Electronic power unit and semiconductor power module

Abstract

A semiconductor power module having an electronic power unit with a substrate having a vertical direction and a flat insulating molded body having a metal layer on a first major surface and a plurality of conductor tracks on a second major surface thereof, and the electronic power unit having a first fastening device or a second fastening device, the substrate being arranged on the substrate of the electronic power unit in a force-fitting or material-bonding manner, the first fastening device being implemented and arranged to arrange the substrate on a cooling device in a force-fitting manner, or a housing section having a second fastening device which is implemented and arranged to arrange the substrate on a cooling device in a force-fitting manner, the edge of the metal layer being offset rearward relative to the edge of the insulating molded body, and in a region adjacent to the first fastening device or the second fastening device, a first edge section of the edge of the metal layer is further offset rearward compared to a second edge section and a third edge section of the edge of the respectively adjacent metal layer.

Description

Technical Field

[0001] The present invention describes an electronic power unit having a substrate with a flat insulating molded body that has a metal layer on its first major surface and a plurality of conductor tracks on its second major surface, and the electronic power unit having a first fastening means or a second fastening means, which is preferably embodied as a cylindrical recess, wherein the substrate is arranged on the substrate of the electronic power unit, and the first fastening means is configured to arrange the substrate in a force-fitting manner on a cooling device, or wherein a housing section has a second fastening means that is embodied to arrange the substrate on a cooling device. The present invention also describes a semiconductor power module having an electronic power unit of this type. Background Art

[0002] In the case of semiconductor power modules, it is fundamentally necessary to configure such semiconductor power modules in a robust manner, and in particular, it is always a challenge not to apply forces to the electronic power unit of such semiconductor power modules that may cause mechanical damage when attaching the semiconductor power module to a cooling device.

[0003] DE 100 63 714A1 discloses a semiconductor power module that includes a ceramic substrate metal-clad on both sides, the ceramic substrate having at least one semiconductor component, connection portions required for generating contacts, and a housing, wherein the ceramic substrate provides an insulating function in addition to basic insulation. The ceramic substrate has a metal cladding that only partially covers the first or second surface of the ceramic, wherein the distance from the metal edge of the first metal cladding to the ceramic edge is less than the distance from the metal edge of the second metal cladding to the ceramic edge, and this serves to increase the insulation strength of the basic insulation of the substrate. Summary of the Invention

[0004] The object of the present invention is to provide an electronic power unit and a semiconductor power module in such a way that, by fastening the electronic power unit to a cooling device, the influence of forces on the electronic power unit is reduced.

[0005] According to the present invention, this object is achieved by an electronic power unit having a substrate which has a vertical direction and a flat insulating molded body, the flat insulating molded body having a metal layer on its first major surface and a plurality of conductor tracks on its second major surface, and the electronic power unit having a first fastening means or a second fastening means, which is preferably embodied as a cylindrical recess, wherein the substrate is arranged on the substrate of the electronic power unit in a force-fitting or material-bonding manner, and the first fastening means is embodied and arranged to arrange the substrate on the cooling device in a force-fitting manner, or alternatively, the housing section has a second fastening means which is embodied and arranged to arrange the substrate on the cooling device in a force-fitting manner, and wherein the edge of the metal layer is offset backward relative to the edge of the insulating molded body, and wherein in the region adjacent to the first fastening means or the second fastening means, a first edge section of the edge of the metal layer is offset further backward compared to a second edge section and a third edge section of the edge of the respectively adjacent metal layer.

[0006] It may be advantageous for the conductor tracks to be embodied by another metal layer which is itself structured and preferably embodied in the same way as the metal layer on the first major surface, or which differs from the metal layer on the first major surface only in having a different thickness.

[0007] It may be particularly advantageous for the first edge section to have a length which is at least five times, preferably at least ten times and preferably at most fifty times the thickness of the metal layer.

[0008] Preferably, in this case, the material-bonding connection is embodied as a welding or sintering connection. Then it is particularly advantageous for the first edge section to have a minimum vertical distance from the first fastening means, more precisely from the central median axis extending through the first fastening means, which is at least ten times, preferably at least twenty-five times and preferably at most three hundred times the thickness of the material-bonding connection.

[0009] Advantageously, the first edge section has a concave, straight or convex extension. In particular, advantageously, the first edge section in the case of a concave extension describes a circular segment which, when viewed in the vertical direction, has a midpoint of the circular segment within the coverage area, preferably in the centre of the coverage area of the first fastening device or the second fastening device, which is embodied as a cylindrical recess. Alternatively, it may be advantageous if the first edge section in the case of a concave extension describes a circular segment which, when viewed in the vertical direction, has a midpoint of the circular segment in the region between the first fastening device and the adjacent edge of the base. Similarly, alternatively, it may be advantageous if the first edge section in the case of a concave extension describes a circular segment which, when viewed in the vertical direction, has a midpoint of the circular segment in the region between the second fastening device and the adjacent edge of the housing section.

[0010] Furthermore, this object is achieved by a semiconductor power module which has the aforementioned electronic power unit, which has power semiconductor components arranged on one of the conductor tracks of the base, and which has internal connection means and connection elements for the electrical external connection of the base. Preferably, in this case, the connection elements are embodied as load connection elements and auxiliary connection elements and preferably project outwards through the housing.

[0011] It may be advantageous if the base is arranged on the base of the electronic power unit in a force-fitting or material-bonded manner and the first fastening device is embodied as a cylindrical recess. In this case, preferably, the housing has another cylindrical recess which is flush with the fastening device embodied as a cylindrical recess.

[0012] By means of this configuration, the mechanical load on the base is effectively reduced.

[0013] Obviously, in cases where this is not excluded or not explicitly excluded, it is naturally possible for there to be a plurality of features mentioned in the singular, in particular fastening devices or power semiconductor components, in the electronic power unit according to the invention or in the semiconductor power module according to the invention.

[0014] It goes without saying that the different embodiments of the invention, whether they are disclosed within the scope of the description of the electronic power unit or the semiconductor power module, can be implemented individually or in any combination in order to achieve improvements. In particular, without departing from the scope of the invention, the features mentioned and explained above and below can be used not only in the combinations described, but also in other combinations or individually. Description of the Drawings

[0015] A further explanation, advantageous details and features of the invention are given in the following ofFigures 1 to 10 is disclosed in the description of an exemplary embodiment of the invention or a corresponding part thereof schematically shown therein.

[0016] Figure 1 A side view showing a first basic embodiment of a semiconductor power module according to the invention.

[0017] Figure 2 A side view showing a second basic embodiment of a semiconductor power module according to the invention.

[0018] Figure 3 A plan view showing a first embodiment of an electronic power unit according to the invention.

[0019] Figure 4 A plan view showing a second embodiment of an electronic power unit according to the invention.

[0020] Figure 5 A view showing a third embodiment of an electronic power unit according to the invention.

[0021] Figures 6 to 10 A view showing a variant of an embodiment of a first edge section of an electronic power unit according to the invention. DETAILED DESCRIPTION

[0022] Figure 1 A side view showing a first basic embodiment of a semiconductor power module according to the invention. It has a substrate 10, the substrate 10 having an insulating molding 2 and on its second main surface 22 a first conductor track 40 and a second conductor track 42 are arranged. A power semiconductor component 44 is arranged on the second conductor track 42 of the substrate 10 and is conductively connected to the second conductor track 42 of the substrate 10 by its contact surface facing the second conductor track 42. Without loss of generality, this conductive connection is in this case implemented as a material-bonded pressure sintering connection.

[0023] The power semiconductor component 44 (more precisely, its contact surface remote from the substrate 10 in the vertical direction N) is connected to the first conductor track 40 by means of an internal connection device 12. The connection device 12 is implemented as a film composite, which includes a first conductive film 120 facing the substrate 10, an electrically insulating film 122 following in the film composite, and a second conductive film 124 following further in the film composite.

[0024] The electronic power unit 1 also has a connecting element 14, more precisely an auxiliary connecting element in this case, for guiding auxiliary potentials such as sensors or control signals. The connecting element 14 is implemented as an industrial standard press-fit contact element. The pins of the press-fit contact element are conductively arranged in a sleeve, where the sleeve is connected in a material-bonded manner to a contact section on the surface of the first conductive film 120 remote from the substrate 10. The press-fit contact element extends through a notch 62 in the housing 6 of the semiconductor power module, which is only shown in cross-section, through the housing.

[0025] The first conductive film 120 is connected to the first conductor track 40 of the substrate 10 by a material-bonded and conductive connection, implemented as an industrial standard pressure sintering connection in this case.

[0026] The substrate 10 also has a metal layer 3 arranged on the first main surface 20 of the insulating molded body 2. The conductor tracks 40, 42 on the second main surface 22 are formed by another metal layer by structuring the other metal layer. The insulating molded body 2 has a thickness of 300 μm in this case, while the metal layers each have a thickness of 350 μm. These are typical values for this type of substrate 10 and also apply to further exemplary embodiments.

[0027] The metal layer 3 is connected to the substrate 5 of the electronic power unit 1 and thus to the substrate 5 of the semiconductor power module by a material-bonded connection 8. The connection 8 has a thickness of approximately 150 μm and is implemented as a solder connection in this case. A sintering connection, especially a pressure sintering connection, is technically equally advantageous as an alternative thereto.

[0028] The substrate 5 has a first fastening device 50 in the edge region, or more precisely in the corner region in this case, which is constructed as a through-going cylindrical notch in this case. In addition, the middle axis 520 of the notch is shown in this figure. The purpose of providing the notch is thus that the semiconductor power module is generally fastened to the cooling device in a force-fitting manner.

[0029] Essentially and in industrial standards, the edge 300 of the metal layer 3 is offset backward relative to the edge 200 of the insulating molded body 2, with the result that the outer peripheral edge section of the first main surface 20 of the insulating molded body 2 is not covered by the metal layer 3. The edge of the metal layer 300 adjacent to the first fastening device 50 is further offset backward in the first edge section 301 compared to in the second edge section 302 and the third edge section 303 (see Figures 3 to 10 ) respectively adjacent to it. Thus, this results in additional sections of the first main surface 20 of the insulating molded body 2 that are not covered by the metal layer 3. In particular, Figure 9 additional features of these edge sections, especially regarding their dimensions, are described in the case of

[0030] Figure 2 A side view showing a second basic embodiment of a semiconductor power module according to the present invention. Compared with the first embodiment, this does not have a substrate. Instead, in this case, the substrate 10 is arranged to be directly disposed on the cooling device. Usually but not absolutely necessary, in the case of this type of embodiment, the substrate 10 is arranged on the cooling device in a force-fitting manner.

[0031] This figure only shows the substrate 10 without power semiconductor components and without internal connection means. The housing 6 is arranged around the periphery of the substrate 10 and also mainly covers the substrate in industrial standards. The housing has a second fastening means 60 in the edge region or in the corner region, and the second fastening means 60 is in turn configured as a through cylindrical notch. In addition, this figure shows the central axis 620 of the notch. The purpose of providing this notch is thus to fasten the semiconductor power module to the cooling device. In this case, the substrate 10 is implemented to be exactly the same as in the first embodiment according to Figure 1 the first embodiment.

[0032] Figure 3 A plan view showing a first embodiment of an electronic power unit 1 according to the present invention. This figure shows a cross-section through the metal layer 3 in a top view seen from the vertical direction N. The substrate 5 is arranged below the metal layer 3 and has first fastening means 50 with a diameter of 8 mm in the corner regions respectively, and the first fastening means 50 is implemented in other aspects as described in reference Figure 1 as described.

[0033] The metal layer 3 has an edge 300 that is offset backward relative to the edge 200 of the insulating molded body 2, and the edge 200 of the insulating molded body 2 is partially shown by a dashed line. Adjacent to all the first fastening means 50 are first edge segments 301 that are further offset backward relative to the edge 200 of the insulating molded body 2. Adjacent to this first segment 301 on the longitudinal side of the electronic power unit 1 is a second edge segment 302 designed in an industrial standard manner, and on the narrow side is a third edge segment 303 also designed in an industrial standard manner. Therefore, these do not offset backward to the same extent as the first segment 301.

[0034] Figure 4 A plan view showing a second embodiment of an electronic power unit 1 according to the present invention. This figure shows a top view of the substrate 10 seen from the vertical direction N, where the conductor tracks are not shown and only one shown power semiconductor component 44 is illustrated. The metal layer 3 is shown by a dashed line below the insulating molded body 2. Further, the substrate 5 is arranged below the molded body, and in this case, the substrate has first fastening means 50 centered on the narrow side respectively.

[0035] The metal layer 3 also has an edge 300 that is offset backward relative to the edge 200 of the insulating molded body 2. Adjacent to each of all the first fastening devices 50 are first edge segments 301, which are further offset backward relative to the edge 200 of the insulating molded body 2. In a further extension of the respective narrow sides of the electronic power unit 1, a second edge segment 302 and a third edge segment 303 designed in an industrial standard manner are adjacent to the first segment 301 centered on the narrow side. Thus, these are not offset backward to the same extent as the first segment 301 respectively.

[0036] Figure 5 Figure 4 shows a third embodiment of an electronic power unit according to the invention, which has a plurality (in this case three by way of example) of substrates 10. In this figure, each substrate 10 arranged directly adjacent to the first fastening device 50 has a first edge segment 301. This is respectively implemented as described with reference to Figure 3 described.

[0037] Figures 6 to 10 Figure 10 shows a detailed view of a variant of an embodiment of the electronic power unit 1 according to the invention, in particular of the region where the first segment 301 is arranged. Figures 6 to 9 Respectively shown in connection with Figure 3 or Figure 5 is the corner region of the equivalent substrate 5. This corner region has a first fastening device 50, which is implemented as a through cylindrical notch. Its virtual coverage surface 500 has a midpoint 52, and a central axis 520 passes through this coverage surface 500 and extends vertically in the Z direction, see Figure 1 . The insulating molded body 2 is shown by a dashed line with its edge 200, and the metal layer 3 on the first main surface 20 of the insulating molded body 2 (see Figure 1 ) is also shown here. The respective embodiments differ in terms of the embodiment of the first edge segment 301. The second edge 302 and the third edge 303 segments adjacent to it respectively are each constructed in the same manner as described with reference to Figure 3 and Figure 5 described.

[0038] According to Figure 6 the first end segment 301 of the embodiment is implemented as an inclined surface of a corner region having a straight extension. According to Figure 7 the first edge segment 301 of the embodiment is implemented as a convex extension. In this case, by way of example only, the transition to the second end segment 302 is implemented in a discontinuous manner, while the transition to the third edge segment 303 is implemented in a continuous manner. According to Figure 8The first edge section 301 of the embodiment is implemented as an example of a curved extension having concave and convex elements (and possibly even straight elements). In this case, by way of example only, the transition to the second end section 302 is implemented in a continuous manner, while the transition to the third edge section 303 is implemented in a discontinuous manner.

[0039] According to Figure 9 The first edge section 301 of the embodiment is implemented with a concave extension, and in this case is more specifically implemented as a circular section 321. In this case, the midpoint of the circle or circular arc section 321 with radius 311 lies on the central axis 520 extending centrally through the first fastening device 50. Alternatively, the midpoint of the circular arc section 321 lies in the projection onto the surface of the base 5 at any location within the covering surface 500 of the first fastening device 50 implemented as a cylindrical recess. Additionally, alternatively, the midpoint 52 of the circular section 321 in the projection onto the surface of the base 5 lies in the region 502 between the first fastening device 50 and the adjacent edge 504 of the base 5.

[0040] Figure 10 shown in Figure 4 the narrow side of the equivalent base 5. The first fastening device 50 is arranged in the middle of this narrow side, and the first fastening device 50 is in turn implemented as a through cylindrical recess. The insulating molded body 2 is shown with its edge 200 by a dashed line, and the metal layer 3 on the first main surface 20 of the insulating molded body 2 (see Figure 1 ) is also shown here. The second edge section 302 and the third edge section 303, each implemented in the same manner as described with reference to Figure 4 , respectively adjoin the first edge section 301. The first edge section 301 is in turn implemented with a concave extension, and in this case is again implemented as a circular section 321. This also applies to the midpoint of the circle or circular section 321 already mentioned with reference to Figure 9 .

Claims

1. An electronic power unit (1), the electronic power unit (1) having a substrate (10), the substrate (10) having a vertical direction (N) and having a flat insulating molded body (2), the flat insulating molded body (2) having a metal layer (3) on its first main surface (20) and having a plurality of conductor tracks (40, 42) on its second main surface (22), and the electronic power unit (1) having a first fastening device (50) or a second fastening device (60); wherein the substrate (10) is arranged on the substrate (5) of the electronic power unit in a force - fitting or material - bonded manner, and the first fastening device (50) is implemented and arranged to arrange the substrate (5) on a cooling device in a force - fitting manner, or alternatively, a housing section (600) has a second fastening device (60), the second fastening device (60) being implemented and arranged to arrange the substrate (10) on a cooling device in a force - fitting manner, and wherein, an edge (300) of the metal layer is offset backward relative to an edge (200) of the insulating molded body (2), and wherein, in a region adjacent to the first fastening device (50) or the second fastening device (60), a first edge section (301) of the edge of the metal layer (3) is further offset backward compared to a second edge section (302) and a third edge section (303) of the edge (300) of the respectively adjacent metal layer (3).

2. The electronic power unit according to claim 1, characterized in that: the first fastening device (50) or the second fastening device (60) is implemented as a cylindrical notch.

3. The electronic power unit according to claim 1, characterized in that: the conductor tracks (40, 42) are implemented by another metal layer (4) which is itself structured.

4. The electronic power unit according to any one of claims 1 to 3, characterized in that: the first edge section (301) has a length of at least five times the thickness of the metal layer (3).

5. The electronic power unit according to claim 4, characterized in that: the first edge section (301) has a length of at least ten times the thickness of the metal layer (3).

6. The electronic power unit according to any one of claims 1 to 3, characterized in that: the first edge section (301) has a length of at most fifty times the thickness of the metal layer (3).

7. The electronic power unit according to any one of claims 1 to 3, characterized in that: a material - bonded connection (8) is implemented as a welded or sintered connection.

8. The electronic power unit according to claim 7, characterized in that: the minimum distance of the first edge section (301) from the first fastening device (50) is at least ten times the thickness of the material - bonded connection (8).

9. The electronic power unit according to claim 8, characterized in that: The minimum distance of the first edge section (301) from the first fastening device (50) is at least twenty-five times the thickness of the material-bonded connection (8).

10. The electronic power unit according to claim 7, characterized in that: The minimum distance of the first edge section (301) from the first fastening device (50) is at most three hundred times the thickness of the material-bonded connection (8).

11. The electronic power unit according to any one of claims 1 to 3, characterized in that: The first edge section (301) has a concave, straight or convex extension.

12. The electronic power unit according to claim 11, characterized in that: In the case of a concave extension, the first edge section (301) describes a circular section (321) which, when viewed in the vertical direction (N), has the midpoint of the circular section within the covering surface (500).

13. The electronic power unit according to claim 12, characterized in that: The midpoint of the circular section is at the center of the covering surface (500) of the first fastening device (50) or the second fastening device (60) which is embodied as a cylindrical recess.

14. The electronic power unit according to claim 11, characterized in that: In the case of a concave extension, the first edge section (301) describes a circular section (321) which, when viewed in the vertical direction (N), has the midpoint (52) of the circular section located in the region (502) between the first fastening device (50) and the adjacent edge (504) of the substrate (5).

15. The electronic power unit according to claim 11, characterized in that: In the case of a concave extension, the first edge section (301) describes a circular section (321) which, when viewed in the vertical direction (N), has the midpoint of the circular section located in the region between the second fastening device (60) and the adjacent edge (602) of the housing section (600).

16. A semiconductor power module having an electronic power unit according to any one of claims 1 to 15, having a power semiconductor element (44) arranged on one of the conductor tracks (40, 42) of the substrate (10), having internal connection means (12), and having connection elements (14) for electrically externally connecting the substrate (10).

17. The semiconductor power module according to claim 16, characterized in that: The connection element (14) is embodied as a load connection element and an auxiliary connection element.

18. The semiconductor power module according to claim 16 or 17, characterized in that: The connection element (14) projects outwards through the housing (6).

19. The semiconductor power module according to claim 16 or 17, characterized in that: The base (10) is arranged on the base (5) of the electronic power unit in a force-fitting or material-bonding manner, and the first fastening device (50) is embodied as a cylindrical recess.

20. The semiconductor power module according to claim 19, characterized in that: the housing has another cylindrical recess flush with the fastening device (50) embodied as a cylindrical recess.

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