a separate component, i.e., a compartment.

[0035] All of these compartments can be formed from the same material. Alternatively, at least two of the compartments can be formed from different materials.

[0036] According to a further embodiment of the insulating metal substrate, at least one of the height and width of the reinforcing structure is uniform. The width of the reinforcing structure is the minimum range of the reinforcing layer from the inner surface to the outer surface in the transverse direction.

[0037] For example, the height of the reinforcing structure is the same throughout the surrounding region. For instance, the width of the reinforcing structure is the same throughout the surrounding region, except for the corner regions of the insulating metal substrate. For example, the corner regions of the reinforcing structure are wider than the regions where the reinforcing structure extends in a straight line.

[0038] For example, the width of the reinforcing structure is 1 mm or more and 20 mm or less, or 10 mm or less. According to further embodiments of the insulating metal substrate, at least one of the height and width of the reinforcing structure is not uniform. Exemplarily, the height of the reinforcing structure differs in at least two regions within the peripheral region. For example, the width of the reinforcing structure differs in at least two regions within the peripheral region.

[0039] According to further embodiments of the insulating metal substrate, the reinforcing structure includes at least one additional reinforcing structure. For example, the additional reinforcing structure is located on the first side of the insulating metal substrate. In this case, the additional reinforcing structure layer faces the upper surface of the metal base.

[0040] The vertical height of the additional reinforcing structure is, for example, 0.5 mm to 8 mm or 5 mm. Exemplarily, the additional reinforcing structure includes or consists of a conductive material such as metal or a metal alloy. The additional reinforcing structure can be formed from the same material as the reinforcing structure or from a different material.

[0041] Advantageously, the additional reinforcing structure further enhances the mechanically stable support for the metal base, dielectric layer, and conductive layer, thereby reducing concave bending of the insulating metal substrate.

[0042] According to further embodiments of the insulating metal substrate, at least one additional reinforcing structure extends into the central region. In particular, the additional reinforcing structure is located in the central region. For example, the additional reinforcing structure extends laterally from the peripheral region in the central region.

[0043] According to a further embodiment of the insulating metal substrate, at least one additional reinforcing structure is formed integrally with the reinforcing structure. In this case, the additional reinforcing structure can be formed as an integral part with the reinforcing structure. For example, the additional reinforcing structure is continuously connected to the additional reinforcing structure.

[0044] Alternatively, the additional reinforcing structures and reinforcements can be formed from different materials and bonded together.

[0045] According to a further embodiment of the insulating metal substrate, at least one additional reinforcing structure is spaced apart from the reinforcing structure. In this case, the additional reinforcing structure can be formed as a separate component from the reinforcing structure. For example, the additional reinforcing structure is not continuously connected to the additional reinforcing structure.

[0046] The additional reinforcing structure is advantageous in that it improves the mechanical stability of the insulating metal substrate. Advantageously, to further suppress or at least reduce concave bending in the central region of the insulating metal substrate, the additional reinforcing structure is positioned in the central region or at locations where the strongest bending is likely to occur.

[0047] According to a further embodiment of the insulating metal substrate, at least one additional reinforcing structure is configured to divide the central region into at least two compartments. For example, the additional reinforcing structure extends entirely between opposing sides of the reinforcing structure, i.e., between opposing inner sides.

[0048] According to further embodiments of the insulating metal substrate, the reinforcing structure includes metal, polymer material and / or inorganic material.

[0049] Exemplary, the height and / or width of the reinforcing structure, and / or the material of the reinforcing structure, are predetermined in accordance with the bending of the metal base, dielectric layer, and conductive layer during the assembly process without the reinforcing structure. For example, the laminate is relatively flat, i.e., does not bend, at an initial temperature T1 during the bonding process with a power semiconductor device, as an example. However, because the metal base has a "mechanical advantage" over the dielectric and conductive layers, the laminate exhibits concave bending during cooling to a further temperature lower than the initial temperature, for example. In this case, the material of the reinforcing structure is predetermined such that the reinforcing structure has a smaller coefficient of thermal expansion than the metal base, and if the metal base has a relatively large coefficient of expansion, it will bend strongly during cooling if the reinforcing structure is not available. The thickness of the reinforcing structure is predetermined, for example, by Young's modulus, which indicates the stiffness of the material of the reinforcing structure. In addition, the long-term behavior of the thermal interface, and thereby reliability, will also be improved by considering that bending behavior is reduced by thermal cycling during the operation of the power semiconductor device.

[0050] At least the flat back surface of the metal base is realized, in particular, by the following equation: d metal_base ε metal_base λmetal_base + d dielectric_layer ε dielectric_layer λ dielectric_layer = d reinforcment_structure ε reinforcment_structure λ reinforcment_structure In the formula, d is the corresponding height, ε is the corresponding Young's modulus, and λ is the corresponding coefficient of thermal expansion.

[0051] For example, depending on the height, Young's modulus, and coefficient of thermal expansion of the reinforcing structure with respect to the metal base, dielectric layer, and / or conductive layer, a predetermined convex bending on the back surface of the metal base can be advantageously achieved, or at least the concave bending can be reduced or suppressed. Such convex bending can advantageously increase the cooling efficiency.

[0052] According to a further embodiment of the insulated metal substrate, the reinforcing structure is disposed on the metal base. For example, in the peripheral region, the metal base does not include a dielectric layer and a conductive layer. The reinforcing structure is in direct contact with the metal base in the peripheral region.

[0053] According to a further embodiment of the insulated metal substrate, the reinforcing structure is disposed on the dielectric layer. For example, the upper surface of the metal base is completely covered with a dielectric layer, but the upper surface of the dielectric layer does not have a conductive layer in its peripheral region. The reinforcing structure is in direct contact with the dielectric layer in the peripheral region.

[0054] Exemplarily, an additional reinforcing structure is disposed on the dielectric layer. In this case, the upper surface of the dielectric layer does not include a conductive layer in the central region where the additional reinforcing structure is disposed.

[0055] According to a further embodiment of the insulated metal substrate, the reinforcing structure is disposed on the conductive layer. For example, the upper surface of the metal base is completely covered with a dielectric layer. The conductive layer is disposed in the peripheral region on the dielectric layer. In this case, at least one of several portions is disposed in the peripheral region. The reinforcing structure is in direct contact with the conductive layer in the peripheral region.

[0056] For example, the additional reinforcing structure is placed on the conductive layer. In this case, the additional reinforcing structure would be located, for example, in the central region of one of the at least one parts.

[0057] According to further embodiments of the insulating metal substrate, the potential of the reinforcing structure is grounded. Exemplarily, the reinforcing structure and / or additional reinforcing structures are electrically connected to a conductive layer or metal base.

[0058] Alternatively, the potential of the reinforcing structure is floating. In this case, for example, the reinforcing structure would not be electrically connected to the conductive layer or metal base.

[0059] According to a further embodiment of the insulating metal substrate, the reinforcing structure is grounded by at least one screw and / or by at least one bonding wire. For example, the reinforcing structure is conductively connected to the metal base via a screw and / or bonding wire, or as part of circuit metallization. Alternatively, the reinforcing structure is conductively connected directly to the base material of the metal base. In particular, the metal base is connected to the ground of the insulating metal substrate.

[0060] Exemplary, the reinforcing structure includes at least one opening that penetrates the reinforcing structure completely in the longitudinal direction. The opening is configured to receive screws or bolts, thereby allowing the reinforcing structure to be connected to a metal base, and in addition, thereby allowing an insulating metal substrate or a finished power module to be connected to a cooler or heat sink. Furthermore, the dielectric layer and / or conductive connection portion includes at least one further opening. This further opening completely overlaps the opening in the transverse direction, and in particular to match it.

[0061] Furthermore, this specification describes a method for manufacturing an insulating metal substrate. This method can or does manufacture the insulating metal substrate described herein. Therefore, features related to the insulating metal substrate are disclosed in relation to the method, and vice versa.

[0062] According to this embodiment of the method, a metal base is provided. According to an embodiment of this method, a dielectric layer is provided on a metal base.

[0063] According to embodiments of the method, a conductive layer is provided on a dielectric layer. Exemplarily, the conductive layer material is coated onto the dielectric layer. The conductive layer material completely covers the upper surface of the dielectric layer. For example, after coating the conductive layer material, the conductive layer material is structured to form a conductive layer. Structuring is achieved, for example, by a chemical etching process and / or a physical etching process.

[0064] Alternatively, a metal base and a circuit metallization portion are provided, and a dielectric layer is formed.

[0065] According to an embodiment of the method, a reinforcing structure is provided, and this reinforcing structure is provided in the peripheral region of the insulating metal substrate.

[0066] Furthermore, such a method for insulating metal substrates has the advantage of reducing process steps in the assembly process, for example, because it eliminates the need for a process to bond the substrate to the base plate.

[0067] According to embodiments of the method, the reinforcing structure is applied to at least one of the metal base, dielectric layer, and conductive layer. In particular, the reinforcing structure is prefabricated and applied to at least one of the metal base, dielectric layer, and conductive layer.

[0068] According to the embodiment of the method, the reinforcing structure is subjected to at least one of the following steps: lamination, bonding, soldering, sintering, brazing, gluing, and screwing.

[0069] According to embodiments of the method, the reinforcing structure is fabricated from a metal-based base material. Exemplarily, a metal-based base material is provided. After providing the metal-based base material, the base material is structured to form an integrated structure, i.e., a metal base and a reinforcing structure from the base material. Structuring is achieved, for example, by an etching or grinding process.

[0070] Figures are attached to provide further understanding. In the figures, elements having the same structure and / or function may be referred to by the same reference numerals. Please note that the embodiments shown in the figures are illustrative and not necessarily drawn to scale. [Brief explanation of the drawing]

[0071] [Figure 1] This is a schematic three-dimensional diagram showing an insulating metal substrate according to an exemplary embodiment. [Figure 2] This is a schematic three-dimensional cross-sectional view showing an insulating metal substrate according to an exemplary embodiment. [Figure 3] This is a schematic three-dimensional cross-sectional view showing an insulating metal substrate according to an exemplary embodiment. [Figure 4] This figure shows a simulation of the vertical displacement of an insulating metal substrate according to an exemplary embodiment, depending on the height of each reinforcing structure made of different materials. [Modes for carrying out the invention]

[0072] The insulating metal substrate 1 according to the exemplary embodiment shown in Figure 1 includes a metal base 2, a dielectric layer 3, and a conductive layer 4, and the metal base 2, dielectric layer 3, and conductive layer 4 are stacked on top of each other in the stacking direction, which is the vertical direction.

[0073] The upper surface of the metal base 2 is completely covered by a dielectric layer 3. The dielectric layer 3 is located on the upper surface of the first side of the insulating metal substrate 1. Furthermore, the dielectric layer 3 is an electrically insulating resin layer formed to provide electrical insulation.

[0074] The conductive layer 4 is positioned on the upper surface of the dielectric layer 3 on the first side 8. Furthermore, the conductive layer 4 includes a conductively formed circuit metallization. In this case, the conductive layer 4 includes a plurality of parts, at least some of which are spaced apart from each other in the transverse direction and extending perpendicularly in the longitudinal direction.

[0075] The metal base 2, dielectric layer 3, and conductive layer 4 are formed as a laminate. Each of the metal base 2, dielectric layer 3, and conductive layer 4 has a height. The metal base 2 is formed to have a uniform height along its extending direction. The dielectric layer 3 is formed to have a uniform height along its extending direction. The conductive layer 4, and in particular some portions thereof, is formed to have a uniform height along its extending direction. "Uniform" means that each height may vary slightly, i.e., by at least up to 5%, due to manufacturing tolerances. The same applies to uniform width.

[0076] In addition, a reinforcing structure 5 is arranged in the peripheral region surrounding the central region of the insulating metal substrate 1. Specifically, the reinforcing structure 5 is arranged on the upper surface of the dielectric layer 3 on the first side 8. The reinforcing structure 5 is in direct contact with the dielectric layer 3.

[0077] In particular, both the metal base 2 and the dielectric layer 3 have a predominantly rectangular shape. "Preferably" means that the rectangular shape has chamfered or rounded corners. Furthermore, the outer surface of the reinforcing structure 5 has a rectangular outline, and the inner surface, which is opposite the outer surface and faces the central region, has an octagonal outline. The lateral distance from the outer surface to the inner surface defines the width of the reinforcing structure 5. The width of the reinforcing structure 5 increases in the direction of each corner of the rectangular outline.

[0078] The upper surface of the dielectric layer 3 does not include the conductive layer 4 in the peripheral region where the reinforcing structure 5 is located. In this case, the conductive layer 4 is located only in the central region that is completely surrounded laterally by the reinforcing structure 5.

[0079] The vertical height of the reinforcing structure 5 is greater than the height of the conductive layer 4. In particular, the height of the reinforcing structure 5 is up to 4.5 mm greater than the height of the conductive layer 4.

[0080] Openings 6 are provided in each region of each corner of the rectangular outer shape. Each of the openings 6 is configured to receive a screw, and the reinforcing structure 5 is grounded to the metal base 2 by the screw.

[0081] Furthermore, recesses 7 are provided in each region of each corner of the rectangular outline, spaced laterally from the opening 6. Each of the recesses 7 has a circumference smaller than the opening 6. Exemplarily, the recesses 7 are configured to receive adjustment pins of part of a power semiconductor component or part of a power semiconductor module configured to be mounted on an insulating metal substrate 1.

[0082] The exemplary embodiment shown in Figure 2 relates to the exemplary embodiment shown in Figure 1. The reinforcing structure 5 is directly disposed on the dielectric layer 3 in the peripheral region that completely encloses the central region.

[0083] In contrast to the exemplary embodiment in Figure 2, the reinforcing structure 5 is located on the conductive layer 4 in the exemplary embodiment in Figure 3. One of several portions of the conductive layer 4 is located in the peripheral region. This portion in the peripheral region is laterally separated from the other portions of the conductive layer 4 in the central region.

[0084] For example, finite element simulations demonstrate the effect of the height and material of the reinforcing structure 5 on the bending of the insulating metal substrate 1 by cooling it by only 100K, as illustrated in Figure 4.

[0085] The insulating metal substrate 1 used for the illustrative simulation has a metal base 2 made of copper. For example, the reinforcing structure 5 of the insulating metal substrate 1 used for the illustrative simulation is made of aluminum. At the initial temperature T1, the insulating metal substrate 1, and in particular the metal base 2, are assumed to be flat and unstressed.

[0086] For illustrative purposes, the exemplary simulation is performed on reinforcing structures 5 having various heights, such as 2 mm, 4 mm, and 8 mm. The longitudinal difference corresponding to the undesirable concave bending on the back surface of the metal base 2 after cooling by only 100 K is defined by the longitudinal difference between the highest and lowest points on the back surface of the metal base 2. The simulation results show longitudinal differences of 0.22 mm for a height of 1 mm, 0.18 mm for a height of 2 mm, 0.13 mm for a height of 4 mm, and 0.04 mm for a height of 8 mm.

[0087] In this case, the difference in the vertical direction, i.e., the bending of the insulating metal substrate 1, will depend on the height of the reinforcing structure 5.

[0088] The schematic diagram in Figure 4 shows simulation results similar to the exemplary simulation, and in particular the effects of various materials on the reinforcing structure 5, especially regarding Young's modulus and thermal expansion coefficient, and the effects of various heights of the reinforcing structure 5. The vertical difference z is shown on the y-axis in mm, and the height d of the reinforcing structure 5 is shown on the x-axis of the schematic diagram.

[0089] Simulation points characterized by triangles correspond to reinforcement structure 5 containing an iron-nickel alloy. Simulation points characterized by filled circles correspond to reinforcement structure 5 containing copper. Simulation points characterized by squares correspond to reinforcement structure 5 containing aluminum. Simulation points characterized by open circles correspond to reinforcement structure 5 containing a magnesium alloy or stainless steel.

[0090] When reinforcing structure 5 includes aluminum, magnesium alloy, or stainless steel, bending is reduced most significantly.

[0091] If the reinforcing structure 5 contains copper, the reduction in bending can be made even less. When reinforcing structure 5 contains an iron-nickel alloy, a stronger inverse effect of bending is achieved, and this increases as the height of reinforcing structure 5 increases. In particular, the iron-nickel alloy has a smaller coefficient of thermal expansion than the metal base 2, while all other materials in reinforcing structure 5 have a larger coefficient of thermal expansion than the metal base 2. [Explanation of symbols]

[0092] Reference sign 1. Insulating metal substrate, 2. Metal base, 3. Dielectric layer, 4. Conductive layer, 5. Reinforcement structure, 6. Opening, 7. Recess, 8. First side.

Claims

1. An insulating metal substrate (1) for a power semiconductor device, - Metal base (2), - A dielectric layer (3) disposed on the metal base (2), - A conductive layer (4) disposed on the dielectric layer (3), - Including the reinforcing structure (5), - The reinforcing structure (5) is arranged in the peripheral region of the insulating metal substrate (1) that at least partially surrounds the central region of the insulating metal substrate (1), - The reinforcing structure (5) does not protrude laterally beyond the metal base (2), - The reinforcing structure (5) is made of metal, - The reinforcing structure (5) includes at least one additional reinforcing structure, - The at least one additional reinforcing structure is an insulating metal substrate (1) extending into the central region.

2. - The dielectric layer (3) is an electrically insulating resin layer, - The conductive layer (4) includes circuit metallization. An insulating metal substrate (1) according to claim 1, which is at least one of the following.

3. - The insulating metal substrate (1) according to claim 1 or 2, wherein the height of the reinforcing structure (5) is greater than or equal to the height of the conductive layer (4).

4. - The insulating metal substrate (1) according to claim 1 or 2, wherein the reinforcing structure (5) is formed continuously.

5. - The insulating metal substrate (1) according to claim 1 or 2, wherein the reinforcing structure (5) is formed discontinuously.

6. - At least one of the height and width of the reinforcing structure (5) is uniform, and / or - The insulating metal substrate (1) according to claim 1 or 2, wherein at least one of the height and width of the reinforcing structure (5) is non-uniform.

7. - The at least one additional reinforcing structure is formed integrally with the reinforcing structure (5), or - The insulating metal substrate (1) according to claim 1, wherein the at least one additional reinforcing structure is spaced apart from the reinforcing structure (5).

8. - The insulating metal substrate (1) according to claim 1, wherein the at least one additional reinforcing structure (5) is configured to divide the central region into at least two sections.

9. - The insulating metal substrate (1) according to claim 1 or 2, wherein the reinforcing structure (5) is disposed on the metal base (2).

10. An insulating metal substrate (1) for a power semiconductor device, - Metal base (2), - A dielectric layer (3) disposed on the metal base (2), - A conductive layer (4) disposed on the dielectric layer (3), - Including the reinforcing structure (5), - The reinforcing structure (5) is arranged in the peripheral region of the insulating metal substrate (1) that at least partially surrounds the central region of the insulating metal substrate (1), - The reinforcing structure (5) does not protrude laterally beyond the metal base (2), - The reinforcing structure (5) is an insulating metal substrate (1) made of metal, - The reinforcing structure (5) is arranged on the dielectric layer (3), - The reinforcing structure (5) is arranged on the conductive layer (4). An insulating metal substrate (1) which is at least one of the following.

11. - The potential of the reinforcing structure (5) is grounded. - The insulating metal substrate (1) according to claim 1 or 2, wherein the reinforcing structure (5) is grounded by at least one screw and / or the reinforcing structure (5) is grounded by at least one bonding wire.

12. A method for manufacturing an insulating metal substrate (1) for a power semiconductor device, - Steps include providing a metal base (2), - The step of providing a dielectric layer (3) which is placed on the metal base (2), - The step of providing a conductive layer (4) which is arranged on the dielectric layer (3), - Includes the step of providing a reinforcing structure (5), - The reinforcing structure (5) is provided in the peripheral region of the insulating metal substrate (1), - The reinforcing structure (5) does not protrude laterally beyond the metal base (2), - The reinforcing structure (5) is made of metal, - The reinforcing structure (5) includes at least one additional reinforcing structure, - A method wherein the at least one additional reinforcing structure extends to the central region of the insulating metal substrate (1).

13. - The reinforcing structure (5) is applied to at least one of the metal base (2), the dielectric layer (3), and the conductive layer (4), - The method according to claim 12, wherein at least one of the steps of lamination, bonding, soldering, sintering, brazing, and screw fastening is applied to the reinforcing structure (5).

14. - The method according to claim 12, wherein the reinforcing structure (5) is made from the base material of the metal base (2).

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