Power semiconductor module

Abstract

The invention relates to a power semiconductor module comprising a substrate, a terminal, and a conductor track. The conductor track includes a narrow region between the terminal and a power semiconductor to enable simple implementation of an electrical current sensor.

Description

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

[0002] Power semiconductor modules are used in many applications where an electrical energy consumer, such as an electric motor or heating element, needs to be supplied with electrical power. It is usually necessary to measure an electrical current flowing through a terminal of the power semiconductor module.

[0003] An object of the invention is to provide a power semiconductor module that is designed alternatively or better than existing solutions, in particular with an improved solution 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 invention relates to a power semiconductor module. The power semiconductor module comprises at least a substrate, a terminal, a conductor track, and a power semiconductor. The conductor track at least partially covers one side of the substrate. The conductor track connects the power semiconductor at least electrically to the terminal. The conductor track comprises a narrow region between the power semiconductor and the terminal, in which a lateral extension of the conductor track transverse to a current flow path between the power semiconductor and the terminal is smaller compared to an adjacent region or both adjacent regions along the current flow path. The module is designed for the mounting of an electrical current sensor above the narrow region of the conductor track. The measuring principle of the current sensor is generally based on magnetic field measurements.

[0005] In such a power semiconductor module, a narrow area can be provided in a conductor track over which a current sensor can be mounted. This narrow area ensures increased current density and thus a higher magnetic field strength at the current sensor. The narrow area also concentrates the flowing current, ensuring that the entire current is measured.

[0006] A power semiconductor module can, in particular, be a module that has a power semiconductor or is at least designed to carry a power semiconductor. The power semiconductor is typically a unit that controls electrical current for an electrical load such as a motor or an electrical heating element. The power semiconductor typically controls voltages and / or currents whose values ​​are generally higher than voltages or currents used in pure logic communication. The substrate can typically be configured as a base and is typically made of a non-conductive material, for example a plastic or ceramic material, which is typically covered with a structured conductive material.The terminal may in particular be made of a conductive material such as copper or aluminum or another metal or conductive material and may in particular be either a solid object or an exposed area on the substrate used to connect the power semiconductor module to an electrical load or another device. Typically, the terminal is designed to carry large currents consumed by the electrical load. The conductive track is typically also made of an electrically conductive material such as copper or aluminum or another metal and is typically also designed to carry the current for the electrical load. The conductive track is typically configured as a foil on the substrate.

[0007] The power semiconductor can be part of the power semiconductor module. Alternatively, there may be a specific location on the power semiconductor module where a power semiconductor can be provided. It is connected to the terminal via the conductive trace. Mounting the current sensor above the conductive trace may, in particular, mean that it is mounted opposite the substrate with respect to the conductive trace.

[0008] The lateral extent is measured across a current flow path. This lateral extent is usually taken in a direction parallel to the substrate. The current flow path can be easily determined in a particular implementation because the current flows along the trace. Alternatively, one can say that the current flow path is defined along an extent of the trace. Alternatively, one can also say that the lateral extent is measured along a longitudinal extent of the trace from the power semiconductor to the terminal at a specific point. The lateral extent should not be confused with a trace thickness. Typically, the trace has a constant thickness, although it may also be possible to use different thicknesses. Typically, the lateral extent is larger, in particular much larger, than the trace thickness.

[0009] Different regions can be defined along the flux path. According to the implementation described here, there is a narrow region with a smaller lateral extent compared to one or both neighboring regions. This is particularly evident when viewing the power semiconductor module from a top view. The power semiconductor module is designed for mounting an electrical current sensor above the narrow region of the conductive path. This can be achieved, for example, by providing a cutout in a cover layer, as described below. There may also be additional means for fixing a current sensor, e.g., solder pins or clip connectors.

[0010] For example, the electrical current sensor may have dimensions of 13 x 6.5 x 1.5 mm. Two of these dimensions can be used to define the extent of the narrow region when viewed from above. The dimensions can also be scaled, e.g., from 0.3x to 5x. Such scaled dimensions can also be used to specify the extent of the narrow region.

[0011] In particular, the power semiconductor module can further comprise a cover layer that completely or partially covers this conductor track on a side opposite the substrate, wherein the cover layer can be designed in particular to fix the electrical current sensor above the narrow region. Such a cover layer can in particular be made of an electrically non-conductive material, e.g., plastic. It can protect the conductor track and other components from unwanted electrical connections. In particular, a cutout can be formed in the cover layer above the narrow region in order to place the electrical current sensor in the cutout. Such a cutout is a defined space in which an electrical current sensor can be placed. For example, the power semiconductor module can be delivered to a customer without the electrical current sensor, wherein the cutout is already formed in the cover layer.The electrical current sensor can then be inserted by the customer. Alternatively, the current sensor can be permanently mounted in the cutout, e.g., glued, and delivered to the customer as a single unit with the power module.

[0012] According to one implementation, the power semiconductor module comprises only one terminal that is electrically connected to the conductive trace. This enables connection using the single terminal. For example, the conductive trace can extend along a straight line between the power semiconductor and the terminal.

[0013] According to one implementation, the power semiconductor module comprises a further terminal, in particular in addition to the previously mentioned terminal. The further terminal can be electrically connected to the power semiconductor by the conductive track, and to the terminal by the conductive track. This enables, for example, the connection of two electrical loads, each of which can be connected to a separate terminal. In such a case, the conductive track can split at one point to connect both terminals to the power semiconductor.

[0014] In particular, an additional current flow path between the power semiconductor and the additional terminal and the current flow path between the power semiconductor and the terminal can overlap, at least in the narrow region. This allows the measurement of both currents flowing through the respective terminals with a single current sensor.

[0015] According to one implementation, 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 by a connecting trace. According to one implementation, the conductive trace may have a further widened region between the narrow region and the further terminal, wherein the further widened region may be connected to the narrow region by a further connecting trace.

[0016] In particular, the widened region, viewed parallel to a longitudinal extension of the narrow region, can have a constant extension between the connecting track and the terminal. In particular, the further widened region, viewed parallel to a longitudinal extension of the narrow region, can have a constant extension between the further connecting track and the further terminal.

[0017] By using such widened regions, a particularly low resistance can be achieved between the narrow region and the terminals. In a top view, this can be seen as an L-shape.

[0018] A longitudinal extension can, in particular, represent the longest extension of the narrow region. The narrow region can, in particular in a plan view, have the shape of a rectangle.

[0019] According to one implementation, the conductive trace may comprise a connection region connecting an end of the narrow region opposite the power semiconductor to the terminal, wherein the end of the narrow region may be closer to an edge of the module than a portion where the connection region contacts the terminal. According to one implementation, the conductive trace may comprise a further connection region connecting an end of the narrow region opposite the power semiconductor to the further terminal, wherein the end of the narrow region is closer to an edge of the module than a portion where the further connection region contacts the further terminal.

[0020] Such an implementation might resemble an S-shape in a top view. It can provide a specifically tailored magnetic field to the current sensor.

[0021] The connecting region can have, at least in straight sections, a constant cross-section perpendicular to the current flow path. The further connecting region can have, at least in straight sections, a constant cross-section perpendicular to the further current flow path. This enables a specific magnetic field structure and a constant current flow.

[0022] The connection region may have at least one straight part oriented parallel to a longitudinal extension of the narrow region and positioned between the narrow region and the terminal. The further connection region may have at least one straight part oriented parallel to a longitudinal extension of the narrow region and positioned between the narrow region and the further terminal. Such straight parts can, in particular, provide an additional magnetic field at the narrow region and thus also at a position of the current sensor.

[0023] The narrow region can be positioned between the terminal and the other terminal. For example, the conductor track can be arranged symmetrically, in particular so that the narrow region defines a mirror line.

[0024] In particular, the terminal may have a constant cross-section transverse to a current flow direction in the terminal. In particular, the further terminal may have a constant cross-section transverse to a current flow direction in the terminal. This may be the case in a specific part of the respective terminal, or it may be the case in the entire terminal.

[0025] The conductor track can be configured as a planar foil on the substrate. In particular, it can have a constant thickness, with such a thickness typically being measured perpendicular to the substrate. The substrate can, in particular, be configured as a plate, which in particular has a constant thickness and can, in particular, correspond to a plane.

[0026] According to one implementation, the terminal and / or the further terminal is / are designed as a bulk connection element, which in particular extends partially over the substrate. Such a terminal can be used in particular for connecting to an external electrical power consumer.

[0027] According to one implementation, the terminal and / or the further terminal is / are configured as an exposed area on the substrate. In particular, this may be an exposed area of ​​conductive material. It may be used to connect other devices, such as external power consumers or power consumers embedded in the module. An exposed area may, for example, not be covered with molding material. Alternatively, it may also be covered.

[0028] It is particularly important to note that the electrical current sensor is mounted above the conductor track and thus also above the substrate. The electrical current sensor is generally not mounted above a terminal. This can lead to higher integration and a more compact module.

[0029] The above-mentioned cover layer can, in particular, be molded. It should be noted that all molding techniques can be used. The use of a cutout, as described above, or another connection with a molded cover layer can lead to very precise placement of the electrical current sensor, as a molding process can be performed with very tight tolerances. No additional space is required for current sensor placement.

[0030] In particular, the current sensor may be a coreless current sensor, i.e., a sensor without a magnetic core. This may be a more compact sensor compared to a current sensor that includes a core.

[0031] The cutout in the cover layer can be etched, milled, or provided during the molding of the cover layer. The electrical current sensor can be connected, in particular, using a flexible layer. This can lead to electrical signals from the sensor. Alternatively, other typical connection techniques such as press-fit pins or solder pins can also be used.

[0032] Further details will become apparent from the described embodiments presented with reference to the accompanying drawings, in which: Fig. 1: a power semiconductor module in a sectional view, Fig. 2: the same power semiconductor module in a different sectional view. Fig. 3: a part of a power semiconductor module according to a first embodiment, Fig. 4: a part of a power semiconductor module according to a second embodiment, Fig. 5: a part of a power semiconductor module according to a third embodiment, Fig. 6: a cross-sectional view of a power semiconductor module, and Fig. 7: a cross-sectional view of another power semiconductor module.

[0033] Fig. 1 shows a power semiconductor module 10 according to a first embodiment in a sectional view. The power semiconductor module 10 comprises a substrate 20 comprising a non-electrically conductive layer such as a ceramic or plastic material. The substrate 20 is provided on a cooling element 11 placed at the bottom of the power semiconductor module 10. The power semiconductor module 10 comprises a terminal 30. The terminal 30 is connected to a power semiconductor 50 via a conductor track 40. The power semiconductor 50 can be used to control the power consumption of an electrical load. The terminal 30 can be used to connect this electrical load to the power semiconductor module 10. The conductor track electrically connects the power semiconductor 50 to the terminal 30.

[0034] The power semiconductor module 10 is covered by a cover layer 25. The cover layer 25 is made of a non-conductive plastic material. It can be applied, in particular, by molding. An electrical current sensor 15 with a connector 17 for reading data is placed in the cover layer 25. The electrical current sensor 15 is used to measure a current flowing through the conductor track 40. This will be described further below.

[0035] Fig. 2 shows the same power semiconductor module 10 as in Fig. 1 in a cross-sectional view, with the electrical current sensor 15 lifted out of its position. It can be seen that a cutout 27 is provided in the cover layer 25, which is used to place the electrical current sensor 15 therein and fix it in a very specific location.

[0036] Fig. Figure 3 shows a top view of the power semiconductor module 10, with the cover layer 25 and the electrical current sensor 15 removed. It is thus a top view directly onto the substrate 20, the terminal 30, and the conductor track 40.

[0037] When electrical current flows from the power semiconductor 50 to the terminal 30, it flows along a current flow path 12 which is Fig. 3 with an arrow. This can also be viewed as an integral over vectors that define a current flow at a specific location, where the current flow path 12 in Fig. 3 is horizontal because the conductor track 14 is mirror-symmetrical with respect to a horizontal imaginary line defined by the arrow indicating the current flow path 12 in Fig. 3. This imaginary line serves merely as a mirror line. Due to this configuration, the current flowing in conductor track 14 does not encounter any structure that would deflect its straight flow, even if the lateral dimension changes.

[0038] The conductor track 40 comprises a narrow region 41 in which a lateral extension, viewed transversely to the current flow path 12, is smaller compared to a first adjacent region 42 and a second adjacent region 43, viewed along the current flow path 12. The first adjacent region 42 connects the narrow region 41 to the power semiconductor 50. The second adjacent region 43 connects the narrow region 41 to the terminal 30. The two adjacent regions 42, 43 have a greater lateral extension than the narrow region 41. As a result, the current is concentrated on the narrow region 41, resulting in a higher current density. The electrical current sensor 15 is placed just above the narrow region 41 to measure the particularly high magnetic field generated by the current flowing through the narrow region 41.

[0039] As in Fig. 3, the terminal 30 is fixed near an edge 28 of the substrate 20. Typically, the edge 28 of the substrate 20 is close to and parallel to an edge of the module 10, which in Fig. 3 is not shown.

[0040] Fig. 4 shows a part of a power semiconductor module 10 according to a second embodiment. The views of Fig. 4 and Fig. 5 are basically identical to the view of Fig. 3.

[0041] In contrast to the first embodiment, the power semiconductor module 10 according to the second embodiment has not only the terminal 30, but also a further terminal 35. To connect the two terminals 30, 35, the conductor track 40 comprises a widened region 60 and a further widened region 65. These widened regions are positioned between the narrow region 41 and the respective terminal 30, 35. The widened region 60 is connected to the narrow region 41 by a connecting track 62. The further widened region 65 is connected to the narrow region 41 by a further connecting track 67. In plan view, the respective widened region 60, 65 and its connecting track 62, 67 have an approximately L-shape. This enables a very low resistance between the connecting track 62, 67 and the respective terminal 30, 35.However, the straight line of current flow in the narrow region 41 is maintained and at the same time a very compact design is provided.

[0042] As in Fig. 4, the narrow area 41 has an extension in the direction of the current flow path 12, which in Fig. 4 horizontally and is much longer compared to the first embodiment. In this direction, which is Fig. 4 is horizontal, it has its longitudinal extension.

[0043] Fig. 5 shows a power semiconductor module 10 according to a third embodiment. In contrast to the second embodiment, the conductor track 40 comprises a connection region 70 between the narrow region 41 and the terminal 30. It also comprises 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 are configured with a constant cross-section transverse to the respective current flow path, at least outside corner regions. The connection region 70 comprises a straight part 72, which is aligned parallel to the current flow path and the extension of the narrow region 41. Likewise, the further connection region 75 comprises a further straight part 77, which also runs parallel to the narrow region 41.This allows a superposition of magnetic fields generated by current flowing in the narrow region 41 and the two straight parts 72, 77, which is measured by a current sensor.

[0044] The interpretation of the connection areas 70, 75, as in Fig. 5, corresponds approximately to an S-shaped design. This can be used to electrically connect the terminals 30, 35 further away from the edge 28 of the substrate 20 than one end of the narrow region 41. This design saves space.

[0045] Fig. 6 shows a part of a power semiconductor module 10 which does not specifically correspond to one of the shown embodiments of the Fig. 1 to 5, but represents an implementation of the connection of the terminal 30 that can be applied to all embodiments shown and to other implementations. The same applies to Fig. 7. In the Fig. In the implementation shown in Figure 6, the connector 30 is attached to the track 40, and the module is enclosed in a molded cover layer 25. The sensor 15 is placed in the cutout 27 in this molded part.

[0046] In the Fig. In the implementation shown in Figure 5, the terminal 30 extends parallel to the substrate 20. It is directly connected to the conductor track 40 by an S-shaped section.

[0047] Fig.Figure 7 shows an alternative implementation. There, the terminal 30 extends vertically upward in a direction perpendicular to the substrate 20. The terminal 30 is embedded in a non-conductive frame 80 of the power module 10. The cover layer 25 in this embodiment can be, for example, a soft gel filling or an epoxy material. The sensor 15 is supported by a sensor carrier 81, in which a cutout 27 allows the correct positioning of the sensor 15 over the conductive track 40. It has one end that extends into the cover layer 25 and is connected to the conductive track 40 by a wire bond 32.

[0048] With the implementations shown, a simple and reliable current measurement can be performed using the electrical current sensor 15, which can be placed in a suitable position and precisely fixed. List of reference symbols 10 power semiconductor modules 11 Cooling element 12 Current flow path 15 electrical current sensor 17 connectors 20 Substrat 25 Cover layer 27 Excerpt 28 Rand 30 connection 32 wire connection 35 additional connections 40 conductor track 41 narrow area 42 first neighboring area 43 second neighboring area 50 power semiconductors 60 widened area 62 connecting railway 65 further expanded area 67 additional connecting lines 70 connection area 72 straight part 75 additional connection area 77 another straight part 80 frames 81 sensor carriers

Claims

[1] Power semiconductor module (10), comprising: - a substrate (20), - a connection (30) and - a conductor track (40), - a power semiconductor (50), - wherein the conductor track (40) at least partially covers one side of the substrate (20), - wherein the conductor track (40) connects the power semiconductor (50) at least electrically to the terminal (30), - wherein the conductor track (40) comprises a narrow region (41) between the power semiconductor and the terminal (30), in which a lateral extension of the conductor track (40) transverse to a current flow path (12) between the power semiconductor (50) and the terminal (30) is smaller compared to an adjacent region (42, 43) or both adjacent regions (42, 43) along the current flow path (12), and - wherein the module (10) is designed to mount an electrical current sensor (15) over the narrow region (41) of the conductor track (40). [2] Power semiconductor module (10) according to claim 1, - further comprising a cover layer (25) which completely or partially covers the conductor track (40) on a side opposite the substrate (20), wherein the cover layer (25) is designed to fix the electrical current sensor (15) over the narrow region (41). [3] Power semiconductor module (10) according to claim 2, - wherein a cutout (27) is formed in the cover layer (25) above the narrow region (41) in order to place the electrical current sensor (15) in the cutout (27). [4] Power semiconductor module (10) according to one of the preceding claims, - wherein the power semiconductor module (10) comprises only one terminal (30) which is electrically connected by the conductor track (40). [5] Power semiconductor module (10) according to one of claims 1 to 3, - wherein the power semiconductor module (10) further comprises a further terminal (35), - wherein the further terminal (35) is electrically connected to the power semiconductor (50) and the terminal (30) by the conductor track (40). [6] Power semiconductor module (10) according to claim 5, - wherein a further current flow path between the power semiconductor (50) and the further terminal (35) and the current flow path (12) between the power semiconductor (50) and the terminal (30) overlap at least in the narrow region (41). [7] Power semiconductor module (10) according to one of claims 5 or 6, - wherein the conductor track (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) by a connecting track (62), and / or - wherein the conductor track (40) has a further widened region (65) between the narrow region (41) and the further connection (35), wherein the further widened region (65) is connected to the narrow region (41) by a further connecting track (67). [8] Power semiconductor module (10) according to claim 7, - wherein the widened region (60) has a constant extension between the connecting track (62) and the terminal (30) parallel to a longitudinal extension of the narrow region (41), and / or - wherein the further widened region (60), seen parallel to a longitudinal extent of the narrow region (41), has a constant extent between the further connecting track (67) and the further connection (30). [9] Power semiconductor module (10) according to one of claims 5 or 6, - wherein the conductor track (40) comprises a connection region (70) connecting one 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 at which the connection region (70) touches the terminal (30), and / or - wherein the conductor track (40) comprises a further connection region (75) which connects an end of the narrow region (41) opposite the power semiconductor (50) to the further terminal (30), wherein the end of the narrow region (41) is closer to an edge of the module (10) than a section at which the further connection region (75) touches the further terminal (35). [10] Power semiconductor module (10) according to claim 9, - wherein the connection region (70) has a constant cross-section transverse to the current flow path (12) at least in straight parts, and / or - wherein the further connection region (70) has a constant cross-section transverse to the further current flow path (12) at least in straight parts. [11] Power semiconductor module (10) according to claim 10, - wherein the connection region (70) has at least one straight part (72) which is aligned parallel to a longitudinal extension of the narrow region (41) and is positioned between the narrow region (41) and the terminal (30), and / or - wherein the further connection region (70) has at least one straight part (77) which is aligned parallel to a longitudinal extent of the narrow region (41) and is positioned between the narrow region (41) and the further connection (30). [12] Power semiconductor module (10) according to one of claims 5 to 11, - wherein the narrow region (41) is located between the connection (30) and the further connection (35). [13] Power semiconductor module (10) according to one of the preceding claims, - wherein the terminal (30) has a constant cross-section transverse to a current flow direction in the terminal (30), and / or - wherein the further connection (35) has a constant cross-section transverse to a current flow direction in the further connection (35). [14] Power semiconductor module (10) according to one of the preceding claims, - wherein the conductor track (40) is designed as a planar film on the substrate (20). [15] Power semiconductor module (10) according to one of the preceding claims, - wherein the terminal (30) and / or the further terminal (35) is designed as a bulk connecting element which extends partially over the substrate (20). [16] Power semiconductor module (10) according to one of the preceding claims, - wherein the terminal (30) and / or the further terminal (35) is / are configured as an exposed region on the substrate (20).

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