Circuit arrangement and method for manufacturing a circuit arrangement

Abstract

A circuit arrangement comprising a circuit carrier having contact pads and conductor tracks thereon, an electronic component on the circuit carrier and generating heat in operation. A heat sink is provided for absorbing heat from the circuit carrier and the electronic component, wherein the heat sink is made of aluminum and is fastened to the circuit carrier and directly abuts against the circuit carrier. At least two electrical contacts are arranged on the upper side of the circuit carrier to which the heat sink abuts, which are separated from one another and the heat sink abuts against the electrical contacts in an electrically conductive manner. The two electrical contacts are electrically connected to the conductor tracks and to a controller in order to measure an electrical through-contact formed by the heat sink via the two electrical contacts.

Description

[0001] Technical Fields and Existing Technologies

[0002] This invention relates to a circuit device comprising a circuit carrier having electronic components thereon and heat sinks for cooling the circuit carrier or at least some of the electronic components. The invention also relates to a method for manufacturing such a circuit device.

[0003] Aluminum heat sinks for use in circuit devices, etc., are known, for example, from DE19712723A1. It is also known in the art, for example from EP4096361A1, that aluminum heat sinks are arranged on a circuit carrier, wherein electronic components such as IGBTs are electrically connected to the circuit carrier. They are also partially attached to the heat sink for efficient cooling.

[0004] Objectives and Solutions

[0005] The purpose of this invention is to provide a circuit device and a method for manufacturing such a circuit device, avoiding the problems in the prior art, and in particular improving the cooling effect of the heat sink on the circuit carrier or electronic components disposed thereon, preferably achieving rapid and efficient manufacturing of such a circuit device.

[0006] This objective is achieved by the circuit device according to the invention having the features of claim 1, and the manufacturing method according to the invention having the features of claim 14. Preferred and advantageous embodiments of the invention are part of the further claims and will be described later. Some features are described only with respect to the circuit device or the method of manufacturing thereof. However, they are valid and applicable to such circuit devices or such methods, individually or independently. The content of the claims becomes part of the specification by express reference.

[0007] The circuit arrangement according to the invention includes a circuit carrier having contact pads and conductor traces thereon. This can be a conventional PCB as well as any other suitable circuit carrier on which electronic components are disposed. These electronic components generate heat during operation, which needs to be dissipated and the electronic components need to be cooled. This helps to prevent damage to the electronic components, the circuit carrier itself, and any other components disposed on or near the circuit carrier. To dissipate heat from the electronic components or for their cooling, at least one heat sink is provided. This heat sink should absorb or draw heat from the circuit carrier and / or the electronic components disposed thereon in a known manner, for example, to dissipate heat to the ambient air or to a cooling airflow from a fan. The heat sink is made of a conductive material, preferably a metal, such as aluminum. Alternatively, the heat sink is at least partially conductive on its outer side, which can be achieved by attaching separate metal strips, etc., to the heat sink. The heat sink is also fastened to the circuit carrier and directly abuts the circuit carrier at least through protruding areas, protrusions, etc. This serves to hold the heat sink in place and in a defined position relative to the circuit carrier and the electronic components thereon.

[0008] The circuit device of the present invention has at least two electrical contacts that are separated from each other or spaced at least a few millimeters or centimeters apart. This can be advantageous, such that the at least two electrical contacts are arranged to be separated from each other or electrically isolated from each other. These electrical contacts are provided or arranged on the side of the circuit carrier to which the heat sink is directly abutted. It has been previously described that the heat sink abuts these electrical contacts in a conductive manner with its conductive material. This allows the heat sink to provide a conductive connection between the at least two electrical contacts. These electrical contacts are also electrically connected to or form part of a conductor trace, wherein the conductor trace is connected to a controller of the circuit device, which may, for example, be ultimately disposed on the circuit carrier itself as a microcontroller. This is used to determine the electrically permeable contact formed by means of the heat sink as an electrical connection element, which includes the two electrical contacts. In short, the conductive material of the heat sink is connected to the two electrical contacts due to its own conductivity or due to the conductivity of the individual metal strip attached thereto. The conductive line can be easily identified or measured to detect whether the heat sink is at least partially connected to the electrical contacts and thus directly abuts the circuit carrier, as defined, resulting in a good mechanical connection between the heat sink and the circuit carrier and a good thermal connection with the defined cooling effect. This is only possible through the heat sink if the at least two electrical contacts are not interconnected, meaning the heat sink is not in its correct position and therefore cannot provide the necessary cooling effect. In this way, other methods of measuring or determining the position of the heat sink on the circuit carrier, including mechanical, optical, or similar methods, are unnecessary. These are generally more complex and costly.

[0009] If the heat sink is made of aluminum, particularly on its outer surface and in the area where it directly abuts the circuit carrier and the aforementioned at least two electrical contacts, this is sufficient for the purposes of the invention. Although aluminum is not a very good electrical conductor on its outer surface, which may be covered with aluminum oxide, this conductivity is still sufficient for the purpose of detecting direct electrical contact between the at least two electrical contacts. If the heat sink is not made of a conductive material, or at least not on its outer surface, a conductive material may be attached or applied specifically for this purpose. For example, this may be in the form of an aluminum strip, brass strip, or copper strip, which may be adhesively fixed to the heat sink, thereby connecting the two areas of the heat sink that directly abut the electrical contacts. In addition to metals such as iron, brass, and copper, other conductive materials used for the heat sink may be ceramic materials with good thermal and / or electrical conductivity, such as, for example, aluminum nitride or silicon carbide.

[0010] In one embodiment of the invention, the two electrical contacts are disposed on opposite regions of the heat sink or in the two regions of the heat sink that are in contact with the circuit carrier and are most widely spaced from each other. These regions are the portions where the heat sink directly contacts the circuit carrier and the electrical contacts disposed on the surface of the circuit carrier. Measuring the electrical contacts in opposite regions of the heat sink has the advantage that, in most cases, the heat sink contacts the circuit carrier in the desired manner not only in these two regions but also in all regions where it will contact the circuit carrier. This embodiment can be a very simple and cost-effective design.

[0011] In another embodiment of the invention, the circuit carrier is provided with four electrical contacts for the heat sink to abut thereon. All four electrical contacts should be electrically isolated from each other and also electrically connected to the aforementioned controller for determining the electrical continuity contact formed via the heat sink. This is particularly advantageous when the heat sink protrudes rectangularly upwards and has four corner regions, all of which should be secured to the circuit carrier. Therefore, the circuit carrier is provided with electrical contacts for each corner region of the heat sink. In yet another advantageous embodiment of the invention, the heat sink is connected to electrical contacts in each region where it abuts the circuit carrier and / or where it is secured to the circuit carrier. Even if the electrical continuity contact increases with this and the effort required for its testing, this ensures a good test of whether the heat sink abuts the circuit carrier as it should.

[0012] In an advantageous embodiment of the invention, the heat sink has metal fasteners, which may be integrated components of the heat sink or fastened to the heat sink by threading, riveting, or pressing with sufficient force. These metal fasteners may, in particular, comprise materials that can be fastened by welding or by a corresponding metal. They may be protrusions in the form of pins or posts, used to securely fasten the heat sink to the circuit carrier, preferably by welding, and alternatively by threading, riveting, pressing, bending, or snap-fitting. Specifically, in embodiments where the metal fasteners are to be welded to the circuit carrier or metal contact pads or contact rings on the circuit carrier, the metal fasteners may be designed as metal pins or posts attached to the heat sink as described above. They may, for example, be screwed into corresponding threads in the heat sink, or alternatively, they may be pushed into or pressed into corresponding holes in the heat sink. A portion of the metal fastener or pin is attached to the heat sink, and another portion protrudes from the heat sink and may protrude through corresponding holes in the circuit carrier, wherein they protrude above and to the outside of the circuit carrier. Here, they can be fastened to metal contact pads on the underside of the circuit carrier by any of the methods described above, preferably by soldering. Soldering has the advantage of providing a secure connection and, in any way, electrical contact with the circuit carrier. These metal pins should also preferably not be electrically connected to electrical contacts to measure whether the heat sink is in contact with the circuit carrier, because they can provide contact in any case, even if, as defined, the heat sink is not in contact with the circuit carrier, or if the heat sink is in a defined relative position to the circuit carrier.

[0013] In another embodiment of the invention, the heat sink can be attached to the circuit carrier via protrusions, which can be in the form of feet. In the region between these protrusions, the heat sink can be at a distance from the upper surface of the circuit carrier, for example, between 2 mm and 20 mm. This lower side of the heat sink can have a relatively large area compared to this region or to the protrusions of the heat sink itself, for example, between 50% and 95%. The space between the lower side of the heat sink and the circuit carrier can preferably be filled with a thermally conductive material that conducts heat from the circuit carrier or electronic components disposed thereon to the heat sink via the lower side. This can be, for example, so-called TI materials such as Gap Pad. Before attaching the heat sink to the circuit carrier, the thermally conductive material should be placed between the heat sink and the circuit carrier to ensure very good contact between the thermally conductive material and the lower side of the heat sink and the upper side of the circuit carrier. The thermal conductivity of such thermally conductive materials can be further enhanced by exposing them to a specific defined pressure in the assembled state. This pressure or compression can be obtained by compressing the thermally conductive material by 5% to 50%, preferably 10% to 30%. Pressure causes the Young's modulus of TI materials, when used as thermal conductors, to exhibit a specific variation as a relationship between stress and the distance it is compressed. At a specific compression point, the stress increases abruptly and very steeply, and this is the point at which the thermal conductor should be compressed in its final assembled state between the heat sink and the circuit carrier. At this specific point, the thermal conductivity is optimal, where the thermal conductor is preferably elastic and perfectly conforms to the surface profile of the circuit carrier, even if conductor traces are present (which results in the circuit carrier surface not being perfectly flat). Such good direct contact would be impossible with metal heat sinks.

[0014] When the electronic components of the circuit carrier to be cooled are positioned on the upper side of the circuit carrier facing the heat sink, or on the lower side of the circuit carrier away from the heat sink, an elastic thermally conductive material can be provided on the lower side of the heat sink. Even when the electronic components are mounted on the lower side of the circuit carrier and the heat sink is located on the opposite side, the heat from the heat-generating electronic components can still be efficiently conducted to the heat sink used for heat dissipation. For this reason, the thermally conductive material is provided on the lower side of the heat sink.

[0015] In a preferred embodiment of the invention, the thermally conductive material can be in the form of a foam and is also an elastic material. It can be attached to the heat sink as a separate, manageable component or part, for example, it can be secured by adhesive to the underside of the heat sink. Furthermore, in the assembled state of the circuit device, the thermally conductive material can be disposed in a compressed form between the heat sink and the circuit carrier or its upper surface. This serves not only to hold the thermally conductive material in a safe and defined position, but also, as mentioned above regarding Young's modulus, to achieve better thermal conductivity. This is quite logical, as the thermally conductive material becomes denser when compressed, which also serves not only to shorten the heat transfer path to the heat sink, but also to enhance thermal conductivity.

[0016] In this assembled state, the thermally conductive material can have a thickness of 0.2 mm to 3 mm, which is quite thin. Specifically, this thickness can be between 0.5 mm and 1.5 mm. Compression of the material can result in a pressure between 10 psi and 90 psi, where the thermal resistance can be reduced by approximately 30% to 60%. The compression ratio of the thermally conductive material can be between 5% and 70%, preferably between 7% and 60%.

[0017] The elastic properties of this type of thermally conductive material allow it to have a hardness ranging from 25 Shore C to 50 Shore C. The thermal resistance can be as low as 1.4 °C x in. 2 / W (°C) (square inches / watt) to 0.4 °C x in 2 Between / W.

[0018] In the method according to the invention for manufacturing such a circuit device, a circuit carrier with holes, contact pads or contact areas, and conductor traces is provided. A heat sink is also provided, preferably with an elastic thermally conductive material firmly attached to its underside. In a subsequent step, the heat sink is pressed against the circuit carrier, particularly at locations corresponding to the assembled state. This pressing can be accomplished with a predetermined force, such that the heat sink abuts against at least some areas where electrical contacts are arranged on the upper side of the circuit carrier. The heat sink then abuts against these electrical contacts. In yet another subsequent step, as described above, preferably by means of soldering in a flow process or wave soldering process, the heat sink is attached to the circuit carrier. The heat sink still abuts against the electrical contacts.

[0019] In a subsequent step, electrical tests are conducted to determine whether the two electrical contacts are electrically connected to each other solely by means of a heat sink or via a heat sink. This can be easily tested by the conductivity of the heat sink, at least on its outer surface, or attributable to its material properties. The resistance does not necessarily have to be reduced to zero, but it should be significantly reduced.

[0020] If the above test is successful, meaning there is an electrical connection between the two electrical contacts via the heat sink itself, the circuit device will be further processed, for example, by attaching other components to the circuit carrier. If the test is unsuccessful, the circuit device can be reworked or discarded. In the first case, an attempt can be made again to attach the heat sink to the circuit carrier, bringing it to the defined position. If this is not possible or feasible, the circuit device that has been manufactured to this point should be discarded.

[0021] These and further features can be collected from the claims, as well as the description and drawings, wherein each feature can be implemented individually or in sub-combinations in each case in embodiments of the invention and other fields, and can constitute an advantageous and independently patentable version, which is claimed herein. The subdivision of this application into sections and intermediate headings does not limit the general validity of the statements made under these provisions. Attached Figure Description

[0022] Embodiments of the present invention are shown in the accompanying drawings and will be described in detail below. The drawings show: Figure 1 This is a side view of a circuit device according to the present invention, which has a PCB, a plurality of IGBTs on the lower side of the PCB and a heat sink on the upper side, the heat sink being spaced apart from the PCB by a certain distance. Figure 2 yes Figure 1 The circuit device, in which the heat sink is pressed against the PCB to enter the final assembly state. Figure 3 This is a view of the underside of the heat sink, which forms the electrical connection between each electrical contact on the PCB. Figure 4 This is a Young's modulus diagram for a specific TI material exhibiting good thermal conductivity and nonlinear behavior with pressure and thickness reduction. Figure 5 Is with Figure 2 Alternative embodiments of heat sinks with similar configurations, and Figure 6 Another alternative embodiment of the invention shows a heat sink that is not made of a conductive material, but has a conductive metal strip on the protruding leg for attaching to the PCB. Detailed Implementation

[0023] Figure 1A circuit device 11 according to the invention is shown in a side view. The circuit device 11 has a PCB 13 forming the circuit carrier described above, wherein the PCB 13 can be a conventional PCB having an upper side 14 and a lower side 15. Conductor traces 17 are provided at least on the lower side 15, and possibly on the upper side 14, some of which lead to conductor pads 18. Electrical contacts 19a and 19d are provided in through-holes in the PCB 13. These electrical contacts 19a and 19d can be manufactured by forming conductive material, such as copper or solder, in the corresponding holes passing through the PCB 13 to form the conductor traces 17 and conductor pads 18. These electrical contacts 19a and 19d may protrude from the upper side 14 by only a small distance, preferably less than half a millimeter, more preferably as low as 0.1 millimeters. These electrical contacts 19a and 19d are connected to the conductor traces 17, some of which lead to the illustrated controller 23. The controller 23 can be implemented in a microcontroller, which can be placed on PCB 13.

[0024] Multiple IGBTs 22, serving as the aforementioned heat-generating electronic components, are disposed on the lower side 15 of the PCB 13, for example, six IGBTs 22. They can be designed and mounted on the PCB 13 using SMD technology. They should maintain good thermal contact with the lower side 15 of the PCB 13 so that their heat can be transferred to the PCB 13 and then to the heat sink 25 located on the upper side 14. This is a common technique in the art, primarily used when such IGBTs 22 or other power electronic components should not or cannot be in direct contact with the heat sink. Alternatively, this may be due to the IGBTs 22 being SMD components.

[0025] The heat sink 25 can be made of aluminum, a very common material for such heat sinks due to its relatively low weight and relatively high thermal conductivity. The heat sink 25, or its outline, has a base plate 27 on which multiple cooling fins 29 are provided, protruding from the base plate 27 in a direction away from the PCB 13. Furthermore, several protruding legs 30 or protruding rails are provided from the underside of the base plate 27 in a direction toward the PCB 13. These have a lower side 31 facing the PCB 13, in which four fastening pins 32 are fixed. These fastening pins 32 are preferably made of a solderable metal, preferably nickel- or tin-plated steel, or copper. The fastening pins 32 can be simply fixed or stamped into corresponding holes on the lower side 31 of the protruding legs 30. The holes can have a slightly smaller diameter so that once the fastening pins 32 are stamped into these holes, they are fixed therein and cannot be removed.

[0026] Because the heat sink 25 is made of aluminum, the lower side 31 of the protruding leg 30 is also aluminum, and therefore both are conductive on their outer sides or surfaces. Figure 1As can be seen from the near-assembled state, the lower side 31 of the protruding leg 30 faces the upper end of the electrical contact 19 at a distance of only 1 mm or 2 mm. The PCB 13 also has corresponding holes for the fastening pin 32.

[0027] To facilitate better heat transfer from the upper side 14 of PCB 13 to the heat sink 25, a TI material 34 is provided between them. This TI material is preferably not only electrically insulating, but it can be a foam and should also primarily be an elastic material. Its thickness can be only a few millimeters, preferably slightly greater than the length of the protruding leg 30 extending downward from the lower side of the base plate 27. Such a TI material is available from Henkel under the commercial name Gap Pad. The TI material 34 possesses two specific properties that are particularly useful and of particular interest in this invention. The first property is that it has a specific Young's modulus, corresponding to the elastic deformation coefficient. Figure 4 Before the specific deformation shown, the relationship between deformation d and the pressure P required for that deformation is linear. This essentially means that TI material 34 is relatively soft or elastic, respectively. Upon reaching a certain pressure P1 (e.g., 30 psi)... Figure 4 After deformation d1), the elasticity of TI material 34 suddenly decreases significantly, or may even lose its elasticity, and therefore can only deform through plastic deformation. Even slight additional deformation requires much greater pressure. When TI material 34 is subjected to... Figure 1 Deformation under more compression Figure 2 After final assembly, when the lower side 31 of the protruding support leg 30 is abutted against the upper side 14 of the PCB 13, the TI material 34 should be positioned... Figure 4 The deformation point d is near or at the front. Then, the elastic behavior of TI material 34 is used for good compressibility, on the one hand for good and direct contact with the upper side 14 of PCB 13, and on the other hand for good and direct contact with the lower side of the base plate 27 of heat sink 25.

[0028] Another specific property of TI material 34 is that it has a thermal property curve that varies with the pressure applied to it. This means that the higher the applied pressure, the better the thermal properties, at least up to a certain point. However, this relationship is not linear with a saturation point. At this saturation point, higher pressures applied to TI material 34 do not necessarily correspond to better thermal properties or thermal conductivity. This results in an optimal pressure or compression for a given thermal conductivity of TI material 34. This leads to the design of the heat sink 25 on the one hand, and the thickness of the TI material 34 on the other hand, being designed such that when the heat sink 25 is in direct contact with the PCB 13, the TI material 34 compressed between the heat sink 25 and the PCB 13 is at a point shortly before it loses its elasticity, and the thermal conductivity of the TI material 34 is at its optimal or desired point.

[0029] Figure 2 The final assembled state of the circuit assembly 11 is shown, with the heat sink 25 directly abutting the PCB 13. Specifically, the lower side 31 of the protruding legs 30 is fully abutting the upper side 14 of the PCB 13. Fastening pins 32 are inserted into corresponding holes in the PCB 13, protruding beyond the lower side 15. They are secured to the PCB 13 by solder 21, preferably to the corresponding conductor pads 18. This is not used to establish any electrical contact, but only for the mechanical fixation of the heat sink 25.

[0030] To verify that the heat sink 25 is indeed fully in contact with the PCB 13, which is necessary for the TI material 34 to have its optimal thermal performance, it is possible to measure whether the lower side 31 of the protruding leg 30 is in contact with the electrical contacts 19 disposed on the upper side 14 of the PCB 13. These electrical contacts 19 are each connected to the controller 23 via conductor traces 17. This allows testing the through-contact of each of the four electrical contacts 19a to 19d with each of the other electrical contacts, such as... Figure 3 As shown. These through contacts are indicated by the thin lines between electrical contacts 19a and 19d. Figure 3 The two lower sides 31 of the protruding support leg 30 are shown to be fully abutting the electrical contacts 19a to 19d. If an electrical continuity can be measured from each electrical contact 19 to all other three electrical contacts, this means that the heat sink 25 is abutting these electrical contacts 19, and therefore also abutting the upper side 14 of the PCB 13. This clearly indicates that the heat sink 25 is in the defined and final assembled state as specified. If any electrical contact 19 is not electrically connected to any or all other electrical contacts 19, this indicates that the heat sink 25 is not abutting the PCB 13 in the specified manner, which will cause the circuit assembly 11 to become a faulty component to be removed or manually repaired.

[0031] By providing electrical contacts 19a to 19d in the corner area of ​​the heat sink 25, it is also possible to... Figure 3 This demonstrates that the final assembly condition specified by the inspection is guaranteed. Since the heat sink 25 is made of robust and stable aluminum, it should not be assumed that any part of it may bend or bulge away from PCB 13.

[0032] Figure 3 The diagram also shows six IGBTs 22, indicated by dashed lines, positioned between two protruding legs 30. It can also be seen that there is a considerable distance between the electrical contacts 19a to 19d and the fastening pins 32.

[0033] Figure 1Another specific feature is the presence of protrusions 28a to 28c on the underside of the base plate 27. These protrusions 28 protrude approximately 0.1 mm to 1 mm. They can be used to apply greater pressure to the TI material 34, with the force located between the upper side 14 of the PCB 13 above the IGBT 22 and the protrusions 28 in a straight line. As a result, the length of the heat transfer path can be shortened at least slightly. Furthermore, the protrusions 28 with sloping side flanges are used to enlarge the surface area of ​​the underside of the base plate 27, which allows for better heat transfer from the TI material 34 to the heat sink 25 or its underside, respectively. The TI material 34 also contacts the interior of the two protruding legs 30 to transfer heat therein.

[0034] The protrusion 28 can be integrally formed on the heat sink 25 as a longitudinal rib, and its direction is parallel to... Figure 1 The line of sight is the same as that of the cooling fins 29. For easier manufacturing, the protruding legs 30 should be formed as tracks, etc. Figure 3 Instead of providing four single legs that must be machined from the material of the heat sink 25, the heat sink can then be made into a profile with an infinite length of cast billet.

[0035] According to Figure 5 In alternative and simplified embodiments of the present invention, circuit device 111 has the same characteristics as referenced circuit device 111. Figure 1 and Figure 2 The same PCB 13. The only difference is that the base board 127 of the heat sink 125 has a flat bottom side, without... Figure 1 and Figure 2 Any protrusions shown. This reduces the amount of work required to manufacture the heat sink 125.

[0036] Figure 6 Another alternative embodiment is shown, which is a view of the lower side of the heat sink 225, and this view substantially corresponds to Figure 3 The heat sink 225 also has two protruding legs 230 in the form of longitudinal tracks, with a recess between them for accommodating the TI material as described above. The heat sink 225 is not made of aluminum, nor is it made of a conductive material at all. For example, it could be made of a ceramic material with good thermal conductivity, which is crucial for a heat sink. However, such a material is electrically insulating, making it impossible to directly measure... Figure 3The through-contact described in the diagram. To avoid this, the left protruding leg 230 is provided with a longitudinal metal strip 233a of constant width. This metal strip 233a can be quite thin, with a thickness of 1 mm or less. It can even be in the form of metal foil and can be fixed to the underside 231 of the left protruding leg 230, for example, by adhesive. Thus, this metal strip 233a corresponds to the conductive surface of the heat sink made of aluminum described above. The metal strip 233a can also contact or be positioned close to the fastening pin 232, which is irrelevant here. Since the metal strip 233a represents the surface of the underside 231 of the protruding leg 230, it can be pressed against the electrical contacts provided in the PCB as described above. This also allows for testing of the through-contact to determine whether the heat sink 225 is in the final assembly state defined on the PCB.

[0037] Another shape of the metal strip 233b is shown on the right protruding support leg 230. This metal strip 233b can be made of the same material with the same thickness, but obviously has a smaller width. This is used to save material and also provides a certain distance to the fastening pin 232.

[0038] Figure 7 It shows the basis Figure 2 Another alternative embodiment is shown. It also illustrates the final assembled state of the circuit assembly 311, with the heat sink 325 abutting the PCB 313 with its protruding legs 330. Specifically, the lower sides 331 of the protruding legs 330 are fully abutting the upper sides 314 or electrical contacts 319a and 319d of the PCB 313, respectively. Fastening pins 332 are inserted into corresponding holes in the PCB 313 such that they protrude beyond the lower side 315 of the PCB 313 for secure fixation by solder 321, preferably onto the corresponding conductor pads. This is not used to establish any electrical contact, but only for the mechanical fixation of the heat sink 325.

[0039] For electrical contacts, contacts 319a and 319d are arranged on the PCB along with two other such electrical contacts. For example... Figure 2 As shown, they abut against the lower side 331 of the protruding leg 330 to establish electrical contact. For this purpose, they protrude slightly from the upper side 314 of the PCB 313, for example, 0.5 mm to 2 mm.

[0040] and Figure 2The difference lies in the fact that the IGBT 322 is positioned on the upper side 314 of the PCB 313 instead of the lower side. The IGBT 322 is positioned fairly directly beneath the protrusions 328a to 328c on the lower side of the base plate 327, which is made of aluminum heat sink 325. This results in a very large compression of the TI material 334, but for a given thermal conductivity of the TI material 334, this compression should still be within the range of optimal pressure or compression, respectively. If possible, the TI material 334 should also retain its optimal thermal properties. Figure 7 One major advantage of this arrangement is that the IGBT 322 is closer to the heat sink 325, with a shorter distance, and therefore better cooling.

Claims

1. A circuit device, comprising: It has a circuit carrier with contact pads and conductor traces. The electronic components on the circuit carrier generate heat during operation, and this heat needs to be dissipated. A heat sink for absorbing heat from the circuit carrier and / or the electronic components on the circuit carrier, wherein: The heat sink is made of a conductive material, especially aluminum. The heat sink is fastened to the circuit carrier and is in direct contact with the circuit carrier. Its features are: At least two electrical contacts are arranged on the upper side of the circuit carrier against which the heat sink is attached, the at least two electrical contacts being separated from each other and the heat sink being conductively abutting against the at least two electrical contacts. The two electrical contacts are electrically connected to the controller to establish an electrical through-contact formed by the heat sink.

2. The circuit device according to claim 1, characterized in that, The two electrical contacts are located on opposite areas of the heat sink, or on the two areas where the heat sink and the circuit carrier are in contact and where the distance between the heat sinks is greatest.

3. The circuit device according to claim 1 or 2, characterized in that, Four electrical contacts are provided for the heat sink to abut against it. All four electrical contacts are electrically isolated from each other and electrically connected to the evaluation component. The heat sink is preferably rectangular and protrudes and has four corner regions, each of which is provided with an electrical contact.

4. The circuit arrangement according to any one of the preceding claims, characterized in that, The heat sink has metal fasteners, or the metal fasteners are fastened to the heat sink, the metal fasteners being made of a weldable material or metal, and the heat sink being fastened to the circuit carrier by means of welding through the metal fasteners.

5. The circuit device according to claim 4, characterized in that, The metal fastener is designed as a metal pin, which is fastened to or secured in the heat sink, particularly by being pressed into a corresponding hole. The metal pin preferably passes through the hole into the circuit carrier and is soldered to a metal fastening pad on the opposite side.

6. The circuit arrangement according to any one of the preceding claims, characterized in that, The heat sink has a protruding area on the lower side facing the circuit carrier, especially on the outer side. The protruding area serves as a fastening foot and abuts against the circuit carrier. At least one recess is provided between the protruding areas, preferably a single recess. The recess is a certain distance away from the circuit carrier and preferably extends parallel to the circuit carrier. The protruding area protrudes from the recess.

7. The circuit device according to claim 6, characterized in that, A thermally conductive material is disposed in the recess, which abuts against the lower side of the heat sink on one side and against the component to be cooled on the other side, which is fastened to the upper side of the circuit carrier.

8. The circuit device according to claim 6, characterized in that, A thermally conductive material is disposed in the recess, which abuts against the recess and thus against the lower side of the heat sink, and also against the circuit carrier itself.

9. The circuit device according to claim 8, characterized in that, At least one electronic component for which heat needs to be dissipated is arranged on the lower side of the circuit carrier opposite the thermally conductive material.

10. The circuit arrangement according to any one of claims 6 to 9, characterized in that, The substrate has a protrusion on its lower side, wherein the protrusion protrudes from the lower side by about 0.1 mm to 1 mm, wherein preferably the protrusion is located directly above the electronic component, and the thermally conductive material is disposed between the protrusion and the electronic component.

11. The circuit arrangement according to any one of claims 7 to 10, characterized in that, The thermally conductive material is a foam and an elastic material, and is attached to the heat sink as a separately manageable component, particularly by adhesive bonding. The thermally conductive material is preferably arranged in a compressed form between the heat sink and the upper side of the circuit carrier.

12. The circuit arrangement according to any one of claims 7 to 11, characterized in that, In the assembled state, the thermally conductive material is compressed and subjected to a specific defined pressure, wherein the thermally conductive material is compressed by 5% to 50%, preferably 10% to 30%.

13. The circuit arrangement according to any one of claims 7 to 12, characterized in that, The thermally conductive material has a thickness of 0.2 mm to 3 mm, particularly 0.5 mm to 1.5 mm.

14. A method of manufacturing a circuit device according to any one of the preceding claims, characterized in that: - In the pre-processing steps, a circuit carrier with holes, contact pads and conductor traces is provided, as well as a heat sink; - In a subsequent step, the heat sink is preferably pressed against the circuit carrier with a predetermined force, such that the heat sink abuts against at least some areas on the upper side of the circuit carrier where the electrical contacts are arranged, and thus abuts against the electrical contacts. - In another subsequent step, particularly by soldering in a flow process or wave soldering process, the heat sink is attached to the circuit carrier; - In another subsequent step, an electrical test is performed to determine whether the two electrical contacts are electrically connected to each other through the heat sink; - Further processing of the circuit device.

15. The method according to claim 14, characterized in that, In the first scenario, where the conductive connection test is successful and measured, the circuit device is further processed; in the second scenario, where the conductive connection test fails, the circuit device is reworked or rejected.

16. The method according to claim 14 or 15, characterized in that, In the subsequent step, the heat sink is pressed against the circuit carrier with a predetermined force, such that the heat sink abuts against at least some areas on the upper side of the circuit carrier where the electrical contacts are arranged, and thus abuts against the electrical contacts.

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