Power semiconductor module with an electrically conductive metal foil

Abstract

Power semiconductor module (1) with a substrate (2), a conductor track (22, 24) arranged thereon, a power semiconductor device (5) arranged thereon with a first contact surface (54) on its first main surface (50) facing away from the conductor track (22, 24), and with a power electronic connection device (3) with an electrically conductive film (34), wherein the power semiconductor device (5) has a first and a second edge (51, 52) adjacent to the first main surface (50), which are connected to each other via a corner (53) arranged between them, wherein the conductive film (34) covers both the corner (53) and adjacent sections of the edges (51, 52) and is electrically connected to a section of the first contact surface (54), wherein the corner section of the conductive film (34) is structured.

Description

[0001] The invention describes a design of at least one conductive film for power semiconductor modules with a substrate and conductor tracks arranged thereon and power semiconductor components arranged thereon.

[0002] DE 10 2020 121 033 A1 discloses a manufacturing method and a power electronic connection device for a power semiconductor module, wherein the connection device is designed as a flexible foil stack of a first and a second electrically conductive foil and an electrically insulating foil arranged between them, wherein at least one of the electrically conductive foils is structured in itself and thus forms a plurality of foil conductor tracks, wherein a first of these foil conductor tracks has a first mean thickness in a first section and has a second mean thickness in a second section, which is at least 10%, preferably at least 20%, less than the first mean thickness.

[0003] In light of the aforementioned prior art, the invention is based on the objective of further developing a power semiconductor module with a substrate in order to meet the different requirements for delicate and precise film structures in order to influence and / or reduce stresses of the film as well as deformations after sintering and to adapt conductor cross-sections and current densities.

[0004] This problem is solved according to the invention by a power semiconductor module with a substrate, a conductor track arranged thereon, a power semiconductor device arranged thereon with a first contact surface on its first main surface facing away from the conductor track and with a power electronic connection device with an electrically conductive film, wherein the power semiconductor device has a first and a second edge adjacent to the first main surface, which are connected to each other via a corner arranged between them, wherein the conductive film covers both the corner and adjacent sections of the edges and is electrically connected to a section of the first contact surface, wherein the corner section of the conductive film is structured.

[0005] It can also be particularly advantageous if the conductive film is intended to carry load currents of a power electronic switching device that is part of the power semiconductor module.

[0006] It can be advantageous if the conductive film as well as the non-conductive film in their unstructured areas have a thickness between 80µm and 250µm, preferably between 100µm and 150µm.

[0007] It may also be preferable if the conductive film has an arc-shaped section in its course over or after at least one of the edges.

[0008] It can be advantageous if the surface of the corner section facing the power semiconductor component is structured.

[0009] Furthermore, it can be advantageous if the surface of the corner section facing away from the power semiconductor component is structured.

[0010] In general, it can be advantageous if the structure is selected from at least one of the following variants: a) Planes Thinning of the surface b) Relief-like thinning of the surface c) Continuous recess between the surfaces.

[0011] It may also be preferred if the structuring has a direction from the center of the power semiconductor device to the corner.

[0012] It can generally be advantageous if the conductive film is part of a connecting device between a first and a second electrically conductive film and an electrically insulating film arranged in between, and if one or both of the electrically conductive films are formed.

[0013] It may still be preferable to achieve surface thinning or continuous recesses between surfaces using laser processing, embossing, or etching. Depending on the desired thinning or recess depth, as well as the material used, it may be necessary to repeat the laser and / or etching process several times until the desired structure is achieved.

[0014] It may also be preferable if an emitter or gate contact surface adjoins the corner.

[0015] The term "mean thickness" has the following meaning. A mean thickness is always determined orthogonally to the direction of current flow. In other words, a current flows through a surface element perpendicular to the direction of current flow, the mean height of which corresponds to the mean thickness of the section. This mean height also corresponds to the height of a virtual surface element of the same area. Advantageously, the first mean thickness has a value between 80 µm and 250 µm, preferably between 100 µm and 150 µm.

[0016] The term "connecting device" has the following meaning. A connecting device can be a stack of one or more conductive or insulating films, used to connect one or more conductive or non-conductive components and contact surfaces.

[0017] Of course, unless explicitly excluded, the features mentioned in the singular, in particular the first foil conductor track, can also be present multiple times in the connection device according to the invention. Within the power semiconductor module, the power semiconductor component, in particular, can be present multiple times and also in different configurations.

[0018] It is understood that the various embodiments of the invention can be implemented individually or in any combination to achieve improvements. In particular, the features mentioned and explained above and below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention.

[0019] Further explanations of the invention, advantageous details and features, will become apparent from the following description of the invention contained in the Fig. 1 to 6 schematically illustrated embodiments of the invention, or of respective parts thereof. Fig. Figure 1 shows an arrangement with a power electronic switching device and a power electronic connecting device according to the state of the art in a side sectional view. Fig. Figure 2 shows a first embodiment of a power semiconductor module according to the invention in a side sectional view. Fig. Figure 3 shows a partial area of ​​a substrate 2 with power semiconductor components of a first embodiment of a power semiconductor module according to the invention without a foil layer. Fig. Figure 4 shows a top view of a power semiconductor component of an embodiment of a power semiconductor module according to the invention, which is partially covered by a foil layer. Fig. Figure 5 shows a top view of a power semiconductor component of a further embodiment of a power semiconductor module according to the invention, which is partially covered by a foil layer. Fig. Figure 6 shows a top view of a power semiconductor component of another possible embodiment of a power semiconductor module according to the invention, which is partially covered by a foil layer.

[0020] Fig. Figure 1 shows a schematic exploded view and a side view of a power electronic switching device 1 as part of a power semiconductor module according to the prior art for mounting on a cooling device, here designed as a liquid cooling device 14. A substrate 2, generally of a conventional design, is shown, comprising an insulating body 20 and electrically insulated conductor tracks 22, 24 arranged on it. These conductor tracks carry different potentials, in particular load potentials, but also auxiliary potentials, especially control and measurement potentials, of the switching device. Specifically, three conductor tracks 22, 24 for load potentials are shown, as are typical for a switching device in a half-bridge topology.

[0021] A power semiconductor device 5 is arranged on a first conductor track 22. This device can be configured, as is customary in the industry, as a single switch, for example as a MOSFET, or as an IGBT with an antiparallel connected power diode, which is shown here. The power semiconductor devices 5, more precisely their first contact surface of the first metallization, are, as is customary in the industry, preferably by means of a pressure-sintered connection 4, electrically conductively connected to the first conductor tracks 22.

[0022] The internal connections of the switching device 1 are formed by means of a connecting device 3 from a film composite consisting of a flexible film stack with alternating electrically conductive films 30, 34 and electrically insulating films 32. Here, the film composite has exactly two conductive films and one insulating film arranged between them. In particular, the conductive films 30, 34 of the connecting device 3 are structured and thus form electrically insulated film conductor tracks. These film conductor tracks connect, in particular, the respective power semiconductor device 5, more precisely its second contact surface on the side facing away from the substrate 2, to a second conductor track 24 of the substrate 2. Here, contact sections of the film conductor tracks are metallurgically bonded to the contact surfaces of the substrate 2 by means of a pressure sintering connection 4.

[0023] Fig. Figure 2 shows a first embodiment of a power semiconductor module according to the invention in a side sectional view. A first and a second conductor track 22, 24 of the substrate 2 of the power semiconductor module are shown, wherein a power semiconductor device 5 is arranged on the first conductor track 22 and electrically connected.

[0024] A connecting device 3 has a first electrically conductive film 30 facing the substrate 2, which is connected to both the power semiconductor device 5 and the first main surface 50 as well as to the second conductor track 24 in the manner described above. In the normal direction N of the substrate 2, the first electrically conductive film 30 is followed by an electrically insulating film and then a second electrically conductive film 32, 34. This second electrically conductive film 34 is structured in a second section 344. This structuring (6) can be implemented by thinning the conductive film 34 or by continuous recesses between the surfaces, while the conductive film in the first sections 342 has no structuring 6.

[0025] It is also shown how the first electrically conductive film 30 has a structuring 6 by thinning the conductive film 30 or by continuous recesses between the surfaces in the first and / or second sections (342,344).

[0026] The task of representing different requirements for delicate and precise foil structures in order to influence and / or reduce foil stresses and deformations after sintering, and to adapt conductor cross-sections and current densities, is solved according to the invention by the structuring 6.

[0027] The connecting element 3 has an arc-shaped section 360 in its path from the power semiconductor component 5 to the second conductor track 24. Viewed in the current flow direction, a second section 344 of the first conductive film 34 is arranged entirely within this arc-shaped section 360. First sections 342 adjoin this on both sides. The second section 344 has a second mean thickness that is 20% less than the mean thickness of the first sections 342.

[0028] Fig. Figure 3 shows a substrate 2 with power semiconductor components 5 in a top view of a first embodiment of a power semiconductor module according to the invention without the conductive film 34 above it.

[0029] Fig. Figure 4 shows a detailed view of a power semiconductor device 5. Fig. 4 in a top view. The conductive film 34 covers the power semiconductor device 5 at least partially and projects beyond it. The structure 6 is formed in the area of ​​corner 53 of the power semiconductor device 5 and makes this underlying layer visible. Corner 53 connects the first and a second edge 51, 52.

[0030] It is shown that the conductive foil 34 can cover both the area of ​​corner 53 and adjacent sections of edges 51,52 at least partially, although corner 53 is not necessarily covered.

[0031] Fig. Figure 5 shows a top view of a power semiconductor component 5 of another possible embodiment of a power semiconductor module according to the invention. The structuring 6 of the conductive film 34 has a direction from the center of the power semiconductor component 5 to the corner 53.

[0032] Fig.Figure 6 shows a top view of another possible embodiment of the power semiconductor module 1 according to the invention. A plurality of structures 6 are introduced into the conductive film 34 along a second edge 52 of the power semiconductor device 5. Reference symbol N Normal direction 1 power semiconductor module 2 Substrat 22 first conductor track 24 second conductor track 3 Connection device 30 conductive foil 32 electrically insulating foil 34 conductive foil 342 first sections 344 second sections 360 arc-shaped section 5 Power semiconductor device 50 first main area 51 First Edge 52 Second Edge 53 Corner 54 first contact surface 6. Structuring QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 121 033 A1

[0002]

Claims

[1] Power semiconductor module (1) with a substrate (2), a conductor track (22, 24) arranged thereon, a power semiconductor component (5) arranged thereon with a first contact surface (54) on its first main surface (50) facing away from the conductor track (22, 24), and with a power electronic connection device (3) with an electrically conductive film (34), wherein the power semiconductor component (5) has a first and a second edge (51, 52) adjacent to the first main surface (50), which are connected to one another via a corner (53) arranged therebetween, wherein the conductive film (34) covers both the corner (53) and sections of the edges (51, 52) adjacent thereto and is electrically conductively connected to a section of the first contact surface (54), wherein the corner section of the conductive film (34) is structured. [2] Power semiconductor module (1) according to claim 1, wherein the conductive foil (34) is intended to carry load currents of a power electronic switching device which is part of the power semiconductor module. [3] Power semiconductor module (1) according to one of the preceding claims, wherein the conductive film (30, 34) and the non-conductive film (32) in their non-structured regions have a thickness between 80µm and 250µm, preferably between 100µm and 150µm. [4] Power semiconductor module (1) according to one of the preceding claims, wherein the conductive foil (34) has an arcuate section (360) in its course over or after at least one of the edges (51, 52). [5] Power semiconductor module (1) according to one of the preceding claims, wherein the surface of the corner section facing the power semiconductor component (5) is structured. [6] Power semiconductor module (1) according to one of the preceding claims, wherein the surface of the corner section facing away from the power semiconductor component (5) is structured. [7] Power semiconductor module (1) according to one of the preceding claims, wherein the structuring (6) is selected from at least one of the following variants: a) Planar thinning of the surface b) Relief-like thinning of the surface c) Continuous recess between the surfaces. [8] Power semiconductor module (1) according to one of the preceding claims, wherein the structuring (6) has a direction of extension from the center of the power semiconductor component (5) to the corner (53). [9] Power semiconductor module (1) according to one of the preceding claims, wherein the conductive foil (34) is part of a connecting device (3) of a first and a second electrically conductive foil (30, 34) and an electrically insulating foil (32) arranged therebetween and in this case forms one of the electrically conductive foils or both electrically conductive foils (30, 34). [10] Power semiconductor module (1) according to one of the preceding claims, wherein the thinning of the surface or the continuous recesses between the surfaces are realized by means of laser processing, embossing, or etching processes. Depending on the desired thinning or recess depth, as well as the material used, it may be necessary to perform the laser and / or etching process several times until the desired structuring (6) is achieved. [11] Power semiconductor module (1) according to one of the preceding claims, wherein an emitter or gate contact surface adjoins the corner (53).

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