Power semiconductor module

Abstract

The invention relates to a power semiconductor module comprising a substrate, a terminal and a conductive trace. The conductive trace includes a narrow region between the terminal and the power semiconductor in order to provide an easy implementation of the current sensor.

Description

Technical Field

[0001] The invention relates to a power semiconductor module. Background Art

[0002] Power semiconductor modules are used in many applications in which consumers of electrical energy, such as electric motors or heating elements, are to be powered. It is typically necessary to measure the current flowing through the terminals of the power semiconductor module. Summary of the Invention

[0003] The object of the present invention is to provide a power semiconductor module that is designed alternatively or better than existing solutions, in particular improved solutions, for mounting a current sensor. This is achieved by a power semiconductor module according to claim 1. Preferred embodiments can be derived from the dependent claims.

[0004] The present invention relates to a power semiconductor module. The power semiconductor module comprises at least a substrate, a terminal, a conductive trace, and a power semiconductor. The conductive trace at least partially covers one side of the substrate. The conductive trace electrically connects the power semiconductor to at least the terminal. The conductive trace comprises a narrow region between the power semiconductor and the terminal, wherein the lateral extent of the conductive trace transversely to the current flow path between the power semiconductor and the terminal is smaller than that of one or two adjacent regions along the current flow path. The module is preferably suitable for mounting a current sensor above the substrate and / or above the narrow region of the conductive trace. The measurement principle of the current sensor is typically based on magnetic field measurement.

[0005] With such power semiconductor modules, a narrow area can be created in the conductive traces over which the current sensor can be mounted. This narrow area provides increased current density and, therefore, a higher magnetic field strength at the current sensor. It also concentrates the flowing current, ensuring that the entire current is measured.

[0006] The module can also be adapted to mount current sensors over narrow areas.

[0007] A power semiconductor module can, in particular, be a module that includes power semiconductors, or is at least suitable for carrying power semiconductors. Power semiconductors are typically entities that control the current flow to an electrical consumer, such as a motor or electric heater. Power semiconductors typically control voltages and / or currents that are typically higher than those used in purely logical communication. The substrate can typically be implemented as a base and can typically be made of a non-conductive material, such as plastic or ceramic, typically covered with a structured conductive material. The terminals can, in particular, be made of a conductive material (such as copper or aluminum) or another metal or conductive material and can, in particular, be blocks or exposed areas on the substrate used to connect the power semiconductor module to an electrical consumer or another entity. The terminals are typically suitable for carrying the high currents consumed by the electrical consumer. The conductive traces are also typically made of a conductive material (such as copper or aluminum) or another metal and are typically also suitable for carrying current for the electrical consumer. The conductive traces are typically implemented as sheets on the substrate.

[0008] The power semiconductor may be part of a power semiconductor module. Alternatively, the power semiconductor may be provided at a designated location on the power semiconductor module. It may be connected to the terminals via conductive traces. Mounting the current sensor above the conductive traces may specifically mean mounting the current sensor opposite the substrate relative to the conductive traces.

[0009] The lateral extension is measured transversely to the current flow path. The lateral extension is typically taken in a direction parallel to the substrate. In a specific embodiment, the current flow path can be easily determined because the current flows along the conductive track. Alternatively, it can be said that the current flow path is defined along the extension of the conductive track. It can also be said that, alternatively, the lateral extension is measured along the longitudinal extension of the conductive track from the power semiconductor to the terminal at a specific point. The lateral extension is not to be confused with the thickness of the conductive track. Typically, the conductive track has a constant thickness, wherein it can also be provided that different thicknesses can be used. Typically, the lateral extension is greater than the thickness of the conductive track, in particular much greater.

[0010] Different regions can be defined along the flow path. According to the embodiments described herein, a narrow region is present that has a smaller lateral extent than one or two adjacent regions. This is particularly visible when viewing the power semiconductor module from above. The power semiconductor module is suitable for mounting the current sensor above the narrow region of the conductive trace. This can be achieved, for example, by providing a cutout in the cover layer, as described further below. Additional means for securing the current sensor may also be present, such as solder posts or clip connections.

[0011] For example, a current sensor may have dimensions of 13 mm x 6.5 mm x 1.5 mm. Two of these dimensions may be used to define the extent of the narrow region when viewed from above. The dimensions may also be scaled, for example, from 0.3x to 5x. Such scaled dimensions may also be used to specify the extent of the narrow region.

[0012] In particular, the substrate may extend in a plane. The conductive traces typically also extend in a plane. The two planes may be parallel to one another. Positioning the current sensor above the substrate and / or above the narrow area particularly means that there is a distance between the current sensor and the substrate and / or the narrow area. For example, if the substrate extends horizontally, positioning the current sensor above the substrate means that the substrate is positioned at a specific vertical height above the substrate. Positioning the current sensor above the narrow area particularly means that the narrow area of ​​the conductive traces is arranged between the substrate and the current sensor.

[0013] In particular, the power semiconductor module may further comprise a covering layer which completely or partially covers the conductive traces on a side opposite the substrate, wherein the covering layer may be particularly suitable for fixing the current sensor above the narrow area. Such a covering layer may in particular be made of a non-conductive material (e.g. plastic). The covering layer may protect the conductive traces and other components from unintended electrical connections. In particular, a cutout may be formed in the covering layer above the narrow area in order to place the current sensor in the cutout. Such a cutout is a defined space in which the current sensor may be placed. For example, the power semiconductor module may be delivered to the customer without the current sensor, but with the cutout already formed in the covering layer. The current sensor may then be inserted by the customer. Alternatively, the current sensor may be permanently mounted (e.g. glued) in the cutout and supplied to the customer as a single unit together with the power module.

[0014] It can be provided that the cutout is arranged completely above the material of the conductive track. This means in particular that there are no holes or cutouts in the conductive track. This ensures a correct measurement.

[0015] In particular, it can be provided that the or each conductive track extends on the substrate in only one plane. This means that there is no second plane of conductive tracks in the power semiconductor module. In particular, it can be provided that there is no overlap between different conductive tracks.

[0016] In particular, it can be provided that the conductive trace always completely covers the substrate in a direction perpendicular to the current flow path. This is typically effective along the extent of the conductive trace perpendicular to the current flow path. In particular, there can be no overflows, cutouts, or holes in the conductive path. This ensures a smooth current flow.

[0017] According to one embodiment, the power semiconductor module comprises only one terminal electrically connected to the conductive trace. This allows the connection to be made using only the terminal. For example, the conductive trace may extend along a straight line between the power semiconductor and the terminal.

[0018] According to one embodiment, the power semiconductor module includes a further terminal, in particular in addition to the terminals already mentioned. This further terminal can be electrically connected to the power semiconductor and the terminal via the conductive trace. This allows, for example, the connection of two electrical consumers, each of which can be connected to a separate terminal. In this case, the conductive trace can be split at one point to connect both terminals to the power semiconductor.

[0019] In particular, the further current flow path between the power semiconductor and the further terminal overlaps the current flow path between the power semiconductor and the terminal at least in the narrow region. This allows both currents flowing through the respective terminals to be measured integrally using only one current sensor.

[0020] According to one embodiment, the conductive trace may have a widened region between the narrow region and the terminal, wherein the widened region may be connected to the narrow region via a connecting trace. According to one embodiment, the conductive trace may have another widened region between the narrow region and the other terminal, wherein the another widened region is connected to the narrow region via another connecting trace.

[0021] In particular, the widened region may have a constant extension between the connection track and the terminal, viewed parallel to the longitudinal extension of the narrow region. In particular, the further widened region may have a constant extension between the further connection track and the further terminal, viewed parallel to the longitudinal extension of the narrow region.

[0022] Using such a widened area, a particularly low resistance can be provided between the narrow area and the terminal. In top view, this can be seen as an L-shape.

[0023] The longitudinal extension can particularly denote the longest extension of the narrow region. In particular, in a top view, the narrow region can have a rectangular shape.

[0024] According to one embodiment, the conductive trace may include a connection region connecting an end portion of the narrow region opposite to the power semiconductor to the terminal, wherein the end portion of the narrow region may be closer to an edge of the module than a portion of the connection region contacting the terminal. According to one embodiment, the conductive trace may include another connection region connecting an end portion of the narrow region opposite to the power semiconductor to the other terminal, wherein the end portion of the narrow region is closer to an edge of the module than a portion of the other connection region contacting the other terminal.

[0025] Such an embodiment may look like an S-shape in a top view. It may provide a specifically tailored magnetic field at the current sensor.

[0026] The connection region may have a constant cross-section transverse to the current flow path, at least in its straight section. The further connection region may have a constant cross-section transverse to the further current flow path, at least in its straight section. This allows for a specific accumulation of magnetic fields and a constant current flow.

[0027] The connecting region may have at least one straight portion oriented parallel to the longitudinal extension of the narrow region and positioned between the narrow region and the terminal. The further connecting region may have at least one straight portion oriented parallel to the longitudinal extension of the narrow region and positioned between the narrow region and the further terminal. Such a straight portion may provide an additional magnetic field, particularly at the narrow region and, therefore, also at the location of the current sensor.

[0028] The narrow region may be positioned between the terminal and the further terminal.For example, there may be a symmetrical arrangement of the conductive tracks, in particular such that the narrow region defines a mirror image line.

[0029] In particular, the terminal may have a constant cross-section transverse to the direction of current flow in the terminal. In particular, the further terminal may have a constant cross-section transverse to the direction of current flow in the terminal. This may be particularly true in the respective portion of the respective terminal or may be true throughout the entire terminal.

[0030] The conductive trace can be implemented as a planar sheet on the substrate. In particular, the conductive trace can have a constant thickness, wherein this thickness is typically measured perpendicular to the substrate. The substrate can in particular be implemented as a plate, in particular a plate of constant thickness, which can in particular correspond to a plane.

[0031] According to one embodiment, the terminal and / or the further terminal is embodied as a block-shaped connecting element, in particular a block-shaped connecting element extending partially over the substrate. Such a terminal can be used in particular for connection to an external power consumer.

[0032] According to one embodiment, the terminal and / or the further terminal is implemented as an exposed area on the substrate. In particular, it can be an exposed area of ​​conductive material. This can be used to connect other entities, such as external electrical consumers or electrical consumers embedded in the module. For example, the exposed area may not be covered by the molding material. However, it can alternatively be covered.

[0033] It should be noted in particular that the current sensor is mounted above the conductive traces and therefore also above the substrate. The current sensor is typically not mounted above the terminals. This can lead to, among other things, higher integration and a more compact module.

[0034] As mentioned above, the cover layer can in particular be molded. It should be noted that all molding techniques can be used. Using the cutouts described above or any other connection to the molded cover layer can result in very precise placement of the current sensor, since the molding process can be performed with very tight tolerances. No additional space is required for the placement of the current sensor.

[0035] The power semiconductor module may further comprise a current sensor. The current sensor may be positioned above the substrate and / or above a narrow area of ​​the conductive trace. With regard to the positioning of the current sensor, all embodiments disclosed herein may apply.

[0036] The current sensor can in particular be a coreless current sensor, ie a sensor without a magnetic core. Compared to a current sensor comprising a core, this can be a more compact sensor.

[0037] The cutouts in the cover layer can be etched, milled, or even provided during the molding of the cover layer. The current sensor can be connected, in particular, using a flexible layer. This allows the electrical signal to be carried away from the sensor. Alternatively, other typical connection techniques, such as press-fit pins or solder pins, can also be used. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Further details will be apparent from the described embodiments given with reference to the accompanying drawings, in which:

[0039] Figure 1 : A power semiconductor module is shown in a cross-sectional view;

[0040] Figure 2 : Another cross-sectional view shows the same power semiconductor module;

[0041] Figure 3 : shows a portion of a power semiconductor module according to a first embodiment;

[0042] Figure 4: shows a portion of a power semiconductor module according to a second embodiment;

[0043] Figure 5 : shows a portion of a power semiconductor module according to a third embodiment;

[0044] Figure 6 : A cross-sectional view showing a power semiconductor module; and

[0045] Figure 7 : A cross-sectional view of another power semiconductor module is shown. DETAILED DESCRIPTION

[0046] It should be noted that the designs shown in the figures, especially the designs of the conductive traces, may have inventive significance.

[0047] Figure 1 A power semiconductor module 10 according to a first embodiment is shown in cross-section. The power semiconductor module 10 includes a substrate 20 comprising a non-conductive layer, such as a ceramic or plastic material. The substrate 20 is disposed on a cooling element 11, which is positioned on the lower portion of the power semiconductor module 10. The power semiconductor module 10 includes terminals 30. The terminals 30 are connected to conductive traces 40 carrying power semiconductors 50. The power semiconductors 50 can be used to control the power consumption of an electrical consumer. The terminals 30 can be used to connect the electrical consumer to the power semiconductor module 10. The conductive traces electrically connect the power semiconductors 50 to the terminals 30.

[0048] The power semiconductor module 10 is covered by a cover layer 25. The cover layer 25 is made of a non-conductive plastic material. The cover layer 25 can be applied, in particular, by molding. A current sensor 15 with connectors 17 is placed in the cover layer 25 for reading data. The current sensor 15 is used to measure the current flowing through the conductive trace 40. This will be described further below.

[0049] Figure 2 The cross-sectional view shows Figure 1 The same power semiconductor module 10 with the current sensor 15 lifted out of its position. It can be seen that a cutout 27 is provided in the cover layer 25, which serves to place the current sensor 15 therein and fix it in a very specific position.

[0050] Figure 3 1 shows a top view of a power semiconductor module 10 with the cover layer 25 and the current sensor 15 removed. Figure 3 is a top view directly on substrate 20 , terminals 30 , and conductive traces 40 .

[0051] When current flows from the power semiconductor 50 to the terminal 30, the current flows along the current flow path 12, which is Figure 3 This can also be thought of as an integral over the vector defining the current flow at a specific location, where the current flow path 12 is Figure 3 This is because the conductive trace 14 is mirror-symmetrical with respect to a horizontal imaginary line, which can be seen in FIG. Figure 3 The current flow path 12 is defined by an arrow in the figure. This imaginary line serves only as a mirror line. Due to this configuration, the current flowing in the conductive trace 14 is not observed to deviate from its straight flow structure even if the lateral dimensions change.

[0052] Conductive trace 40 includes a narrow region 41 having a smaller lateral extent, as viewed transversely to current flow path 12, than first and second adjacent regions 42, 43, when viewed along current flow path 12. First adjacent region 42 connects narrow region 41 to power semiconductor 50. Second adjacent region 43 connects narrow region 41 to terminal 30. Both adjacent regions 42, 43 have a greater lateral extent than narrow region 41. This concentrates the current at narrow region 41, resulting in a higher current density. Current sensor 15 is positioned directly above narrow region 41 to measure the particularly high magnetic field generated by the current flowing through narrow region 41.

[0053] As in Figure 3 As seen in FIG, the terminals 30 are secured near the edge 28 of the substrate 20. Typically, the edge 28 of the substrate 20 is close to and parallel to the edge of the module 10. Figure 3 Not shown in the figure.

[0054] Figure 4 A portion of a power semiconductor module 10 according to a second embodiment is shown. Figure 4 and Figure 5 The view is in principle the same as Figure 3 Vision Figure 1 To.

[0055] In contrast to the first embodiment, the power semiconductor module 10 according to the second embodiment has not only a terminal 30 but also a further terminal 35. To connect the two terminals 30, 35, the conductive trace 40 includes a widened region 60 and a further widened region 65. These widened regions are positioned between the narrow region 41 and the respective terminals 30, 35. The widened region 60 is connected to the narrow region 41 via a connecting trace 62. The further widened region 65 is connected to the narrow region 41 via a further connecting trace 67. In a top view, the respective widened regions 60, 65 and their connecting traces 62, 67 have a roughly L-shape. This allows for very low resistance between the connecting traces 62, 67 and the respective terminals 30, 35. However, the straight line of current flow in the narrow region 41 is preserved, while providing a very compact design.

[0056] As in Figure 4 As seen in FIG. 1 , the narrow region 41 is an extension in the direction of the current flow path 12. Figure 4 is horizontal and longer than the first embodiment. Figure 4 The narrow region 41 has its longitudinal extension in this direction, which is horizontal.

[0057] Figure 5 A power semiconductor module 10 according to a third embodiment is shown. In contrast to the second embodiment, the conductive trace 40 includes a connection region 70 between the narrow region 41 and the terminal 30. Similarly, it includes a further connection region 75 between the narrow region 41 and the further terminal 35. The connection region 70 and the further connection region 75, at least outside the corner regions, are embodied with a constant cross-section transverse to the respective current flow paths. The connection region 70 includes a straight portion 72 oriented parallel to the current flow path and the extent of the narrow region 41. Similarly, the further connection region 75 includes a further straight portion 77 oriented parallel to the narrow region 41. This allows the magnetic fields generated by the current flowing in the narrow region 41 and the two straight portions 72 , 77 to be superimposed, and these magnetic fields are measured by the current sensor.

[0058] like Figure 5 The design of the connection regions 70, 75 shown corresponds approximately to an S-shaped design. This can be used to electrically connect terminals 30, 35 that are further away from the edge 28 of the substrate 20 than the end of the narrow region 41. This design saves space.

[0059] Figure 6 A portion of a power semiconductor module 10 is shown, which is not specifically based on Figures 1 to 5 One of the embodiments shown, but Figure 6 The diagram shows an embodiment of the connection of the terminal 30 which can be applied to all the illustrated embodiments and other embodiments. Figure 7The same is true. Figure 6 In the embodiment shown, the terminals 30 are attached to the traces 40 and the module is enclosed in a molded cover 25. The sensor 15 is placed in a cutout 27 in the molding.

[0060] exist Figure 5 In the embodiment shown, the terminal 30 extends parallel to the substrate 20. The terminal 30 is directly connected to the conductive trace 40 via the S-shaped portion.

[0061] Figure 7 An alternative embodiment is shown. There, terminals 30 extend vertically upward, perpendicular to substrate 20. Terminals 30 are embedded in a non-conductive frame 80 of power module 10. In this embodiment, cover layer 25 may be, for example, a soft gel filler or epoxy material. Sensor 15 is supported by sensor support 81, wherein cutouts 27 enable sensor 15 to be properly positioned above conductive trace 40. It has ends extending through cover layer 25 and connected to conductive trace 40 via wire connectors 32.

[0062] By means of the embodiment shown, a simple and reliable current measurement can be performed using the current sensor 15 , which can be placed at a suitable location and can be fixed accurately. List of reference numerals 10 Power semiconductor modules 11 Cooling element 12 Current flow path 15 Current sensor 17 Connectors 20 substrate 25 Covering 27 incision 28 Edge 30 terminals 32 Wire connector 35 other terminal 40 conductive traces 41 Narrow Area 42 First adjacent area 43 Second adjacent area 50 Power Semiconductors 60 widening area 62 connection traces 65 Another widened area 67 Another connection trace 70 connection area 72 straight part 75 Another connection area 77 Another straight section 80 frames 81 Sensor support.

Claims

1. A power semiconductor module (10), comprising: substrate (20), terminal(30), conductive traces (40), and Power semiconductors (50), wherein the conductive trace (40) at least partially covers one side of the substrate (20), wherein the conductive trace (40) electrically connects the power semiconductor (50) at least to the terminal (30), wherein the conductive trace (40) comprises a narrow region (41) between the power semiconductor and the terminal (30), in which the lateral extension of the conductive trace (40) transversely to the current flow path (12) between the power semiconductor (50) and the terminal (30) is smaller than that of one adjacent region (42, 43) or two adjacent regions (42, 43) along the current flow path (12), and The module (10) is adapted to mount a current sensor (15) above the substrate (30) above the narrow area (41) of the conductive trace (40).

2. The power semiconductor module (10) according to claim 1, Also included is a cover layer (25) that completely or partially covers the conductive trace (40) on a side opposite to the substrate (20), wherein the cover layer (25) is adapted to fix the current sensor (15) over the narrow area (41).

3. The power semiconductor module (10) according to claim 2, in, A cutout (27) is formed in the cover layer (25) above the narrow area (41) so as to place the current sensor (15) in the cutout (27).

4. The power semiconductor module (10) according to claim 3, in, The cutout (27) is arranged completely over the material of the conductive trace (40).

5. The power semiconductor module (10) according to any one of the preceding claims, in, The or each conductive trace (40) extends on the substrate (20) in only one plane.

6. The power semiconductor module (10) according to any one of the preceding claims, in, The conductive trace (40) always completely covers the substrate (20) along a direction perpendicular to the current flow path (12).

7. The power semiconductor module (10) according to any one of the preceding claims, in, The power semiconductor module (10) includes only one terminal (30) electrically connected via the conductive trace (40).

8. The power semiconductor module (10) according to any one of claims 1 to 6, in, The power semiconductor module (10) further comprises a further terminal (35), The further terminal (35) is electrically connected to the power semiconductor (50) and the terminal (30) via the conductive trace (40).

9. The power semiconductor module (10) according to claim 8, in, Another current flow path between the power semiconductor (50) and the further terminal (35) overlaps the current flow path (12) between the power semiconductor (50) and the terminal (30) at least in the narrow region (41).

10. The power semiconductor module (10) according to claim 8 or 9, in, The conductive trace (40) has a widened region (60) between the narrow region (41) and the terminal (30), wherein the widened region (60) is connected to the narrow region (41) via a connecting trace (62); and / or, The conductive trace (40) has a further widened region (65) between the narrow region (41) and the further terminal (35), wherein the further widened region (65) is connected to the narrow region (41) via a further connecting trace (67).

11. The power semiconductor module (10) according to claim 10, in, The widened region (60) has a constant extension between the connecting track (62) and the terminal (30), viewed parallel to the longitudinal extension of the narrow region (41); and / or, Therein, viewed parallel to the longitudinal extension of the narrow region (41), the further widened region (60) has a constant extension between the further connecting track (67) and the further terminal (30).

12. The power semiconductor module (10) according to claim 8 or 9, in, The conductive trace (40) includes a connection region (70) connecting an end of the narrow region (41) opposite the power semiconductor (50) to the terminal (30), wherein the end of the narrow region (41) is closer to an edge of the module (10) than a portion of the connection region (70) contacting the terminal (30); and / or, The conductive trace (40) includes another connection region (75) connecting an end portion of the narrow region (41) opposite to the power semiconductor (50) to the other terminal (30), wherein the end portion of the narrow region (41) is closer to an edge of the module (10) than a portion of the other connection region (75) contacting the other terminal (35).

13. The power semiconductor module (10) according to claim 12, in, The connecting region (70) has, at least in a straight portion, a constant cross section transversely to the current flow path (12); and / or, The further connecting region (70) has, at least in a straight section, a constant cross section transversely to the further current flow path (12).

14. The power semiconductor module (10) according to claim 13, in, The connecting region (70) has at least one straight portion (72) oriented parallel to the longitudinal extension of the narrow region (41) and positioned between the narrow region (41) and the terminal (30); and / or, The further connection region (70) has at least one straight portion (77) oriented parallel to the longitudinal extension of the narrow region (41) and positioned between the narrow region (41) and the further terminal (30).

15. The power semiconductor module (10) according to any one of claims 8 to 14, in, The narrow region (41) is positioned between the terminal (30) and the further terminal (35).

16. The power semiconductor module (10) according to any one of the preceding claims, in, The terminal (30) has a constant cross-section transverse to the direction of current flow in the terminal (30); and / or, The further terminal (35) has a constant cross section transverse to a direction of current flow in the further terminal (35).

17. The power semiconductor module (10) according to any one of the preceding claims, in, The conductive traces (40) are implemented as planar sheets on the substrate (20).

18. The power semiconductor module (10) according to any one of the preceding claims, in, The terminal (30) and / or the further terminal (35) are implemented as block-shaped connecting elements extending partially over the substrate (20).

19. The power semiconductor module (10) according to any one of the preceding claims, in, The terminal (30) and / or the further terminal (35) are implemented as exposed areas on the substrate (20).

20. The power semiconductor module (10) according to any one of the preceding claims, Also included is a current sensor (15) positioned above the substrate (20) and over the narrow region (41) of the conductive trace (40).

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