Method for producing semiconductor module having at least one semiconductor component and heat sink

Abstract

The invention relates to a method for producing a semiconductor module (4) having at least one semiconductor component (28) and a heat sink (2), comprising the following steps: providing the heat sink (2) made of a first metal material; introducing (54) a cavity (14) into the heat sink surface (12), the cavity (14) having a bottom surface (16), which extends in particular parallel to the heat sink surface (12), and at least one wall (18); applying (56) a second metal material having a higher thermal conductivity than the first metal material in the cavity (14) by means of a thermal spraying method to form a thermal diffusion layer (22); the semiconductor component (28) is connected (60) to the thermal diffusion layer (22). In order to improve the thermal contact of the second metal material in the cavity (14), it is proposed that, when the cavity (14) is introduced (54), an obtuse angle (alpha) is formed between the bottom surface (16) and the at least one wall (18).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a semiconductor module having at least one semiconductor component and a heat sink, the method comprising the following steps: providing a heat sink made of a first metal material; introducing a cavity into the heat sink surface, wherein the cavity has a bottom surface and at least one wall portion extending in particular parallel to the heat sink surface; coating a second metal material having a higher thermal conductivity than the first metal material in the cavity by means of a thermal spraying method to form a heat diffusion layer; and connecting the semiconductor component to the heat diffusion layer.

[0002] Furthermore, the present invention relates to a semiconductor module having at least one semiconductor component and a heat sink, the heat sink being made of a first metal material and comprising at least one cavity having a bottom surface and at least one wall portion, the cavity having a bottom surface extending in particular parallel to a surface of the heat sink, wherein a second metal material having a higher thermal conductivity than the first metal material is applied in the cavity by means of a thermal spraying method to form a heat diffusion layer, wherein the semiconductor component is connected to the heat diffusion layer.

[0003] Furthermore, the invention relates to a power converter comprising at least one such semiconductor module.

[0004] Furthermore, the invention relates to a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to simulate the behavior, in particular the thermal behavior and / or the electrical behavior, of such a semiconductor module. Background Art

[0005] In such a power converter, the semiconductor components are generally fixed to the heat sink. A power converter can be understood, for example, as a rectifier, an inverter, a frequency converter or a DC voltage converter. The semiconductor components are usually implemented as electronic modules, which have a housing and are screwed to the heat sink via a solid metal substrate. Furthermore, the semiconductor components can be directly connected to the heat sink, i.e. without the need for additional connecting elements such as a base plate. The semiconductor components can include, but are not limited to, transistors, in particular insulated-gate bipolar transistors (IGBTs) and / or metal-oxide-semiconductor field effect transistors (MOSFETs).

[0006] Publication WO 2011 / 024377 A1 describes a semiconductor module including: a heat dissipation element including a first element containing aluminum and a second element containing copper, the second element being embedded in the first element and surrounded on all sides by the first element; and a semiconductor element thermally connected to the heat dissipation element.

[0007] Publication WO 2022 / 002464 A1 describes a power module comprising at least two power units, each of which comprises at least one power semiconductor and a substrate. In order to reduce the structural space required for the power module and improve heat dissipation, it is proposed that at least one power semiconductor is connected to the corresponding substrate in a material-matched manner, wherein the substrates of at least two power units are directly connected to the surface of a common heat sink in a material-matched manner. The heat sink is made of a first metal material. A cavity filled with a second metal material is introduced on its surface, wherein the thermal conductivity of the second metal material is higher than that of the first metal material. The second metal material is introduced into the cavity by means of an additive method, for example, by means of cold gas spraying. Summary of the invention

[0008] The application of the second metallic material by additive methods then brings challenges to the thermal contact in the cavity. Against this background, the object of the present invention is to improve the thermal contact of the second metallic material in the cavity.

[0009] According to the invention, this object is achieved for a method of the type mentioned at the outset in that during the introduction of the cavity an obtuse angle is respectively formed between the bottom surface and at least one wall.

[0010] Furthermore, according to the invention, this object is achieved by a semiconductor module of the type mentioned in the introduction in that an obtuse angle is formed between the bottom surface and at least one wall section.

[0011] Furthermore, according to the invention, the object is achieved by a power converter comprising at least one such semiconductor module.

[0012] Furthermore, according to the invention, the object is achieved by a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to simulate the behavior, in particular the thermal behavior and / or the electrical behavior, of such a semiconductor module.

[0013] The advantages and preferred embodiments listed below in connection with the method can be transferred analogously to the semiconductor module, the power converter and the computer program product.

[0014] The present invention is based on the following considerations, namely by improving the adhesion of the coated particles, improving the thermal connection of the heat diffusion layer applied by means of thermal spraying in the cavity of the heat sink for semiconductor modules. In order to produce such a heat diffusion layer, a cavity is introduced in the heat sink surface, wherein the cavity has a bottom surface and at least one wall portion extending in particular parallel to the heat sink surface. For example, the bottom surface is implemented as a rectangle or a square, and the cavity has four walls. Alternatively, the cavity can have an elliptical or circular bottom surface including a surrounding wall portion. For example, the introduction of the cavity can be achieved by means of a cutting method, in particular milling. In another step, by means of a thermal spraying method, a second metal material having a higher thermal conductivity than the first metal material of the heat sink is applied to the bottom surface and at least one wall portion of the cavity, thereby forming a heat diffusion layer in the cavity. For example, the first metal material is an aluminum alloy, and the second metal material contains copper or a copper alloy. Examples of thermal spraying methods include, but are not limited to, cold gas spraying, wherein particles of the second metal material, in particular copper particles, are sprayed, thereby forming a material-matched connection. By connecting the semiconductor components to the heat diffusion layer, an optimized heat removal is achieved during operation of the semiconductor module due to heat diffusion.

[0015] When the cavity is introduced, an obtuse angle is formed between the bottom surface and at least one wall, wherein an obtuse angle is defined in this context as an angle between 95° and 175°. As a result, in particular for a bottom surface extending parallel to the heat sink surface, at least one wall forms an acute angle in the range of 5° to 85° relative to the heat sink surface, so that the cavity has a substantially trapezoidal cross section. By means of such an angle, a surface enlargement is primarily achieved, which has a positive effect on the adhesion of the second metal material in the cavity. In addition, the surface enlargement is suitable with regard to heat transfer to the heat sink. Furthermore, the spray particle jet of the thermal spraying method is incident at a more favorable angle, so that a stronger adhesion of the second metal material in the cavity and an improved thermal contact are obtained.

[0016] A computer program product comprising instructions that, when the program is executed by a computer, cause the computer to simulate, in particular the thermal and / or electrical behavior of the described semiconductor module can comprise a "digital twin", also referred to as a "digital twin", or can be designed as such a digital twin. For example, such a digital twin is shown in the publication US 2017 / 0286572 A1. The disclosure of US 2017 / 0286572 A1 is incorporated into the present application by reference. A "digital twin" is, for example, a digital representation of components related to the operation of a semiconductor module.

[0017] At least one additional recessed portion is introduced into the bottom surface of the cavity, which is smaller than the bottom surface of the cavity, wherein a coating of a second metal material is realized in the cavity and the at least one additional recessed portion by means of a thermal spraying method, thereby forming a heat diffusion layer with different thicknesses. The at least one additional recessed portion can have a rectangular or square bottom surface. For example, an obtuse angle is formed between the bottom surface of the recessed portion and the wall, which can correspond to or differ from the obtuse angle of the cavity. Due to the obtuse angle, the additional recessed portion also has a substantially trapezoidal cross section. The additional recessed portion filled with the second metal material ensures a local thickening of the heat diffusion layer, which improves the thermal connection of the semiconductor component, for example, when hot spots occur.

[0018] Another embodiment provides that the obtuse angle between the bottom surface and the at least one wall portion is in the range of 95° to 150°, in particular 110° to 150°, more particularly 130° to 150°. With such an angle, an optimized adhesion and improved thermal contact of the second metal material in the cavity are achieved.

[0019] Another embodiment provides that the application of the second metallic material is achieved at a spraying angle in the range of 60° to 90°, in particular 70° to 90°, of the thermal spraying method. For example, particles of the second metallic material are applied in a spray jet, which can also be referred to as a spray particle jet, by means of a spraying device, which in particular includes a spray gun, wherein the spray jet is incident at a spraying angle. A spraying angle in the range of 60° to 90° ensures that the rebound of the particles during the thermal spraying method is reduced to a minimum and that the particles can be applied to the carrier material in a defined manner. In addition to the obtuse angle between the bottom surface and the at least one wall portion, a tilting of the spraying device, in particular a dynamic tilting or a position-dependent tilting, can also achieve such an adjustment of the spraying angle within the range of the at least one wall portion.

[0020] Another embodiment provides that after the second metal material is applied, the surface of the heat sink is milled. In this way, a flat surface of the heat diffusion layer is produced and a plane-flush connection of the heat diffusion layer to the heat sink surface is achieved, so that, for example, a flat substrate of a semiconductor component can be connected to the heat diffusion layer in a simple, space-saving manner and with low thermal resistance.

[0021] Another embodiment provides that when the cavity is introduced, a concave curved profile surface is formed between the bottom surface and at least one wall and / or between at least two walls. Such a concave curved profile surface can be produced, for example, by a cutting method, in particular by means of a rotary milling cutter, and causes a surface enlargement in the connecting region between the bottom surface and at least one wall or between at least two walls, thereby improving the adhesion and thermal contact of the second metallic material in the cavity.

[0022] Another embodiment provides that the semiconductor component comprises at least one semiconductor element and a substrate, wherein the substrate of the semiconductor component is connected flush with the heat diffusion layer. The substrate is mainly a dielectric material layer metallized on both sides. The substrate can be implemented as a DCB (Direct Copper Bonded) substrate, for example, wherein the dielectric material layer can contain aluminum oxide or aluminum nitride. At least one semiconductor element can have, but is not limited to: a transistor, in particular a vertical transistor and / or a diode. The transistor, in particular the vertical transistor, can be implemented mainly as an insulated gate bipolar transistor (IGBT). By means of planar coupling with the heat diffusion layer, a good thermal connection of the at least one semiconductor element is achieved.

[0023] Another embodiment provides that the substrate of the semiconductor component is directly connected to the heat diffusion layer in a material-fitting manner. A direct material-fitting connection with the heat diffusion layer of the heat sink can be established mainly by soldering, sintering or adhesion. "Direct material-fitting connection" can be understood as a straight-through connection, which includes a connecting agent for establishing a material-fitting connection, such as an adhesive, solder, sintering paste, etc., but excludes additional connecting elements such as additional conductors, spacers, substrates, thermal conductive paste, etc. Due to the omission of such additional connecting elements, an improved thermal connection of at least one semiconductor component is achieved, thereby improving heat dissipation. In addition, the direct material-fitting connection saves structural space.

[0024] Another embodiment provides that the surface of the heat diffusion layer substantially corresponds to the area of ​​the substrate, wherein the substrate of the semiconductor component is connected to the heat diffusion layer over the entire surface. For example, the heat diffusion layer is connected to the substrate substantially flush. This targeted arrangement of the heat diffusion layer is cost-effective and enables an optimized thermal connection of the semiconductor component.

[0025] Another embodiment provides that at least one additional recess is arranged in a vertical projection plane of at least one semiconductor element. For example, the additional recess can have a bottom surface that is adapted to the bottom surface or the footprint of the semiconductor element. Such an additional recess arranged below the at least one semiconductor element and filled with a second metal material ensures a local thickening of the heat diffusion layer, which improves the thermal connection of the semiconductor elements of the semiconductor assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Hereinafter, the present invention is described and explained in more detail based on the embodiments shown in the drawings.

[0027] In the attached picture:

[0028] Figure 1 shows a schematic three-dimensional cross-sectional view of a heat sink for a semiconductor module,

[0029] Figure 2 A three-dimensional schematic diagram showing the thermal spraying method,

[0030] Figure 3 shows a schematic cross-sectional view of a first specific embodiment of a semiconductor module,

[0031] Figure 4 shows an enlarged schematic cross-sectional view of a first specific embodiment of a semiconductor module,

[0032] Figure 5 shows an enlarged schematic cross-sectional view of a second specific embodiment of a semiconductor module,

[0033] Figure 6 A flow chart showing a method for manufacturing a semiconductor module,

[0034] Figure 7 shows a schematic three-dimensional sectional view of a third embodiment of a semiconductor module,

[0035] Figure 8 A schematic three-dimensional sectional view showing a fourth embodiment of a semiconductor module, and

[0036] Fig. 9 A schematic diagram of a power converter is shown. DETAILED DESCRIPTION

[0037] The embodiments explained below are preferred embodiments of the present invention. In these embodiments, the components of the described embodiments represent individual, mutually independently considered features of the present invention, which also improve the present invention independently and are therefore also considered as components of the present invention individually or in a combination different from the shown combination. Moreover, the described embodiments can also be supplemented by other features of the present invention that have been described.

[0038] The same reference symbols have the same meaning in different figures.

[0039] Figure 1 2 shows a schematic three-dimensional cross-sectional view of a heat sink 2 for a semiconductor module 4. The heat sink has a base plate 6 with cooling ribs 8, wherein the cooling ribs 8 are connected to the base plate 6. Figure 1 In the embodiment, the base plate 6 and the cooling ribs 8 of the radiator 2 are designed as a single piece. The radiator 2 is configured to conduct a cooling fluid, in particular a gaseous one, via the cooling ribs 8 into a coolant flow direction 10, wherein the coolant flow direction 10 extends substantially parallel to the planar radiator surface 12. The cooling fluid is, for example, air, which flows by means of a fan via the cooling ribs 8 of the radiator 2 into the coolant flow direction 10, wherein for reasons of clarity, the cooling ribs 8 are shown in FIG. Figure 1The fan is not shown in the figure. The base plate 6 has a substantially constant first strength s1 in the range of 3.5 mm to 5 mm, in particular 3.5 mm to 4 mm, while the second strength s2 of the cooling ribs 8 is smaller than the first strength s1 of the base plate 6 .

[0040] The heat sink 2 is made of a first metal material. The first metal material can be mainly an aluminum alloy, which contains, for example, 0.1% to 1.0%, in particular 0.1% to 0.6% of silicon. Such a heat sink 2 can be made mainly by extrusion. Furthermore, the cooling ribs 8 of the heat sink 2 made of an aluminum alloy are arranged so that the ratio of the length 1 of the cooling rib 8 to the distance a between the cooling ribs 8 is at least 10: 1 / a ≥ 10.

[0041] Furthermore, the heat sink 2 has, for example, two cavities 14 arranged in the base plate 6, which have a bottom surface 16 extending parallel to the heat sink surface 12, in particular substantially flat, and a plurality of walls 18. The bottom surface 16 is, for example, embodied in a rectangular shape. An obtuse angle α, for example 140°, is formed between the bottom surface 16 and the wall 18, so that the cross section of the cavity 14 is substantially trapezoidal. Alternatively, the angle α between the bottom surface 16 and the wall 18 can be in the range of 95° to 150°, in particular 110° to 150°, more particularly 130° to 150°. For example, the introduction of the cavity 14 can be achieved by means of a cutting method, such as milling. A concave curved profiled surface 20 is formed between the bottom surface 16 and the wall 18 and between adjacent wall portions 18.

[0042] A second metal material having a higher thermal conductivity than the first metal material is arranged in the cavity 14. For example, the second metal material comprises copper or a copper alloy. The second metal material is applied by means of a thermal spraying method, for example by means of cold gas spraying, to form a heat diffusion layer 22, wherein the second metal material is connected to the first material in a material-matching manner by the thermal spraying method. In addition, the second metal material of the heat diffusion layer 22 arranged in the cavity 14 is substantially plane-flushly bonded to the heat sink surface 12, thereby forming a flat surface. Such a plane-flush bond can be produced, for example, by face milling. Due to the obtuse angle α between the bottom surface 16 and the wall portion 18, during the thermal spraying method, the particles of the second metal material are incident at a more favorable angle, thereby obtaining a stronger adhesion and improved thermal contact of the second metal material in the cavity 14. The concave curved profiled surface 20 between the bottom surface 16 and the wall portion 18 and between adjacent wall portions 18 also makes a more favorable spraying angle and improved thermal contact possible.

[0043] Figure 2 A three-dimensional schematic diagram of the thermal spraying method is shown. Figure 21 shows the application of a second metallic material by means of cold gas spraying. The second metallic material is applied in a spray jet 26, which can also be referred to as a spray particle jet, by means of a spraying device 24, which comprises, for example, a spray gun. The spraying process is mainly carried out at a spraying angle β in the range of 60° to 90°, in particular 70° to 90°. In addition to the obtuse angle α between the bottom surface 16 and the wall 18, the dynamic tilting or position-dependent tilting of the spraying device 24 also leads to an optimization of the spraying angle β in the region of the wall 18. Figure 2 The other designs of the heat sink 2 correspond to Figure 1 Design in.

[0044] Figure 3 A schematic three-dimensional cross-sectional view of a first embodiment of a semiconductor module 4 is shown, wherein, in addition to the heat sink 2, the semiconductor module also includes a semiconductor component 28. The semiconductor component 28 has a semiconductor element 30, which is implemented as a transistor, in particular a vertical transistor, or as a diode. The transistor can be implemented mainly as an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET) or a bipolar transistor. A diode, in particular an antiparallel diode, can be assigned to the transistor. The semiconductor element 30 is connected to a substrate 32 in a material-bonded manner, wherein the material-bonded connection can be established mainly by soldering and / or sintering.

[0045] The substrate 32 has a dielectric material layer 34, which contains a ceramic material such as aluminum nitride or aluminum oxide or an organic material such as polyamide. The dielectric material layer 34 can have a thickness of 25 μm to 400 μm, in particular 50 μm to 250 μm. In addition, the substrate 32 has a structured first metallization layer 36 on the side facing the semiconductor element 30, and a second metallization layer 38 on the side facing away from the semiconductor element 30. The substrate 32 of the semiconductor component 28 is connected to the heat diffusion layer 22 of the heat sink 2 in a full-plane and directly material-bonded manner through the second metallization layer 38. In addition, the cavity 14 is implemented so that the heat diffusion layer 22 is essentially flush with the substrate 32. A material-bonded connection with the heat sink 2 is established by soldering or sintering. A direct material-bonded connection with the heat diffusion layer 22 of the heat sink 2 can be established mainly by soldering, sintering or adhesion. A "direct material-fit connection" can be understood as a through connection, which includes a connecting agent for establishing a material-fit connection, such as an adhesive, solder, sintering paste, etc., but excludes additional connecting elements such as additional conductors, spacers, substrates, thermal conductive paste, etc. On the side facing away from the substrate 32, the semiconductor element 30 is connected to the first metallization layer 36 of the substrate 32 through a wiring element 40. The wiring element 40 can include, but is not limited to: at least one bonding wire and / or at least one ribbon bonding element.

[0046] The semiconductor component 28 is arranged in a housing 42, for example made of plastic. The housing 42 is arranged on the heat sink 2 via a form-fitting connection 44 with a blind hole 46. A freely positionable contact 50 extending through the housing cover 48 is connected to the first metallization layer 36 of the substrate 32 in a material-fitting manner, for example by soldering or sintering. The semiconductor component 28 is potted in the housing 42 by a potting compound 52. Figure 3 The other designs of the heat sink 2 correspond to Figure 1 Design in.

[0047] Figure 4 An enlarged schematic cross-sectional view of a first embodiment of a semiconductor module 4 is shown within the range of an obtuse angle α between the bottom 16 and the wall 18 of the cavity 14. The thickness d of the heat diffusion layer 22 is greater than half the first strength s1 of the base plate 6 of the heat sink 2, thereby achieving a very good thermal connection of the semiconductor element 30. The heat diffusion layer 22 is essentially flush with the base plate 32, wherein the obtuse angle α is implemented so that the heat diffusion layer 22 below the semiconductor element 30 has its maximum thickness d. Figure 4 Other designs of the semiconductor modules 4 in correspondence Figure 3 Design in.

[0048] Figure 5 An enlarged schematic cross-sectional view of a second embodiment of a semiconductor module 4 is shown within the obtuse angle α between the bottom surface 16 and the wall 18 of the cavity 14. The thickness d of the heat diffusion layer 22 is less than half of the first strength s1 of the bottom plate 6 of the heat sink 2, thereby achieving a sufficient thermal connection of the semiconductor element 30, especially for lower power situations. The base plate 32 protrudes from the heat diffusion layer 22, wherein the heat diffusion layer 22 below the semiconductor element 30 has its maximum thickness d. Figure 5 Other designs of the semiconductor modules 4 in correspondence Figure 4 Design in.

[0049] Figure 6 Shown is the method used to manufacture Figures 3 to 5 Flowchart of a method for a semiconductor module 4 shown in any one of the above. The method comprises introducing 54 a cavity 14 into a heat sink surface 12 of a heat sink 2 made of a first metal material. The cavity 14 has a flat bottom surface 16 and at least one wall 18. When the cavity 14 is introduced 54, an obtuse angle α is formed between the bottom surface 16 and the wall 18, wherein in this context, the obtuse angle is between 95° and 175° (95° ≤ α ≤ 175°). In addition, when the bottom surface 16 is rectangular or square, the cavity 14 can be implemented in the shape of a truncated pyramid, or when the bottom surface 16 is elliptical or circular, the cavity can be implemented in the shape of a truncated cone.

[0050] In a further step, a second metal material having a higher thermal conductivity than the first metal material is applied 56 in the cavity 14 by means of a thermal spraying method to form the heat diffusion layer 22. In particular, the second metal material is applied by means of cold gas spraying.

[0051] After the second metallic material has been applied 56 , optionally, face milling 58 of the heat sink surface 12 is performed so that the heat diffusion layer 22 is joined flush with the heat sink surface 12 .

[0052] In a further step, a connection 60 is achieved between the semiconductor component 28 and the heat diffusion layer 22. The semiconductor component 28 has at least one semiconductor element 30 and a substrate 32, wherein the substrate 32 of the semiconductor component 28 is directly connected to the heat diffusion layer 22 in a materially bonded manner, in particular over the entire surface. The materially bonded connection to the heat sink 2 can be established primarily by soldering or sintering.

[0053] Figure 7 A schematic three-dimensional cross-sectional view of a third embodiment of a semiconductor module 4 is shown, wherein the semiconductor module 4 has, for example, two semiconductor components 28 connected to a common heat sink 2. The bottom surface 16 of the cavity 14 has an additional recess 62, which is smaller than the bottom surface 16 of the cavity 14 and is arranged in the vertical projection plane of the semiconductor element 30. The additional recess 62 protrudes beyond the bottom surface of the semiconductor element 30. By means of a thermal spraying method, a second metal material is introduced into the cavity 14 and into the additional recess 62, thereby forming a heat diffusion layer 22 with different thicknesses d1, d2, wherein the second thickness d2 is greater than the first thickness d1. The additional recess 62 arranged below the semiconductor element 30 and filled with the second metal material ensures a local thickening of the heat diffusion layer 22, which improves the thermal connection of the semiconductor element 30.

[0054] Like the cavity 14, the additional recess 62 has a substantially flat rectangular bottom surface 16 and a plurality of walls 18. An obtuse angle α is formed between the bottom surface 16 and the walls 18, which can correspond to or differ from the obtuse angle α of the cavity. Due to the obtuse angle α, the additional recess 62 also has a substantially trapezoidal cross section. Concave curved profile surfaces 20 are also formed between the bottom surface 16 and the walls 18 of the additional recess 62 and between adjacent walls 18. Figure 7 Other designs of the semiconductor modules 4 in correspondence Figure 3 Design in.

[0055] Figure 8A schematic three-dimensional cross-sectional view of a fourth embodiment of a semiconductor module 4 is shown. The bottom surface 16 of the cavity 14 has an additional recess 62 of different depths, which is arranged in the vertical projection plane of the semiconductor element 30. By filling the additional recess 62 of different depths with a second metal material by means of a thermal spraying method, a heat diffusion layer 22 with different thicknesses d1, d2, d3 is formed, wherein the second thickness d2 is greater than the first thickness d1, and the third thickness d3 is greater than the second thickness d2. By varying the thickness d2, d3 of the heat diffusion layer 22 by means of the additional recess 62 arranged below the semiconductor element 30 and filled with the second metal material, the thermal connection can be adapted to the dissipated heat of the semiconductor element 30 occurring during operation. For example, for an IGBT, the heat diffusion layer 22 has a greater thickness d2, d3 than for a diode, due to the greater waste heat to be dissipated. Figure 8 Other designs of the semiconductor modules 4 in correspondence Figure 7 Design in.

[0056] Fig. 9 A schematic diagram of a power converter 64 comprising a semiconductor module 4 is shown. The power converter 64 can comprise more than one semiconductor module 4.

[0057] In summary, the present invention relates to a method for manufacturing a semiconductor module 4 having at least one semiconductor component 28 and a heat sink 2, the method comprising the following steps: providing a heat sink 2 made of a first metal material; introducing 54 a cavity 14 into a heat sink surface 12, wherein the cavity 14 has a bottom surface 16 and at least one wall portion 18 extending in particular parallel to the heat sink surface 12; coating 56 a second metal material having a higher thermal conductivity than the first metal material in the cavity 14 by means of a thermal spraying method to form a heat diffusion layer 22; and connecting 60 the semiconductor component 28 to the heat diffusion layer 22. In order to improve the thermal contact of the second metal material in the cavity 14, it is proposed that when the cavity 14 is introduced 54, an obtuse angle α is formed between the bottom surface 16 and the at least one wall portion 18.

Claims

1. A method for producing a semiconductor module (4) having at least one semiconductor component (28) and a heat sink (2), the method comprising the following steps: - providing a heat sink (2) made of a first metal material; - introducing (54) a cavity (14) into the heat sink surface (12); The cavity (14) has a bottom surface (16) and at least one wall portion (18), which extends in particular parallel to the heat sink surface (12). - coating (56) a second metal material having a higher thermal conductivity than the first metal material in the cavity (14) by means of a thermal spraying method to form a heat diffusion layer (22); - connecting (60) the semiconductor component (28) and the heat diffusion layer (22), wherein, when the cavity (14) is introduced (54), an obtuse angle (α) is formed between the bottom surface (16) and at least one of the wall portions (18), It is characterized in that At least one additional depression (62) is introduced into the bottom surface (16) of the cavity (14), The recessed portion is smaller than the bottom surface (16) of the cavity (14), The second metal material is coated (56) in the cavity (14) and at least one additional recess (62) by means of the thermal spraying method, thereby forming a heat diffusion layer (22) with different thicknesses (d1, d2, d3).

2. The method according to claim 1, in, The second metallic material is applied (56) at a spraying angle (β) of the thermal spraying method in the range of 60° to 90°, in particular in the range of 70° to 90°.

3. The method according to any one of claims 1 or 2, in, After coating (56) the second metal material, face milling (58) of the heat sink surface (12) is performed.

4. The method according to any one of the preceding claims, in, When the cavity (14) is introduced (54), a concavely curved profile surface (20) is formed between the bottom surface (16) and at least one of the wall portions (18) and / or between at least two of the wall portions (18).

5. The method according to any one of the preceding claims, in, The semiconductor component (28) comprises at least one semiconductor element (30) and a substrate (32). The substrate (32) of the semiconductor component (28) is connected flush with the heat diffusion layer (22).

6. The method according to claim 5, in, The substrate (32) of the semiconductor component (28) is directly connected to the heat diffusion layer (22) in a material-bonded manner.

7. The method according to any one of claims 5 or 6, in, The surface of the heat diffusion layer (22) substantially corresponds to the surface of the substrate (32), The substrate (32) of the semiconductor component (28) is connected to the heat diffusion layer (22) over the entire surface.

8. The method according to any one of claims 5 to 7, in, At least one additional recess (62) is arranged in a vertical projection plane of at least one semiconductor element (30).

9. A semiconductor module (4) comprising at least one semiconductor component (28) and a heat sink (2), The heat sink is made of a first metallic material and comprises at least one cavity (14) having a bottom surface (16) extending in particular parallel to the heat sink surface (12) and at least one wall portion (18), in, A second metal material having a higher thermal conductivity than the first metal material is coated in the cavity (14) by means of a thermal spraying method to form a heat diffusion layer (22); The semiconductor component (28) is connected to the heat diffusion layer (22). Wherein, an obtuse angle (α) is formed between the bottom surface (16) and at least one of the wall portions (18), It is characterized in that The bottom surface (16) of the cavity (14) has at least one additional recess (62), The recessed portion is smaller than the bottom surface (16) of the cavity (14), wherein the second metal material is introduced into the cavity (14) and at least one additional recess (62) by means of the thermal spraying method, Thus, a heat diffusion layer (22) having different thicknesses (d1, d2, d3) is formed.

10. The semiconductor module (4) according to claim 9, in, The obtuse angle (α) between the bottom surface (16) and at least one of the wall portions (18) is in the range of 95° to 150°, in particular in the range of 110° to 150°, and further in particular in the range of 130° to 150°.

11. The semiconductor module (4) according to claim 9 or 10, in, The second metal material (42) is connected to the first metal material in a material-matched manner and is substantially flush with the heat sink surface (12).

12. The semiconductor module (4) according to any one of claims 9 to 11, in, A concave curved profiled surface (20) is formed between the bottom surface (16) and at least one of the wall portions (18) and / or between at least two of the wall portions (18).

13. The semiconductor module (4) according to any one of claims 9 to 12, in, The semiconductor component (28) comprises at least one semiconductor element (30) and a substrate (32). The substrate (32) of the semiconductor component (28) is connected flush with the heat diffusion layer (22).

14. The semiconductor module (4) according to claim 13, in, The substrate (32) of the semiconductor component (28) is directly connected to the heat diffusion layer (22) in a material-bonded manner.

15. The semiconductor module (4) according to claim 13 or 14, in, The substrate (32) of the semiconductor component (28) is connected to the heat diffusion layer (22) over the entire surface, and The heat diffusion layer (22) is substantially flush with the substrate (32).

16. The semiconductor module (4) according to any one of claims 13 to 15, in, At least one additional recess (62) is arranged in a vertical projection plane of at least one semiconductor element (30).

17. A power converter (64) comprising at least one semiconductor module (4) according to any one of claims 9 to 16.

18. A computer program product comprising instructions which, when executed by a computer, cause the computer to simulate the behavior, in particular the thermal behavior and / or the electrical behavior, of a semiconductor module (4) according to any one of claims 9 to 16.

Images