Semiconductor module

Description

[0001] The invention is based on a semiconductor module according to the preamble of independent patent claim 1.

[0002] Semiconductor modules embodied in molded packages are known from the prior art as integrated half-bridge circuits (B2), which are constructed, for example, as "leadless chip-scale packages" (a leadless package the size of a die). This design is intended, for example, for the construction of power electronic pulse-controlled inverter assemblies on printed circuit boards. The molded package is flush with the exposed surfaces of lead frames, with which the half-bridge circuit is soldered to the circuit board. In this "leadless" design, the lead frames of the half-bridge circuits do not extend beyond the outer edges of the molded package. The half-bridge circuit comprises two transistors, each arranged between two carriers within a package and electrically connected to the carriers.Currents from the half-bridge circuit flow across the circuit board, generating high power dissipation densities in the immediate vicinity of the exposed surfaces of the leadframes. The phase current of the half-bridge circuit introduced into the circuit board is connected there via a tap to the phase current wire, which then leads into a stator winding of a connected electrical machine.

[0003] Power semiconductor modules are also known that are installed in so-called "mold packages." Contacting is established via lateral contact pins (e.g., SOIC packages or DPAK / LFPAK) or via contact surfaces on the underside (e.g., QFN). Thermal dissipation can occur via the underside, the top, or both sides. In the packages listed, the power semiconductors are installed in only one contact level, meaning that all contacts required for interconnection must be considered in this level on the carrier substrate for further installation. This can result in disadvantages in circuit design regarding space requirements, heat dissipation, and current carrying capacity.

[0004] DE 10 2009 006 152 A1 discloses an electronic component comprising a carrier, a first semiconductor chip, a second semiconductor chip, and a metallic clip, which are surrounded by a molded housing. The first semiconductor chip is applied to the carrier with a first surface. The metallic clip is bent in an S-shape and connects a second surface of the first semiconductor chip, which is opposite the first surface, to a first surface of the second semiconductor chip, wherein the first surface of the second semiconductor is arranged in a different plane of the electronic component. A second surface of the second semiconductor chip can be connected to a second metallic clip. The metallic clips can be produced by punching, embossing, pressing, cutting, sawing, or milling.The S-shaped metallic clip can, for example, create a current bridge between a drain potential of a first, low-side transistor and a source potential of a second, high-side transistor in a half-bridge circuit.

[0005] In addition, document US 2014 / 110776 A1 shows a semiconductor module corresponding to the preamble of claim 1. Disclosure of the invention

[0006] The semiconductor module with the features of independent patent claim 1 has the advantage that, for example, contact surfaces can be exposed on the surface of the housing using a so-called FAM (Film Assisted Molding) process and can be thermally, electrically, and mechanically contacted after the molding process during further processing. The exposed contact surfaces are in contact with the installed semiconductor components via a thermally and electrically conductive connection clip. This creates a new path through which current and heat can flow.

[0007] The semiconductor module according to the invention is designed as a half-bridge circuit. Advantageously, embodiments of the semiconductor module according to the invention can be provided for installation on an electronic circuit carrier, which is directly combined with an electrical machine to form a "power pack." Advantageously, a phase potential tap of the corresponding half-bridge circuit can be directly connected to a phase current wire of a stator winding of the electrical machine, without conducting the phase current through the circuit carrier on which the semiconductor module is arranged.

[0008] Embodiments of the semiconductor module according to the invention can generally be used for all package types and technologies (standard, leadless, PCB embedding). By rotating or flipping the first semiconductor component, a corresponding current flow in the substrate or within the housing occurs exclusively in the vertical direction, thus allowing the use of substrates less suitable for high currents, such as PCB material. Furthermore, cost-effective LGA and / or BGA packages can also be used for embodiments of the semiconductor module according to the invention, since the exposed contact point of the connecting clip enables slug-up cooling outside the housing, and no heat dissipation function is required in the substrate.

[0009] In addition, the current path being routed outside the housing advantageously eliminates the heat input with high power loss density inside the semiconductor module and the associated reliability risks due to delamination of the molded housing, solder joint breaks, bond breaks, etc. Embodiments of the proposed semiconductor module have no current constrictions inside and are therefore electrically and thermally much more resilient while maintaining at least the same reliability and service life as comparable power semiconductor modules of conventional design.

[0010] Embodiments of the present invention provide a semiconductor module with at least two semiconductor components, each having an active semiconductor layer arranged on a carrier within a housing, wherein a current path between the at least two semiconductor components is formed by means of a metallic connecting clip which connects a first electrode of a first semiconductor component to a second electrode of a second semiconductor component. In this case, the first semiconductor component and the second semiconductor are arranged on the carrier rotated by 180° to one another, such that the first electrode of the first semiconductor and the second electrode of the second semiconductor are arranged in a common plane and are each electrically connected to a first clip side of the metallic connecting clip. In addition, a second clip side of the connecting clip forms an exposed contact point.Preferably, the exposed contact point is flush with a first surface of the housing.

[0011] According to the invention, a contact element outside the housing forms an additional high-current path and heat path. The contact element has a contact surface that is connected to the exposed contact point of the connecting clip via an electrically conductive connecting layer.

[0012] In addition, the inclusion of the contact element removes some of the contacts from the aforementioned contact plane. This results in advantages in circuit design regarding space requirements, heat dissipation, and current carrying capacity.

[0013] According to the invention, the first semiconductor component is designed as a low-side switching transistor and the second semiconductor component is designed as a high-side switching transistor of the half-bridge circuit, wherein first electrodes of the semiconductor components are designed as drain electrodes, second electrodes of the semiconductor components are designed as source electrodes and third electrodes of the semiconductor components are designed as gate electrodes.

[0014] The measures and developments listed in the dependent claims enable advantageous improvements of the semiconductor module specified in independent patent claim 1.

[0015] The contact element can have a heat dissipation surface facing away from the contact point, which can be connected to a heat sink. Advantageously, the contact element can form a heat sink that acts as a thermal storage device due to its three-dimensional expansion. The contact element is thicker than the connecting clip and has a volume that is 5 to 50 times larger than the volume of the connecting clip. The additional thermal storage volume of the contact element can convert pulsed heat flows into direct current heat flows, thus enabling greater heat dissipation performance. The thickness of the contact element also spreads the heat, so that a larger surface is available for heat transport through the electrically non-conductive heat transfer medium.

[0016] The contact element advantageously has a heat dissipation surface which can be connected to a heat sink via an electrically non-conductive heat transfer medium.

[0017] In an advantageous embodiment of the semiconductor module, the contact element can have a contacting area that protrudes laterally beyond the housing and can be contacted with an electrical conductor. This advantageously allows a high-current interface to be formed outside the housing, at which an end region of the electrical conductor can be connected to the contacting area by means of soldering, resistance or laser welding, insulation displacement, crimping, or press-fit connection. Of course, other suitable connection techniques can also be used to electrically connect the contacting area to the electrical conductor and form the corresponding high-current path.

[0018] In a further advantageous embodiment of the semiconductor module, the shape of the contact surface of the contact element can be adapted to the shape of the exposed contact point of the second clip side of the connecting clip in order to enable optimized current and heat transfer.

[0019] In an alternative design of the semiconductor module, an angled end region of an electrical conductor can form the contact element and, taking strain relief and assembly tolerances into account, can be electrically connected directly to the contact point using a durable connection technology.

[0020] In a further advantageous embodiment of the semiconductor module, the housing can be designed as a molded housing. This enables cost-effective production of the semiconductor module.

[0021] In a further advantageous embodiment of the semiconductor module, the at least two semiconductor components can be designed as power semiconductor components, which have the same area requirements and form a half-bridge circuit for an electrical machine. Advantageously, a phase current wire of an electrical machine can then form the electrical conductor.

[0022] The semiconductor components can be designed, for example, as IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), etc.

[0023] In a further advantageous embodiment of the semiconductor module, several intelligent power components such as MOSFETs with driver ASICs and multi-chip packages with multiple motor phases (half-bridge, B6 bridge, also 2, 4, 5,... half-bridges) can be combined in one semiconductor module. For example, three semiconductor component pairs, each consisting of a first semiconductor component as a low-side switching transistor and a second semiconductor component as a high-side switching transistor electrically connected to the first semiconductor component via the metallic connecting clip, can form a bridge circuit module for three phase current wires of an electrical machine. In a further advantageous embodiment of the semiconductor module, the housing can be connected on its first surface to a heat sink, which can rest on at least one heat dissipation surface of at least one contact element.In addition, the housing can be placed on a circuit board on its second surface.

[0024] An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. In the drawing, identical reference numerals designate components or elements that perform identical or analogous functions. Short description of the drawings

[0025] Fig. 1 shows a schematic perspective view of a section of an embodiment of a semiconductor module according to the invention from above. Fig. 2 shows a schematic perspective view of the semiconductor module according to the invention from Fig. 1 from underneath. Fig. 3 shows a schematic partial sectional view of the semiconductor module according to the invention from Fig. 1 and 2 . Fig. 4 shows a schematic perspective view of the semiconductor module according to the invention from Fig. 1 to 3without contact element. Fig. 5 shows a schematic perspective view of a section of the semiconductor module according to the invention from Fig. 1 to 4 without housing. Fig. 6 shows a schematic perspective view of a contact element of the semiconductor module according to the invention from Fig. 1 to 4 with a contacted electrical conductor. Embodiments of the invention

[0026] As from Fig. 1 to 6As can be seen, the illustrated embodiment of a semiconductor module 1 according to the invention comprises at least two semiconductor components 10, 20, each of which has an active semiconductor layer 12, 22 arranged on a carrier 2 within a housing 3. A current path is formed between the at least two semiconductor components 10, 20 by means of a metallic connecting clip 30, which connects a first electrode 14 of a first semiconductor component 10 to a second electrode 26 of a second semiconductor component 20. In this case, the first semiconductor component 10 and the second semiconductor 20 are arranged on the carrier 2 rotated by 180° to one another, so that the first electrode 14 of the first semiconductor 10 and the second electrode 26 of the second semiconductor 20 are arranged in a common plane and are each electrically connected to a first clip side 32 of the metallic connecting clip 30.In addition, a second clip side 34 of the connecting clip 30 forms an exposed contact point 4.1, which is flush with a first surface 4 of the housing 3.

[0027] As from Fig. 1 to 6 As can be further seen, a contact element 5 outside the housing 3 forms an additional high-current path and heat path and has a contact surface 5.1 facing the contact point 4.1. The contact surface 5.1 is permanently connected to the exposed contact point 4.1 of the second clip side 34 via an electrically conductive connecting layer 5.3, which is designed, for example, as a solder layer. The contact element 5 has a heat dissipation surface 5.2 facing away from the contact point 4.1, which can be connected to a heat sink. As can be seen in particular from Fig. 3As can be seen, the contact element 5 has a volume that is between 5 and 50 times larger than the connecting clip 30. As a result, the contact element 5 forms a heat sink that acts as a thermal storage device. The additional thermal storage volume of the contact element 5 allows pulsed heat flows to be converted into direct current heat flows, thus enabling greater heat dissipation performance.

[0028] The semiconductor module 1 can, for example, be designed as a three-phase B6 bridge circuit with six semiconductor components 10, 20 for an electrical machine (not shown). In the illustrated embodiment, however, only one pair of semiconductor components is shown, each consisting of a first semiconductor component 10 as a low-side switching transistor and a second semiconductor component 20 as a high-side switching transistor, electrically connected to the first semiconductor component 10 via the metallic connecting clip 30. In the illustrated embodiment, the semiconductor components 10, 20 are each designed as MOSFETs (metal-oxide-semiconductor field-effect transistors), which have the same area requirements.Here, first electrodes 14, 24 of semiconductor components 10, 20 are each designed as drain electrodes, second electrodes 16, 26 of semiconductor components 10, 20 are each designed as source electrodes, and third electrodes 18, 28 of semiconductor components 10, 20 are each designed as gate electrodes. Alternatively, semiconductor components 10, 20 can also be designed, for example, as IGBTs (Insulated Gate Bipolar Transistors).

[0029] As is particularly evident from Fig. 3 and 5As can also be seen, the first semiconductor components 10, which are designed as low-side switching transistors, are each arranged face-down on the carrier 2, i.e. the second electrodes 14, which are designed as source electrodes, and the third electrodes 18, which are designed as gate electrodes, of the first semiconductor elements 10 face the carrier 2 and are connected to corresponding contact points on the carrier 2 via electrically conductive connecting layers 36, which are designed, for example, as solder layers. These contact points are connected to exposed contact points 7.1 on a second surface 7 via vias in the carrier 2. The first electrodes 14, which are designed as drain electrodes, of the first semiconductor components 10 are each electrically connected to the first clip side 32 of the connecting clip 30 via an electrically conductive connecting layer 36, which is designed, for example, as a solder layer.

[0030] As from Fig. 3and 5As can also be seen, the second semiconductor components 20, which are designed as high-side switching transistors, are each rotated by 180° compared to the first semiconductor components 10 and are arranged face-up on the carrier 2, i.e. the first electrodes 24, which are designed as drain electrodes, of the second semiconductor components 20 face the carrier 2 and are each connected to corresponding contact points on the carrier 2 via an electrically conductive connecting layer 36, which is designed, for example, as a solder layer. These contact points are also connected to exposed contact points 7.1 on the second surface 7 via vias in the carrier 2. The second electrodes 14, which are designed as source electrodes, of the second semiconductor elements 20 are electrically connected to the first clip side 32 of the connecting clip 30 via electrically conductive connecting layers 36, which are designed, for example, as solder layers.The third electrodes 28 of the second semiconductor components 20, designed as gate electrodes, are connected, for example, via bonding wires to corresponding contact points of the carrier 2. These contact points are also connected to exposed contact points 7.1 on the second surface 7 via vias in the carrier 2.

[0031] As from Fig. 1 to 6As can also be seen, in the illustrated embodiment only one contact element 5 is arranged on the first surface 4 of the housing 3, i.e. a top side or cooling side of the semiconductor module 1. In addition to these contact elements 5, metallic blocks (not shown) designed only as heat sinks can be arranged on the first surface 4 of the housing. These metallic blocks serve to dissipate heat from further exposed contact surfaces (not shown) which are not formed by a first clip side 32 of a connecting clip 30. The further exposed contact surfaces are each connected to a contact surface of the metallic blocks via a thermally conductive connecting layer. Since the heat dissipation surfaces 5.2 of the contact elements 5 are arranged in a common plane, onto which a heat sink is placed and connected to the heat dissipation surfaces 5 via an electrically insulating but thermally conductive connecting layer.2 and the contact elements 5, the metallic blocks compensate for the height difference between the other exposed contact surfaces and the heat sink. Thus, the heat dissipation surfaces of the metallic blocks can also be connected to the applied heat sink via an electrically insulating but heat-conducting connecting layer. Alternatively, the heat sink can be designed with a corresponding bulge so that it can rest simultaneously on the heat dissipation surfaces 5.2 of the contact elements 5 and on the other exposed contact surfaces. The contact elements 5, the metallic blocks, and the connecting clips 30 are preferably made of copper or another suitable material.

[0032] In the illustrated embodiment, the housing 3 is designed as a molded housing and can be connected at its first surface 4 to the heat sink, which can be placed on the heat dissipation surfaces 5.2 of the contact elements 5 and the metallic blocks and connected to them, as explained above. The housing 3 can be placed with its second surface 7, i.e., with an underside or circuit board side of the semiconductor module 1, on a circuit board (not shown). In this case, the contact points 7.1 exposed on the second surface 7 are electrically connected to corresponding contact points on the circuit board.

[0033] As from Fig. 1 to 6As can also be seen, the contact element 5 shown has a contacting area 5.4, which projects laterally beyond the housing 3 and can be contacted with an electrical conductor 9. Thus, three contact elements 5 of a semiconductor module 1 designed as a B6 bridge circuit can each be electrically connected to a phase current wire of the electrical machine via the contact area 5.4. An end area 9.1 of the electrical conductor 9 or phase current wire can be connected to the corresponding contacting area 5.4, for example, by means of soldering, resistance or laser welding, insulation displacement, crimping, or press-fit connection. In order to connect the exposed contact points 4.1 on the first surface 4 as well as possible to the contact elements 5 and the metallic blocks in terms of heat and current, the shapes of the contact surfaces 5.1 of the contact element 5 and the shape of the metallic blocks are each adapted to the shapes of the respective exposed contact point 4.1.

[0034] In an alternative embodiment (not shown), an angled end portion of an electrical conductor 9 forms the contact element 5, taking strain relief and assembly tolerances into account. Here, the electrical conductor 9 is electrically connected directly to a corresponding contact point 4.1 via a durable connection technology, and the end portion of the electrical conductor 9 has sufficient volume to act as a thermal storage device.

Claims

1. Semiconductor module (1) having at least one first and one second semiconductor component (10, 20), wherein the first semiconductor component (10) is in the form of a low-side switching transistor and the second semiconductor component (20) is in the form of a high-side switching transistor of a half-bridge circuit and each have an active semiconductor layer (12, 22) arranged within a housing (3) on a carrier (2), wherein first electrodes (14, 24) of the semiconductor components (10, 20) are configured as drain electrodes, second electrodes (16, 26) of the semiconductor components (10, 20) are configured as source electrodes, and third electrodes (18, 28) of the semiconductor components (10, 20) are configured as gate electrodes, wherein a current path between the at least two semiconductor components (10, 20) is formed by means of a metallic connection clip (30) which connects the first electrode (14) of the first semiconductor component (10) to the second electrode (26) of the second semiconductor component (20), wherein the first semiconductor component (10) and the second semiconductor component (20) are arranged on the carrier (2) in a manner rotated about 180° with respect to one another, the second electrode (16) and the third electrode (18) of the first semiconductor component (10) and the first electrode (24) of the second semiconductor component (20) face the carrier and the first electrode (14) of the first semiconductor component (10) and the second electrode (26) of the second semiconductor component (20) are arranged in a common plane, and wherein the first electrode (14) of the first semiconductor component (10) and the second electrode (26) of the second semiconductor component (20) are each electrically connected to a first clip side (32) of the metallic connection clip (30) and a second clip side (34) of the connection clip (30) forms an exposed contact point (4.1), wherein the semiconductor module outside the housing (3) has a contact element (5) having a contact surface (5.1) which faces the contact point (4.1) of the second clip side (34) and which is permanently connected via an electrical conductive connection layer (5.3) to the exposed contact point (4.1) of the second clip side (34), characterized in that the contact element (5) is set up to form an additional high-current path as a phase potential tap of the half-bridge circuit which faces away from the carrier.

2. Semiconductor module (1) according to Claim 1, wherein the contact element (5) has a heat-removal surface (5.2) which faces away from the contact point (4.1) and can be connected to a heat sink.

3. Semiconductor module (1) according to Claim 1 or 2, wherein the contact element (5) forms a heat sink acting as a thermal store and has a volume which is greater than a volume of the connection clip (30) by a factor of 5 to 50.

4. Semiconductor module (1) according to any one of the preceding claims, wherein the contact element (5) has a contact-connection area (5.4) which protrudes laterally beyond the housing (3) and can be contact-connected to an electrical conductor (9).

5. Semiconductor module (1) according to Claim 4, wherein the shape of the contact surface (5.1) of the contact element (5) is adapted to the shape of the exposed contact point (4.1) of the second clip side (34) of the connection clip (30).

6. Semiconductor module (1) according to any one of Claims 1 to 3, wherein an angled end region of an electrical conductor (9) forms the contact element (5).

7. Semiconductor module (1) according to any one of the preceding claims, wherein the housing (3) is embodied as a moulded housing.

8. Semiconductor module (1) according to any one of the preceding claims, wherein the at least two semiconductor components (10, 20) are embodied as power semiconductor components which have the same surface area requirement.

9. Semiconductor module (1) according to Claim 8, wherein three semiconductor component pairs form a bridge circuit module for three phase current wires of an electric machine.

10. Semiconductor module (1) according to any one of the preceding claims, wherein the housing (3) can be connected, at its surface (4) which faces away from the carrier, to a heat sink which rests on at least one heat-removal surface (5.2) of at least one contact element (5).

11. Semiconductor module (1) according to any one of the preceding claims, wherein the housing (3) is mounted, on its side facing away from the contact element (5), on a printed circuit board.

12. Contact arrangement comprising a semiconductor module (1) according to Claim 4 or according to any one of Claims 5, 7, 8, 9, 10 and 11 when dependent on Claim 4, wherein an end region (9.1) of the electrical conductor (9) is connected to the contact-connection region (5.4) of the contact element (5) by means of soldering, resistance or laser welding, insulationdisplacement connection, crimping or press-fit connection.

13. Contact arrangement according to Claim 12, wherein a phase current wire of an electric machine forms the electrical conductor (9).

14. Contact arrangement according to Claim 12, wherein the semiconductor module is arranged on a circuit carrier, wherein the conductor (9) is connected to the phase potential tap of the semiconductor module (1), without passing the phase current through the circuit carrier.