Printed circuit board assembly

Abstract

The invention relates to a printed circuit board assembly which has a printed circuit board with an upper face (11), a lower face (12), multiple metal layers (13), and multiple electrically insulating layers (14). The printed circuit board assembly additionally comprises a metal heat sink (3) on which the lower face (12) of the printed circuit board (1) lies at least in some regions, wherein the metal heat sink (3) has a heat sink potential (φK). According to the invention, the bottom metal layer (131) of the printed circuit board (1) is set to the heat sink potential (φK) while the other metal layers (132) of the printed circuit board (1) have an electric potential which deviates therefrom.

Description

[0001] PCB layout

[0002] Description

[0003] The invention relates to a printed circuit board arrangement according to the preamble of patent claim 1.

[0004] Printed circuit board-based power electronics assemblies are known in which power semiconductors are embedded in electrical modules soldered to the underside of a multilayer printed circuit board or carrier board, thus establishing electrical contact. The electrical modules, each equipped with a power semiconductor, are also referred to as prepackage modules. To cool the prepackage modules, the prepackage modules are known to protrude into cavities of a heat sink and are pressed onto the heat sink via a thermal interface material (TIM). The carrier board rests on the sides of these cavities, so that the carrier board itself is also cooled by the heat sink.

[0005] A multilayer printed circuit board or carrier board comprises metal layers and electrically insulating layers. The metal layers are, for example, copper layers. The electrically insulating layers are, for example, layers of FR4 material consisting of epoxy resin and fiberglass fabric. If, as is the case here, prepackage modules with power semiconductors are arranged on a carrier board, the internal copper layers of the carrier board are at a high-voltage potential, which is, for example, approximately 1000 V. The electrically insulating layers of the carrier board and a thermal interface material, which is typically arranged between the carrier board and the heat sink, ensure electrical insulation between the metallic layers of the carrier board and the electrical potential of the heat sink, which is, for example, 0 V.However, there is the problem that it is unavoidable that the thermal interface material contains air pockets. Air pockets are either contained in the thermal interface material itself or they form at the interface between the thermal interface material and the circuit board. Since air has a significantly lower permittivity than the electrically insulating layers of the carrier board (e.g. FR4), a much stronger electric field develops in the air pockets than in the insulating layers of the carrier board. At the same time, air has a low dielectric strength, so air pockets pose a significant risk of partial discharges. Partial discharges lead to degradation of the circuit board material and thus to a reduction in the insulation properties and the service life of the circuit board.To solve this problem, it is known to make the electrically insulating layers of the carrier board thicker or to space the carrier board away from the heat sink. However, this impairs the thermal connection between the carrier board and the heat sink and increases space requirements and material costs.

[0006] The invention is based on the object of providing a printed circuit board assembly with an electrical printed circuit board and a heat sink, which provides effective electrical insulation between the metal layers of the printed circuit board and the heat sink, in which the risk of partial electrical discharges is reduced.

[0007] This object is achieved by a printed circuit board assembly having the features of claim 1. Embodiments of the invention are specified in the dependent claims.

[0008] The invention accordingly contemplates a printed circuit board assembly comprising a printed circuit board with a top side and a bottom side, a plurality of metal layers, and a plurality of electrically insulating layers. The printed circuit board assembly further comprises a metallic heat sink, on which the printed circuit board rests at least partially with its bottom side. The metallic heat sink has a defined electrical potential, which in the context of the present invention is referred to as the heat sink potential.

[0009] The bottom metal layer of the circuit board is connected to the heat sink potential, while the other metal layers of the circuit board have a different electrical potential. The inventive solution is based on the idea of ​​shifting the potential difference between the heat sink potential and the high-voltage potential of the metal layers into the circuit board, namely between the bottom metal layer of the circuit board and the metal layers arranged above it. This is achieved by connecting the bottom metal layer of the circuit board to the same potential as the heat sink. The bottom metal layer of the circuit board serves as a shield, with the electrical field associated with the potential difference remaining within the circuit board.Accordingly, the electrically insulating layer (e.g., FR4 material) between the bottom metal layer and the adjacent metal layer serves as the sole insulating layer for insulating the carrier board from the heat sink. However, unlike air, the electrically insulating layer of the circuit board has a significantly higher dielectric strength, thus minimizing the risk of partial discharges.

[0010] However, there is no potential difference or electrical voltage between the bottom metal layer of the circuit board and the heat sink, eliminating the risk of partial discharges in the heat sink. The solution according to the invention thus reduces the risk of partial discharges and thus improves the insulation properties and the service life of the circuit board or carrier board.

[0011] A further advantage associated with the invention is that, due to the fact that the risk of partial discharges between the circuit board and the heat sink is avoided, fewer requirements are placed on a thermal interface material arranged between the circuit board and the heat sink for thermal connection. In particular, it is harmless if air pockets are present in such a thermal interface material. The solution according to the invention thus also enables an effective thermal connection between the circuit board and the heat sink and improves the cooling of components arranged on the top side of the circuit board.

[0012] It should be noted that, for the purposes of the present invention, the side of the circuit board facing the heat sink is always referred to as the underside of the circuit board, regardless of the spatial orientation of the circuit board and the heat sink.

[0013] One embodiment of the invention provides that the lowest metal layer is a lower outer layer of the circuit board. In this embodiment, the lowest layer of the circuit board, which represents the lower outer layer, is thus formed by a metal layer. This lower outer layer is connected to the heat sink potential.

[0014] Alternatively, the bottom metal layer of the circuit board can be formed by an inner layer. In this case, the bottom metal layer is the lowest inner layer of the circuit board's metal layers. In this design variant, this layer is connected to the heat sink potential.

[0015] It should be noted that the other metal layers of the circuit board that are not at the heat sink potential can be at the same or different potentials. For example, they may be at a high-voltage potential.

[0016] In order for the lowest metal layer of the circuit board to be at the potential of the heat sink, one embodiment of the invention provides that the lowest metal layer and the heat sink are connected to each other by a short-circuit path, which provides an electrical short circuit between the lowest metal layer and the heat sink.

[0017] One embodiment provides at least one screw connection, which is designed and configured to press the circuit board against the heat sink. It can be provided that the bottom metal layer of the circuit board is connected to the heat sink potential via the screw connection. The screw connection thereby provides an electrical short circuit between the heat sink and the bottom metal layer.

[0018] In one embodiment, the connection of the lowest metal layer to the potential of the heat sink by means of one or more screw connections is carried out in that the screw connection comprises a metal screw which extends through a mounting hole of the circuit board and is screwed into the metallic heat sink, the mounting hole in the circuit board plane in which the lowest metal layer is formed has a circumferential metallization, and the circumferential metallization is in electrical contact with the lowest metal layer or is formed by it.

[0019] The bottom metal layer is connected to the heat sink potential via the surrounding metallization and the metal screw. The surrounding metallization and the metal screw form a short-circuit path between the heat sink and the bottom metal layer. The heat sink potential is, for example, the grounded ground potential. In principle, however, the heat sink can also have a different potential; in this case, it is only necessary that the other metal layers of the circuit board have a different potential than the heat sink potential. The other metal layers of the circuit board that are not exposed to the heat sink potential are exposed to a high-voltage potential, for example.Despite the large potential difference between the adjacent metal layers, the risk of partial discharges is minimized because the electrically insulating layer (e.g. FR4) arranged between these metal layers has a significantly higher dielectric strength than air.

[0020] A further embodiment of the invention provides that the bottom metal layer covers at least 2 / 3, for example, at least 1 / 2 or at least 4 / 5 of the circuit board surface. The greater the percentage of the circuit board surface covered by the bottom metal layer, the better the shielding and protection against partial discharges provided.

[0021] A further embodiment provides at least one electrical module arranged on the underside of the circuit board, wherein the heat sink has a cavity into which the electrical module protrudes, and wherein the circuit board rests on the heat sink adjacent to the cavity. This provides a particularly effective structure in which the electrical modules are effectively cooled, the circuit board resting on the heat sink to the side of the cavity is also cooled via a thermal interface material, and the risk of partial discharges is simultaneously minimized.

[0022] One embodiment variant provides that the electrical module comprises: a ceramic circuit carrier which has an insulating ceramic layer and an upper metallization layer arranged on the upper side of the ceramic layer, an electrical component which is arranged on the upper side of the upper metallization layer and is electrically connected thereto, an upper side of the electrical module which is arranged on the underside of the printed circuit board, and a underside of the electrical module.

[0023] The underside of the electrical module is thermally coupled to the heat sink, for example via a thermal interface material. The electrical component is, for example, the actual power semiconductor, such as a power MOSFET or an IGBT component. The ceramic circuit carrier serves to electrically insulate the electrical component from the heat sink and, at the same time, to thermally connect it to the heat sink. The ceramic circuit carrier, together with the semiconductor component and an enclosure, e.g. made of potting material, forms the electrical module, which can be connected to the printed circuit board or a carrier board via contacts formed on its surface. Such an electrical module is also referred to as a prepackage module.

[0024] The invention is explained in more detail below with reference to the figures of the drawing using several exemplary embodiments. They show:

[0025] Figure 1 shows an embodiment of a printed circuit board arrangement comprising a printed circuit board, electrical modules arranged on the underside of the printed circuit board and a heat sink, wherein the printed circuit board rests on the heat sink in some areas on its underside and a lowermost metal layer of the printed circuit board is connected to the electrical potential of the heat sink;

[0026] Figure 2 shows a section of a printed circuit board arrangement according to Figure 1, in which the printed circuit board rests on the heat sink via a thermal interface material, wherein a lowermost metallic inner layer of the printed circuit board is placed on the electrical potential of the heat sink;

[0027] Figure 3 shows a section of a printed circuit board arrangement according to Figure 1, in which the printed circuit board rests on the heat sink via a thermal interface material, wherein a lowermost metallic outer layer of the printed circuit board is placed on the electrical potential of the heat sink;

[0028] Figure 4 shows a sectional view of the printed circuit board assembly of Figure 1 in the region of a screw connection, via which the printed circuit board is screwed to the heat sink, wherein the screw connection has a metal screw and a circumferential metallization that provides an electrical short circuit between the heat sink and the lowest metal layer of the printed circuit board; Figure 5 shows the printed circuit board assembly of Figure 4 in a view from below onto the printed circuit board, wherein the printed circuit board is provided with a lowest metal layer on its underside and the lowest metal layer is contacted by the circumferential metallization of the screw connection; and

[0029] Figure 6 shows an embodiment of an electrical module in the form of a prepackage module.

[0030] Figure 1 shows a printed circuit board assembly comprising a printed circuit board 1 and a heat sink 3. The printed circuit board 1 consists of a plurality of printed circuit board layers arranged one above the other. The printed circuit board layers comprise metal layers 13 and electrically insulating layers 14 arranged between the metal layers 13. The metal layers 13 are, for example, copper layers. The electrically insulating layers are, for example, material layers made of FR4. A topmost printed circuit board layer forms a top side 11 of the printed circuit board 1, and a bottommost printed circuit board layer forms a bottom side 12 of the printed circuit board 1.

[0031] Electrical modules 2 are arranged on the underside 12 of the printed circuit board 1. The connection to the printed circuit board 1 is made, for example, via surface mounting or through-hole mounting. Additionally, electrical components 95 can also be arranged on the top side 11 of the printed circuit board 1. The modules 2 are active modules, which, for example, comprise components or assemblies of the power electronics and which require cooling by the heat sink 3. For this purpose, the heat sink 3 has a recess 30 into which the modules 2 to be cooled protrude.

[0032] To improve the thermal connection, a thermal interface material 91 is provided between the modules 2 to be cooled and the heat sink 3. The thermal interface material 91 is, for example, a heat-conducting mat.

[0033] The printed circuit board 1 is screwed to the heat sink 3 via screw connections 5. The screw connections 5 comprise metal screws 51 that extend through a mounting hole 17 of the printed circuit board 5 and are screwed into the metallic heat sink 3. The metal screws 51 rest, for example, on the top side 11 of the printed circuit board 1 via a washer 52 and a metallization 53. They provide a compressive force with which the printed circuit board 1 is pressed against the heat sink 3. In particular, they provide the compressive force with which the modules 2 to be cooled, arranged on the underside 2 of the printed circuit board, are pressed against the surface of the heat sink 3 to provide a good thermal transition.

[0034] The heat sink 3 can have numerous configurations. It is made, for example, of a metal such as aluminum or an aluminum alloy and has cooling surfaces not shown separately. It can be an active heat sink, which is actively cooled by a fan (not shown) or by means of a liquid cooling system (not shown), or a passive heat sink.

[0035] Outside the cavity 30, the printed circuit board 1 rests with its underside 12 on the top side 31 of the metallic heat sink 3. The top side 31 of the heat sink 3 is flat, just like the underside 12 of the printed circuit board 1, and the two surfaces run parallel to one another. Provision is made for a thermal interface material 92 to be arranged between the underside 12 of the printed circuit board 1 and the top side 31 of the metallic heat sink 3 in order to improve the thermal connection between the printed circuit board 1 and the heat sink 3. The thermal interface material 92 is, for example, a thermally conductive mat or a large-area adhesive film made of TIM material. In the area where the printed circuit board 1 rests on the heat sink 3 via the thermal interface material 92, the printed circuit board 1 and the electrical components 95 arranged on the top side 11 of the printed circuit board 1 are cooled.

[0036] The heat sink 3 is at a defined electrical potential <PK, das gleich dem Massepotenzial ist und beispielsweise bei 0 V oder einer geringen Voltzahl liegt. Dagegen liegen die Metalllagen 13 der Leiterplatte 1 auf einen Hochvoltpotenzial von beispielsweise ca. 1000 V. Es ist vorgesehen, das auch die unterste Metalllage 131 der Leiterplatte 1 auf das elektrische Potenzial q> K of the heat sink 3. The manner in which this is achieved and variants thereof are described in Figures 2-5. As a result, the bottom metal layer 131 of the circuit board 1 acts as a shield. The electric field generated due to the large voltage difference of, for example, 1000 V remains within the circuit board 1, with the electrically insulating layer 14 between the bottom metal layer 131 and the further metal layer 132 arranged above it serving as the only insulating layer for insulating the circuit board 1 from the heat sink 3.

[0037] If, on the other hand, the bottom metal layer 131 of the circuit board were also subjected to a high-voltage potential, as is known in the prior art, the electric field associated with the voltage difference would extend between the underside 12 of the circuit board 1 and the top side 31 of the heat sink 3, thereby passing through the thermal interface material 92. In such a case, there would be a considerable risk that air pockets in the thermal interface material 92 would cause partial discharges, since air has a lower permittivity than material used in circuit boards to form electrically insulating layers (e.g., FR4). For example, air has a permittivity of approximately one, whereas the material FR4 has a permittivity in the range of five. Since the electric field strength increases with decreasing permittivity values, an increased field strength occurs in air.Such behavior is known in high-voltage technology in layered insulation systems as the effect of field displacement, whereby the electric field is displaced into the insulating material with the lower permittivity. Since air also has a lower dielectric strength, the risk of partial discharges increases. These problems are avoided by applying the heat sink potential to the bottom metal layer 131.

[0038] It is provided that the lowermost metal layer 131 covers a substantial area of ​​the circuit board 1 so that the said shielding is realized in an effective manner, for example at least 2 / 3 or at least % or at least 4 / 5 of the area of ​​the circuit board 1.

[0039] Figure 1 also shows thermal conduction paths A from the circuit board 1 into the heat sink 3 and heat conduction paths B from the electrical modules 2 into the heat sink 3.

[0040] Figure 2 shows an enlarged view of a region of the printed circuit board 1 of Figure 1 which rests on the heat sink 3 via a thermal interface material 92, i.e. represents a region laterally spaced from the cavity 30 of the heat sink 3.

[0041] As explained, the circuit board 1 comprises a plurality of metal layers 13 (for example, copper layers) and a plurality of electrically insulating layers 14 (for example, layers made of FR4 material). A thermal interface material 92 is arranged between the underside 12 of the circuit board 1 and the metallic heat sink 3. The metallic heat sink 3 has a potential q>K, which is, for example, the ground potential. A schematically illustrated short-circuit path 6 is provided, which electrically connects the heat sink 3 to the lowest metal layer 131 of the metal layers 13. The short-circuit path 6 is illustrated only schematically. An example of the implementation of the short-circuit path 6 is explained with reference to Figures 4 and 5. The further metal layer 132 arranged above the metal layer 131, in contrast, is subjected to a high-voltage potential of, for example, 1000 V.The only insulation layer between the two metal layers 131, 132 is provided by the electrically insulating layer 141 located between them. This layer has a comparatively high permittivity, which contributes to reducing the local electric field. It also has a significantly higher dielectric strength than air, thus minimizing the risk of partial discharges.

[0042] In the embodiment of Figure 2, the lowest metal layer 131 represents a lowest inner layer 16 of the circuit board 1, i.e. it does not form an outer layer.

[0043] Figure 3 shows an embodiment that corresponds to the embodiment of Figure 2 except that the bottom metal layer 131 forms a lower outer layer 15 of the circuit board. Again, a schematically illustrated short-circuit path 6 is implemented between the heat sink 3 and the bottom metal layer 131, so that the bottom metal layer 131 is connected to the heat sink potential >K. The additional metal layers 132 arranged above the outer layer 15 or bottom metal layer 131, in contrast, are connected to a high-voltage potential, whereby they can be connected to the same potential or, alternatively, to a different potential.

[0044] Figures 4 and 5 show an exemplary embodiment for implementing the short-circuit path 6 shown only schematically in Figures 2 and 3. It is provided that the short-circuit path is implemented via the screw connection 6. According to Figure 4, the screw connection 5 comprises a metal screw 51 which extends through a mounting hole 17 in the circuit board 1 and is screwed into the metallic heat sink 3, so that the metal screw 51 is at the heat sink potential q>K. It is further provided that the mounting hole 17 in the circuit board plane, in which the bottom metal layer 131 is formed, has a circumferential metallization 7. The circumferential metallization 7 is formed, for example, by a circumferential copper plating. The circumferential metallization 7 is likewise connected to the heat sink potential >K via the metal screw 51.

[0045] In the embodiment of Figure 4, the circumferential metallization 7 is formed in the plane of the lower outer layer 15, which is formed by the lowest metal layer 131, as can be seen from Figure 5. This corresponds to the embodiment of Figure 3. Alternatively, the lowest metal layer 131 could be an inner layer, as shown in Figure 2. In this case, the circumferential metallization 7 would be formed in the plane of this inner layer.

[0046] The surrounding metallization 7 is in electrical contact with the bottom metal layer 131 or merges into it, as can be seen in Figure 5. Thus, the bottom metal layer 131 is also connected to the heat sink potential >K.

[0047] It is understood that electrical contact surfaces on the underside of the circuit board 1 in the area of ​​the cavity 30, which serve to contact the electrical modules 2, are each connected, for example via vias, to a metal layer of the circuit board which is at a high-voltage potential.

[0048] It is pointed out that Figure 5 is a hybrid representation in that the area 10 in which the electrical modules 2 protrude into a cavity 30 of the heat sink 3 is shown in a view from above, while outside the area 10, Figure 5 is a view from below of the lowest metal layer 131 or outer layer 15 of the printed circuit board 1.

[0049] The provision of a short-circuit path according to the embodiment of Figures 4 and 5 is to be understood merely as an example. Alternatively, additional conductive structures or electrical conductors can be provided that connect the bottom metal layer 131 of the circuit board 1 to the heat sink potential q>K.

[0050] The electrical modules of Figure 1 can be designed in embodiments according to Figure 6. According to this, the electrical module 2 comprises a ceramic circuit carrier 23, an electrical component 24, and electrical contacts 25. The electrical component 24 is, for example, a power semiconductor.

[0051] The ceramic circuit carrier 23 comprises an insulating ceramic layer 231, an upper metallization layer 232 arranged on top of the ceramic layer 231, and an optional lower metallization layer 233 arranged on the underside of the ceramic layer 23. The electrical component 24 is arranged on the upper metallization layer 232. The ceramic circuit carrier 23 and the electrical component 24 are arranged in a substrate 26 that defines the external dimensions of the electrical module 2. The substrate 26 is, for example, a potting compound in which the ceramic circuit carrier 23 and the electrical component 24 are embedded, or a printed circuit board in which the ceramic circuit carrier and the electrical component are embedded.

[0052] The substrate 26 comprises a top side 21, which also forms the top side of the electrical module 2. A bottom side of the substrate 26 runs flush with the lower metallization layer 233. The bottom side of the substrate 26 and the lower metallization layer 233 form the bottom side 22 of the electrical module 2. According to the exemplary embodiment of Figure 1, the bottom side 22 is connected to a heat sink 3 via a thermal interface material 91.

[0053] The top side 21 of the electrical module 2 has a plurality of electrical contacts 25, which serve to contact corresponding contacts of the circuit board 1. The electrical contacts 25 include vias to a bottom side potential and to top side potentials of the electrical component 24. For example, the electrical contacts 25 provide a source terminal, a gate terminal, and a drain terminal of the electrical component 24.

[0054] The ceramic circuit carrier 23 with the ceramic layer 231 serves, on the one hand, to electrically insulate the electrical component 24 arranged on the ceramic circuit carrier 23 from the heat sink and, at the same time, provides a thermal connection to the heat sink.

[0055] It is understood that the invention is not limited to the embodiments described above, and various modifications and improvements may be made without departing from the concepts described herein. It is further understood that any of the described features may be used separately or in combination with any other features, provided they are not mutually exclusive. The disclosure extends to and encompasses all combinations and subcombinations of one or more features described herein. Where ranges are defined, these include all values ​​within these ranges, as well as all subranges that fall within a range.

Claims

Patent claims 1. Printed circuit board arrangement, comprising: a printed circuit board (1), comprising: o a top side (11), o a bottom side (12), o several metal layers (13), o several electrically insulating layers (14), a metallic heat sink (3) on which the printed circuit board (1) is mounted with its bottom side (12) rests at least partially, wherein the metallic heat sink (3) has a heat sink potential ( <PK) aufweist, dadurch gekennzeichnet, dass die unterste Metalllage (131) der Leiterplatte (1) auf das Kühlkörperpotenzial (<PK) gelegt ist, während die anderen Metalllagen (132) der Leiterplatte (1) ein davon abweichendes elektrisches Potenzial aufweisen.

2. Printed circuit board arrangement according to claim 1, characterized in that the lowermost metal layer (131) is a lower outer layer (15) of the printed circuit board (1).

3. Printed circuit board arrangement according to claim 1, characterized in that the lowermost metal layer (131) is the lowermost inner layer (16) of the metal layers (13) of the printed circuit board (1).

4. Printed circuit board arrangement according to one of the preceding claims, characterized in that the lowermost metal layer (131) of the printed circuit board (1) and the heat sink (3) are connected to one another by a short-circuit path (6).

5. Printed circuit board arrangement according to one of the preceding claims, characterized by at least one screw connection (5) which is provided and designed to press the printed circuit board (1) against the heat sink (3).

6. Printed circuit board arrangement according to claim 5, characterized in that the bottom metal layer (131) of the printed circuit board (1) is connected to the heat sink potential ( <PK) gelegt ist. Printed circuit board arrangement according to claim 6, characterized in that the screw connection (5) comprises a metal screw (51) which extends through a mounting hole (17) of the printed circuit board (1) and is screwed into the metallic heat sink (3), the mounting hole (17) has a circumferential metallization (7) in the printed circuit board plane in which the bottommost metal layer (131) is formed, and the circumferential metallization (7) is in electrical contact with the bottommost metal layer (131) or is formed by it. Printed circuit board arrangement according to one of the preceding claims, characterized in that the heat sink potential ( <PK) des Kühlkörpers (3) gleich dem Massepotenzial ist. Leiterplattenanordnung nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die anderen Metalllagen (132) der Leiterplatte (1), die nicht mit dem Kühlkörperpotenzial (<PK) beaufschlagt sind, mit einem Hochvoltpotenzial beaufschlagt sind.Printed circuit board assembly according to one of the preceding claims, characterized in that the bottom metal layer (131) covers at least two-thirds of the surface of the printed circuit board (1). Printed circuit board assembly according to one of the preceding claims, characterized by at least one electrical module (2) arranged on the underside (12) of the printed circuit board (1), wherein the heat sink (3) has a cavity (30) into which the electrical module (2) projects, and wherein the printed circuit board (1) rests on the heat sink (3) adjacent to the cavity (30).Printed circuit board arrangement according to claim 11, characterized in that the electrical module comprises: a ceramic circuit carrier (23) which has an insulating ceramic layer (231) and an upper metallization layer (232) arranged on the upper side of the ceramic layer (231), an electrical component (24) which is arranged on the upper side of the upper metallization layer (232) and is electrically connected thereto, an upper side (21) of the electrical module (2) which is arranged on the underside (12) of the printed circuit board (1), and a underside (22) of the electrical module (2).

13. Printed circuit board arrangement according to claim 11 or 12, characterized in that the underside (22) of the electrical module (2) is thermally connected to the heat sink (3) via a thermal interface material (91).

14. Printed circuit board assembly according to one of claims 11 to 13, characterized in that the electrical modules (2) comprise semiconductor components, in particular power semiconductors.

15. Printed circuit board assembly according to one of the preceding claims, characterized in that the printed circuit board (1) rests with its underside (12) on the heat sink (3) via a thermal interface material (92).

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