Contact device for power semiconductor chip and power electronics module

Abstract

The invention relates to a contact device for a power semiconductor chip and a power electronics module. The contact device comprises a substrate; at least two power semiconductor chips which are arranged on the substrate with first electrical terminals and are in electrical contact with the substrate; and at least one contact region directed towards the outside of the substrate, with which electrical terminals of the same type of the power semiconductor chip are to be in electrical contact; the invention relates to a power semiconductor device comprising at least one power semiconductor chip, and a contact component which is formed as an electrically conductive metal film which has an electrically insulating layer on at least one surface section, the electrically insulating layer each having a recess to the metal film for receiving and contacting an electrical terminal of one of the power semiconductor chips, and the contact component being formed as an electrically conductive metal film. At least one portion of the metal film also protrudes from the electrically insulating layer and is in electrical contact with an associated contact region of the substrate in order to electrically contact similar electrical terminals of the power semiconductor chip.

Description

Technical Field

[0001] The invention relates to the field of electric vehicles, in particular to the electrical contacting of power electronics modules and power semiconductor chips for electric drives. Background Art

[0002] The use of electronic device modules, such as power electronic device modules, in motor vehicles has increased significantly in recent decades. This is due on the one hand to the need to improve fuel saving and vehicle performance, and on the other hand to the progress of semiconductor technology. The main component of such electronic device modules is a DC / AC inverter (Inverter), which is used to energize electric machines such as electric motors or generators with multi-phase alternating current (AC). In this case, the direct current (DC) generated by a DC energy source such as a battery is converted into a multi-phase alternating current (AC). For this purpose, the inverter includes a large number of electronic components such as power semiconductor chips, with which a bridge circuit (e.g., a half-bridge) is realized.

[0003] Standardized electronic device modules already exist, which usually consist of two MOSFET chips (power semiconductor chips), whose drains are applied to a printed circuit board (PCB) or a substrate (DCB) by means of a sintered layer. These modules are called DDP modules (DDP = Discrete Dual Package). The source terminals of the two chips are connected to copper tongues extending from the printed circuit board (PCB) or the substrate (DCB) by means of copper ribbons or bonding wires to transfer current from the electronic device module. Both types of connection allow for a non-optimal low-inductance connection of the power semiconductors of the chips. Higher commutation inductances increase the voltage drop at the chip. The fact that this additional voltage drop cannot be measured at the outside of the chip is another reason for keeping the inductance so low. Summary of the invention

[0004] It is therefore an object of the present invention to provide an improved type of connection for transmitting current from a power semiconductor chip out of a power electronics module.

[0005] This object is achieved by the features of the independent claim. Advantageous embodiments are the subject matter of the dependent claims.

[0006] A contact device for a power semiconductor chip is proposed, which comprises: a substrate; at least two power semiconductor chips arranged on the substrate with first electrical terminals and electrically contacted therewith; and at least one contact area pointing outward from the substrate, with which similar electrical terminals of the power semiconductor chips are to be electrically contacted; and a contact component, which is formed as a conductive metal film, which has an electrically insulating layer on at least one surface section, wherein the electrically insulating layer respectively has a recess extending to the metal film for accommodating and contacting each electrical terminal of one of the power semiconductor chips, and wherein at least one portion of the metal film also extends from the electrically insulating layer and is electrically contacted with the corresponding contact area of ​​the substrate in order to electrically contact similar electrical terminals of the power semiconductor chip.

[0007] In one embodiment, the power semiconductor chip is formed as a MOSFET, and the first electrical terminal is in contact with the drain of the MOSFET, and wherein the metal film is used as a source region, and the source terminal of the power semiconductor chip is electrically contacted with the corresponding recess of the metal film, respectively, and the contact area is a source contact area, which is in contact with a portion of the metal film extending from the electrical insulating layer.

[0008] In one embodiment, the contact device also has two additional contact areas pointing outward from the substrate, the additional contact areas serving as gate contact areas and Kelvin source contact areas, and wherein the metal film is divided into additional zones by at least one electrically insulating layer, the additional zones respectively forming gate zones and Kelvin source zones of each power semiconductor chip in the power semiconductor chip, and wherein a recess is provided in the electrically insulating layer for each of the zones, and each recess is electrically contacted with an associated electrical terminal of the associated power semiconductor chip, and wherein additional portions of the metal film also extend out from the electrically insulating layer, respectively, wherein one additional portion serves as a gate contact and the other additional portion serves as a Kelvin source contact, and are electrically contacted with the associated contact areas of the substrate.

[0009] In one embodiment, the gate region and the Kelvin source region are located at mutually opposite outer end regions of the power semiconductor chip and are electrically contacted with the associated contact regions via connections electrically insulated from one another in the x and y directions or in the z direction.

[0010] In one embodiment, the metal film is formed of copper.

[0011] In one embodiment, the metal film has electrically insulating layers on both sides.

[0012] Furthermore, a power electronics module is provided which has at least one topology switch having at least two power semiconductor chips arranged parallel to one another, which are contact-connected by means of a contacting device according to one of the preceding claims.

[0013] Furthermore, a power electronics device for operating a three-phase electric motor of a vehicle is provided, wherein the power electronics device comprises a power electronics device module and at least one ECU (computing unit), which is connected to the electric motor and to the power electronics device module for controlling and regulating the electric motor. The ECU can be arranged as part of the power electronics device module or separately from the power electronics device module.

[0014] Furthermore, an electric drive of a motor vehicle is provided, which has a three-phase electric motor and a battery and power electronics connected to both.

[0015] Furthermore, a motor vehicle is provided which has an electric drive in the form of an electric axle drive.

[0016] Further features and advantages of the invention are apparent from the following description of exemplary embodiments of the invention with the aid of the drawings, which show details according to the invention, and from the claims. The individual features can be realized individually or in any desired combination in the variants of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Preferred embodiments of the invention are explained in more detail below with reference to the drawings.

[0018] Figure 1 The schematic structure of a DDP module according to the prior art is shown;

[0019] Figure 2 shows the principle structure of a contact member according to an embodiment of the present invention;

[0020] Figure 3 shows the principle structure of a contact member according to another embodiment of the present invention;

[0021] Figure 4 The basic structure of a contact component having two metal films arranged one above the other according to another embodiment of the present invention is shown.

[0022] In the following description of the figures, identical elements or functions are provided with the same reference symbols. DETAILED DESCRIPTION

[0023] As already mentioned at the beginning of this article, in current DDP modules, current transmission between power semiconductor chips 10, such as MOSFETs, arranged on a printed circuit board (PCB) or substrate (DCB) 1 of a power electronics module is achieved so far in the following way, that is, the electrical terminals of the power semiconductor chips 10 that are not directly in contact with the printed circuit board or substrate (DCB) are connected to the associated contact areas 11-13 of the printed circuit board or substrate (DCB) by means of copper strips or bonding wires. Figure 1 In the embodiment of the present invention, this is the connection of an electrical terminal 101 of the respective power semiconductor chip 10 to the contact region 11 . In the case of a MOSFET as power semiconductor chip 10 , the electrical terminal 101 is the source terminal and the contact region 11 is the source contact region 11 .

[0024] In order to achieve a better low-inductance connection of the power semiconductors of the power semiconductor chip 10 , a contact device 100 is proposed, as described below. This contact device has a substrate 1 , a power semiconductor chip 10 and a contact component 20 , which enables a more flat connection and electrical contacting of the power semiconductor chip 10 .

[0025] One embodiment of the contact device 100 is Figure 2 An alternative embodiment is shown in Figure 3 Shown in.

[0026] The contact member 20 is formed as a conductive metal film 22. This metal film 22 can be deformed, in particular deep drawn, in the z direction. For this purpose, the metal film advantageously has a maximum thickness of 1 mm (in the z direction). The metal film has an electrically insulating layer 21 on at least one surface section. In the electrically insulating layer 21, a recess 211 extending to the metal film 22 is provided for each power semiconductor chip 10 to be contacted. The recess 211 thus exposes the metal of the metal film 22 again. The recess 211 is used to contact the electrical terminal 101 of one of the power semiconductor chips 10 when the contact member 20 is applied to the substrate 1. The recess 211 advantageously has the same size as the electrical terminal 101 of the power semiconductor chip 10, so that as comprehensive a contact as possible can be achieved. The contact can be achieved here, for example, by means of welding or sintering.

[0027] Furthermore, a section 221 of the metal film 22 projects from the electrically insulating layer 21 in order to establish contact with contact regions 11 - 13 of the substrate 1 pointing outward from the power electronics module, for example with a negative DC contact or a drain contact of a further power semiconductor.

[0028] The metal film 22 is preferably made of copper. The metal film is sized so that the metal film matches the electrical conductivity of the power semiconductor chip 10 and the number of power semiconductor chips 10. The surface of the substrate 1 covered by the metal film 22 depends on the structure of the substrate 1. The size and orientation of the insulating area of ​​the metal film 22 depend on the size and positioning of the power semiconductor chip 10 on the substrate 1. The metal film 22 provides a connection surface for the terminals 101 and the power supply contact (recess 211) of the two power semiconductors 10. Depending on the embodiment, a contact surface for the auxiliary source (Calvin source) and the gate contact is also provided. The goal is to contact the electrical terminal 101 of the power semiconductor chip 10 with as large an area as possible. However, it is also possible that the electrical insulating layer 21 only forms a frame around the recess 211, that is, it is roughly larger than the surface covered by the power semiconductor chip 10. Therefore, it is sufficient to surround the outer area of ​​the power semiconductor chip 10 where the reverse voltage drops. Therefore, easier positioning is achieved, because the tolerance is larger.

[0029] The following embodiments are described using a MOSFET with drain, source, gate and signal (Kelvin source) terminals as the power semiconductor to be contacted of the power semiconductor chip 10. However, other power semiconductors with corresponding electrical terminals, such as IGBTs, can also be used, wherein of course the terminals must be selected accordingly (MOSFET: gate-drain-source; IGBT: gate-collector-emitter).

[0030] As already explained in the introduction, the drain of the MOSFET, which is arranged on one side of the power semiconductor chip 10 (and therefore not visible in the figure), is directly connected (electrically and mechanically contacted) to the substrate 1. The source terminal is provided on the side facing away from the power semiconductor chip 10. Figure 1 In the figure, it is marked as electrical terminal 101. In addition, the substrate 1 also has a source contact area 11, a gate contact area 12 and a signal contact area (Calvin source contact) 13, which provide a connection portion pointing outward from the substrate 1 (of the power electronic device module). The contact area 11 is electrically contacted with the associated electrical terminal (only the terminal 101 is shown in the figure). For this purpose, according to the invention, a contact component 20 is now provided instead of a copper strip or a welding wire. The contact areas 12 and 13 can be contacted like the contact area 11, or, as has been done so far, for example, by means of welding wires.

[0031] exist Figure 2 1 shows an embodiment of a contact member 20, in which a recess 211 and a portion 221 of the metal film 22 extending from the electrical insulating layer 21 are provided for contact with a power source, that is, used as a source region S. The recess 211 is arranged at the power semiconductor chip 10 arranged on the substrate 1. Figure 1The metal film 22 is connected to (electrically and mechanically contacted with) the electrical terminal 101 shown. The portion 221 extending from the metal film 22 is connected to (electrically and mechanically contacted with) the contact area 11 of the substrate 1, which thus serves as the power contact area 11 of the power semiconductor module. Therefore, based on the recess 211 and the portion 221 of the metal film 22 extending from the metal film 22, an electrically conductive connection between these components is established.

[0032] exist Figure 3 Another embodiment is shown in FIG. 2 , in which not only the contact with the power supply is realized, but also the contact with the gate and the Kelvin source is realized. For this purpose, two other regions are provided in the metal film 22, which are respectively used as the gate region G and the Kelvin source region K electrically insulated therefrom by the electrically insulating layer 21. The electrically insulating layer 21 also has corresponding recesses 211 for these regions G and K. In order to achieve this, it should be noted that the metal film 22 is formed in multiple parts here with electrical insulation between the individual parts (in a manner of stacking one above the other in the z direction or side by side in the x and y directions) so as to electrically separate the region S from the regions G and K.

[0033] The gate region and the Kelvin source region G, K of each power semiconductor chip 10 are located in a region of the respective power semiconductor chip 10 that is specifically provided for this purpose (the source region S is located in the region of the power semiconductor chip 10). Figure 3 occupies its center), such as in Figure 3 However, the gate contact area and Kelvin source contact areas 12, 13 of the substrate 1 are located next to the source contact area 11. This location can be contacted by all gate contact areas and signal contact areas 12, 13 without direct connection, because otherwise there would be a conflict with the contact to the source. It is therefore recommended to realize the connection on the area of ​​the metal film 22 opposite the part 221 of the metal film 22 protruding from the substrate 1 through the recess 212 formed as a line in the electrically insulating layer 21, such as in Figure 3 As shown by the dotted line in FIG.

[0034] exist Figure 4 In another embodiment shown (for example, shown for the gate region G and the Kelvin source region K), the contact member 20 can also be formed by two (or more) metal films 22 arranged one above the other and separated from each other by an electrical insulating layer 21. With this arrangement, multiple signals can be transmitted in different planes. This is mainly beneficial for the connection of the gate region G and the signal region (Kelvin source K) in order to achieve the smallest possible inductance.

[0035] The present invention has been described with respect to two power semiconductor chips 10 . However, a person skilled in the art can also integrate more than two power semiconductor chips 10 without difficulty.

[0036] The proposed film technology (metal film 22 ) makes it possible to achieve extremely low inductances in the control and power circuits.

[0037] The power electronic device module within the scope of the present invention is used to operate the electric drive of a motor vehicle driven by a battery. The motor vehicle is especially a commercial vehicle or a private car such as a truck or a bus. The power electronic device module includes a DC / AC inverter (English: Inverter), which is formed by a plurality of topological switches, which are in turn composed of a plurality of power semiconductor chips 10. In addition, the power electronic device module may also include an AC-DC rectifier (English: Rectifier), a DC / DC converter (English: DC / DC Converter), a transformer (English: Transformer) and / or other electrical converters or a part of such a converter or may be a part of them. The power electronic device module is particularly used to energize an electric motor, such as an electric motor and / or a generator. The DC / AC inverter is preferably used to generate a multi-phase alternating current from a direct current generated by a DC voltage of an energy source, such as a battery or a storage battery.

[0038] A DC / DC converter and inverter 1 for an electric drive (electric drive for short) of a motor vehicle, in particular a private passenger car and a commercial vehicle as well as a bus, is designed for the high voltage range and in particular for a reverse voltage level of approximately 650 volts and above.

[0039] The inverter arrangement described is used, for example, in a motor vehicle. The motor vehicle can have, in particular, an axle which is electrically driven by an electric drive.

[0040] Reference numerals list

[0041] 100 contact devices

[0042] 1 substrate, such as DBC

[0043] 10Power semiconductor chips

[0044] 10110 electrical terminals

[0045] Source contact area of ​​111

[0046] 121 gate contact area

[0047] Signal contact area of ​​131 (Kelvin source contact)

[0048] 20 Contact member

[0049] 21 Electrical insulation layer

[0050] 211 concave part

[0051] 22 metal film

[0052] 221 A section of a metal film

[0053] S source region

[0054] G Gate region

[0055] K Kelvin source region

Claims

1. A contact device (100) for a power semiconductor chip (10), the contact device comprising: - base plate (1), - at least two power semiconductor chips (10) arranged on the substrate (1) with first electrical terminals and in electrical contact therewith, and - at least one contact region (11-13) pointing outwardly from the substrate (1), to which a similar electrical terminal (101) of the power semiconductor chip (10) is to be electrically contacted, - a contact component (20) which is formed as an electrically conductive metal film (22) which has an electrically insulating layer (21) on at least one surface section, wherein: The electrically insulating layer (21) has a respective recess (211) extending to the metal film (22) for accommodating and contacting an electrical terminal (101) of one of the power semiconductor chips (10), and wherein: At least a portion (221) of the metal film (22) also extends from the electrically insulating layer (21) and is electrically contacted with the associated contact region (11-13) of the substrate (1) so as to electrically contact similar electrical terminals (101) of the power semiconductor chip (10).

2. The contact device (100) according to claim 1, wherein: - the power semiconductor chip (10) is formed as a MOSFET, and the first electrical terminal is in contact with a drain of the MOSFET, and wherein: - the metal film (22) serves as a source region (S) and the source terminal (101) of the power semiconductor chip (10) is in electrical contact with the associated recess (211) of the metal film (22), and The contact region (11) is a source contact region, which is in contact with a portion (221) of the metal film (22) that protrudes from the electrically insulating layer (21).

3. The contact device (100) according to claim 2, further comprising two further contact regions (12, 13) pointing outwardly from the substrate (1), the further contact regions serving as gate contact regions (12) and Kelvin source contact regions (13), and wherein: - the metal film (22) is divided into further regions (G, K) by at least one electrically insulating layer (21), the further regions respectively forming a gate region (G) and a Kelvin source region (K) of each of the power semiconductor chips (10), and wherein a recess (211) is provided in the electrically insulating layer (21) for each of the regions (G, K), and each recess (211) is in electrical contact with an associated electrical terminal of the associated power semiconductor chip (10), and wherein, - Further parts of the metal film (22) each protrude from the electrically insulating layer (21), wherein one further part serves as a gate contact and the other part serves as a Kelvin source contact and is in electrical contact with the associated contact regions (12, 13) of the substrate (1).

4. The contact device (100) according to claim 3, wherein: The gate region (G) and the Calvin source region (K) are located at mutually opposite outer end regions of the power semiconductor chip (10), and - Electrical contact is made with the associated contact regions (12, 13) via connections which are electrically insulated from one another in the x-direction and the y-direction or in the z-direction.

5. The contact device (100) according to any one of the preceding claims, wherein The metal film (2) is formed of copper.

6. The contact device (100) according to any one of the preceding claims, wherein: The metal film (22) has an electrically insulating layer (21) on both sides.

7. A power electronics module comprising at least one topology switch having at least two power semiconductor chips (10) arranged parallel to one another and contacted by means of a contacting device (100) according to any of the preceding claims.

8. A power electronic device for operating a three-phase electric motor of a vehicle, wherein: The power electronic device has: - A power electronics module according to claim 7, and - At least one ECU which is connected to the electric motor for controlling and regulating the electric motor and to the power electronics module. 9 . An electric drive for a motor vehicle, comprising a three-phase electric motor and a battery and a power electronics device according to claim 8 connected to both. 10 . A motor vehicle having an electric drive according to claim 9 , which is designed as an electric axle drive.

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