Power electronic switching device

Abstract

A power electronic switching device is presented with a substrate having an insulating body and a first and a second conductor track arranged thereon, which are spatially separated from one another by a trench having a first and a second trench side surface opposite the first and a trench bottom surface connecting them, with a normal direction, with a power semiconductor component arranged on a first conductor track, wherein a side surface of the power semiconductor component runs parallel to a first trench section of the trench and has a first distance from the first trench side surface adjacent to the power semiconductor component,wherein the side surface and a part of the adjacent surface of the power semiconductor component is covered with a first dam made of a first insulating material with a first dam height relative to the trench bottom surface, and wherein a second dam made of a second insulating material with a second dam height relative to the trench bottom surface is arranged between the side surface and the second trench side surface.

Description

The invention describes a power electronic switching device having a substrate and a trench having a first and a second trench side surface, a connecting trench bottom surface and a bank.In general, power electronic switching devices with a substrate are known from the prior art, on which power semiconductor components, such as power semiconductor switches and diodes, for example, are arranged and electrically conductively connected to one another by means of a conduction layer of the substrate and an electrical connection device, which can be present, for example, in the form of bonding wires and / or a foil composite. For the electrical insulation and / or for the protection of the respective lateral edge of the power semiconductor components, an insulation body made of silicone surrounding the respective lateral edge of the power semiconductor components is usually arranged, wherein the connection device is arranged above the insulation body made of silicone.DE 10 2007 006 706 A1 discloses a circuit arrangement with a connecting device and a semiconductor component, wherein an insulating material is arranged between the connecting device and an associated edge of the semiconductor component.DE 10 2020 127 606 A1 discloses a method for production and a power electronic switching device having a substrate having a normal direction with a first and a second conductor track, wherein a power semiconductor component is arranged on the first conductor track by means of an electrically conductive connection, wherein the power semiconductor component has a laterally encircling edge and, on its first main side facing away from the substrate, an edge region and a contact region, having a connecting device which is electrically conductively connected to a contact surface of the contact region, and having a heat-conducting device which forms an electrically insulating, thermally highly conductive connection between the connecting device and the substrate.With the knowledge of these stated circumstances, the object of the invention is to provide an improved power electronic switching device in which the service life of the individual components is increased.This object is achieved according to the invention by a power electronic switching device having a substrate which has an insulating body and, arranged thereon, a first and a second conductor track which are spatially separated from one another in each case by a trench having a first and a second trench side surface situated opposite the first trench side surface and a trench bottom surface connecting the latter, having a normal direction, having a power semiconductor component arranged on a first conductor track, wherein a side surface of the power semiconductor component runs parallel to a first trench section of the trench and has a first distance from the first trench side surface thereof adjacent to the power semiconductor component, wherein the side surface and a part of the adjacent surface of the power semiconductor device are covered with a first bank of a first insulation material having a first bank height relative to the trench bottom surface, and wherein between the side surface and the second trench side surface a second bank 7 of a second insulation material having a second bank height relative to the trench bottom surface is arranged.It can be advantageous if the first one is arranged at a distance from the second dam.It can also be advantageous if the second bank height is less than the first bank height.Furthermore, it may be advantageous if the second bank is arranged on a surface of the first conductor track and has the second bank height as viewed in the normal direction.It may be preferred if the second bank is arranged on the trench bottom surface and has the second bank height as viewed in the normal direction.It can also be preferred if the second bank height of the second bank is greater, in particular at least 20% greater, than a trench depth.It can likewise be advantageous if the second bank fills the trench completely and covers a conductor track section adjoining one of the trench side surfaces.In addition, it may be advantageous if the length of the second bank is at least 20%, preferably at least 50% and in particular preferably at least 10%, of the length of the power semiconductor component.It can also be preferred that the surface of the second dam is a contour and has local indentations as viewed from the normal direction of the trench bottom surface. It may be preferred here if the height of the local indentations of the second dam relative to the trench bottom surface is at least 95%, preferably at least 90% and particularly preferably at least 85% of the second dam height.Furthermore, it may be preferred if a second bank is formed on the first conductor track if the distance between the side face of the power semiconductor component and the first trench side face corresponds to at most 40 times, preferably at most 20 times, the trench depth.It may also be preferred if the second bank is arranged on the first conductor track and a third bank made of a second insulation material having a third bank height relative to the trench bottom surface is arranged between the second bank and the second trench side surface, wherein the third bank height is not greater than the second bank height.It can also be advantageous if a connecting device having a first and a second electrically suffering, preferably self-structured, metallic foil with an electrically insulating foil arranged therebetween is arranged on the power semiconductor component, the first and second dam in such a way that the contour of the connecting device follows the common contour of the first and second dam.Furthermore, it can be advantageous if the region between the connecting device and the substrate is filled with a third, preferably gel-like, insulation material.It is understood that the various embodiments of the invention may be realized individually or in any combination in order to achieve improvements. In particular, the features mentioned above and explained here or in the following can be used not only in the combinations indicated, but also in other non-exclusive combinations or alone, without departing from the scope of the present invention.Further explanations of the invention, advantageous details and features will become apparent from the following description of the exemplary embodiments of the invention schematically illustrated in FIGS. 1 to 7 or of respective parts thereof. FIG. 1 shows a first configuration of a power electronic switching device according to the invention with a first bank. FIG. 2 shows a second embodiment of a power electronic switching device according to the invention, having a first and a second bank. FIG. 3 shows a third embodiment of a power electronic switching device according to the invention, having a first, a second and a third bank. FIG. 4 shows a top view of a power electronic switching device with a first, a second and a third bank. FIG. 5 shows a second dam in detail in a top and side view. FIG. 6 shows a power electronic switching device according to the invention with a connecting device. FIG. 7 shows a power electronic switching device according to the invention with a third insulation material.FIG. 1 shows a section of a first embodiment of a power electronic switching device according to the invention with a substrate 1. The insulating body 2 is here formed purely by way of example from a ceramic substrate customary in the art, on which a first conductor track 30, here on the left and a second conductor track 32, here on the right, made of copper are arranged in the z direction. The first and second conductor tracks 30, 32 are arranged spaced apart from one another by a trench 4 formed angularly by way of example, having a first trench side surface 40, 42 and a second trench side surface opposite the first trench side surface in the x direction. The two trench side surfaces 40, 42 are connected to one another by a trench bottom surface 44. The trench bottom surface 44 is arranged on the insulating body in the normal direction, i.e. positive z-direction. The distance between the two trench side surfaces 40, 42 accordingly corresponds here to the trench bottom surface 44. the first conductor track 30 is thus spatially separated from the second conductor track 32, that is to say the conductor tracks 30, 32 do not touch one another. The trench 4 furthermore has a trench depth 930. This corresponds here by way of example to the thickness of the first and second conductor tracks 30, 32. A power semiconductor component 5, here by way of example a silicon carbide MOS-FET, is arranged on the first conductor track 30 in a materially bonded and electrically conductive manner. Alternatively, the power semiconductor switch can also be designed as an IGBT or as a diode. The power semiconductor component 5 has a side surface 50 which is oriented parallel to the first trench side surface 40. Between the lateral surface 50, arranged laterally to the right here, of the first trench lateral surface 40 is a first distance 900. This first distance 900 thus corresponds to a portion of the first conductor track 30 between the power semiconductor component 5 and the trench 4.Furthermore, a first bank 6 with a first bank height 910 made of an insulation material customary in the art, here silicone, is arranged on a part of the surface of the first conductor track 30 and is connected thereto in a materially bonded manner. The first bank 6 accordingly extends over a section of the first conductor track 30 in the z direction and in this case covers the side face 50 of the power semiconductor component 5 completely and a part, in this case an edge section of the surface 52. Here, to the right next to the first bank 6, a second bank 7 is arranged completely on the first conductor track 30 relative to the trench bottom surface 44 and is likewise connected thereto in a materially bonded manner. The second dam 7 is formed from a second insulation material, here likewise from silicone, by way of example. The second dam 7 is arranged at a distance from the trench 4 and its trench side surface 40 and from the first dam 6. The first and second dam 6, 7 therefore do not touch. The second bank 7 has a second bank height 920. This second bank height 920 is formed smaller than the first bank height 910 in the normal direction. The two dams 6, 7 have a round cross-sectional shape. Alternatively, the cross sections of the dams 6, 7 may also be formed differently. The second bank height 920 is greater than the trench depth 930 of the trench 4 in the normal direction.Alternatively, the second bank height 920 may also be 20%, 30% or 40% greater than the trench depth 930 in the normal direction. Furthermore, the first bank height 910 can alternatively also be formed to be smaller than the second bank height 920. The dams can furthermore also be formed from another insulation material and in particular from another casting resin.The second bank 7 is therefore formed on the first conductor track 30 if the first distance 900 between the side surface 50 of the power semiconductor component 5 and the first trench side surface 40 of the trench 4 corresponds to at most 40 times, preferably at most 20 times, the trench depth 930, i.e. provides sufficient space to be able to place the second bank 7 completely on the first conductor track 30, such that sufficient distance to the first bank 6 can be ensured.Alternatively, the substrate 1 can also have more than two conductor tracks and trenches arranged therebetween.FIG. 2 shows a section of a second embodiment of a power electronic circuit according to the invention. The structure of the substrate 1 with the insulating body 2 and the first and second conductor tracks 30, 32 and the trench 4 formed thereon is similar to the power electronic circuit shown in FIG. 1. FIG. 2 differs from FIG. 1 in that the first distance 900 is less pronounced, that is to say the power semiconductor component 5 is arranged further in the x direction toward the trench 4, but still at a distance therefrom. Furthermore, only the first bank 6 is arranged here on a section of the surface of the first conductor track 30 and connected thereto in a materially bonded manner. The first bank 6 also extends here over a part of the surface 52, the side surface 50 and over a section of the first conductor track 30, in the region of the distance 900, that is to say between the side surface 50 of the power semiconductor component 5 and the first trench side surface 40 of the trench 4. The second bank 7 covers a trench section, more precisely an edge section of the first conductor track 30, the first trench side surface 40 and extends beyond the trench bottom surface 44 in the positive x direction towards the second trench side surface 42, but does not contact the latter.Alternatively, the second bank 7 can also completely fill the trench 4, such that the entire trench 4 is filled with the insulation material and thus the first trench side surface 40, the second trench side surface 42 and the trench bottom surface are completely wetted with the insulation material. In this case, the insulation material can cover, for example beyond a trench side surface 42, one of the two conductor tracks 30, 32 or also both conductor tracks 30, 32 in an adjoining conductor track section at the edge of the trench 4. Alternatively, the trench 4 can also fill only the entire trench depth 930 and not protrude beyond the trench 4 onto the conductor tracks 30, 32.FIG. 3 shows a section of a third embodiment of a power electronic circuit according to the invention. The structure of the power electronic circuit corresponds to that in FIG. 1, 3 differs from FIG. 1 in that a third bank 8 is arranged completely on the trench bottom surface 44 of the trench 4 and is connected thereto in a materially integral manner. The third dam 8 here too consists of a second insulating material, likewise for example silicone. The third bank 8 has a third bank height 925 that is formed smaller in the z direction than the second bank height 920 of the second bank 7. the third bank 8 thus does not project beyond the second bank 7 as a whole. The cross-sectional shape of the third bank 8 corresponds here by way of example to a half ellipse, with the result that the mass of the insulation material concentrates approximately at the center of the trench bottom surface 44 and therefore the first and second trench side surfaces 40, 42 are not covered by the third bank 8 and therefore do not touch it. Here, the third bank 8 is formed more toward the second trench side surface 42 in the x direction, for example. Thus, the distance between the first trench side surface 40 and the third bank 8 is greater than the distance between the third bank 8 and the second trench side surface 42.FIG. 4 shows a detail of a power electronic switching device having a substrate 1 and a trench 4 and four power semiconductor components 5 in a plan view. The substrate 1 also has a first conductor track 30, shown on the right, and a second conductor track 32, shown on the left, separated by the trench 4. The trench 4 likewise has a first trench side surface 40, which adjoins the first conductor track 30, and a second trench surface 42, which adjoins the second conductor track 32, and a connecting trench bottom surface 44, which connects the first and second trench side surfaces 40, 42 to one another. Two of the four power semiconductor components 5 are arranged on the first conductor track 30 and the other two power semiconductor components 5 are arranged on the second conductor track 32 and are each connected thereto in a materially bonded manner. The power semiconductor components 5 are designed here as MOSFETs by way of example. Their side surfaces each have a length 950. On the first conductor track 30, which is narrower here by way of example, a power semiconductor component 5 is arranged in the upper region. This is completely surrounded by a first bank 6 and completely covers the power semiconductor component 5 at parts of the surface 50, more precisely at the edge section of the power semiconductor component 5, and at the side surfaces thereof. The first dam 6 is formed, for example, as an approximately uniform dam, illustrated as a rectangle with rounded corners. The first bank 6 accordingly has an approximately uniform first bank height 910. To the right next to the first bank 6, a second bank 7 is arranged spaced apart in the x direction between the first bank 6 and the trench 4. This second dam 7 is exemplarily designed to be relatively wider than the first dam 6, here approximately twice as thick. The length 940 of the second bank 7 corresponds to the length of a side surface 50 of the power semiconductor component 5 with the completely enclosed first bank 6. the length 940 of the second bank 7 is thus formed larger than the length 950 of the power semiconductor component 5 and is therefore over 100% of this length 950. The second bank 7 is likewise formed as an approximately uniform bank and therefore has an approximately uniform second height 920 overall.In the lower left corner region of the first conductor track 30, the second power semiconductor component 5 is arranged at a distance from the edge of the first conductor track 30. The centers of the two power semiconductor components 5 are aligned along a straight line in the y direction. A second first bank 6 completely covers the side surface 50 directed toward the trench 4 and parts of the subsequent side surfaces and the surface 52 of the power semiconductor component 5. the second first bank 6 therefore extends from the lower right corner region via the side surface 50 to the upper right corner region of the power semiconductor component 5. the second first bank 7 is likewise formed as a uniform bank and therefore has a second bank height 920, which is approximately uniform overall, without indentations on the surface and side surfaces. The thickness of this first bank 6 corresponds to the thickness of the first bank 6 described above. Furthermore, the length of this first bank 6 corresponds to the length 940 of the second bank 7. a further second bank 7 is likewise arranged in the x direction between the first bank 6 and the trench 4, toward the first trench side surface 40. The two second dams 7 are aligned along a straight line in the x direction. They also have the same thickness. This second bank 7 is likewise designed, for example, as an approximately uniform bank and therefore has an approximately uniform second bank height 920 overall. The length 940 of the second bank 7 is, however, here formed to be significantly shorter in relation to the first second bank 7 and is here approximately 80% of the length 950 of the power semiconductor component 5.In the trench 4, a third dam 8 is arranged in the middle at a uniform distance from the two trench side surfaces 40, 42 on the trench bottom surface. This third bank 8 extends from the edge of the insulating body 2 towards the center of the trench 4 and has a length which is twice as large as the second bank 7 arranged at a distance. The third dam 8 furthermore has no indentations on the surface, here likewise shown as a rectangle with rounded corners. It is thus formed as a third dam 8 with a uniform contour. The side surfaces of the third dam 8 also have no indentations. Alternatively, a plurality of third dams 8 having the illustrated length or a plurality of third dams 8 having shorter lengths which correspond to at least 20% of the power semiconductor module 5 or else having different lengths could also be arranged in the trench 4.On the second conductor track 32, a third power semiconductor element 5 having a first bank 6 is arranged in the upper right corner region. The construction corresponds to that of the power semiconductor component 5 opposite in the x-direction on the first conductor track with the first bank 6. Between the second trench side surface 42 of the trench 4 and the power semiconductor component 5, a first and a second bank 7, 8 are arranged spaced apart from one another in series in the positive x-direction on the second conductor track 32. The third dam 8 is shorter and narrower than the second dam 7 arranged next to it on the right. However, the third bank 8 has a length that is greater than the length 950 of the illustrated power semiconductor device 5 without the first enclosing bank 6. On the other hand, the larger second bank 7 has a length exceeding the total length of the power semiconductor device 5 having the first bank 6. Both dams 7, 8 have a contour and thus local indentations on the respective surfaces and side surfaces and thus do not have a uniform height, cf. FIG. 5. The two centers of the two power semiconductor components 5 on the second conductor track 32 are likewise on one plane, as viewed in the y direction.FIG. 5 shows an example of a second dam 7 made of a second insulation material, also here made of silicone by way of example, in a top view and side view. The second bank 7 is arranged on a first conductor track 30 and connected thereto in a materially bonded manner. Adjacent to the first conductor track there is a trench 4 with a trench bottom surface 44. The surface of the second bank 7 has a contour 70 which, starting from the trench bottom surface 44, that is to say in the positive z direction, has local indentations. The contour 70 here is identical, for example, to a mountain-valley contour. The second dam 7 basically has a second dam height 920, which is the maximum dam height here. Due to less insulation material at the locations at which the local indentations are formed, the local indentations have a lower height 922 locally than a minimum bank height. By way of example, the second dam 7 has six indentations which are arranged distributed over the dam at regular intervals. The height 922 of the local indentations is, for example, 85% of the second bank height 920. Furthermore, more or less than six local indentations can also be formed. The indentations may also be arranged irregularly or a plurality of indentations may be arranged directly next to one another on the dam.The plan view shows the outline of the second dam 7 illustrated in the side view from above. The local indentations on the surface of the second dam 7 are visible here by the narrower sections offset in the x direction into the interior of the dam. The portions forming the larger second bank height 920 have a larger perimeter than the portions formed by the local indentations and have a lower height 922.FIG. 6 shows the structure of the power electronic circuit from FIG. 3, FIG. 6 differs from FIG. 3 in that the power electronic circuit has a connecting device 100 for electrical contacting. The connecting device 100 here consists, for example, of a first and a second electrically conductive, structured metallic foil, wherein an electrically insulating foil is arranged between these two foils. The connecting device 100 is arranged in the normal direction on the power semiconductor component 5, the first second and third dam 6, 7, 8, shown spaced apart here for the sake of simplicity of illustration. The connecting device 100 therefore maps the contour of the first second and third dam 6, 7, 8. Depending on the number, arrangement and contour of the dams, the connecting device 100 maps the overall contour of the structure of the power electronic circuit. The connecting device 100 can therefore also cover, for example, only a first and a second bank 6, 7 or a first and a third bank and one or more power semiconductor components 5.FIG. 7 shows the structure of the power electronic circuit from FIG. 6, FIG. 7 differs from FIG. 6 in that a third insulation material 9, formed by way of example as a silicone gel, is arranged in the region between the connecting device 100 and the substrate 1. The third insulation material 9 is completely filled into the interspace and encloses the surfaces of the two conductor tracks 30, 32, the trench 4 and the dams 6, 7, 8, so that the connecting device 100 is likewise in contact with the third insulation material 9. Alternatively, the third insulation material 9 can also be formed from plastics of different Shore hardnesses.List of reference characters1 Substrate 2 Insulating body 30 First conductive track 32 Second conductive track 4 Trench 40 First trench side surface 42 Second trench side surface 44 Trench bottom surface 5 Power semiconductor component 50 Side surface 52 Surface 6 First bank 7 Second bank 70 Contour 8 Third bank 9 Third insulation material 100 Connecting device 900 First distance 910 First bank height 920 Second bank height 922 Height of the local indentations 925 Third bank height 930 Trench depth 30 940 Length of the second bank 950 Length of the power semiconductor componentReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2007 006 706 A1

[0003] DE 10 2020 127 606 A1

[0004]

Claims

Power electronic switching device having a substrate (1) which has an insulating body (2) and arranged thereon a first and a second conductor track (30, 32) which are in each case spatially separated from one another by a trench (4) having a first and a second trench side surface (40, 42) lying opposite the first and a trench bottom surface (44), which connects said trench bottom surface, having a normal direction, having a power semiconductor component (5) arranged on a first conductor track (30), wherein a side surface (50) of the power semiconductor component (5) runs parallel to a first trench section of the trench (4) and has a first distance (900) from the first trench side surface (40) thereof which is adjacent to the power semiconductor component (5), wherein the side surface (50) and a part of the adjacent surface (52 of the power semiconductor device (5) is covered with a first bank (6) made of a first insulation material having a first bank height (910 relative to the trench bottom surface (44), and wherein between the side surface (50 and the second trench side surface (42) a second bank (7) made of a second insulation material having a second bank height (920) relative to the trench bottom surface (44) is arranged.The power electronic switching device according to claim 1, wherein the first one is arranged spaced apart from the second bank (6, 7).The power electronic switching device of claim 1 or 2, wherein the second bank height (920) is less than the first bank height (910).The power electronic switching device according to claim 1 to 3, wherein the second bank (7) is disposed on a surface of the first conductive path (30) and has the second bank height (920) as viewed in the normal direction.The power electronic switching device according to claim 1 to 3, wherein the second bank (7) is arranged on the trench bottom surface (44) and has the second bank height (920) as viewed in the normal direction.The power electronic switching device according to claim 5, wherein the second bank height (920) of the second bank (7) is greater, in particular at least 20% greater, than a trench depth (930).Power electronic switching device according to Claim 5 or 6, wherein the second bank (7) fills the trench (4) completely and covers a conductor track section adjoining one of the trench side surfaces (40, 42).Power electronic switching device according to one of the preceding claims, wherein the length (940) of the second bank (7) is at least 20%, preferably at least 50% and in particular preferably at least 100% of the length (950) of the power semiconductor component (5).Power electronic switching device according to one of the preceding claims, wherein the surface of the second dam (7) is a contour (70) and has local indentations as viewed from the normal direction of the trench bottom surface (44).Power electronic switching device according to Claim 5, wherein the height (922) of the local indentations of the second bank (7) relative to the trench bottom surface (44) is at least 95%, preferably at least 90% and particularly preferably at least 85% of the second bank height (920.Power electronic switching device according to one of the preceding claims, wherein a second bank (7) is formed on the first conductor track (30) when the distance (900 between the side surface (50) of the power semiconductor component (5) and the first trench side surface (40) corresponds to at most 40 times, preferably at most 20 times, the trench depth (930).Power electronic switching device according to one of the preceding claims, wherein the second bank (7) is arranged on the first conductor track (30), and a third bank (8) made of a second insulation material having a third bank height (925) relative to the trench bottom surface (44) is arranged between the second bank (7) and the second trench side surface (42), wherein the third bank height (925) is not greater than the second bank height (912).Power electronic switching device according to one of the preceding claims, wherein a connecting device (100) comprising a first and a second electrically suffering, preferably self-structured, metallic foil with an electrically insulating foil arranged therebetween is arranged on the power semiconductor component (5), the first and second dam (6, 7) in such a way that the contour of the connecting device (100) follows the common contour of the first and second dam (6, 7).Power electronic switching device according to claim 13, wherein the region between the connecting device (100) and the substrate (1) is filled with a third, preferably gel-like, insulation material (9).

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