Half-bridge package and electronic power module comprising a plurality of such half-bridge packages

Abstract

The invention relates to a half-bridge package (205) comprising two ceramic substrates (500, 505), a first power semiconductor (510) being provided on the first ceramic substrate and a second power semiconductor (515) being provided on the second ceramic substrate; a first load connection (410) which is connected to a first frame segment (520) of a first lead frame (525); two second load connections (415, 420) which are connected to a second frame segment (530) of the first lead frame; and a third load connection (425) which is connected to a third frame segment (535) of the first lead frame, said second frame segment (530) being electrically connected to the first power semiconductor and to the second ceramic substrate (505). The half-bridge package further comprises a second lead frame (537) having a fourth frame segment (539), which is positioned spatially between the second frame segment of the first lead frame and the two ceramic substrates, said fourth frame segment being electrically connected to the second power semiconductor and to the first ceramic substrate, and each ceramic substrate is equipped with a control connection (555), each of which is electrically connected to a signal transmission element (430) for controlling the half-bridge package and to the power semiconductors of the respective ceramic substrate via connecting elements (560). The invention also relates to an electronic power semiconductor, an electric drive axle and a motor vehicle.

Description

[0001] Half-bridge package and electronic power module with several such

[0002] Half-bridge packages

[0003] The present invention relates to a half-bridge package for an electronic power module and to an electronic power module for an engine control system comprising a plurality of such half-bridge packages. Furthermore, the invention relates to an electric drive axle comprising such a power module and to a motor vehicle.

[0004] For example, DE 10 2009 044 659 A1 discloses a power semiconductor module comprising a lead frame, a power semiconductor element, and a cylindrical conductor. A portion of the lead frame, the power semiconductor element, and the cylindrical conductor are each sealed with a compression-molding resin, with terminal portions of the lead frame protruding from peripheral side portions of the power semiconductor module, and an opening of the cylindrical conductor being exposed on an upper surface of the power semiconductor module.

[0005] One object of the invention is to provide a compact half-bridge package that can achieve improved performance within a given installation space. The invention achieves this object by means of the subject matter of the independent claims. Subordinate claims specify preferred embodiments.

[0006] According to a first aspect of the invention, a half-bridge package for an electronic power module comprises a first ceramic substrate and a second ceramic substrate, wherein a first power semiconductor is arranged on the first ceramic substrate and a second power semiconductor is arranged on the second ceramic substrate, a first load terminal connected to a first frame segment of a first leadframe, two second load terminals connected to a second frame segment of the first leadframe, and a third load terminal connected to a third frame segment of the first leadframe, wherein the second frame segment of the first leadframe is electrically connected to the first power semiconductor and to the second ceramic substrate, wherein the half-bridge package further comprises a second leadframe with a fourth frame segment,which is spatially arranged between the second frame segment of the first leadframe and the two ceramic substrates, wherein the fourth frame segment of the second leadframe is electrically connected to the second power semiconductor and to the first ceramic substrate, and wherein a control terminal is arranged on each ceramic substrate, which is electrically connected to signal transmission elements for controlling the half-bridge package and via connecting elements to the power semiconductors of the respective ceramic substrate.

[0007] The half-bridge package is understood as the B2 package of an electronic power module. The half-bridge package forms a half-bridge of a motor control system. Several half-bridges, preferably three half-bridges, can be provided in a separately controllable manner to operate an electrical machine of a motor vehicle. The half-bridge package is used to switch current, particularly for loads in the several tens of kW range, especially for electrical machines, e.g., for a motor vehicle.

[0008] The first load terminal and the third load terminal have the same potential. The second load terminal has a different potential. Current symmetry can be achieved by appropriately arranging the first load terminal, the second load terminals, the third load terminal, and the power semiconductors—in other words, by selecting a suitable topology for the half-bridge package. The half-bridge package is current-symmetrical if the current flow within the half-bridge package, in particular within the ceramic substrate, is evenly distributed. This means that the current in different paths or branches of a circuit is always the same. Current symmetry ensures that the circuit functions properly and that no undesired effects occur. In addition, a half-bridge package as described herein improves electrical testability, which can increase yield.Furthermore, the heat dissipation of the power semiconductors can be optimized, in particular through heat spreading. The first or second ceramic substrate can be an AMB substrate (Active Metal Brazing) or a DPC substrate (Direct Plated Copper). The two ceramic substrates are preferably arranged in a common plane and spaced apart from one another. The first ceramic substrate forms the so-called "high side" of the electronic power module and the second ceramic substrate forms the so-called "low side" of the electronic power module, or vice versa. The ceramic substrate assigned to the "high side" is located on the side with the higher electrical potential reference and is connected to the high potential.The ceramic substrate assigned to the “low-side” is located on the side with the lower electrical potential reference, i.e. the ground or the negative supply potential, and is connected to the so-called “low potential”.

[0009] The load connections of the first leadframe can be formed from a common sheet metal and formed into a stamped grid by punching and forming, and then brought into their final shape. The frame segments are formed by punching and forming the sheet metal. After punching and forming the sheet metal, bonding the frame segments to the ceramic substrate, and subsequent encapsulation, a remaining frame, which may have been fixed during production, can be separated from the load connections, in particular to separate the load connections of the first leadframe from one another.

[0010] The first and third load terminals are configured to electrically connect a busbar to the power semiconductors of the half-bridge package, with a connection between the ceramic substrates being established via the second leadframe. The first and third load terminals together form the AC terminal, or the "source" side, of the half-bridge package. This allows the half-bridge package to be designed more compactly. The power density can be increased while maintaining a compact design. The second load terminal forms the DC plus terminal, or the "drain" side, of the half-bridge package.

[0011] The load terminals can have several integrally connected legs, connectors, arms, and / or connection sections. One connection leg of each load terminal, i.e., a leg that serves as a connection element for the external connection of the half-bridge package and has a contact surface, can be arranged three-dimensionally in space such that the contact surfaces of all load terminals of the half-bridge package are arranged in a common plane, in particular on an upper side of the half-bridge package encapsulated after production. This can improve the connection to the half-bridge package in the motor control system.

[0012] The load terminals are connected to lead frames, which comprise frame segments, i.e., connecting or guide frames. The respective frame segment carries the applied electrical energy to the power semiconductors of the respective ceramic substrate. If a plurality of first or second power semiconductors are provided, the second and fourth frame segments can be configured such that the electrical energy is distributed evenly among all first or second power semiconductors via cross connectors, branches, connection sections, or the like.

[0013] The control terminal is to be understood as the gate conductor of the respective ceramic substrate of the half-bridge package. Each ceramic substrate has a separate control terminal. The respective control terminal comprises a signal substrate with a ceramic layer arranged between a lower copper layer facing the respective ceramic substrate and an upper copper layer. The lower copper layer of the signal substrate has the same potential as the upper copper layer of the ceramic substrate. The upper copper layer of the control terminal is electrically connected to the signal transmission elements and the connecting elements. The ceramic layer is an electrical insulation layer. The ceramic layer is formed, for example, from aluminum oxide or silicon nitride. The lower copper layer of the signal substrate is configured to be connected to the associated ceramic substrate.The upper copper layer of the signal substrate is electrically connected to the signal transmission elements and the connecting elements. Sintered layers are preferably applied to the upper copper layer of the signal substrate for secure electrical connection of the signal transmission elements and the connecting elements. The upper copper layer of the control connection and / or the respective ceramic substrate can be segmented. Segmentation may be necessary to electrically connect only the required parts. The segmentation of the upper copper layer can be achieved by targeted etching after its application to the ceramic layer.

[0014] The connecting elements are preferably wire-shaped, in particular as bond wires. Two bond wires each electrically connect the upper copper layer of the control terminal to a first or second power semiconductor. The bond wires are made, for example, of aluminum, copper, or another material with good electrical conductivity.

[0015] A power semiconductor is a current valve with an input, an output, and a control terminal. The input and output are connected to the upper copper layer or the frame segment of the respective leadframe. The respective power semiconductor can be electrically insulated by encapsulation, particularly injection molding, preferably transfer molding. Current scaling can be achieved by the number and size of the parallel-connected power semiconductors.

[0016] The ceramic substrate is preferably substantially rectangular, in particular square. Each ceramic substrate preferably has a ceramic layer between a lower copper layer and an upper copper layer, wherein the respective first power semiconductor is arranged between the upper copper layer of the first ceramic substrate and the second frame segment of the first leadframe and is electrically connected thereto, and wherein the respective second power semiconductor is arranged between the upper copper layer of the second ceramic substrate and the fourth frame segment of the second leadframe and is electrically connected thereto. The ceramic layer of the respective ceramic substrate is an electrical insulation layer. The ceramic layer is formed, for example, from aluminum oxide or silicon nitride.The lower copper layer of the respective ceramic substrate is designed to be connected to a heat sink or cooling plate for heat dissipation. In other words, the lower copper layer of the respective ceramic substrate is designed for cooling connection. The lower copper layer is to be understood as the back or underside of the package, which is, for example, integrally connected to the heat sink. The heat sink is preferably part of an electronic power module. The upper copper layer of the respective ceramic substrate is at least electrically connected to other components of the half-bridge package.

[0017] In addition to the electrical connection, a thermal connection of the upper copper layer of the respective ceramic substrate is preferably made with the first load terminal, the second load terminals, the third load terminal, the control terminal and the power semiconductors.

[0018] Preferably, first sintered layers are applied to the upper copper layer of the first ceramic substrate in order to at least electrically connect this upper copper layer to the third frame segment of the first leadframe, to first connection sections of the second frame segment of the first leadframe, and to the first power semiconductors. The first connection sections are preferably designed and arranged such that a mirror-symmetrical arrangement occurs on the first ceramic substrate. Preferably, second sintered layers are applied to the upper copper layer of the second ceramic substrate in order to at least electrically connect this upper copper layer to the first frame segment of the first leadframe, to second connection sections of the fourth frame segment of the second leadframe, and to the second power semiconductors.The second connection sections are designed and arranged such that a mirror-symmetrical arrangement is achieved on the second ceramic substrate. Due to the large number of components connected to the upper copper layer of the first or second ceramic substrate, a large number of separate first sintered layers are also arranged on the surface of the upper copper layer of the ceramic substrate. The sintered layers can alternatively each be formed as solder layers. Whenever sintered layers are mentioned above and below, a solder layer can alternatively be provided, and vice versa.

[0019] The first sintered layers act as receptacles for further components of the half-bridge package, wherein in particular power semiconductors arranged on the receptacles are electrically connected in parallel between the upper copper layer of the respective ceramic substrate and the second or fourth frame segment.

[0020] A sintered layer is designed to establish or secure an electrical connection between two components of the half-bridge package. Furthermore, the sintered layer improves the thermal properties in the contact area. The sintered layer enables a reliable and permanent connection between two components. The sintered layer is created through a sintering process in which powder particles, a sintered paste, or a sintered film are melted using heat and pressure, thus producing a dense and homogeneous layer that enables, in particular, efficient heat transfer. The sintered layer can be made of various materials that are both electrically conductive and have good thermal properties.When it is said that two components are electrically connected to one another, this also means that a sintered layer, and optionally further layers, can be arranged between these components.

[0021] Preferably, the first load terminal is electrically connected to the upper copper layer of the second ceramic substrate, the second load terminals are electrically connected to the upper copper layer of the second ceramic substrate, and the third load terminal is electrically connected to the upper copper layer of the first ceramic substrate. The second load terminals are thermally coupled to the second ceramic substrate or the upper copper layer of the second ceramic substrate. The third load terminal is thermally coupled to the first ceramic substrate or the upper copper layer of the first ceramic substrate. In addition, the second leadframe, in particular the fourth frame segment, is thermally coupled to the first ceramic substrate or the upper copper layer of the first ceramic substrate. Thermal coupling effects cooling of the respective frame segment.If the connection points to the respective ceramic substrate are located directly in front of or near the load terminals, the cooling effect can ensure that no heat is introduced into the load terminals or that the temperature of the load terminals is lower. This can also reduce the temperature in the busbars connected to the load terminals.

[0022] The signal transmission elements are preferably sleeve-shaped and / or pin-shaped. Sleeve-shaped signal transmission elements can serve as receptacles for electrical conductors for signal transmission, for example, control pins. Compared to control pins applied directly to the control connection, sleeves have the advantage that a compression tool can be better sealed during the subsequent encapsulation process, with the electrical connection being created only after encapsulation. A so-called flex film, i.e., a flexible printed circuit board, can be bonded to the sleeve.

[0023] Preferably, exactly two signal transmission elements are connected to the control terminal of the respective ceramic substrate. In other words, exactly two sleeves and / or signal pins are connected to the upper copper layer of the respective control terminal or signal substrate. If two signal transmission elements are provided, these pins are intended for gate control of the high-side or low-side of the half-bridge package. The respective power semiconductor is controlled via the two signal transmission elements, the upper copper layer of the signal substrate, and the connecting elements. The signal transmission elements are connected to the associated power semiconductors for signal transmission.

[0024] According to one embodiment, the first load terminal is spatially arranged between the two second load terminals. In other words, the first frame segment of the first leadframe is arranged between two sheet metal sections of the second frame segment, each of which forms one of the second load terminals. The first load terminal and the second load terminals are preferably arranged on one of the shorter side edges of the half-bridge package, whereas the third load terminal is arranged on the opposite side edge of the half-bridge package. Thus, the half-bridge package is externally connected via its respective head end.Preferably, a third sintered layer, a bond buffer layer, and either a fourth sintered layer or solder layer are arranged between the second frame segment of the first leadframe and the at least one first power semiconductor, and between the fourth frame segment of the second leadframe and the at least one second power semiconductor, starting from the respective power semiconductor. In other words, the bond buffer layer is arranged between the fourth sintered layer or the solder layer and the third sintered layer, wherein the solder layer or the fourth sintered layer is assigned to the second or fourth frame segment of the first or second leadframe, respectively, and the third sintered layer is assigned to the respective power semiconductor. The third sintered layer creates a dense, homogeneous connection layer between the respective power semiconductor and the bond buffer. The bond buffer can be a copper layer.The solder layer or the fourth sinter layer creates a dense, homogeneous connection layer between the bond buffer layer and the second or fourth frame segment of the first or second leadframe.

[0025] The bond buffer is a layer that reduces mechanical stress on the power semiconductor. The bond buffer compensates for different thermal expansion coefficients between the second or fourth frame segment of the first or second leadframe and the associated power semiconductor. Furthermore, the bond buffer better dissipates heat from the first or second power semiconductor. This prevents temperature hotspots, reducing stress on the respective power semiconductor and resulting in an improved service life. Thus, the bond buffer layer further improves the performance of the half-bridge package.

[0026] A solder layer is "softer" than a sintered layer and can therefore compensate for forces that can arise from so-called "thermal mismatch." "Thermal mismatch" refers to the situation when two components or materials have different thermal expansion coefficients and therefore expand or contract differently when the temperature changes. This can lead to stresses and deformations, especially when the materials or components are connected to one another. The thermal discrepancy can cause cracks, delamination, or other damage. The solder layer is designed to compensate for this discrepancy. The solder layer can be formed depending on the design of the respective leadframe, in particular any cross-connectors, connecting sections, or arm segments. The solder layer can be segmented and, in principle, have any surface geometry.

[0027] The half-bridge package preferably comprises two or more first power semiconductors and an identical number of second power semiconductors. In other words, the half-bridge package has just as many first power semiconductors as second power semiconductors. The number of power semiconductors can be increased on a given area of ​​the respective ceramic substrate. This makes it possible to maximize the packaging density of the half-bridge package and to scale the current. The at least two first power semiconductors are arranged in series and spaced from one another on the first ceramic substrate or the upper copper layer of the first ceramic substrate. If there are four or more first power semiconductors, these can be arranged in rows and columns evenly spaced from one another on the first ceramic substrate. The at least two second power semiconductors are arranged in series and spaced from one another on the second ceramic substrate orthe upper copper layer of the second ceramic substrate. With four or more second power semiconductors, these can be arranged in rows and columns evenly spaced from one another on the second ceramic substrate. With six power semiconductors, a 2x3 arrangement on the upper ceramic layer of the corresponding ceramic substrate is advantageous for each ceramic substrate. The associated control terminal can be elongated and arranged parallel between the two rows of three power semiconductors. This also improves current symmetry.

[0028] Current scaling can be achieved by adjusting the number of chips. Six first power semiconductors and six second power semiconductors are preferably provided. The size or area of ​​the power semiconductors can also be adjusted to accommodate current scaling. A surface area of ​​20, 25, or 32 mm per power semiconductor is conceivable. 2However, for reasons of current symmetry, it is advantageous if all power semiconductors have the same size or area, i.e. the same properties.

[0029] The second frame segment of the first leadframe preferably comprises a first cross-connector, onto which at least one of the first connection sections is formed in order to connect the second frame segment of the first leadframe to the first power semiconductor. If a plurality of first cross-connectors are provided, these can be interconnected if necessary, for example, to improve current symmetry. Alternatively or additionally, the fourth frame segment of the second leadframe comprises at least one second cross-connector, onto which at least one of the second connection sections is formed in order to connect the fourth frame segment of the second leadframe to a second power semiconductor. If a plurality of second cross-connectors are provided, these can be interconnected if necessary, for example, to improve current symmetry.The first and second connection sections preferably come into contact at least in sections with the said solder layer or a sintered layer between the respective power semiconductor and the associated frame segment.

[0030] To insulate the components of the half-bridge package, the half-bridge package is encapsulated using injection molding. In other words, the half-bridge package is encapsulated in a molding process. The molding process involves molding a plastic housing made of insulating material around one or more power semiconductors. Encapsulation protects the power semiconductors and the leadframe segments from external influences such as moisture and dust. The molding process involves injecting liquid plastic as insulating material into a mold in which the components of the half-bridge package are placed. After the plastic has hardened, the mold or tool is removed, protecting the half-bridge package.

[0031] The half-bridge package is encapsulated using transfer or compression molding, for example. In transfer molding, a defined amount of a molding material, typically a thermoset or thermoplastic, is filled into a mold cavity through a sprue. During transfer molding, the mold walls are typically heated to a temperature above the melting temperature of the molding material to ensure good flow properties of the material within the cavity. A wide variety of thermoplastics and thermosets are suitable for transfer molding.

[0032] In a second aspect of the invention, an electronic power module according to the invention comprises a heat sink on which a plurality of half-bridge packages according to the first aspect of the invention are arranged. The lower copper layer of the ceramic layer of the respective half-bridge package can be connected to the heat sink, for example, using so-called nanowire technology, by sintering, soldering, or pressing using an organic insulator. The lower copper layer can be connected directly to the heat sink. Alternatively, an insulation layer can be arranged between the lower copper layer and the heat sink.

[0033] Preferably, three half-bridge packages are arranged on the heat sink. Each half-bridge package forms a half-bridge. In an alternative embodiment, six half-bridge packages are arranged on the heat sink, with two half-bridge packages being combined to form a half-bridge. The half-bridges are preferably electrically connected in parallel. With three half-bridge packages, one half-bridge package is provided per switching position or phase. With six half-bridge packages, two half-bridge packages are provided per switching position or phase. Regardless of the number of half-bridge packages, all half-bridge packages can be arranged and cooled on a common heat sink, for example designed as a cooling plate or the like. The number of half-bridge packages used can be chosen arbitrarily.

[0034] In a third aspect of the invention, an electric drive axle according to the invention, also called an E-axle, comprises an electric machine and an electronic power module proposed therein according to the second aspect of the invention. The electric machine is preferably a three-phase electric machine. The power module is provided in a motor controller that controls the electric machine. In addition to the electric machine, the electric drive axle can include an optional transmission to provide torque and speed for driving a drive wheel of the motor vehicle. In addition to the electric machine, a motor controller can also be included. The electric machine is supplied with electrical energy from an energy storage device.

[0035] In a fourth aspect of the invention, a motor vehicle according to the invention comprises an electric drive axle according to the invention or an electronic power module according to the invention. The motor vehicle is in particular an electric vehicle or a hybrid vehicle and can in particular comprise a motorcycle, a passenger car, a truck, or a bus. The motor vehicle comprises at least two axles. Preferably, two axles are provided, wherein at least one of the axles is an electric drive axle and can be driven by at least one electric machine.

[0036] The above definitions as well as explanations of technical effects, advantages, and advantageous embodiments of the half-bridge package according to the invention according to the first aspect of the invention also apply mutatis mutandis to the power module according to the invention according to the second aspect of the invention, to the electric drive axle according to the invention according to the third aspect of the invention, and to the motor vehicle according to the invention according to the fourth aspect of the invention, and vice versa. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention.

[0037] To the extent that elements are designated by means of a numbering, for example "first component", "second component" and "third component", this numbering is intended purely for differentiation in the designation and does not represent a dependency of the elements on one another or a mandatory sequence of the elements. This means, in particular, that a device does not have to have a "first component" in order to be able to have a "second component". The device can also comprise a "first component" and a "third component" without necessarily having a "second component".

[0038] The invention will now be described in more detail with reference to the accompanying figures, in which:

[0039] Figure 1 is a highly schematic view of a motor vehicle with an electric drive axle;

[0040] Figure 2 shows an exemplary motor control of the drive axle, comprising an electronic power module with half bridges according to the invention;

[0041] Figure 3 is a schematic view of the electronic power module according to the invention shown in Figure 2 with several half-bridge packages according to the invention;

[0042] Figure 4 shows a first schematic perspective view of an exemplary half-bridge package according to Figure 3 according to a preferred embodiment;

[0043] Figure 5 is a schematic cross-sectional view of the half-bridge package according to Figure 3 and Figure 4 without showing an insulating material;

[0044] Figure 6 shows a second schematic perspective view of the half-bridge package according to Figures 3 to 5 without showing the insulation material;

[0045] Figure 7 shows a third schematic perspective view of the half-bridge package according to Figures 3 to 6 without showing the insulation material and the first leadframe;

[0046] Figure 8 shows a fourth schematic perspective view of the half-bridge package according to Figures 3 to 7 without showing the insulation material and the leadframes; and

[0047] Figure 9 shows a detailed sectional view of the half-bridge package according to Figures 3 to 8 to illustrate an electronic connection of a second power semiconductor to the second leadframe; identical or similar components are provided with the same reference numerals. Figure 1 shows an electric drive axle 100 in a motor vehicle 105. The motor vehicle 105 can additionally include an internal combustion engine 110, which is connected to a drive wheel 120 of the motor vehicle 105 via a transmission 115. In this case, the motor vehicle 105 would be a hybrid vehicle.

[0048] The electric drive axle 110 comprises an electric machine 125, which can also act on the drive wheel 120, preferably by means of the transmission 115. Furthermore, a power converter 130 can be provided, which can be fed with electrical energy from an electrical energy storage device 135. The electrical energy storage device 135 is preferably electrochemically constructed, but a fuel cell or another power source can also be used, for example. The power converter 130, as a motor controller, is preferably configured to provide phase-shifted alternating currents to the electric machine 125. The electric machine 125 is implemented, for example, as a permanent magnet synchronous machine, but other embodiments are also possible. The voltages and frequencies of the alternating currents provided can be determined such that the electric machine 125 converts orrotates at a predetermined speed. A field-oriented control can be implemented to control the direction of rotation and speed. The nominal voltage of the electrical energy storage device 135 is typically several hundred to over 1000 V. The current through the electric drive motor 125 can be several hundred A.

[0049] Figure 2 shows the power converter 130 with a power module 200, comprising three half-bridge packages 205, each forming a half-bridge and being controllable, for example, by means of a common control device 210. The power converter 130 is configured to control the rotational behavior of the electric machine 125 and typically operates digitally using a microcomputer. A power converter is an electronic circuit used to control the direction or magnitude of the electrical current. Power converters are typically used to convert alternating current (AC) into direct current (DC), or vice versa. The power converter 130 can, in particular, operate as a rectifier or inverter. Each half-bridge package 205 comprises two halves 215, 220, wherein the two halves 215, 220 are connected in series between DC voltage potentials of the energy storage device 135 as shown.A DC link capacitor 225 is preferably provided between the potentials. A center tap 230 between the halves 215, 220 of the respective half-bridge package 205 is connected to a corresponding phase of the electric machine 125. The upper half 215 of the semiconductor package 205 lies between a high potential of the energy storage device 135 and the center tap 230, and the lower half 220 of the semiconductor package 205 lies between the center tap 230 and a low potential of the energy storage device 135.

[0050] The halves 215, 220 of the respective semiconductor package 205 can be controlled independently of one another, each like an electrical switch, to close or open. The control device 210 is configured to alternately close and open the halves 215, 220 of the semiconductor package 205, such that at no time are both halves 215, 220 of a semiconductor package 205 closed. A voltage that occurs at the center tap 230 of the respective semiconductor package 205 depends on a ratio of the duty cycles of the upper half 215 and the lower half 220 of the respective semiconductor package 205. During normal operation of the electrical machine 125, predetermined currents through the halves 215, 220 of the semiconductor package 205 can thus be controlled.

[0051] Figure 3 shows the electronic power module 200 according to Figure 2 in a top view. The power module 200 comprises a heat sink 300, on which three half-bridge packages 205, each consisting of two halves 215, 220 connected in series, are arranged. Each half-bridge package 205 is assigned as a B2 package to a switching position of the power module 200. Alternatively, the power module 200 can also be arranged with six half-bridge packages 205 together on the heat sink 300, with two half-bridge packages 205 each being assigned as B2 packages to a switching position of the power module 200. The half-bridge packages 205 are identical regardless of their number, which is why only one exemplary half-bridge package 205 is shown and described below in Figures 4 ff. The other half-bridge packages 205 are designed analogously.

[0052] Figure 4 shows the half-bridge package 205 after its manufacture as a separately handleable unit. The half-bridge package 205 is encapsulated by an insulating material 400, which forms a housing for the half-bridge package 205 to protect the individual components of the half-bridge package 205, where necessary, from interaction with one another and from external influences, particularly dirt and moisture. The encapsulation is manufactured by injection molding. On the flat upper side 405 of the half-bridge package 205, a first load terminal 410, two second load terminals 415, 420 and a third load terminal 425 are shown, wherein the first load terminal 410 is arranged between the two second load terminals 415, 420 and on a short edge of the half-bridge package 205, and wherein the third load terminal 425 is arranged on the opposite side of the half-bridge package 205.

[0053] The load terminals 410-425 each have a surface that lies in a plane with the surface 405 of the insulation material 400, thereby forming the flat upper surface of the half-bridge package 205 shown in Figure 4. The half-bridge package 205 can be externally connected to a busbar arrangement (not shown here) via the load terminals 410-425.

[0054] Furthermore, two pairs of sleeves are arranged in the region of a longitudinal axis 427 of the half-bridge package 205, each sleeve being a signal transmission element 430, each of which is provided for gate control. Each pair of sleeves is assigned to one of the aforementioned halves 215, 220 of the half-bridge package 205 for controlling power semiconductors. Signal pins can be inserted or pressed into the sleeves to establish a signal-transmitting connection.

[0055] The first and third load terminals 410, 425 are assigned to a "drain" side. The second load terminals 415, 420 are assigned to a "source" side. The "gate," in the form of the signal transmission elements 430, is the electrode between the "source," i.e., the second load terminals 415, 420, and the "drain," i.e., the first and third load terminals 410, 425, and serves to control the switching behavior of the half-bridge package 205. It enables the activation and deactivation of the individual halves 215, 220 of the half-bridge package 205.

[0056] For a better understanding and to illustrate the structure of the half-bridge package 205, the electrically insulating insulation material 400 according to Figure 4 is not shown in the following Figures 5 to 9.

[0057] According to Figures 5 to 8, the first half 215 of the half-bridge package 205 has a first ceramic substrate 500, and the second half 220 of the half-bridge package 205 has a second ceramic substrate 505. The ceramic substrates 500, 505 are each rectangular and arranged at a distance from one another, with the insulating material shown in Figure 4 being arranged in an electrically insulating manner between the ceramic substrates 500, 505. The ceramic substrates 500, 505 are arranged in a common plane and are configured to be thermally coupled to the heat sink 300 shown in Figure 3.

[0058] In this case, six parallel-connected first power semiconductors 510, which are assigned to the first ceramic substrate 500, and six parallel-connected second power semiconductors 515, which are assigned to the second ceramic substrate 505, are arranged between the aforementioned load terminals 410-425 and are controllable via the signal transmission elements 430 assigned to the respective ceramic substrate 500, 505. According to Figure 8, the first power semiconductors 510 are arranged in a 2x3 arrangement on the surface of the first ceramic substrate 500, and the second power semiconductors 515 are also arranged in a 2x3 arrangement on the surface of the second ceramic substrate 505. The number of first power semiconductors 510 corresponds to the number of second power semiconductors 515.

[0059] The first load terminal 410 is connected to a first frame segment 520 of a first leadframe 525. The second load terminals 415, 420 are connected to a second frame segment 530 of the first leadframe 525, see Figure 5. The third load terminal 425 is connected to a third frame segment 535 of the first leadframe 525. The half-bridge package 205 further comprises a second leadframe 537 with a fourth frame segment 539, wherein the fourth frame segment 539 is spatially arranged between the second frame segment 530 of the first leadframe 525 and the two ceramic substrates 500, 505. In other words, the fourth frame segment 539 lies in a plane that lies between the plane of the ceramic substrates 500, 505 and a further plane in which the second frame segment 530 of the first leadframe 525 is arranged. The planes run essentially parallel.

[0060] According to Figure 5 in combination with Figure 9, each ceramic substrate 500, 505 has an electrically insulating ceramic layer 540 between a lower copper layer 545 and an upper copper layer 550. The first load terminal 410 or the first frame segment 520 is electrically and thermally connected to the upper copper layer 550 of the second ceramic substrate 505. The second load terminals 415, 420 or the second frame segment 530 are electrically and thermally connected to the upper copper layer 550 of the second ceramic substrate 505. The third load terminal 425 or the third frame segment 535 is electrically and thermally connected to the upper copper layer 550 of the first ceramic substrate 500.In this context, Figure 8 further shows that the upper copper layer 550 of the second ceramic substrate 505 is segmented to prevent unwanted electrical interaction between the first load terminal 410 and the second load terminals 415, 420. Thus, the upper copper layer 550 of the second ceramic substrate 505 is island-shaped in the region of the respective second load terminal 415, 420, here in the corners of the second ceramic substrate 505.

[0061] According to Figure 8, first sintered layers 800 are applied to the upper copper layer 550 of the first ceramic substrate 500 in order to electrically connect this upper copper layer 550 to the third frame segment 535 of the first leadframe 525, to first connection sections 600 of the second frame segment 530 of the first leadframe 525, which are shown in Figure 6, and to the first power semiconductors 510. Furthermore, according to Figure 8, second sintered layers 805 are applied to the upper copper layer 550 of the second ceramic substrate 505 in order to electrically connect this upper copper layer 550 to the first frame segment 520 of the first leadframe 525, to second connection sections 700 of the fourth frame segment 539 of the second leadframe 537, which are shown in Figure 7, and to the second power semiconductors 515.

[0062] According to Figure 5 in conjunction with Figure 6, the first power semiconductors 510 are arranged between the upper copper layer 550 of the first ceramic substrate 500 and the second frame segment 530 of the first leadframe 525 and are electrically connected thereto. For this purpose, the second frame segment 530 has two mirror-symmetrically formed first cross-connectors 605, onto which the first connection sections 600 are formed in order to connect the second frame segment 530 of the first leadframe 525 to two first power semiconductors 510 each. In the present case, two first cross-connectors 605, each with two first connection sections 600, are provided. The first cross-connectors 605 and the first connection sections 600 are arranged such that current symmetry is ensured in the first ceramic substrate 500.

[0063] According to Figure 7 in conjunction with Figure 5, the second power semiconductors 515 are arranged between the upper copper layer 550 of the second ceramic substrate 505 and the fourth frame segment 539 of the second leadframe 537 and are electrically connected to them. For this purpose, the fourth frame segment 539 of the second leadframe 537 has two mirror-symmetrical second cross-connectors 705, onto which the second connection sections 700 are formed in order to connect the fourth frame segment 539 of the second leadframe 537 to two second power semiconductors 515 each. In addition, individual second connection sections 700 are formed directly on the fourth frame segment 539 in order to directly connect the fourth frame segment 539 to a second power semiconductor 515 each. The second cross-connectors 705 and the second connection sections 700 are arranged such that a current symmetry is provided in the second ceramic substrate 505.According to Figure 7, the fourth frame segment 539 of the second leadframe 537 is contacted to the first ceramic substrate 500 via five third connection sections 710, three of which are arranged spaced apart from one another on a side of the first ceramic substrate 500 facing the second ceramic substrate 505, and one each in a corner on a side of the first ceramic substrate 500 facing away from the second ceramic substrate 505. The number of third connection sections 710 can be adapted depending on the requirements and design of the half-bridge package 205. For example, the three adjacent third connection sections 710 can be combined to form two or one fourth connection section.

[0064] According to Figure 5 in conjunction with Figures 6 to 8, a control terminal 555 is arranged on each ceramic substrate 500, 505, on which the aforementioned signal transmission elements 430 for controlling the half-bridge package 205 are arranged. The control terminal 555 has a multi-layer structure. The respective control terminal 555 is to be understood as a gate rotor or signal substrate, wherein the respective control terminal 555 forwards signals, which are conducted into the half-bridge package 205 via the signal transmission elements 430, via connecting elements 560 to the associated power semiconductors 510, 515. The respective control terminal 555 has a ceramic layer 565, which is arranged between a lower copper layer 570 and an upper copper layer 575.The lower copper layer 570 of the respective control terminal 555 is electrically connected to the upper copper layer 550 of the respective ceramic substrate 500, 505 via a sintered layer (not shown here). The aforementioned connecting elements 560 are directly electrically connected to the upper copper layer 575 of the control terminal 555, with two connecting elements 560 each contacting one of the power semiconductors 510, 515. The upper copper layer 575 of the respective control terminal 555 is segmented, as can be clearly seen in Figure 8. In other words, the upper copper layer 575 of the respective control terminal 555 consists of several segments, the design of which is adapted to the arrangement of the connecting elements 560 and signal transmission elements 430.According to Figure 9, an example of a layer structure between the fourth frame segment 539 of the second leadframe 537 and one of the first power semiconductors 515 of the second ceramic substrate 505 is shown, wherein starting from the upper copper layer 550 of the second ceramic substrate 505, i.e. from bottom to top, the second sintered layer 805, thereon the second power semiconductor 515, thereon a third sintered layer 900, thereon a bond buffer formed as a copper layer.

[0065] Layer 905, on top of which a fourth sintered layer 910, which can alternatively be formed as a solder layer, and on top of which the second connection section 700 of the fourth frame segment 539 of the second leadframe 537 is arranged. Thus, the second leadframe 537 is soldered onto the second power semiconductor 515. The connection between the first leadframe 525 or the second frame segment 530 of the first leadframe 525 and the first power semiconductors 510 is designed analogously, wherein instead of the second sintered layer 805, the first sintered layer 800 is arranged between the upper copper layer 550 of the first ceramic substrate 500 and the first power semiconductor 510.

[0066] Reference symbol

[0067] 100 electric drive axles

[0068] 105 Motor vehicle

[0069] 110 combustion engine

[0070] 115 gearboxes

[0071] 120 drive wheel

[0072] 125 electric machine

[0073] 130 power converters

[0074] 135 energy storage

[0075] 200 power module

[0076] 205 half-bridge package

[0077] 210 Control device

[0078] 212 half-bridge package

[0079] 215 upper half of the half-bridge package

[0080] 220 lower half of the half-bridge package

[0081] 225 DC link capacitor

[0082] 230 center tap

[0083] 300 heat sinks

[0084] 400 insulation material

[0085] 405 top

[0086] 410 First load connection

[0087] 415 Second load connection

[0088] 420 Second load connection

[0089] 425 Third load connection

[0090] 427 Longitudinal axis

[0091] 430 Signal transmission element

[0092] 500 First ceramic substrate

[0093] 505 Second ceramic substrate 510 First power semiconductor

[0094] 515 Second power semiconductor

[0095] 520 First frame segment

[0096] 525 First leadframe

[0097] 530 Second frame segment

[0098] 535 Third frame segment

[0099] 537 Second leadframe

[0100] 539 Fourth frame segment

[0101] 540 Ceramic layer of the ceramic substrate

[0102] 545 Lower copper layer of the ceramic substrate

[0103] 550 Upper copper layer of the ceramic substrate

[0104] 555 control connection

[0105] 560 connecting element

[0106] 565 Ceramic layer of the control terminal

[0107] 570 Lower copper layer of the control connection

[0108] 575 Upper copper layer of the control connection

[0109] 600 First connecting section

[0110] 605 First cross connector

[0111] 700 Second connecting section

[0112] 705 Second cross connector

[0113] 710 Third connecting section

[0114] 800 First sinter layer

[0115] 805 Second sintered layer

[0116] 900 Third sinter layer

[0117] 905 Bond buffer layer

[0118] 910 sintered layer

Claims

Patent claims 1. Half-bridge package (205) for an electronic power module (200), comprising a first ceramic substrate (500) and a second ceramic substrate (505), wherein a first power semiconductor (510) is arranged on the first ceramic substrate (500) and a second power semiconductor (515) is arranged on the second ceramic substrate (505), a first load terminal (410) which is connected to a first frame segment (520) of a first leadframe (525), two second load terminals (415, 420) which are connected to a second frame segment (530) of the first leadframe (525), and a third load terminal (425) which is connected to a third frame segment (535) of the first leadframe (525), wherein the second frame segment (530) of the first leadframe (525) is the first power semiconductor (510) and the second ceramic substrate (505) is electrically connected,the half-bridge package (205) further comprises a second leadframe (537) with a fourth frame segment (539) spatially arranged between the second frame segment (530) of the first leadframe (525) and the two ceramic substrates (500, 505), wherein the fourth frame segment (539) of the second leadframe (537) is electrically connected to the second power semiconductor (515) and to the first ceramic substrate (500), and wherein a control terminal (555) is arranged on each ceramic substrate (500, 505), which is electrically connected to signal transmission elements (430) for controlling the half-bridge package (205) and via connecting elements (560) to the power semiconductors (510, 515) of the respective ceramic substrate (500, 505).

2. Half-bridge package (205) according to claim 1, wherein each ceramic substrate (500, 505) has a ceramic layer (540) between a lower copper layer (545) and an upper copper layer (550), wherein the respective first power semiconductor (510) is arranged between the upper copper layer (550) of the first ceramic substrate (500) and the second frame segment (540) of the first leadframe (525) and is electrically connected thereto, and wherein the respective second power semiconductor (515) is arranged between the upper copper layer (550) the second ceramic substrate (505) and the fourth frame segment (539) of the second leadframe (537) and is electrically connected thereto.

3. The half-bridge package (205) of claim 2, wherein the first load terminal (410) is electrically connected to the upper copper layer (550) of the second ceramic substrate (505), wherein the second load terminals (415, 420) are electrically connected to the upper copper layer (550) of the second ceramic substrate (505), and wherein the third load terminal (425) is electrically connected to the upper copper layer (550) of the first ceramic substrate (500).

4. Half-bridge package (205) according to claim 2 or claim 3, wherein first sintered layers (800) are applied to the upper copper layer (550) of the first ceramic substrate (500) in order to at least electrically connect the upper copper layer (550) to the third frame segment (535) of the first leadframe (525), to first connection sections (600) of the second frame segment (530) of the first leadframe (525) and to the first power semiconductors (510).

5. Half-bridge package (205) according to one of claims 2 to 4, wherein second sintered layers (805) are applied to the upper copper layer (550) of the second ceramic substrate (505) in order to at least electrically connect the upper copper layer (550) to the first frame segment (520) of the first leadframe (525), to second connection sections (700) of the fourth frame segment (539) of the second leadframe (537) and to the second power semiconductors (515).

6. Half-bridge package (205) according to one of the preceding claims, wherein the signal transmission elements (430) are sleeve-shaped and / or pin-shaped.

7. Half-bridge package (205) according to one of the preceding claims, wherein the first load terminal (410) is spatially arranged between the two second load terminals (415, 420).

8. Half-bridge package (205) according to one of the preceding claims, wherein a third sintered layer (900), a bond buffer layer (905) and either a fourth sintered layer (910) or solder layer are arranged between the second frame segment (530) of the first leadframe (525) and the at least one first power semiconductor (510) and between the fourth frame segment (539) of the second leadframe (537) and the at least one second power semiconductor (515) starting from the respective power semiconductor (510, 515).

9. Half-bridge package (205) according to one of the preceding claims, comprising two or more first power semiconductors (510) and an identical number of second power semiconductors (515).

10. Half-bridge package (205) according to claim 9 in conjunction with claim 4, wherein the second frame segment (530) of the first leadframe (525) comprises a first cross-connector (605) on which at least one of the first connection sections (600) is formed in order to connect the second frame segment (530) of the first leadframe (525) to a first power semiconductor (510).

11. Half-bridge package (205) according to claim 9 or claim 10 in conjunction with claim 5, wherein the fourth frame segment (539) of the second leadframe (537) comprises a second cross-connector (705) on which at least one of the second connection sections (700) is formed in order to connect the fourth frame segment (539) of the second leadframe (537) to a second power semiconductor (515).

12. Half-bridge package (205) according to one of the preceding claims, wherein the half-bridge package (205) is encapsulated by injection molding.

13. Electronic power module (200) for a motor control, comprising a heat sink (300) on which a plurality of half-bridge packages (205) according to one of the preceding claims are arranged.

14. Electronic power module (200) according to claim 13, wherein three or six half-bridge packages (205) are arranged on the heat sink (300).

15. Electric drive axle (100) comprising an electric machine (125) and an electronic power module (200) according to claim 13 or claim 14.

16. Motor vehicle (105) comprising an electric drive axle (100) according to claim 15.

Images