Multilayer embedded half-bridge circuit and multiphase bridge circuit from it
Patent Information
- Application Number
- DE102024207124
- Authority / Receiving Office
- DE · DE
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-07-29
- Publication Date
- 2025-08-28
Smart Images
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Abstract
Description
[0001] Electric vehicles feature power electronics in the form of a traction inverter, which, at power levels significantly higher than 100 kW and voltages of, for example, 400 or 800 V, converts the direct current of the traction battery into a multi-phase alternating current. This alternating current is fed to an electric motor, which generates torque.
[0002] To implement such a traction inverter, power semiconductors such as power transistors are used. These transistors, on the one hand, have a high current-carrying connection and interconnection, and, on the other hand, generate high levels of waste heat that must be dissipated. Finally, especially at high edge steepness, switching these transistors generates noise that must be reduced, preferably through clever wiring (especially of the DC supply voltage).
[0003] The task is therefore to achieve a high current carrying capacity with clever cable routing in a half-bridge, which is particularly suitable for traction inverters.
[0004] This problem is solved by the subject matter of claim 1. Further properties, features, embodiments, and advantages are revealed by the dependent claims, the description, and the figures.
[0005] An embedded half-bridge circuit with a multi-part printed circuit board is proposed. It comprises a first group of semiconductor elements and a second group of semiconductor elements. The first group forms the high-side transistor, and the second group forms the low-side transistor. The first group and the second group are connected in series (with respect to the power path), with the connection point forming an AC connection or phase connection, and the outer ends (the ends not connected to each other or to the connection point) can be connected to two DC supply potentials of a DC supply voltage.
[0006] The first and second groups of home elements are provided in the circuit board and are thus “embedded”, which is a technical term for the placement of components (here: semiconductor elements) within a circuit board or between layers of a circuit board.
[0007] The circuit board has at least three conductor layers, namely a contact conductor layer, a first connection conductor layer, and a second connection conductor layer. A semiconductor layer is provided in which the semiconductor elements are arranged. The semiconductor layer is typically made of electrically insulating material, with the semiconductor elements embedded in this insulating material. Furthermore, the semiconductor layer can comprise a conductive layer, which, however, has a recess in which the semiconductor elements are arranged, preferably also embedded in insulating material within the recess. The insulating material is in particular a resin material, for example prepreg. The conductor layers are preferably layers of copper or an alloy thereof. The insulating material is also provided in layer form between the conductor layers, resulting in a laminated structure.
[0008] The conductor layers are particularly structured, i.e., they have physically separated sections that allow different voltage potentials due to the physical separation. This allows conductor paths to be formed in a known manner. Insulating layers are provided between the conductor layers, through which vias can extend. These vias connect different conductor layers and can, in particular, individually connect different sections of one conductor layer to different sections of another conductor layer.
[0009] The half-bridge circuit proposed here has a contact conductor layer. This can be the topmost layer of the circuit and thus form an externally accessible surface (possibly covered by a protective varnish). Alternatively, this layer is covered by an insulating layer, which in turn is followed by a conductive connection layer, which is electrically connected to the contact conductor layer through the insulating layer and also covers the contact conductor layer. The contact conductor layer is structured and has at least a first, a second, and a third contact surface. The first contact surface is preferably implemented multiple times. This also applies to the second and third contact surfaces.If there are multiple first contact surfaces, these are interconnected, preferably via conductor tracks provided by the conductor layer, or by providing the contact surfaces in the same (continuously conductive) section of the conductor layer. This can also be done for the second and third contact surfaces if multiple contact surfaces are provided. The contact conductor layer has trenches running through its entire thickness, separating the one or more first contact surfaces from the one or more second contact surfaces and the one or more third contact surfaces, as well as trenches separating the one or more second contact surfaces from the one or more third contact surfaces.
[0010] The half-bridge circuit further comprises a first interconnect layer, a semiconductor layer, and a second interconnect layer. The semiconductor layer is provided between the two interconnect layers. Thus, the first interconnect layer is above the semiconductor layer, and the second interconnect layer is below the semiconductor layer. The terms "top" and "bottom" do not refer to a horizon or a gravitational field, but rather serve as a standard visual orientation, which can refer to a drawing. The first interconnect layer is provided on the semiconductor layer via an insulating layer, or the first interconnect layer is provided directly on the semiconductor layer, provided that the semiconductor layer has an insulating layer above the semiconductor elements.The second connecting conductor layer is provided on the semiconductor layer via an insulating layer, or the first connecting conductor layer is provided directly on the semiconductor layer, provided the semiconductor layer has an insulating layer beneath the semiconductor elements. In other words, the semiconductor elements of the semiconductor layer are interposed (in an insulating manner) between the two connecting conductor layers mentioned. The semiconductor elements are connected on both sides (i.e., top to bottom) to the connecting conductor layers, in particular via vias that extend from the connecting conductor layers to the semiconductor element or its surface, and that extend through the insulating layers between the semiconductor element and the connecting conductor layers.
[0011] The layers mentioned here are arranged one above the other. The semiconductor layer is sandwiched between the connecting conductor layers (first and second connecting conductor layers). The connecting conductor layers each have at least two physically separate sections, which can thus carry different potentials or are not connected to each other by the respective connecting conductor layer.
[0012] A first section of the second interconnect layer (beneath the semiconductor layer) is electrically connected to undersides (i.e., surfaces of the semiconductor elements facing the second interconnect layer) of the first group of semiconductor elements. The connection is provided by vias extending from the underside of the first group of semiconductor elements to the first section of the second interconnect layer. Because the vias all lead to the first section, all undersides of the first group of semiconductor elements are electrically connected. This results in part of a parallel circuit of these semiconductor elements (first group).
[0013] The second connecting conductor layer has a second section. This lies next to the first section. “Next to” means offset in a direction that lies in the direction of extension of the circuit board. The second section of this conductor layer is also connected to the undersides of semiconductor elements, namely to the undersides of the second group of semiconductor elements. The two groups do not overlap. This means that the undersides of the two groups of semiconductor elements are connected to (electrically speaking) different sections of the second connecting conductor layer. The connection between the underside and the section is the same as for the first section, i.e. it is provided by vias that lead from the second section to the undersides of the second group of semiconductors.Since the undersides of the second group of semiconductor elements are all connected to the same section, namely the second section, they are all electrically connected. This results in part of a parallel circuit of these semiconductor elements (second group).
[0014] The undersides of the semiconductors are electrically conductive and lead to an electrode of the semiconductor. The semiconductor elements preferably provide transistors, so that, for example, the underside represents a drain connection (or a collector connection) of the first or second group. These electron connections are discharged via the different sections of the second connecting conductor layer. The first group of semiconductor elements can be regarded as a common first switching element. The second group of semiconductor elements can be regarded as a common second switching element. The first section serves to electrically connect a first connection of the first switching element, and the second section serves to electrically connect a first connection of the second switching element.
[0015] The same is also provided above the semiconductor layer by the first connecting conductor layer. This also has a first and a second section. The first section of the first connecting conductor layer is connected to the upper sides of the first group of semiconductor elements. The second section of the first connecting conductor layer is connected to the upper sides of the second group of half-elements. The connections are provided by vias; as with the second connecting conductor layer, the upper sides of the first group of half-elements are connected by the common connection to the first section. In addition, the upper sides of the second group of semiconductor elements are connected by the common connection to the second section of the first connecting conductor layer. These each represent part of a parallel connection.Since the top and bottom sides of the first group of semiconductor elements are connected to the first sections of the two connecting conductor layers, the elements are connected in parallel by connecting them to the same first sections of the two connecting conductor layers. The same applies to the second group of semiconductor elements and the second sections.
[0016] The first section of the first connecting conductor layer (connected to the top surfaces of the first group of semiconductor elements) is connected to the second section of the second connecting conductor layer (connected to the bottom surfaces of the second group of semiconductor elements). This creates a series connection of the first group of semiconductor elements with the second group of elements. Overall, this results in a series connection of the first switching element (represented by the parallel-connected first group of semiconductor elements) and the second switching element (represented by the parallel-connected second group of semiconductor elements). This series connection of two switching elements is also called a half-bridge. The connection itself corresponds to the connection point of the half-bridge, the potential of which is dissipated via a third contact surface.The ends of the two switching elements that are not connected to one another are connected to different contact surfaces, namely to (at least) one first contact surface and (at least) one second contact surface. The first and second contact surfaces serve to apply a supply voltage, in particular a DC supply voltage. The connection between the first section of the first connecting conductor layer and the second section of the second connecting conductor layer extends through the semiconductor layer, preferably without, however, contacting the semiconductors. The connection can be provided by one of several (parallel) vias. The connection can be viewed as the connection point between the two switches or transistors of the half-bridge. The connection extends in a section of the circuit board between the first group of semiconductor elements and the second group of semiconductor elements.
[0017] The (at least one) first contact surface is connected to the second section of the first connecting conductor layer. This, in turn, is connected to the top side of the second group of semiconductor elements. The top side of the semiconductor elements can represent a source (or emitter) connection. The first contact surface thus serves to contact the source or emitter of the second group of semiconductor elements. The second group of semiconductor elements or the second switching element can be considered the low-side switch of the half-bridge, while the first group thus forms the high-side switch of this half-bridge.Since the first contact surface is formed by the contact conductor layer to which the first connection conductor layer is connected (insulated), the connection between the first contact surface and the relevant section of the first connection conductor layer can be provided by a via that extends only through the insulation layer between the contact conductor layer and the first connection conductor layer.
[0018] The (at least one) second contact surface is connected to the second connecting conductor layer, in particular to the first section thereof. Since this section is connected to the underside of the first group of semiconductor elements, this second contact surface (of the second connecting conductor layer) can represent the drain (or collector) connection. The second contact surface thus serves to contact the drain or collector of the first group of semiconductor elements. The second contact surface thus forms the positive supply voltage connection, while the first contact surface forms the negative supply voltage connection. It is assumed here that the semiconductor elements are transistors, although a similar arrangement can also be provided for diodes. It is relevant that the opposite sides of the semiconductor element (top side, bottom side) represent different electrodes or connections of the power path of the semiconductor element.Then, as shown, a half-bridge can be formed in a simple manner by dividing the connecting conductor layer into first and second sections by means of a first and a second connecting conductor layer, between which the semiconductor layer is located, the inner connection of which is provided by a connection between corresponding sections of different connecting conductor layers. The corresponding contacting is achieved by the three contact surfaces, which are connected to the aforementioned connection (phase), as well as to the second section of the first connecting conductor layer and to the first section of the second connecting conductor layer, respectively. The inner connection can thus be arranged between the various groups of semiconductor elements, wherein furthermore the third contact surface can be provided on one side, while the first contact surface is located in the middle or on the other side of the three contact surfaces.This enables a low-induction supply of the supply potentials to the first and a second contact surface, especially since the third contact surface (phase) is located at the edge of the other two potentials and not between the contact surfaces of the supply potentials.
[0019] Embodiments provide that the (at least one) third contact surface is connected to the second connection conductor layer via vias. The vias lead from the contact layer (i.e. from the third contact surface of this layer) to the second section of the second connection conductor layer. The second section of the second connection conductor layer is thus not only connected (via vias) to the underside of the second group of hybrid elements, but also to the third contact surface. The second section of the second connection conductor layer is accordingly wide. The vias lead in particular from the second section of the second connection conductor layer via an additional section of the first connection conductor layer, which is electrically separated from the other sections of the first connection conductor layer. This is provided by first vias.Second vias connect this additional section to the third contact area. This results in a series connection of the first and second vias. In specific embodiments, there is only one via and / or only one second via, so that the first vias can be provided one or more times, and the second vias can also be provided one or more times.
[0020] An alternative embodiment provides for the (at least one) third contact surface to be connected to the first section of the first connecting conductor layer via (at least one) via. The at least one via extends from the third contact surface to the first section of the first connecting conductor layer, and thus only through the insulating layer between the contact conductor layer and the first connecting conductor layer. This is preferably provided when the second contact surface or the first contact surface does not extend over the entire first section of the first connecting conductor layer, thus providing sufficient space for the third contact surface.
[0021] Furthermore, the contact surfaces can each be designed as a free, conductive surface configured for surface contacting of the half-bridge circuit. "Free" refers to a surface whose conductive surface protrudes into the free space outside the half-bridge circuit and can thus be directly contacted from there. A contact surface with an applied protective varnish that can be pierced for contacting can also be considered a free, conductive surface (since contact was made from the outside by removing the protective varnish). An alternative embodiment provides a connection layer arranged on the contact surfaces or on the contact conductor layer by means of an insulation layer. The connection layer can provide external connection surfaces. These are individually connected to the contact surfaces.The connection can be provided by means of vias leading from the connection layer to the contact conductor layer. The various contact surfaces are individually connected to the outer connection surfaces provided by sections of the connection layer. The connection surfaces are formed by the connection layer, which can also be referred to as an additional conductor layer. The contact layer itself is physically protected by the connection layer and the underlying insulation layer. The application surfaces can be provided by sections of the connection layer or by metal inserts, for example, copper inserts, which form busbars. In particular, the circuit board can have a connection layer as mentioned above in addition to the contact conductor layer and the two connecting conductor layers.This would result in a five-layer structure, especially if the semiconductor layer is formed as a separate layer (conductor layer). A (conductive) heat dissipation layer can be provided by means of an insulation layer beneath the second connecting conductor layer, resulting in a six-layer structure. The heat dissipation layer can be completely insulated from the second connecting conductor layer, or it can itself have sections that are connected to components (sections, semiconductor elements) of the remaining circuit.
[0022] According to a further aspect, the second contact area (for a positive supply potential) is arranged above the first section of the first connecting layer or also above the second section of the first connecting conductor layer. In this case, the second contact area can be provided above the (second) section of the first connecting conductor layer that is connected to upper sides of the second group of semiconductor elements via vias. If the second contact area additionally extends laterally beyond the second section of the first connecting conductor layer, for example as a lateral projection, then the at least one second contact area can also be provided above the first section of the first connecting conductor layer, in particular in the vicinity of the first contact area. This reduces the connection inductance.
[0023] Furthermore, the (at least one) first contact surface (for a negative supply potential) can be arranged between the first and the second section of the first connecting conductor layer, i.e., above a location between these sections. In this case, the connection between the contact surface and the first section of the second connecting conductor layer pierces the first section or the first section thereof. An opening can thus be provided in the first connecting conductor layer, through which a connection between the first contact surface and the second connecting conductor layer (i.e., the first section thereof) extends. This enables electrical insulation between the second section of the first connecting conductor layer and the connection leading from the second connecting conductor layer to the first contact surface. Alternatively, the first contact surface can be provided next to the semiconductor elements, i.e.,in an edge region of the circuit board. The third contact surface can be provided in an opposite edge region. In particular, the first contact surface can be provided above a location adjacent to the first and second sections of the first connecting conductor layer. In particular, a third section of the first connecting conductor layer can be provided that lies adjacent to the first and second sections of this conductor layer, for example, at an edge region, wherein in particular the first contact surface is arranged above the third section and is connected to it, in particular, via vias.
[0024] One embodiment provides that the at least one third contact surface is provided above the first section of the first connecting conductor layer. Natively, the at least one third contact surface can be arranged adjacent to this section, in particular in an edge region above a location adjacent to the sections of the first connecting conductor layer. The at least one third contact surface is provided, in particular, for connecting a phase. The third contact surface can also be considered an AC connection, in particular if the half-bridge is provided in an inverter.
[0025] The circuit board may have a cooling layer. This is preferably made of a metallic material such as copper or a copper alloy, or even of aluminum or an aluminum alloy. The cooling layer is arranged beneath the second connecting conductor layer. An insulating layer is provided between these two layers. The cooling layer may be completely electrically insulated from the second connecting conductor layer by the insulating layer. However, said conductor layer or the cooling layer may be divided into sections that are connected to sections of the second connecting conductor layer via vias. The cooling layer may generally be electrically connected to the second connecting conductor layer or sections thereof, in particular by means of vias. The vias extend through the insulating layer between the cooling layer and the second connecting conductor layer.Vias extending through the insulation layer may be provided. These electrically connect the cooling layer to the second connecting conductor layer, either completely or in sections.
[0026] The semiconductor elements can be unhoused or housed power transistors, for example in the form of chips (bare dies). The semiconductor elements are preferably each provided with a metal body and an unhoused power transistor, namely a semiconductor chip. The semiconductor elements can be provided as metal bodies carrying one or more power transistors. In this case, the power transistors have the form of bare dies, i.e. semiconductor chips. The semiconductor chips have two electrodes arranged on opposite sides, namely the top and bottom, of the semiconductor element. The semiconductor chips each have a bottom side with which the semiconductor chip is attached to the metal body, in particular in an electrically conductive manner. The semiconductor chips can be soldered or sintered onto the metal body. In particular, the semiconductor chip can be embedded in the surface of the metal body.For this purpose, the metal body has a recess (blind hole) in which the semiconductor chip is arranged, wherein the underside of the semiconductor chip is connected to the bottom of the recess in an electrically conductive manner, in particular by sintering or soldering.
[0027] The half-bridge circuit may include an intermediate circuit capacitor. This is preferably arranged over the contact surfaces, in particular over the first and second contact surfaces. The intermediate circuit capacitor is preferably arranged over those contact surfaces that are connected to the first section of the second connecting conductor layer and to the top surfaces of the second group of semiconductor elements. The intermediate circuit capacitor may have two bottom-side contacts. A first of these contacts may be connected to the first contact surface, and a second of these contacts may be connected to the second contact surface. As a result, the intermediate circuit capacitor is directly connected with low inductance (to the supply potentials that are carried in the circuit board).
[0028] Signal lines or sections thereof can be formed in the circuit board. In particular, the first connection conductor layer or the contact conductor layer can form such signal lines or sections thereof by structuring. The signal lines or sections thereof lead to the semiconductor elements, for example to a control terminal thereof, but can also lead to a temperature sensor. Temperature sensors can be arranged directly below, next to, or directly above the semiconductor elements. Temperature sensors can in particular be provided in the semiconductor layer. The signal lines can in particular also be designed as drain or source taps or as collector or emitter taps, for example to feed back corresponding signals.
[0029] The circuit board may further comprise an area where a control circuit is provided which is connected to the elements in a controlling manner.
[0030] A multi-phase bridge circuit, for example a B6C bridge, or a fully controllable AC bridge with more or fewer phases than three, can comprise several of the half-bridge circuits described here. The contact surfaces of the individual half-bridge circuits connected to the first section of the second connection conductor layer (configured to provide first contact surfaces, i.e., configured for connection to a positive supply potential) are preferably electrically connected to one another. This latter connection can be provided by a connection in a module frame carrying the half-bridge circuits. Likewise, the contact surfaces of the individual half-bridge circuits connected to the top surfaces of the second group of semiconductor elements (second contact surfaces, for connection to a negative supply potential) can be electrically connected to one another.This can also be achieved by a connection in a module frame that supports the half-bridge circuits. The third contact surfaces or the respective potentials of the multiple half-bridge circuits are preferably contacted individually, in particular by different phases of a component that can be connected to the bridge circuit.
[0031] Another possibility is to provide the half-bridge circuits of the multi-phase bridge circuit in different sections of the same circuit board. In this case, the half-bridge circuits are located next to each other. Furthermore, the half-bridge circuits can be provided by physically independent, individual circuit board sections. These two circuit board sections form the respective circuit board of the half-bridge circuit. The half-bridge circuit sections or the respective circuit boards can be jointly supported by a module frame (see above).
[0032] The layers can be arranged in the following sequence (with an insulating layer in between): contact conductor layer, first connecting conductor layer, second connecting conductor layer, then, if applicable, a cooling layer. If present, a bonding layer can precede the contact conductor layer in the sequence. Additional covering or protective layers can be provided, in particular above the contact conductor layer, above the bonding layer, below the cooling layer, or below the second connecting conductor layer or the subsequent insulating layer. An insulating layer can precede the contact conductor layer in this sequence. The second contact conductor layer can be followed by an insulating layer.
[0033] The first connecting conductor layer can be interposed in an insulating manner between the contact conductor layer and the second connecting conductor layer. The semiconductor layer can be located between the first and second connecting conductor layers.
[0034] Furthermore, “electrically separated” means in particular that there is no direct electrical connection in the layer in question; however, connections via semiconductor elements may be provided.
[0035] "Insulating" means electrically insulating, whereby thermal conductivity may be provided. An insulating layer beneath the second connecting conductor layer can be formed with a higher thermal conductivity coefficient than the insulating material between the other layers, particularly in the form of a ceramic layer. "Interposed insulatingly" means that the respective layers are connected to one another via insulating layers. The layers extend along a main extension direction (length, width, not thickness) of the circuit board. This also applies to the semiconductor elements.
[0036] The term "section" refers to a section along the main extension direction (width, length) of the circuit board and refers in particular to the entire thickness of the circuit board. The term "connected" refers in particular to a direct connection between the aforementioned components, whereby the connection extends from one connection to the other. The vias run perpendicular to the extension plane of the circuit board. The contact surfaces are in particular circular, oval, in the form of an elongated hole, or polygonal, such as square or rectangular.
[0037] The semiconductor elements include power transistors designed for continuous currents of more than 10 A or more than 100 A. In particular, the power transistors have a blocking voltage of at least 200 V, and in particular of more than 400 V, for example, more than 600 V. The power transistors are MOSFETs or IGBTs. In particular, the conduction transistors can be SiC MOSFETs or GaN MOSFETs.
[0038] The Fig. 1 and Fig. 2 serve to explain in more detail exemplary embodiments of the half-bridge circuit described here. Fig. 1 and Fig. 2 are cross-sectional views. Fig. Figure 3 schematically shows an embodiment of a multiphase bridge circuit with the circuits described here.
[0039] The Fig. 1 and Fig. 2 each show a printed circuit board (PCB) with a contact conductor layer L1 arranged in an insulating manner over a first connection conductor layer L2. The first connection conductor layer L2 is in turn arranged in an insulating manner over a semiconductor layer H1, beneath which a second connection conductor layer L3 is located (electrically insulated).
[0040] A first group HS and a second group LS of semiconductor elements extend within the semiconductor layer HI. The semiconductor elements each comprise a metal body in which a semiconductor chip T (configured as a transistor) is embedded. The underside of the chip T is connected to the metal body M.
[0041] The contact conductor layer L1 is divided into different sections, which implement first, second and third contact surfaces KP, KN and KW. The contact surfaces can each be provided multiple times, for example by repeating them in a direction perpendicular to the plane of the drawing. This applies to the first, second and third contact surfaces KP, KN and KW. On the first contact surface KP there is a corresponding connecting body VP. This also applies accordingly to the connecting body VN on the second contact surface KN and to the connecting body PH above the third contact surface KW. The connecting bodies can also be provided as conductor tracks or as contact surfaces located on an insulation layer ISO. This layer ISO can carry a further conductor layer L, which is also referred to as a connection layer. The further conductor layer L can form contact surfaces KN line or even correspondingly designed connecting bodies.The connecting bodies can extend through the insulation layer ISO directly to the respective contact surfaces, or the contact surfaces, such as the contact surface KN', can be provided as a section of the further conductor layer L, which is connected to the respective surface of the contact conductor layer L1 via a via KNV.
[0042] A stator ZK can be provided between this conductor layer L or directly on the contact conductor layer L1. This is located above the first contact surface VP and below the second contact surface VN. These two contact surfaces serve to feed the supply potential. The capacitor can thus have bottom contacts that are directly connected to these surfaces, or that are connected to the contact surfaces with connections leading to them.
[0043] It can be seen that the first connecting conductor layer L2 is divided into two sections, namely the first section A3 and the second section A4. These are electrically insulated from one another by a gap. The second connecting conductor layer also has two sections that are insulated from one another by a gap, namely the first section A1 and the second section A2. The first section A3 of the first connecting conductor layer L2 is connected on the top side to the first group of semiconductor elements HS, in particular to their transistors T (or their top side contact). The first section A1 of the second connecting conductor layer L3 is connected on the bottom side to the first group of semiconductor elements HS, in particular to their transistors T (or the bottom side of the metal body M in which the transistor T is attached). Thus, sections A1 and A3 contact the two ends of the first group of semiconductor elements HS. HS stands for "high side".
[0044] Accordingly, the second section A4 of the first connecting conductor layer L1 is connected on the top side to the surface contacts of the second group of semiconductor elements LS. On the bottom side, these semiconductor elements LS are connected to the second section A2 of the second connecting conductor layer L3. LS stands for "lowside."
[0045] The connection V connects the first section A3 of the first connecting conductor layer L2 to the second section of the second connecting conductor layer L3. This connection V, as well as the connections between the aforementioned sections and the semiconductor elements, are vias between the respective layers or semiconductor elements. The vias D1 to D4 are shown as examples, with D1 and D2 connecting the first section A1 of the second connecting conductor layer L3 to the underside of the first group of semiconductor elements HS, and D3 and D4 connecting the second section A2 of the second connecting conductor layer L3 to the underside of the first group of semiconductor elements HS. As with other vias, it can be seen that these can be provided by several parallel via elements.
[0046] The connection V creates a connection point between the two elements of the half-bridge, namely the first switching element formed by the first group HS of half-elements and the second switching element formed by the second group LS of switching elements. The semiconductor elements of the first group HS are connected in parallel. This also applies to the second group LS. The respective connection point is connected to the third contact surface KW.
[0047] In the Fig. 1, this is achieved by connecting the second section of the second connecting conductor layer L3 to the third contact surface KW via two consecutive vias DO', DU'. The vias DO', DU' are connected to a third section of the first connecting conductor layer L1 via a third section. This results in the third contact surface KW being positioned at one end, while the contact surfaces KP, KN for the supply voltage (DC voltage) are located at the opposite end.
[0048] In the Fig. 2, the third contact surface KW is formed by a section of the contact conductor layer L1, which is directly connected to the first section A3 of the first connecting conductor layer L2 via several adjacent vias DP. Thus, in the Fig. 2 the contact area KW above the semiconductor elements of the first group HS and directly above the section A3.
[0049] The first contact surface KP is in the Fig. 1 on the left edge of the printed circuit board PCB shown as a section of the contact conductor layer L1. The first contact area KP is connected to the section A1 of the second connecting conductor layer L3 via successive first and second vias DO, DU. For this purpose, the first connecting conductor layer L2 provides an additional section which is connected to the contact area KP at the top (as a section of layer L1) via the vias DO. This additional section is further connected to the section A1 of the conductor layer L3 at the bottom via the vias DU. This results in the first contact area KP being positioned next to the point where the semiconductor elements are located, i.e. at the edge, with the underside contacting of the semiconductor elements via the vias D1, D2, the section A2 and the vias DU, DO.
[0050] In the Fig. 2, the first contact surface KP is located in a region between the groups of semiconductor elements HS, LS, wherein in the same way the first contact surface KP is connected to the section A1 of the layer L3 via an additional section of the layer L2 and via two consecutive vias DO, DU. In this case, the additional section of the layer L2, which is connected to the first contact surface KP, is provided in an opening O provided in the section A3. However, the section A3 is not severed by the opening O, but rather conductor track sections or conductor surfaces result in regions of the layer L2 that are located outside the opening O. Thus, the section A3 can be provided as a surface that is continuous except for the opening O. The opening O is located within the circumference of the section A3.
[0051] In the Fig. 1, the second contact surface KN is provided as a section in the contact conductor layer. In an area above the second group of semiconductor elements LS there is a second section A4 of the layer L2. This is connected to the section representing the surface KN by means of vias DN. The vias DN connect the section of L1 representing the surface KN to the section A4 (second section of the first connecting conductor layer L2). The contact surface KN can also be located at a different location than that shown, for example above the elements LS, although there would be a greater distance to the first contact surface KP there. Thus, starting from the location where the semiconductor elements LS are located, there is a projection projecting towards the first contact surface KP, wherein the second contact surface KN is provided at a location on the projection that is opposite the first contact surface KP.a respective connecting element VN.
[0052] In the Fig. 2, the contact surface KN is provided by a section of the contact conductor layer L1. This section lies above the section A4, ie the second section of the first connection conductor layer L2. These sections in the contact conductor layer L1 and in the first connection conductor layer L2 (= section A4) lie above each other and are connected by means of intermediate vias. A comparable connection is shown in Fig. 2 is provided for the contact surface KW, which is formed by a section of the contact conductor layer L1, which in turn is connected via vias DP to the underlying section A3 of the first connection conductor layer L2.
[0053] Based on the Fig. 2 shows, by way of example, that a cooling layer KS can be connected. This is formed, for example, below layer L3, in particular on an insulation layer ISO', which connects the cooling layer KS to layer L3. The insulation layer ISO' can also be attached to the underside of the second connecting conductor layer L3 without a subsequent cooling layer KS. The kitchen is KS is only shown for a small section. The valid KS can be a copper layer or an aluminum layer. The cooling layer KS can be thicker than the layers L1 to L3 (individually).
[0054] In contrast to the Fig. 1 is the section of layer L1, which constitutes the third contact surface KW, in the Fig. 2 over a section A3 of the first connecting conductor layer L2, which is connected to the semiconductor elements (reference symbol HS) by means of vias D11, D12.
[0055] Further vias in the Fig. 2 are represented by the reference symbols D13, D14, which connect the section A4 of the layer L2 with the surface contacts of the hybrid elements LS.
[0056] In contrast to the Fig. 1, the second contact surface KN is located in the Fig. 2 over the section A4 of the layer L2 and thus over those of the semiconductor elements LS, to which this section A4 is also connected. Fig. 2 a connection of the second contact surface KN leading essentially in the thickness direction. In the Fig. 1, however, a projection extends from the area of the conductor layer L1 that lies above the section A4 to the first contact surface KP, so that the second contact surface KN does not lie above the section A4 of the layer L2, which is connected to the semiconductor elements LS by means of vias. The connection of the second contact surface in Fig. 1 thus has a significant horizontal portion, i.e., a section that runs along the direction of the printed circuit board (PCB). While this results in a longer line length, it allows for the direct arrangement of the second contact surface (KN) to the first contact surface (KP). This, in turn, enables a low-inductance connection of supply busbars.
[0057] The Fig. Figure 3 schematically shows a multi-phase bridge circuit with several embedded half-bridge circuits. The bridge circuit is three-phase, with each phase being implemented by a half-bridge circuit 1, 2, 3. The bridge circuit has a module frame R (electrically insulating, e.g., made of plastic) in or on which two busbars HV+, HV- are provided. Furthermore, the frame has three individual phase contacts P1, P2, P3. Each of the illustrated half-bridge circuits 1, 2, 3 has a group of first contact surfaces KP, second contact surfaces KN, and third contact surfaces KW. The contact surfaces KP of the half-bridge circuits 1, 2, 3 are connected to the positive busbar HV+. The contact surfaces KN of the half-bridge circuits 1, 2, 3 are connected to the positive busbar HV. This makes it easy to apply a supply voltage (DC voltage) to the bridge circuit by contacting the current rails HV-, HV+.The contact surfaces KP and KN of half-bridge circuits 1, 2, and 3 are arranged at the illustrated upper end of the respective half-bridge circuit. This corresponds to an embodiment according to . Fig. 1. Accordingly, the third contact surfaces KW are provided at the opposite end. These are connected to individual phase contacts P1, P2, and P3. The windings of an electrical machine or the phases of a three-phase system can be connected to these, depending on whether the bridge circuit is operated as an inverter for an electrical machine or as a rectifier, for example, for three-phase alternating current.
[0058] Finally, the semiconductor elements HS, LS of each half-bridge circuit are shown in dashed lines. These semiconductor elements are located in a plane below the contact surfaces KP, KN, KW, so that the semiconductor elements are shown in dashed lines. It can be seen that the group of low-side semiconductor elements is provided in the lower half, and the high-side semiconductor elements in the upper half of the half-bridge circuits. With regard to the connection between these elements and also to the contact surfaces, reference is made to the Fig. 1. The connections between the first and second contact surfaces KN, KP and the associated busbars HV+, HV- are shown as individual connections, although preferably a common strip can be used. For example, all second contact surfaces KN can be connected to the busbar HV- via a conductive strip (approximately one strip per half-bridge circuit), and all first contact surfaces KP can be connected to the busbar HV+ via another conductive strip (approximately one further strip per half-bridge circuit). Fig. 3 and also the Fig.1 shows that these strips or common connections between the half-bridge circuits 1, 2, 3 and the module frame R can be routed closely together, for example as superimposed strips with an insulating layer in between. Since the first and second contact surfaces are close to one another, the area between the positive and negative supply potential can be kept very small, resulting in a low-inductance connection to a DC voltage source (such as an intermediate circuit capacitor and / or a high-voltage battery). A common intermediate circuit capacitor can be arranged on the contact surfaces KP, KN of the half-bridge circuits 1, 2, 3 in order to connect the intermediate circuit capacitor with low inductance.
Claims
[1] Embedded half-bridge circuit with a multilayer printed circuit board (PCB) comprising: a) a contact conductor layer (L1) with at least a first, a second and a third contact surface (KP, KN, KW) which are electrically separated from one another; b) a first connecting conductor layer (L2); c) a semiconductor layer (HI) in which a first and a second group of semiconductor elements (HS, LS) are provided and d) a second connecting conductor layer (L3), wherein the layers (L1, L2, HI, L3) are arranged one above the other, the semiconductor layer (HI) is located between the first connecting conductor layer (L2) and the second connecting conductor layer (L3), and a first section (A1) of the second connecting conductor layer (L3) is connected via vias (D1, D2) to undersides of the first group of semiconductor elements (HS) and a second section (A2) of the second connecting conductor layer (L3) is connected via vias (D3, D4) to undersides of the second group of semiconductor elements (LS), wherein the first and second sections (A1, A2) of the second connecting conductor layer (L3) are electrically separated from one another, and a first section (A3) of the first connecting conductor layer (L2) is connected to upper sides of the first group of semiconductor elements (HS) via vias (D11, D12) and a second section (A4) of the first connecting conductor layer (L2) is connected to upper sides of the second group of semiconductor elements (LS) via vias (D13, D14), wherein the first and second sections (A3, A4) of the first connecting conductor layer (L2) are electrically separated from one another; wherein the first section (A3) of the first connecting conductor layer (L2) is electrically connected to the second section (A2) of the second connecting conductor layer (L3), at least a first of the contact surfaces (KN) is connected to the second section (A4) of the first connecting conductor layer (L2) via vias (DN) and at least a second of the contact surfaces (KP) is connected to this first section (A1) via vias (DO, DU) which lead from the contact conductor layer (L1) to the first section (A1) of the second connecting conductor layer (L3). [2] Embedded half-bridge circuit according to claim 1, wherein at least a third of the contact surfaces (KW) is connected to the second connecting conductor layer (L3) via vias (DO', DU') leading from the contact conductor layer (L1) to the second section (A2) of the second connecting conductor layer (L3), or at least a third of the contact surfaces (KW) is connected to the first section (A3) of the first connecting conductor layer (L2) via vias (DP). [3] Embedded half-bridge circuit according to claim 1 or 2, wherein the contact surfaces (KP, KN, KW) provide a free, conductive surface configured for surface contacting of the half-bridge circuit, or an insulation layer (ISO) is provided on the contact surfaces (KP, KN, KW), on which insulation layer, in turn, external connection surfaces (KN') are provided, which are individually connected to the contact surfaces (KP, KN, KW), wherein the connection surfaces (KN') are formed by a further conductor layer (L). [4] Embedded half-bridge circuit according to claim 1, 2 or 3, wherein the at least one second contact surface (KN) is arranged above the first or the second section (A3, A4) of the first connecting conductor layer (L2) or above a location between these sections (A3, A4). [5] Embedded half-bridge circuit according to one of the preceding claims, wherein the at least one first contact surface (KP) is arranged above a location between the first or the second section (A3, A4) of the first connecting conductor layer (L2) or adjacent to these sections (A3, A4). [6] Embedded half-bridge circuit according to one of the preceding claims, wherein the at least one third contact surface (KW) is provided above the first section (A3) of the first connecting conductor layer (L2) or is arranged next to this section (A3). [7] Embedded half-bridge circuit according to one of the preceding claims, wherein a cooling layer (KS) made of metallic material is attached to the second connecting conductor layer (L3) via an insulating layer (ISO'), wherein the cooling layer (KS) is electrically insulated from the second connecting conductor layer (L3) by the insulating layer (ISO'), or wherein vias extending through the insulating layer electrically connect the cooling layer (KS) to the second connecting conductor layer (L3). [8] Embedded half-bridge circuit according to one of the preceding claims, wherein the semiconductor elements (HS, LS) are unhoused or housed power transistors, or wherein the semiconductor elements (HS, LS) each have a metal body and at least one power transistor semiconductor chip (T), wherein the power transistor semiconductor chip (T) is applied to the metal body (M) or the power transistor semiconductor chip (T) is embedded in the surface of the metal body (M). [9] Embedded half-bridge circuit according to one of the preceding claims, which has an intermediate circuit capacitor (ZK) which is arranged above the contact surfaces (KP, KN) which are connected to the first section (A1) of the second connecting conductor layer (L3) and to the upper sides of the second group of semiconductor elements (LS), or which is at least electrically connected to these contact surfaces. [10] Embedded half-bridge circuit according to one of the preceding claims, wherein the first connecting conductor layer (L2) and / or the contact conductor layer (L1) form signal lines or sections thereof which lead to the semiconductor elements (HS, LS) and / or to at least one temperature sensor which is arranged directly below, next to or directly above the semiconductor elements (HS, LS). [11] Multi-phase bridge circuit with a plurality of embedded half-bridge circuits according to one of the preceding claims, wherein the contact surfaces (KP, KN) of the individual half-bridge circuits connected to the first section (A1) of the second connecting conductor layer (L3) are electrically connected to one another, and the contact surfaces (KP, KN) of the individual half-bridge circuits connected to the upper sides of the second group of semiconductor elements (LS) are also electrically connected to one another. [12] A multi-phase bridge circuit according to claim 11, wherein the embedded half-bridge circuits are provided in different sections of the same continuous printed circuit board, or wherein the embedded half-bridge circuits are provided by physically independent, individual printed circuit board pieces forming the respective printed circuit board of the half-bridge circuit.
Citation Information
Patent Citations
Power semiconductor module with integrated thick-film printed circuit board
DE102011083223A1