Power semiconductor module with a pressure device

Abstract

A power semiconductor module is presented, comprising a substrate with a normal direction, a plurality of insulated conductor tracks arranged on a substrate base body, a power semiconductor device arranged on a conductor track, an internal connection device, a pressure device formed with a rigid base body having a flat main surface facing the substrate, and an insulating body formed with an insulating base body and studded bodies projecting from it towards the substrate, wherein these are arranged in associated recesses of the base body, wherein an insulating material is arranged between the main surface of the base body and the substrate including the connection device.wherein the surfaces of the stud bodies facing the substrate are in direct contact with the connecting device or with the substrate, and wherein the base body has a protruding elevation extending from its flat main surface.

Description

[0001] The invention describes a power semiconductor module with a substrate having a plurality of conductor tracks arranged on a substrate body of the substrate, with a power semiconductor device arranged on a conductor track, with an internal connection device, with a printing device.

[0002] DE 10 2021 115 926 B3 discloses a pressure device for the indirect or direct application of pressure to power semiconductor components of a power semiconductor module, comprising a pressure plate, a pressure stud element made of an elastic material, which has a pressure stud plate and pressure studs projecting from it, and a receiving device for receiving the pressure stud element, which has a base plate provided with recesses, wherein the recesses extend through the base plate, wherein the pressure stud plate is arranged on the base plate and the pressure studs extend through the recesses and project beyond the main side of the base plate on the side facing away from the pressure stud plate, wherein the pressure stud plate is arranged between the pressure plate and the base plate.

[0003] A disadvantage of this known pressure device is its instability when pressure is applied, as well as the resulting uneven pressure distribution.

[0004] DE 10 2015 114 188 A1 discloses a submodule comprising a substrate, a power semiconductor device, a connecting device, a terminal device, and an insulating body. The substrate has electrically insulated conductor tracks, with the power semiconductor device arranged on one of these tracks and thus electrically connected to it. The connecting device is designed as a foil composite and thus forms a first main surface facing the power semiconductor device and the substrate, and a second main surface opposite the first, with the submodule being internally connected to the circuit by means of the connecting device. The insulating body has a first sub-body that is connected to an edge of the substrate and also has a first recess for the terminal device.The insulating body also comprises a second sub-body, which is designed as a pressure body and has a second recess from which a pressure element protrudes. The first sub-body is connected to the second sub-body such that the second sub-body is movably arranged relative to the first sub-body in the direction of the substrate, in order to press with the pressure element onto a section of the second main surface of the foil composite, this section being arranged in projection along the normal direction of the power semiconductor device within the surface of the power semiconductor device.

[0005] A disadvantage of this known state of the art is the imprecise positioning of the printing element as well as its low inherent stability.

[0006] Based on the prior art, the invention aims to improve the design of the printing device and thus increase its service life.

[0007] This problem is solved according to the invention by a power semiconductor module with a substrate having a normal direction, with a plurality of insulated conductor tracks arranged on a substrate base body of the substrate, with a power semiconductor device arranged on a conductor track, with an internal connection device, with a pressure device formed with a rigid base body having a flat main surface facing the substrate and with an insulating body, formed with an insulating base body and studded bodies projecting away from it in the direction of the substrate, wherein these are arranged in associated recesses of the base body, wherein an insulating material is arranged between the main surface of the base body and the substrate including the connection device.wherein the surfaces of the stud bodies facing the substrate are in direct contact with the connecting device or with the substrate, and wherein the base body has a protruding elevation extending from its flat main surface.

[0008] The term "direct contact" is understood here and in the following to mean that there is no other object, gap, or empty space between the two contact partners.

[0009] It can be advantageous if the protruding elevation is in mechanical contact with the connecting device or with the substrate.

[0010] It can also be advantageous if the protruding ridge is not in mechanical contact with the connecting device or with the substrate.

[0011] It may be preferable if the base body and the protruding elevation are formed in one piece.

[0012] It may also be preferable if the studded bodies are deformed when pressure is applied using the pressure device.

[0013] It may also be preferred if the insulating base body is arranged in a main recess of the base body.

[0014] It may further be preferred if the connecting device is formed from a first electrically conductive film and a first electrically insulating film, wherein the electrically conductive film preferably forms a plurality of film conductor tracks.

[0015] It can be advantageous if the connecting device, viewed in the normal direction, has a top surface against which a first stud body presses and is thereby deformed.

[0016] It can also be advantageous if the surface of a studded body protrudes from the associated recess in a negative normal direction.

[0017] Furthermore, it can be advantageous if the protruding elevation has a surface that is arranged parallel to the flat main surface. It can also be advantageous if the protruding elevation has a cuboid base shape.

[0018] It can also be advantageous to have a metal body on the side of the insulating material base facing away from the substrate.

[0019] It is understood that the features and configurations of the power semiconductor module mentioned above and below can be implemented individually or in any combination to achieve improvements. In particular, the features mentioned above and explained here or below can be used not only in the combinations specified, but also in other non-mutually exclusive combinations or individually, without departing from the scope of the present invention.

[0020] Further explanations of the invention, advantageous details and features will become apparent from the following description of the invention contained in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6 schematically illustrated embodiments of the invention or of respective parts thereof. Fig. Figure 1 schematically shows a first embodiment of a power semiconductor module according to the invention in exploded view. Fig. Figure 2 shows this power semiconductor module in its assembled state. Fig. Figure 3 shows selected components of this power semiconductor module. Fig. Figure 4 shows the second embodiment of a power semiconductor module according to the invention in a three-dimensional exploded view. Fig. Figure 5 shows the printing element of the second embodiment of a power semiconductor module according to the invention in a three-dimensional sectional view. Fig. Figure 6 schematically shows a third embodiment of a power semiconductor module according to the invention. Fig. Figure 1 schematically shows a first embodiment of a power semiconductor module 1 according to the invention in exploded view in side view arranged on a cooling device, here designed as a liquid cooling device 14. Fig. Figure 2 shows this power semiconductor module in its assembled state, while Fig. Shows 3 selected components of this power semiconductor module.

[0021] The figure shows a substrate 2, constructed in a generally standard manner, with a ceramic body 20 and electrically insulated conductor tracks 22, 24, 26 arranged on it. These conductor tracks exhibit different potentials during operation of the power semiconductor module 1, particularly load potentials, but also auxiliary potentials, especially control and measurement potentials. Specifically, three conductor tracks 22, 24, 26 for load potentials are shown, as are typical for a power semiconductor module 1 in a half-bridge topology.

[0022] On a first and a second conductor track 22, 26, a power semiconductor device 5 is arranged, which, according to industry practice, can be designed as a single switch, for example as a MOSFET, or as an IGBT with an antiparallel connected power diode. The power semiconductor devices 5, more precisely their first contact surface, are, according to industry practice, preferably by means of a pressure-sintered connection 4, electrically conductively connected to the first conductor tracks 22.

[0023] The internal connections of the power semiconductor module 1 are formed by means of an internal connection device 3 made of a film composite, which is a flexible film stack comprising alternating electrically conductive films 30, 34 and electrically insulating films 32. Here, the film composite has exactly two conductive films 30, 34 and one insulating film 32 arranged between them. In particular, the conductive films 30, 34 of the connection 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 conductor track 22, 24, 26 of the substrate 2. In this embodiment, 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.

[0024] For external electrical connection, the power electronic power semiconductor module 1 has load and auxiliary connection elements (not shown).

[0025] The described power semiconductor module 1, more precisely its substrate 2, is arranged on a liquid cooling device 14, the surface of which is covered with a thermally conductive layer 140. Power semiconductor modules 1 according to the invention can, of course, include further components not explicitly described herein, as described in the prior art.

[0026] The pressure device 6 of the power semiconductor module 1 is also shown. This pressure device 6 has a rigid base body 7, here made of a rigid plastic, and an insulating body 60, wherein the insulating body 60 is made of silicone rubber with a first Shore A hardness of 60. The base body 7 itself has a main surface 700 facing the substrate 2 and a main recess 768 on the side facing away from the substrate 2. The insulating body 60 has an insulating base body 68 and stud bodies 62, 64 projecting away from it in the direction of the substrate 2, i.e., in the negative z-direction, whereby only three stud bodies 62, 64 are shown here as an example. The stud bodies 62, 64 are arranged apart from each other. The base body 7 itself is arranged in this main recess 768. The stud bodies 62,64 are further arranged in associated recesses 762,764 of the base body 7.These recesses 762,764 extend from the main recess 768 of the base body 7 through it and through the main surface 700.

[0027] Two embodiments of stud bodies 62, 64 are shown here. Two first stud bodies 62 designed as pressure bodies, which protrude from the associated recesses 762 (see figure). Fig. 2 and Fig. 3, and are designed and intended, after complete training and especially during operation of the power semiconductor module 1, so that their respective first surface 620 facing the substrate 2 is in direct mechanical contact with the connecting device 3, more precisely with its top surface 340.

[0028] A second stud body designed as an additional body 64, cf. Fig. 2 and Fig. 3 are here exemplarily designed and intended, after the complete training and especially in the operation of the power semiconductor module 1, such that their respective second surface 640 facing the substrate 2 is neither in direct mechanical contact with the connecting device 3 nor with the substrate 2.

[0029] The second stud body 64 projects beyond the main surface 700 of the base body 7 in the negative normal direction N, i.e., towards the substrate 2. This second stud body 64 is also aligned in the normal direction N with a gap 224 between two conductor tracks 22, 24.

[0030] The base body 7 also has, extending from its flat main surface 700, a projecting elevation 72, for example cuboid in shape, or more precisely, a trapezoidal prism, with a surface 720 that is arranged parallel to the flat main surface 700. The projecting elevation 72 is thus formed in the negative z-direction relative to the surface 340 of the internal connecting element 3. The surface 340 of the internal connecting element 3 and the surface 720 of the projecting elevation 72 are in mechanical contact in a fourth contact section 722. The projecting elevation 72 therefore presses against the normal direction N on the surface 340 in the region of the fourth contact section 722. Alternatively, the projecting elevation 72 can also be in mechanical contact with the substrate 2.Furthermore, the base body 7 has a further elevation 70 extending from its flat main surface 700. This elevation 70 is in mechanical contact with the internal connection device 3 in a third contact section 702, which is also arranged in the normal direction N above a gap 224 between the end sections of the two opposing conductor tracks 22 and 24. The further elevation 70 is formed in the negative z-direction below the stud body 64 and thus below its recess 764. The base body 7, the projecting elevation 72, and the further elevation 70 are formed in one piece from plastic. Alternatively, the elevations 70 and 72 and the base body 7 can also be formed in two pieces and, for example, arranged in the base body 7 by means of a snap-fit ​​mechanism.

[0031] The power semiconductor module 1 further comprises a standard pressure introduction device, which (not shown) is supported against the liquid cooling device 14, and introduces pressure 74 onto the insulating base body 68. This pressure 74 is then transferred as a partial pressure 740 directly to the foil composite via the first studded elements 62 (see also...). Fig. 2. The applied pressure 74 presses the entire substrate 2 onto the liquid cooling device 14. The studded bodies 62 are thus deformed and pressed against the normal direction N to the internal connection device 3 and are arranged on it. Second contact sections 662 of the studded bodies 62 are in direct contact with first contact sections 262 of the substrate 2, here the upper surface 340 of the internal connection device 3, with the first contact sections 262 being arranged in the normal direction N above in the area of ​​the power semiconductor components 5. The contact sections 262, 662 are aligned in the x-direction such that they are arranged exactly one above the other in the z-direction. The studded bodies 62 thus indirectly press on the power semiconductor components 5.

[0032] This pressure introduction is illustrated by the pressure introduction described in Fig. 2 is the first stud body 62 opposite the one in Fig. The state shown in section 1 is deformed without pressure being applied. In contrast, the second studded body 64 remains undeformed even when pressure is applied.

[0033] Furthermore, explicitly in Fig. As shown in Figure 2, an insulating material 8 is arranged in the space between the main surface 700 of the base body 7 and the substrate 2, including the connecting device 3. The surface of the studded body 64, i.e., the additional body, facing the substrate 2, is in direct contact exclusively with the insulating material 8.

[0034] Fig. Figure 4 shows the second embodiment of a power semiconductor module 1 according to the invention in a three-dimensional exploded view, while Fig. Figure 5 shows the pressure element of this second embodiment in a three-dimensional sectional view. The power semiconductor module has a frame-like housing 10 with two load connection elements on one narrow side of the housing 10 and another load connection element on the opposite narrow side. The auxiliary connection elements are arranged on one long side and are designed as press-pin elements.

[0035] The frame-like housing 10 encloses the substrate 2 of the power semiconductor module 1, wherein the substrate 2 already contains the Fig. 1 components described, such as power semiconductor devices 5, conductor tracks 22 and the spaces 224 arranged between them. Also in Fig. Figure 4 shows the pressure device 6, which has a further recess aligned with a substrate recess. This substrate recess and the further recess are designed and configured to accommodate a standard pressure induction device (not shown).

[0036] Fig. Figure 5 shows the first stud bodies 62 in the recesses 762 of this design, which functionally correspond to the Fig. 1, Fig. 2 to Fig. The pressure device 6 described in section 3 corresponds to the first embodiment. The pressure device 6 shown here differs from the first embodiment in that, extending from its flat main surface 700 on the narrow sides of the base body, it has projecting elevations 72 that are not in mechanical contact with either the internal connecting device 3 or the substrate 2. The projecting elevations 72 and the substrate or the internal connecting device 3 therefore do not touch each other.

[0037] In addition, a metal body 9 is arranged on the side of the insulating material base body 60 facing away from the substrate 2, which serves to distribute the pressure on the insulating material body 60 and via this to the first stud bodies 62 and protruding elevations 72.

[0038] Fig. Figure 6 schematically shows a third embodiment of a power semiconductor module 1 according to the invention. This differs from those according to the Fig. 1, Fig. 2 to Fig.3 by the design of the connecting device 3 as a wire bond connection 36. Accordingly, the first surface of the first stud body 62 presses against the substrate 2, in this configuration against a conductor track of the substrate 2. In addition, the projecting elevation 72 is cylindrical, more precisely teardrop-shaped, and presses against the normal direction N onto the space 224 between the two end sections of two conductor tracks. The base body 7 also has a cuboid-shaped further elevation 70, which is not in any mechanical contact with the substrate 2 and whose surfaces are surrounded by and in contact with the insulating material 8. Here too, the base body 7 and the elevations 70, 72 are formed in one piece from a rigid plastic.

[0039] The described design of the protruding or further elevation 70,72 results in positive effects regarding the stability of the pressure device. Furthermore, this ensures a uniform pressure distribution. Reference sign 1 Power semiconductor module 10 cases 14 Liquid cooling system 140 Thermally conductive layer 2 Substrat 20 substrate bodies 22 insulated conductor tracks 224 space 24 insulated conductor tracks 26 insulated conductor tracks 262 first contact section 3 internal connection device 30 electrically conductive foil 32 electrically insulating foil 34 electrically conductive foil 340 Top 36 Wire bond connection 4 Pressure sintering connection 5 Power semiconductor device 6 Printing device 60 insulating bodies 62 studded bodies 620 surface 64 studded bodies 68 Insulating material base bodies 680 first surface 662 second contact section 7 Basic shapes 70 further increases 700 main area 72 prominent increase 702 third contact section 720 second surface 722 fourth contact section 74 Print 740 partial print 762 Exclusion 764 Exclusion 768 Main cutout 8 Insulating material 9 metal bodies N Normal direction

Claims

Power semiconductor module (1) with a substrate (2) having a normal direction (N), with a plurality of insulated conductor tracks (22, 24, 26) arranged on a substrate base body (20) of the substrate (2), with a power semiconductor device (5) arranged on a conductor track (22), with an internal connection device (3), with a pressure device (6) formed with a rigid base body (7) having a flat main surface (700) facing the substrate (2) and with an insulating body (60), formed with an insulating base body (68) and stud bodies (62, 64) projecting away from it in the direction of the substrate (2), wherein these are arranged in associated recesses (762, 764) of the base body (7), wherein an insulating material (8) is arranged between the main surface (700) of the base body (7) and the substrate (2) together with the connection device (3),wherein the surfaces (620) of the stud body (62) facing the substrate (2) are in direct contact with the connecting device (3) or with the substrate (2) and wherein the base body (7) has a projecting elevation (72) extending from its flat main surface (700). Power semiconductor module according to claim 1, wherein the protruding elevation (72) is in mechanical contact with the connecting device (3) or with the substrate (2). Power semiconductor module according to claim 1, wherein the protruding elevation (72) is not in mechanical contact with the connecting device (3) or with the substrate (2). Power semiconductor module according to one of the preceding claims, wherein the base body (7) and the protruding elevation (72) are formed in one piece. Power semiconductor module according to one of the preceding claims, wherein the studded bodies (62,64) are deformed when pressure is applied by means of the pressure device (6). Power semiconductor module according to one of the preceding claims, wherein the insulating base body (68) is arranged in a main recess (768) of the base body (7). Power semiconductor module according to one of the preceding claims, wherein the connecting device (3) is formed from a first electrically conductive film (30) and a first electrically insulating film (32), wherein the electrically conductive film (30) preferably forms a plurality of film conductor tracks. Power semiconductor module according to claim 6, wherein the connecting device (3) has a top surface (340) viewed in the normal direction (N), against which a first stud body (62) presses and is thereby deformed. Power semiconductor module according to one of the preceding claims, wherein the surface (640) of a stud body (62) projects out of the associated recess (762,764) in a negative normal direction (N). Power semiconductor module according to one of the preceding claims, wherein the protruding elevation (72) has a surface (720) arranged parallel to the planar main surface (700). Power semiconductor module according to one of the preceding claims, wherein the protruding elevation (72) has a cuboid shape. Power semiconductor module according to one of the preceding claims, wherein a metal body (9) is arranged on the side of the insulating body (60) facing away from the substrate (2).

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