POWER ELECTRONIC SWITCHING DEVICE, ARRANGEMENT HEREWITH AND METHODS FOR PRODUCING THE SWITCHING DEVICE

Abstract

A switching device has a substrate and a power semiconductor component, comprising a connection device and a pressure device wherein the substrate has tracks electrically insulated from one another. The power semiconductor component is on one of the tracks with a first main surface and is conductively connected thereto. The device is embodied as a film composite having a conductive film and an insulating film that forms a first and a second main surface. The switching device is connected internally in a circuit-conforming manner by the connection device and a contact area of the connection device is connected to a first contact area of one of the tracks in a force-locking and electrically conductive manner. There is a pressure body projecting to the substrate and pressing onto a first section of the second main surface of the film composite.

Claims

1. A power electronic switching device (1), comprising: a substrate (2) having at least one power semiconductor component (7) arranged thereon; a connection device (3) for said power semiconductor component (7); a pressure device (5) providing an urging pressure to said connection device 3; the substrate (2) having a plurality of conductor tracks (22) electrically insulated from one another; said power semiconductor component (7) having a first semiconductor main surface (70) arranged on one of the conductor tracks (22) and being electrically conductively connected thereto; the connection device (3) being a film composite, said film composite further comprising: at least one electrically conductive film (30, 34) and an electrically insulating film (32); said film composite forming at least a first film main surface (300) and a second film main surface (340); the switching device (1) is connected in a circuit-conforming manner by means of the connection device (3) and a first connection contact area (308, 342) of the connection device (3) is connected to a first conductor contact area (222) of one of the plurality of conductor tracks (22) in a force-locking and electrically conductive manner; said pressure device (5) has a pressure body (50) and at least one pressure element (52) projecting therefrom in the direction of the power semiconductor component (7); wherein the pressure element (52) presses onto a first film section (346) of the second main film surface (340) of the film composite (3); and the pressure element (52), said first film section (346) and the first conductor contact area (222) of the conductor track (22) are arranged in alignment with one another in a direction that is normal (N) to the substrate 2.

2. The switching device, according to claim 1, further comprising: a second connection contact area (304) of the connection device (3) connected to a first semiconductor contact area (720) of a second semiconductor main surface (72) of the power semiconductor component (7) in at least one of a force-locking manner and a cohesive and electrically conductive manner.

3. The switching device, according to claim 2, wherein: the power semiconductor component (7) is electrically conductively connected by a second semiconductor component contact area (700) of said first semiconductor main surface (70) to an assigned conductor track (22) in one of a force-locking manner and a positively locking and electrically conductive manner.

4. The switching device, according to claim 1, wherein: the pressure body (50) has at least one first cutout (500); and said at least one pressure element (52) projecting from said at least first cut out (500).

5. The switching device, according to claim 4, wherein: the at least one first cutout (500) of the pressure body (50) is embodied as a depression proceeding from a first pressure element main surface (502); the pressure element (52) filling the cutout (500) of the pressure body (50); and the pressure element (52) projecting outwardly from the cutout (500) of the pressure body beyond the first pressure element main surface (502) thereof.

6. The switching device, according to claim 1, wherein: the pressure body (50) consists of a high-temperature-resistant thermoplastic; said high-temperature-resistant thermoplastic being one selected from the group consisting of: polyphenylene sulphide; and the pressure element (52) consists of an elastomer selected from a group consisting of: a silicone elastomer and a crosslinked liquid silicone elastomer.

7. The switching device, according to claim 1, wherein: a cohesive connection of said connection device (3) is embodied as at least one of a soldering connection, an adhesive connection, and a pressure sintering connection.

8. A switching device arrangement, comprising: A power electronic switching device (1) according to claim 1, further comprising: a cooling device (4); a pressure introducing device (6); and wherein the pressure introducing device (6) is supported at least one of directly and indirectly against the cooling device (4) and said pressure introducing device introduces a pressure proximately centrally on the pressure device (5) thereby connecting said cooling device (4) and said switching device (1) in a force-locking manner.

9. The arrangement, according to claim 8, wherein: a heat-conducting layer (40) is arranged between the substrate (2) and the cooling device (4); and said heat-conducting layer has thickness of less than 20 m.

10. The arrangement, according to claim 8, wherein: the cooling device (4) is at least one of a baseplate of a power semiconductor module and a heat sink.

11. A method for producing a configuration of a power electronic switching device (1), comprising the steps of: A. providing a substrate (2), further comprising: an insulation layer (20) and conductor tracks (22) electrically insulated from one another; wherein, on one of the conductor tracks (22), a power semiconductor component (7) is arranged and is connected to the conductor track (22) in a cohesive manner; B. providing a connection device (3), wherein: said connection device is embodied as a film stack embodied alternately with two electrically conductive, inherently structured films (30, 34) and an electrically insulating film (32) between the two conductive films (30, 34); C. arranging an adhesive substance (36) on one of the substrate (2) and the connection device (3) at at least one adhesive section which does not serve for an electrically conductive connection between said substrate (2) and said connection device (3); D. arranging and adhesively connecting the connection device (3) to the substrate (2) by means of the adhesive substance (36); and E. introducing an urging pressure on the connection device (3) by positioning a pressure device (5) and a pressure introducing device (6) so that a force-locking and electrically conductive connection is formed between the connection device (3) and the conductor track (22).

12. The method, according to claim 11, further comprising the steps of: forming a force-locking and electrically conductive connection between the connection device (3) and the power semiconductor component (7).

13. A method for producing a configuration of a power electronic switching device (1), comprising the steps of: a. providing a substrate (2), said substrate (2) further comprising: an insulation layer (20) and conductor tracks (22) electrically insulated from one another; b. providing a connection device (3) embodied as a film stack arranged alternately with two electrically conductive structured films (30, 34) spaced by an electrically insulating film (32) between the two conductive films (30, 34); c. arranging a power semiconductor component (7) on an assigned conductor track (22); d. arranging an adhesive substance (36) between respective said power semiconductor component (7) and said assigned conductor track (22) and adhesively fixing the power semiconductor component (7) on said conductor track (22); e. arranging and adhesively connecting the connection device (3) to the substrate (2) by with said adhesive substance (36); and f. introducing a pressure on the connection device (3) with a pressure device (5) and a pressure introducing device (6) and providing a force-locking electrically conductive connection between the connection device (3) and an assigned conductor track (22).

14. The method, according to claim 13, further comprising the steps of: forming a force-locking electrically conductive connection between both the connection device (3) and the power semiconductor component (7), and between the power semiconductor component (7) and the assigned conductor track (22).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 shows, in an exploded illustration, an arrangement according to the invention comprising a power electronic switching device according to the invention.

[0037] FIGS. 2 to 5 show different configurations of power electronic switching devices according to the invention.

[0038] FIGS. 6A, 6B, 6C, and 6D show a plan view of a power electronic switching device in different sectional planes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Reference will now be made in detail to embodiments of the invention. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. The word couple and similar terms do not necessarily denote direct and immediate connections, but also include connections through intermediate elements or devices. For purposes of convenience and clarity only, directional (up/down, etc.) or motional (forward/back, etc.) terms may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope in any manner. It will also be understood that other embodiments may be utilized without departing from the scope of the present invention, and that the detailed description is not to be taken in a limiting sense, and that elements may be differently positioned, or otherwise noted as in the appended claims without requirements of the written description being required thereto.

[0040] Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments of the present invention; however, the order of description should not be construed to imply that these operations are order dependent.

[0041] Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes certain technological solutions to solve the technical problems that are described expressly and inherently in this application. This disclosure describes embodiments, and the claims are intended to cover any modification or alternative or generalization of these embodiments which might be predictable to a person having ordinary skill in the art.

[0042] Those of skill would further appreciate that the various illustrative blocks, modules, circuits, described in connection with the embodiments disclosed herein may be implemented as electronic hardware on a specific purpose machine without departing from the scope and spirit of the present invention.

[0043] FIG. 1 shows, in a schematic exploded illustration, a first configuration of a power electronic switching device 1 according to the invention. The illustration shows a substrate 2 embodied in principle, and comprising an insulating substance body 20 and conductor tracks 22 arranged thereon and respectively electrically insulated from one another, conductor tracks 22 having different potentials, in particular load potentials, but also auxiliary, in particular switching and measurement, potentials, of the switching device 1. Three conductor tracks 22 having load potentials such as are typical of a half-bridge topology are specifically illustrated here.

[0044] A respective power semiconductor component 7 is arranged on two conductor tracks 22, which power semiconductor component 7 can be embodied in a routine manner, and as an example as an individual switch, for example as a MOS-FET, or as an IGBT with a power diode connected in antiparallel, which is illustrated here. The power semiconductor components 7, more precisely their first contact area (700, cf. FIG. 2) of the first main surface (70, cf. FIG. 2), are electrically conductively connected to conductor tracks 22 cohesively in a manner routine in the art, preferably by means of a pressure sintering connection 84.

[0045] The internal connections of switching device 1 are formed by means of a connection device 3 made from a film composite having alternately electrically conductive films 30, 34 and electrically insulating films 32. Here the film composite has exactly two conductive films and one insulating film arranged therebetween. In this case, the surface of said film composite 3 facing the substrate 2 forms the first main surface 300 of said film composite, while the opposite surface forms the second main surface 340 of said film composite. Particularly the conductive films 30, 34 of the connection device 3 are inherently structured and thus form conductor track sections electrically insulated from one another. The conductor track sections connect in particular the respective power semiconductor component 7, more precisely the contact areas thereof on the side facing away from the substrate 2, to conductor tracks 22 of the substrate.

[0046] For external electrical linking, the power electronic switching device 1 has load and auxiliary terminal elements, only a load terminal element being illustrated here. A load terminal element is embodied without restriction here as a contact spring 12. In principle, parts of the connection device 3 itself can also be embodied as load or auxiliary terminal elements. The auxiliary terminal elements (not illustrated), such as gate or sensor terminals, are preferably likewise embodied in a routine manner in the art.

[0047] The pressure device 5, has a first main surface 502 facing the substrate 2 and a second main surface facing away from the substrate 2 and is illustrated here at a distance (in the exploded view) from the connection device 3, for the sake of clarity. The pressure device 5 consists of a pressure body 50 and a plurality, three being illustrated, of pressure elements 52. The pressure body 50 is embodied particularly rigidly in order to be able to pass on pressure introduced by it homogeneously to the pressure elements 52. The pressure elements 52 are arranged in cutouts 500 of the pressure body 50, which are embodied as depressions proceeding from a first main surface 502. They completely fill said cutouts 500 and project from them at the first main surface 502 in the direction of the substrate 2.

[0048] For this purpose and against the background of the thermal loads during operation of the switching device, the pressure body 50 consists of a high-temperature-resistant thermoplastic, in particular of polyphenylene sulphide. The pressure elements 52 must be able to exert a substantially constant pressure during operation and in this case in particular at different temperatures. For this purpose, the pressure elements 52 consist of an elastomer, preferably of a silicone elastomer, particularly preferably of so-called crosslinked liquid silicone (LSRLiquid Silicone Rubber).

[0049] The arrangement furthermore has a heat sink 4, the surface of which is covered with a heat-conducting layer 40, on which the power electronic switching device 1, more precisely the substrate 2 thereof, is arranged. On account of the configuration of the arrangement according to the invention, the heat-conducting layer 40 can have a very small thickness, which here is between 5 m and 10 m. In principle, the heat-conducting layer 40 could be completely dispensed with. This is dependent on the surface constitution, in particular the roughness of the heat sink 4 and other operational factors.

[0050] Alternatively, the insulation layer 20 of the substrate 2 can be embodied as an electrically insulating film that is laminated directly onto the heat sink 4. In this case, too, the conductor tracks 22 can be embodied as planar conduction elements composed of copper. The latter then advantageously have a thickness of 0.5 mm to 1.0 mm.

[0051] The arrangement furthermore has a pressure introducing device 6, which is arranged above the connection device 3. By means of pressure introducing device 6, which is supported against the heat sink in a manner not illustrated, pressure 60 is introduced on the pressure body 50. Pressure 60 is transmitted in each case as partial pressure 62 by means of the pressure elements 52 directly to a first section 346 and a second section 344 of the second main surface 340 of the film composite 3, as will be understood by those skilled in the art. The second section 344 then indirectly presses, with formation of the force-locking connection, a contact area (304, cf. FIG. 2) of the first main surface 300 of the film composite 3 onto an assigned contact area (720, cf. FIG. 2) of the second main surface 72 of the power semiconductor component 7. Said second section 344 is arranged within the area 74 of the power semiconductor component 7 in projection along a direction N that is normal (perpendicular) to the substrate 2. The first section 346 indirectly presses, with formation of the force-locking connection, a contact area 308 of the first main surface 300 of the film composite 3 onto a contact area 222 of the assigned conductor track 22 of the substrate 2.

[0052] The introduced pressure 60 furthermore presses the entire substrate 2 onto the heat sink 4. The pressure contacts, of that electrically conductive between the connection device 3 and the power semiconductor component 7, and respectively the connection device 3 and the substrate 2, and also the thermally conductive between the substrate 2 and the heat sink 4, is effected in each case in the direction of the normal N to the substrate 2, or the substrate 2. Consequently, firstly, a highly efficient force-locking and electrically conductive connection between the connection device 3 and the power semiconductor component 7 and also between the connection device 3 and the assigned conductor track 22 is formed, this connection exhibiting extremely low contact resistance. Secondly, at the same time a likewise efficient, thermally conductive connection between the substrate 2 and the heat sink 4 is formed, which connection also forms its most effective heat transfer precisely at that location with the highest evolution (creation) of heat, that is to say the power semiconductor component 7. This is of great benefit to the present invention.

[0053] FIG. 2 shows a sectional view of a first configuration of a power electronic switching device 1 according to the invention, such as is basically already illustrated in FIG. 1.

[0054] The illustration here shows the substrate 2, comprising one insulating layer 20 and two conductor tracks 22. On the right-hand conductor track, a power semiconductor component 7, embodied as a power diode, is arranged and electrically conductively connected to the conductor track 22 by means of a cohesive connection, here a pressure sintering connection 84.

[0055] The connection device 3 has a first electrically conductive film 30, of which the contact area 304 is connected in a force-locking manner to the corresponding contact area 720 of the power semiconductor component 7.

[0056] This force-locking connection is formed by a partial pressure 62, cf. FIG. 1, being introduced directly on a second section 344 of the second main surface 340 of the connection device, here of the film composite 3. It is to be understood that partial pressure 62 occurs proximate pressure elements 52. The respective contact locations 304, 720 of the force-locking connection are preferably provided here with a gold surface, in particular a few micrometres thin gold layer, since these materials and forms have the best contact properties and contact resistances. Moreover, the respective contact locations 304, 720 of the force-locking connection have a roughness depth (Rz) of less than 5 m, in particular of less than 2 m, and a mean roughness (Ra) of less than 1 m, in particular of less than 0.5 m, in each case determined in accordance with EN ISO 4287.

[0057] The second contact area 720 (see FIG. 2) of the power semiconductor component 7 is electrically conductively connected to the left-hand conductor track 22. For this purpose, the first metal film 30 of the film composite 3 extends from the contact location 304 with the power semiconductor component 7 as far as a contact location 222 of the left-hand conductor track 22. The connection there between the contact location 222 of the conductor track 22 of the substrate and the contact location 308 of the first conductive film 30 of the film composite 3 is embodied in a force-locking manner. This connection is carried out by a partial pressure 62, cf. FIG. 1 etc., being introduced directly on a first section 344 of the second main surface 340 of the connection device, here of the film composite 3. The constitution of the respective contact locations 222, 308 is preferably implemented analogously to the contact locations described above in the context of said figure.

[0058] The connection device 3 further has an electrically insulating film 32 and a further electrically conductive film 34, which in interaction form the further circuit-conforming internal connection of the power electronic switching device 1.

[0059] Moreover, the power electronic switching device 1 comprises a preferably gel-like insulating substance 38, which is arranged in the interspace between substrate 2, connection device 3 and power semiconductor component 7. Said insulating substance serves for internal electrical insulation, in particular that between the first conductive film 30 of the connection device 3 and the right-hand conductor track 22 of the substrate 2.

[0060] FIG. 3 shows a sectional view of a second configuration of a power electronic switching device 1 according to the invention. The electrically conductive connection between the power semiconductor component 7 and the connection device 3 is formed here once again by means of the force-locking connection described above. The cohesive connection of the power semiconductor component 7 to the right-hand conductor track 22 of the substrate 2 assigned thereto is likewise formed in the manner as described above. The force locking connection of the connection device 3 to the left-hand conductor track 22 of the substrate assigned thereto is likewise formed in the manner as described above.

[0061] In contrast to the first configuration in accordance with FIG. 2, here the connection device 3 has, in the contact regions with respect to the power semiconductor component 7 and also with respect to the left-hand conductor track, only sections of the first electrically conductive film 30 which are not directly connected to one another. Rather, plated-through holes 320 from the first conductive film 30 to the second conductive film 34 through the insulating film 32 are arranged in said sections. Consequently, the electrical connection between the left-hand conductor track 22 and the power semiconductor component 7 is effected via the second electrically conductive film 34. Moreover, a terminal element 12, embodied here by way of example as a spring contact element, is illustrated on the left-hand conductor track 22.

[0062] FIG. 4 shows a sectional view of a third configuration of a power electronic switching device 1 according to the invention, said third configuration being produced in accordance with the first method according to the invention. The substrate 2 with the power semiconductor component 7 is embodied here in the manner as already described in the case of FIG. 3.

[0063] An electrically insulating adhesive substance 36, preferably an adhesive based on silicone rubber, is arranged on the substrate 2 between the two conductor tracks 22 and in a manner overlapping the latter in edge regions. Without application of pressure by means of the pressure device 5, said adhesive substance 36 provides for an adhesive, that is to say at least adherent, connection between the substrate 2 in the section 228 thereof and the connection device 3 in the section 348 thereof. What is essential here is that the adherent connection does not contribute to the electrical conduction and is thus also only arranged in sections 228, 348 in which no electrically conductive contact is formed between the connection device 3 and the substrate 2, more precisely a conductor track 22 or the power semiconductor component 7.

[0064] The electrically conductive connection between the power semiconductor component 7 and the left-hand conductor track 22 by means of the connection device 3 is formed here by the second electrically conductive film 34 rather than by the first electrically conductive film. In this case, in contrast to the configuration in accordance with FIG. 3, no section of the first conductive film 30 and thus also no plated-through hole is necessary in the region of the left-hand conductor track 22. In the region of the power semiconductor component 7, the configuration of the connection device 3 is as described with regard to FIG. 3.

[0065] The electrically conductive connection between the connection device 3 and the power semiconductor component 7 and between the connection device 3 and the assigned left-hand conductor track 22 of the substrate 2, is embodied in each case as a force-locking connection. For this purpose, a respective partial pressure 62 (cf. also FIG. 1) is introduced on the respective connection by means of a respective assigned pressure element 52 of the pressure device 5. In this case, therefore, a partial pressure 62 is exerted on a first section 346 of the second main surface 340 of the connection device, as a result of which a contact area 342 of the second electrically conductive film 34 is pressed onto a contact area 222 of the left-hand conductor track 22 and is electrically conductively connected thereto in a force-locking manner.

[0066] A major advantage of this third configuration of the power electronic switching device 1 is that a cohesive and electrically conductive connection needs to be formed here exclusively at the substrate level, that is to say between the power semiconductor component 7 and the assigned right-hand conductor track 22. Such connections are routine in the art and are relatively simple to produce even in the case of pressure sintering connections. The connection device 3 is then only connected in an adherent manner, which is likewise simple to implement and enables a sufficient fixing of the connection partners, that is to say of the substrate 2 and the connection device 3. It is only during the operation of the power electronic switching device that the described application of pressure takes place, which here forms the force-locking electrically conductive contact between the connection device 3 and the power semiconductor component 7 and also between the connection device 3 and the conductor track 22 of the substrate 2.

[0067] FIG. 5 shows a sectional view of a fourth configuration of a power electronic switching device 1 according to the invention, said configuration being produced in accordance with the second method according to the invention. In contrast to FIG. 4, here the connection between the power semiconductor component 7 and the assigned conductor track 22 of the substrate 2 is also formed in a force-locking manner. For this purpose, the power semiconductor component 7 is also fixed to the assigned conductor track 22 by means of the adhesive substance 36.

[0068] FIGS. 6A-6D shows a plan view of a power electronic switching device 1 in different sectional planes. The sectional plane in accordance with FIG. 6A shows two power semiconductor components 7, which are arranged typically, but in a manner not illustrated, on a common conductor track of a substrate. Without restricting the generality, this involves a transistor having a central gate terminal area and emitter terminal areas bordering the latter, and a diode having a cathode terminal area.

[0069] FIG. 6B shows the first, inherently structured, electrically conductive film 30 of the connection device 3. This forms an electrically conductive connection between the emitter terminal areas of the transistor and the cathode terminal area of the diode. In this case, a cutout is implemented for the gate terminal area of the transistor.

[0070] FIG. 6C shows the second inherently structured electrically conductive film 34 of the connection device 3. This forms an electrically conductive connection to the gate terminal area of the transistor.

[0071] FIG. 6D shows as it were the footprint of the contact elements of the contact device that are assigned to the power semiconductor components 7, wherein only one contact element is assigned to the transistor, on account of the square basic shape thereof, and two contact elements are assigned to the diode, on account of the rectangular basic shape thereof. The respective footprint corresponds to those second sections 344 on the second main surface 340 of the connection device 3 which are arranged in alignment with the power semiconductor components in the direction of the normal and are projected here onto the respective power semiconductor component. It becomes clear here that the area of the footprint, that is to say that area which is intended for introducing pressure, covers the largest possible portion of the area of the power semiconductor component, without going beyond said area.

[0072] Also, the inventors intend that only those claims which use the words means for are intended to be interpreted under 35 USC 112, sixth paragraph. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims.

[0073] Where a specific numerical value is mentioned herein, it should be considered that the value may be increased or decreased by 20%, while still staying within the teachings of the present application, unless some different range is specifically mentioned. Where a specified logical sense is used, the opposite logical sense is also intended to be encompassed.

[0074] Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it will be apparent to those skills that the invention is not limited to those precise embodiments, and that various modifications and variations can be made in the presently disclosed system without departing from the scope or spirit of the invention. Thus, it is intended that the present disclosure cover modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.