Method for producing an SMD power semiconductor component module and SMD power semiconductor component module

Abstract

The present invention relates to a method for producing an SMD power semiconductor component module, comprising the following steps: providing an SMD circuit carrier (1, 10) equipped with contact points (3) and an insulation; providing at least one discrete power semiconductor component (4) equipped with electrically conductive connection elements (5), preferably connection legs; arranging the at least one discrete power semiconductor component (4), equipped with electrically conductive connection elements (5), on the side of the SMD circuit carrier (1, 10) equipped with the contact points (3), wherein the connection elements (5) of the power semiconductor component (4) contact the contact points (3) of the SMD circuit carrier (1, 10); and, connecting the connection elements (5) to the respectively assigned contact points (3) by laser welding.

Description

[0001] Method for producing an SMD power semiconductor component module and SMD power semiconductor component module

[0002] The present invention relates to a method for producing an SMD power semiconductor component module, in which at least one discrete power semiconductor component provided with electrically conductive connection elements is mounted on an SMD circuit carrier provided with contact points in SMD design. The mechanical fastening and electrical contacting take place on the same side of the SMD circuit carrier. Furthermore, the present invention relates to an SMD power semiconductor component module produced by the method according to the invention.

[0003] Technological background

[0004] Discrete SMD power semiconductor components are now used in large quantities as SMD components and are soldered onto SMD circuit carriers, e.g., printed circuit boards (PCBs) or IMS substrates, using a soft soldering process. All three contacts of the component—collector, emitter, and gate—are soldered to a power line on the SMD circuit carrier. As the performance of power semiconductor chips increases, so do the currents, so newer power semiconductor chips have a higher current-carrying capacity. The higher currents in these components cause the contacts to heat up more rapidly, reducing reliability in applications. The type of connection between the contacts in the power semiconductor component thus determines the current-carrying capacity of the power semiconductor component. This means that the current must be reduced or limited if necessary to ensure the required reliability of the circuit.This becomes particularly relevant when the power circuit is built with SMD components on circuit boards, which, unlike PCBs, can also provide enhanced cooling for the circuit. In this case, the small copper cross-sections of the terminal pins and the additional ohmic resistances due to the soft solder connection result in losses that hinder the efficient utilization of the chips' current-carrying capacity or reduce the circuit's reliability.

[0005] Printed state of the art

[0006] A method according to the preamble of claim 1 is known from DE 10 2013 213 448 B4. Here, power semiconductors are mounted on the top side of a substrate, the underside of which is connected to a heat sink. The electrical connection between the power semiconductors and the contact points of the substrate is achieved by soldering in a reflow process.

[0007] EP 2 458632 A1 discloses a heat sink module for electronic semiconductor devices, in which several electronic semiconductor devices are fixed to a ribbed discharge body by means of a mounting frame, leaf springs, and mounting screws. The mounting frame determines the precise arrangement of the individual semiconductor devices. The connecting pins of the electronic semiconductor devices extend vertically through a printed circuit board and are connected to the printed circuit board on the side opposite the heat sink module by wave welding or point-to-point welding. The mechanical mounting plane and the electrical connection plane of the electronic semiconductor devices are therefore located on different sides of the printed circuit board.

[0008] DE 10 2019 205 772 A1 discloses a power module with housed power semiconductors for the controllable electrical power supply of a consumer. For cooling, a heat sink with a cooling surface is arranged on the underside of a printed circuit board. The power semiconductors are attached directly to the heat sink and protrude through through-holes that must be provided in the printed circuit board. The connection elements of the power semiconductors are electrically connected to connection surfaces on the side of the printed circuit board facing away from the heat sink. Soldering, in particular split-head soldering, but also welding, is mentioned as a possible connection method. However, this is not an SMD power semiconductor component, since the power semiconductor is attached directly to the heat sink. The power semiconductors must be provided with insulation on their underside, since they are attached directly to the top of the heat sink.

[0009] Object of the present invention

[0010] The object of the present invention is to provide a method which allows SMD power semiconductor component modules with high current carrying capacity to be manufactured using simple production technology.

[0011] Solution to the task

[0012] The above object is achieved by the features of claim 1. Advantageous embodiments of the inventive method are claimed in the dependent claims. An SMD power semiconductor component module according to the invention is taught in claim 25.

[0013] The inventive method for producing an SMD

[0014] Power semiconductor component module includes the following steps:

[0015] Provision of an SMD circuit carrier provided with contact points and insulation or an insulator,

[0016] Providing at least one discrete power semiconductor component provided with electrically conductive connection elements,

[0017] Arranging the at least one discrete power semiconductor component provided with electrically conductive connection elements on the side of the SMD circuit carrier provided with the contact points, wherein the connection elements of the power semiconductor component contact the contact points of the SMD circuit carrier, and connecting the connection elements to the respectively assigned contact points by laser welding.

[0018] Preferably, in the context of the method according to the invention, power semiconductor components with an underside electrical contact (ie without insulation) are used.

[0019] Preferably, the SMD circuit carrier includes a cooling function.

[0020] Preferably, the SMD circuit carrier is a printed circuit board, a so-called IMS substrate, or a lead frame. The IMS substrate is a conductor track structure on an insulator. Lead frames are metallic grids, e.g., stamped grids, that represent conductor tracks. These can be insulated and / or provided with a cooling structure, a heat sink, or a cooling layer.

[0021] In the course of the method according to the invention, the power semiconductor component is thus attached in SMD construction to the same side of the SMD circuit carrier on which the electrical contacting of its connection elements to the SMD circuit carrier takes place. The mechanical attachment level and electrical contacting level are thus the same or at least parallel to one another on one and the same side of the SMD circuit carrier. This considerably simplifies the assembly of SMD power semiconductor component modules. Because the connection elements are connected to the respective contact points by laser welding instead of soldering, the current-carrying capacity of the SMD power semiconductor component module is also considerably improved. During laser welding, the connection elements and contact points are melted in the relevant area of ​​the laser beam, resulting in an intimate connection between the joining partners.Laser welding thus makes it possible to create a monometallic connection. This results in the advantage that this type of material-to-metal connection allows operation of the SMD power semiconductor module at higher currents than with soldered connections. Furthermore, the connection according to the invention also allows operation of the SMD power semiconductor module at higher temperatures than those possible with a soldered connection. Furthermore, more sustainable operation under high load cycling conditions is possible compared to a soldered connection. This makes it possible to achieve a high level of reliability for the SMD power semiconductor module. Furthermore, it ensures that the power semiconductor module can be operated at the full performance capacity of its power semiconductor components, meaning that no "limitation" is necessary.

[0022] The contacting (of the contact point and the connecting element) is a contacting process that is typical for a soldered connection, in which the contact point and / or the connecting element are made of copper or a copper alloy. As a result, the method according to the invention can be used with conventional semiconductor components (e.g., TO 263; D 2Pack, SO-8) or circuit carriers (e.g. printed circuit boards, PCBs, DCB substrates, IMS substrates, lead frames) where appropriate contacting is still provided. This is particularly advantageous when the power circuit is built with SMD components on IMS substrates, which, in contrast to PCBs, can also assume an increased cooling function for the circuit. In this case, the small copper cross-sections of the connections and the additional ohmic resistances during conventional soft soldering would lead to losses that hinder the economical utilization of the current carrying capacity of the chips or reduce the reliability of the circuit. This can be effectively avoided by the invention. The contact point and / or the connection element can be pre-tinned.

[0023] It is advantageous if the connecting element is designed to run parallel to the main extension surface of the SMD circuit carrier in the region of the connecting element in which the laser welding takes place.

[0024] The connecting elements are preferably so-called connecting pins, which have particularly small connection cross-sections. The method according to the invention is particularly advantageous in this case, since the laser-welded connection results in lower ohmic resistances compared to a soldered connection.

[0025] Preferably, the laser welding connection in the power semiconductor component can be limited to the area of ​​the connecting pins. Preferably, no laser welding connection is provided in the area of ​​the further underside contact area of ​​the power semiconductor component with the SMD circuit carrier.

[0026] The connecting pins are preferably designed in a stepped configuration so that, on the one hand, they run parallel to the joining plane in the area to be welded and / or are adapted to the overall height of the assembly. On the other hand, this provides the advantage that the laser beam can be coupled unobstructed and evenly onto the area to be welded from above.

[0027] Studies have shown that it is particularly advantageous if the laser weld is formed by a continuous melting zone. This allows for a uniform energy input with a small contact area due to the narrow lead pins, thus creating an effective and stable contact.

[0028] It is particularly advantageous if, alternatively or additionally, the laser welding connection is performed using a wobbling laser beam. This also increases the coupling area of ​​the laser beam, thus avoiding excessive local melting, which can lead to holes.

[0029] Laser welding is preferably performed with an IR laser. The use of an IR laser has proven to be very advantageous because its use initially forms an oxide, particularly copper oxide, on the surface of the weld. This reduces the reflectivity of the laser beam and thus allows for improved coupling of the laser beam or its energy. According to a further embodiment, the at least one discrete power semiconductor component provided with electrically conductive connection elements, preferably the plurality of power semiconductor components, can be located between the SMD circuit carrier and a holding part.

[0030] Due to a special embodiment of the method according to the invention, the at least one discrete power semiconductor component provided with electrically conductive connection elements, preferably the plurality of power semiconductor components, can first be positioned and fixed on the holding part before laser welding. In this case, the holding part acts as a transfer part. In this case, the discrete power semiconductor component or the plurality of discrete power semiconductor components can already be fixed to the holding part in a special arrangement, for example in a circular or star-shaped arrangement. This can be an arrangement that is finally determined in advance for a specific application. In an expedient embodiment, the holding part can remain on the power semiconductor component module to be produced, so that the power semiconductor components are reliably stabilized in their position during the subsequent laser welding.The holding part also serves as a mechanical bearing in the overall arrangement.

[0031] In an alternative embodiment of the invention, the at least one discrete power semiconductor component or the plurality of discrete power semiconductor components can be grasped in a special arrangement, for example, in a circular or star-shaped arrangement, e.g., by a gripper, and positioned on the power semiconductor component module to be manufactured. Subsequently, the respective power semiconductor component is fixed in position using the holding part only during laser welding. The holding part can then be removed again. In this case, the holding part acts only as a temporary holder during laser welding.

[0032] The power semiconductor components can be fixed to the holding part by adhesive bonding, for example by means of adhesive dots on the upper surfaces of the power semiconductor components. The holding part advantageously has welding windows through which the laser welding takes place. This allows for advantageous coupling of the laser beam from above. At the same time, other areas of the SMD circuit carrier are protected or shielded from being affected by the laser beam. In particular, welding residues can be retained thanks to the shielding. Furthermore, the presence of welding windows enables the application of insulating material to the welding points or the application of a potting compound, provided that the entire volume, which is also formed or at least limited by the holding part, can be filled with material.

[0033] In addition, a pressure contact for electrical and thermal contacting in the SMD power semiconductor component module can be created between the at least one power semiconductor component and the SMD circuit carrier via the holding part by clamping the arrangement of power semiconductor component and circuit carrier between the holding part and a counter-bearing, preferably on the installation side. The latter can be, for example, a heat sink located on the underside of the SMD circuit carrier or an installation-side counter-bearing, e.g. a housing part, with which the power semiconductor component module is installed in use. In addition, because the holding part is used to clamp the respective power semiconductor component, there is no need to adapt the shape or design of the power semiconductor component itself, e.g. for pressing it in.The power semiconductor component itself does not need to be adapted, but merely needs to rest on the conductor track structure of the SMD circuit carrier located on the insulator. The pressure contact can be achieved in particular, for example, by screwing the holding part to the heat sink or by pressing the holding part onto the SMD circuit carrier. The pressure contact creates reliable electrical and thermal contact between the power semiconductor component and the SMD circuit carrier, which always ensures good electrical and thermal contact even in the event of temperature fluctuations or mechanical influences. According to a further expedient embodiment, an elastic element can be arranged between the at least one power semiconductor component and the holding part. This ensures that the power semiconductor components are pressed onto the SMD circuit carrier with the same or at least a similar force.In addition, this design makes it possible to create a pressure contact by clamping the holding part even in the case of height differences due to different high-power semiconductor components.

[0034] Conveniently, the elastic element is a silicone foam pad.

[0035] The at least one power semiconductor component, preferably a plurality of power semiconductor components, can first be positioned in a predetermined arrangement and / or orientation on a preferably self-adhesive mounting film and fixed there, wherein the holding part can then be fixed on the at least one power semiconductor component, preferably on the plurality of power semiconductor components, in the arrangement and / or orientation previously determined on the mounting film. The method according to the invention thus allows the arrangement of power semiconductor components to be prefabricated, e.g., on an industrial scale, before the arrangement is transferred to a holding part to be used as a transfer part or removed by a gripper.For example, a plurality of arrangements and / or orientations of a plurality of power semiconductor components can be provided on a supply roll for the manufacturing process.

[0036] The foil is removed from the holding part to be used as a transfer part after the power semiconductor components have been fixed to the latter.

[0037] The film is preferably a self-adhesive film.

[0038] The method according to the invention also allows the power semiconductor component module to be designed with a low-inductance interconnect layer. A low-inductance interconnect layer primarily enables fast switching. In particular, a multilayer SMD circuit carrier comprising at least a first and a second insulator as well as a first and a second conductor track structure can also be produced within the scope of the method according to the invention, wherein the contact point can be located on the first conductor track structure or the second conductor track structure. A structure with more than two insulators or insulation layers can also be produced.

[0039] The method according to the invention also allows the second insulator with the second conductor track structure to be arranged laterally relative to the semiconductor component. Here, too, laser welding of the connection elements of the power semiconductor component with the laterally arranged second conductor track structure can be performed in the manner according to the invention.

[0040] In particular, the contact point can be located on the second conductor track structure, with the second insulator being angled to the second conductor track structure, and the first conductor track structure being angled correspondingly or according to the second insulator and being continued by the latter. The contact is located in the region of the second conductor track structure arranged parallel to the first insulator.

[0041] To fulfill the cooling function, a cooler, preferably in the form of a heat sink, can be expediently arranged beneath the SMD circuit carrier for heat dissipation. In particular, a heat sink made of aluminum, preferably pure aluminum, can be provided due to its high thermal conductivity. With these cooling devices and conditions, the semiconductor chips contained in the semiconductor components can meet optimal performance and reliability requirements.

[0042] Particularly advantageously, the semiconductor component can be designed for a minimum current of 5 A or a minimum voltage of 24 V. The method according to the invention is particularly suitable for this area of ​​power electronics, since the laser welding connection allows for the high temperatures caused by the high currents and voltages of the semiconductor components and does not limit the performance and reliability of the circuit.

[0043] The semiconductor component can be either active or passive. Active and passive semiconductor components are discrete (housed) power components, which can be selected according to the circuit requirements and parameters. The semiconductor chips contained therein are designed to meet optimal performance and reliability requirements under the given cooling conditions. Other (passive) switching components can also be welded or pressure-contacted.

[0044] The semiconductor component can have an electrically and thermally conductive base surface that can be contacted by means of pressure contact with the SMD circuit carrier or the conductor track structure arranged thereon. For this purpose, for example, a circumferential frame of the holding part can be pressed onto an edge region of the insulator. In particular, the holding part can have at least one projection that engages in a corresponding recess at the edge region of the insulator for pressing, or vice versa. In particular, a locking or snap-in connection of the parts can also be provided. By pressing or the locking or snap-in connection, the pressure contact can be established securely and permanently with the necessary pressure or pressing force.

[0045] Advantageously, the electrically and thermally conductive base surface of the semiconductor component can be coated with a silver or silver alloy, thus ensuring a good ohmic and thermal contact over time. A good ohmic contact ensures good current conduction, and a good thermal contact results in good heat dissipation and thus appropriate cooling.

[0046] The coating of silver or a silver alloy can have a thickness of 0.1 pm to 0.5 pm, in particular of 0.1 pm to 0.3 pm. The present invention further relates to an SMD power semiconductor component module produced by a method according to at least one of claims 1 to 24.

[0047] Description of the invention based on exemplary embodiments

[0048] The invention is explained in more detail using exemplary embodiments in the drawing figures. They show:

[0049] Fig. 1 is a highly simplified schematic representation of the provision of several power semiconductor components in a specific arrangement and / or orientation on a placement film;

[0050] Fig. 2 is a highly simplified schematic representation of the transfer of the power semiconductor components arranged on the placement foil in the relevant arrangement and / or orientation to a holding part, which in this example serves as a transfer part;

[0051] Fig. 3 shows a highly simplified schematic representation of laser welding for connecting connection elements of the power semiconductor component to contact points of an SMD circuit carrier in the form of a lead frame;

[0052] Fig. 4 is a highly simplified schematic representation of the arrangement shown in Fig. 3 after completion;

[0053] Fig. 5 is a highly simplified schematic representation of the laser during the laser welding process;

[0054] Fig. 6 shows a highly simplified schematic representation of the melting region in the region of the connection element of the power semiconductor component and the contact point of the SMD circuit carrier in a first embodiment; Fig. 7 shows a highly simplified schematic representation of the melting region in the region of the connection element of the power semiconductor component and the contact point of the SMD circuit carrier in a further embodiment;

[0055] Fig. 8 is a highly simplified schematic representation of a further embodiment of an SMD power semiconductor component module produced by the method according to the invention in the region of a power semiconductor component in the form of a lead frame with two insulators;

[0056] Fig. 9 is a highly simplified schematic representation of a further embodiment of an SMD power semiconductor component module produced by the method according to the invention in the region of a power semiconductor component in the form of a lead frame with two insulators;

[0057] Fig. 10 is a highly simplified schematic representation of the arrangement shown in Fig. 4 with the retaining part locked or pressed onto the insulator;

[0058] Fig. 11 is a highly simplified schematic representation of a further embodiment of an SMD power semiconductor component module produced by the method according to the invention in the region of a power semiconductor component with a holding part which has been applied after laser welding has been carried out to produce a pressure contact;

[0059] Fig. 12 is a highly simplified schematic representation of a further embodiment of an SMD power semiconductor component module produced by the method according to the invention in the region of a power semiconductor component module using an elastic element between the holding part and the power semiconductor component to produce a pressure contact;

[0060] Fig. 13 is a highly simplified schematic representation of the arrangement according to Fig. 10 with the additional use of an elastic element and a holding part which is not provided as a transfer part; and

[0061] Fig. 14 is a highly simplified schematic representation of a holding part for ensuring pressure contact for a plurality of power semiconductor components arranged on an SMD circuit carrier.

[0062] Fig. 1 shows the provision of a plurality of power semiconductor components 4, not insulated on their underside, in a placement machine 13 on a placement film 11, which is pulled off a roll 17 and rewound onto another roll 17 with the power semiconductor components 4 arranged on it. The power semiconductor components 4 are discrete power semiconductor components with connection elements 5 in the form of connection legs. Typically, one connection leg is provided for each power semiconductor component 4, one for the collector, one for the emitter, and one for the gate of the power semiconductor component 4. The placement machine 13 comprises, for example, a metallic carrier plate 14. The metallic carrier plate 14 causes an electrostatic discharge of the power semiconductor components 4.

[0063] The assembly film 11 is preferably a one-sided self-adhesive film.

[0064] During the assembly of the mounting film 11 with the power semiconductor components 4, an arrangement and / or alignment of the power semiconductor components 4 can thus be determined as intended for later use, depending on requirements. This therefore involves an arrangement and / or alignment of the power semiconductor components 4 relative to one another or among one another that can already be prefabricated within the scope of the provision of the majority of the power semiconductor components 4. For example, this can be a ring-shaped or star-shaped arrangement. This enables large-scale prefabrication of power semiconductor component groups. The grouped power semiconductor components can be provided in roll form together with the mounting film 11.

[0065] According to the method according to the invention, the assembly of power semiconductor components 4 arranged on the assembly film 11 is transferred to a holding part 9, positioned thereon, and fixed in place. This takes place on an equipment board 15. The assembly film 11 is provided on the equipment board 15 together with the power semiconductor components 4 located thereon. Adhesive 12 is applied to the upper side of each power semiconductor component 4, and then the holding part 9 is applied to the upper side of the respective power semiconductor component 4 provided with adhesive 12. This permanently connects the holding part 9 to the pre-assembled arrangement of power semiconductor components 4. The assembly film 11 is then removed. The holding part 9 is provided with individual welding windows 8. The holding part 9 is preferably a plastic plate ora plate-shaped part of a component for later use.

[0066] Fig. 3 shows the contacting of a power semiconductor component 4, which is already connected to the holding part 9, with an SMD circuit carrier 1 in the form of a lead frame using a laser welding connection. It should be noted that Fig. 3 shows only a partial area of ​​a holding part 9 provided in the manufacturing process.

[0067] The lead frame comprises an insulator 2 and a conductor track structure 2a or contact points 3 located on the insulator 2 for contacting the connection elements 5 of the power semiconductor components 4. The conductor track structure of the lead frame can be punched, etched, or laser-cut. The respective power semiconductor component 4 has an electrically conductive base area 4a on which a coating 6 is located. The coating 6 is preferably a coating made of silver or a silver alloy. The coating made of silver or a silver alloy can have a thickness of 0.1 pm to 0.5 pm, in particular 0.1 pm to 0.3 pm.

[0068] A cooler 7 is positioned on the underside of the insulator 2, which serves to dissipate the thermal energy generated during operation of the power semiconductor components 4.

[0069] Instead of the SMD circuit carrier 1 in the form of a lead frame, an SMD circuit carrier in the form of a printed circuit board or an IMS substrate could also be used.

[0070] The arrangement of the power semiconductor components 4 and the retaining part 9 adhering thereto is aligned with the SMD circuit carrier 1 such that the connection elements 5 of the respective power semiconductor component 4 are located at the contact points 3 of the SMD circuit carrier 1. The connection elements 5 of the power semiconductor component 4 are preferably designed in a stepped manner and run parallel to the main extension surface of the SMD circuit carrier 1 in the contact area with the contact point 3.

[0071] The contact point 3 and the connection element 5 are made of a material comprising copper or a copper alloy. The connection elements 5 of the power semiconductor components 4 can be provided with an Sn-Ag coating (not shown in the figures). The latter is typically provided as a soldering aid to avoid copper oxides during the typically occurring soldering process.

[0072] Within the scope of the method according to the invention, the contact between the connection element 5 and the contact point 3 is not created by soldering, but by means of a laser welding connection 16.

[0073] In the course of the method according to the invention, the power semiconductor component 4 is fastened in SMD design to the same side of the SMD circuit carrier 1 on which the electrical contacting of the connection elements 5 of the same to the SMD circuit carrier 1 takes place. The mechanical fastening plane and the electrical contacting plane are thus identical or at least parallel to one another on one and the same side of the SMD circuit carrier 1. Due to the connection of the connection elements 5 to the respectively assigned contact points 3 by the laser welding connection 16 instead of a soldering connection, the current-carrying capacity of the manufactured SMD power semiconductor component module is considerably improved. During laser welding, the connection elements and contact points are melted in the relevant area of ​​the laser beam, resulting in an intimate connection between the joining partners.Laser welding creates a monometallic connection, unlike soldering. This results in the advantage that this type of material-to-material connection allows operation of the SMD semiconductor component module at higher currents than with a soldered connection. Furthermore, the connection according to the invention also allows operation of the SMD power semiconductor component module at higher temperatures than those possible with a soldered connection. Furthermore, more sustainable operation under high load cycling conditions is possible compared to a soldered connection. This enables a high level of reliability for the SMD power semiconductor component module. Finally, this ensures that the power semiconductor component module can be operated at the full performance capacity of its power semiconductor components, meaning that no "limitation" is necessary.

[0074] Due to the holding part 9 arranged on the upper side with the welding windows 8 formed therein, the laser beam 18 can be advantageously coupled from above. At the same time, other areas of the SMD circuit carrier 1 are protected or shielded from impairment by the laser beam 18, in particular from welding residues. In addition, the welding windows 8 enable the introduction of insulating material 26 (in Fig. 4, for example, in the form of insulating droplets) in the area of ​​the laser welding or the introduction of insulating material 26 in the form of potting compound by completely potting a cavity at least partially delimited by the holding part 9, as shown by way of example in Fig. 10.According to an expedient alternative embodiment of the method according to the invention, at least one power semiconductor component, preferably a plurality of power semiconductor components, can be removed from a supply, e.g., a correspondingly populated component foil 11, by a gripper (not shown in the drawing figures) in a desired arrangement and arranged on the SMD circuit carrier. In such a procedure, the holding part 9 according to Fig. 3 serves to locally fix the power semiconductor components 4 during the laser welding process. In this case, the holding part 9 does not serve as a transfer part, but merely for fixation during laser welding.

[0075] According to Fig. 4, a pressure contact between the power semiconductor component 4 and the SMD circuit carrier 1 can be created by means of the holding part 9 for electrical and thermal contacting. According to Fig. 4, this can be achieved by the holding part 9 and the SMD circuit carrier 1 clamping the power semiconductor component 4. This can be achieved, for example, by the holding part 9 being screwed to the cooler 7 using screws 25. It is noted that, for the sake of simplicity, only one screw 25 is shown in Fig. 4. The entire arrangement comprising the holding part 9, the power semiconductor components 4, the SMD circuit carrier 1 and the cooler 7 can be arranged, for example, on a bearing cover of an electrical device, e.g., an electric motor. For example, certain electrical loads or electrical components (e.g.,Motor coils) can be connected directly.

[0076] Alternatively, the holding part 9 can also be pressed onto the SMD circuit carrier 1 in order to create the pressure contact. For this purpose, for example, a circumferential frame 27 of the holding part 9 can be pressed onto an edge region 28 of the insulator 2. By pressing or the locking or snap connection, the pressure contact can be created securely and permanently with the necessary pressure or pressing force. In particular, a locking or snapping into place of the parts can also be provided (see Fig. 10). A press connection and / or locking connection is provided with the reference number 29. In particular, the holding part 9 can have at least one projection (not shown in Fig. 10) which engages or locks or snaps into a corresponding recess (also not shown in Fig. 10) in the edge region 28 of the insulator 2, or vice versa. By means of the press, locking and / or snapping connection, the pressure contact can be created with the necessary pressure or pressing force.Pressing force can be produced safely and permanently.

[0077] Fig. 5 shows a highly simplified schematic representation of the design and operation of the laser to be used to produce the laser weld 16. This is preferably a so-called fiber laser 22, in which the laser beam 18 is provided via a fiber optic cable 19. A scanner 24 can move the laser beam 18 according to the required application. The scanner 24 can ensure that the laser beam 18, for example, performs a circular movement (KB) around a central axis, as shown in Fig. 5. Alternatively or additionally, the laser beam 18 can also perform a wobbling movement (WB), as also shown in Fig. 5.

[0078] Fig. 5 shows an example of a coupling surface 23 of the laser beam 18 in a snapshot during the circular movement KB and during the wobble movement WB. The laser is preferably an IR laser.

[0079] The laser's focus spot has a diameter in the range of 20-50 pm, in particular 30-40 pm. The melting region 21 created by the laser beam 18 is at least substantially continuous, for example, point-shaped or circular. The diameter of the melting region 21 is in a range of 60-100 pm, preferably 70-90 pm.

[0080] Fig. 6 shows, in a highly simplified schematic representation, the laser weld 16, which has at least a substantially circular melting region 21. In the representation shown in Fig. 6, the at least substantially point-shaped or circular shape of the melting region 21 is determined by the substantially circular cross-section of the laser beam 18.

[0081] In the alternative embodiment shown in Fig. 7, an at least substantially point-shaped or circular melting region 21 is also provided. However, the latter is caused by the special movement of the laser beam 18, namely a circular movement KB, see Fig. 5. The circular movement can be further superimposed by a wobbling movement WB.

[0082] Fig. 8 shows, in a highly simplified schematic representation, a power semiconductor component module manufactured according to the method of the invention, with a low-inductance structure, which comprises a multilayer SMD circuit carrier 10 in the form of a multilayer leadframe. The multilayer SMD circuit carrier 10 shown in Fig. 8 comprises a first insulator 2, assigned to the cooler 7, with a punched or cut conductor track structure 2a and contact points 3, as well as a second insulator 20 located thereon with an associated punched or cut conductor track structure 20a. The connection element 5 of the power semiconductor component 4 contacts the contact point 3 of the conductor track structure 2a. A corresponding structure enables particularly fast switching behavior of the electronic circuit.

[0083] Fig. 9 shows, in a highly simplified schematic representation, another variant of a power semiconductor component module that can be manufactured according to the method according to the invention. This is also a multilayer SMD circuit carrier 1 in the form of a multilayer lead frame, which has a first insulator 2 provided with a conductor track structure 2a, which is connected to the cooler 7, and a second insulator 20 located thereon, which is provided with a second conductor track structure 20a and is of angled design. The respective connection element 5 of the power semiconductor component 4 is contacted with the contact point 3 of the second conductor track structure 20a of the second insulator 20 by means of a laser weld 16. In the case shown in Fig.In the power semiconductor component module shown in Figures 8 and 9, a multilayer printed circuit board or a multilayer IMS substrate could also be used instead of an SMD circuit carrier 10 in the form of a multilayer lead frame.

[0084] Otherwise, the two embodiments of the power semiconductor component modules correspond to the power semiconductor component module from Fig. 4. The two embodiments of Figs. 8 and 9 also comprise, in the ready-to-use state, a holding part 9 arranged on the upper side, with which a pressure contact can be produced in the manner already described for Fig. 4.

[0085] In the embodiment shown in Fig. 11, in contrast to the embodiment according to Fig. 4, the pressure contact is exerted on the power semiconductor component 4 by means of a holding part 90, which has no through-openings for the laser beam. In this embodiment, the laser welding of the connection elements 5 of the power semiconductor component 4 was performed before the application of the holding part 90. For example, the laser welding could have been achieved by using a holding part 9 with a welding window 8, which was provided only temporarily for fixing the power semiconductor component 4 during laser welding and was subsequently removed. Therefore, the holding part 90 shown in Fig. 11 does not require a welding window. Otherwise, the embodiment according to Fig. 11 corresponds to the embodiment of the invention according to Fig. 4.

[0086] Fig. 12 shows a further embodiment of the respective present invention, in which an elastic element 91 is inserted between the holding part 90 and the respective power semiconductor component 4, by means of which a controlled pressure is applied to the power semiconductor component 4 to ensure pressure contact. The elastic element 91 is expediently a silicone foam pad. By means of the elastic element 91, a uniform contact pressure can be applied to a plurality of power semiconductor components 4 via the holding part 90. In the same way, it is also possible that, if a holding part 9 equipped with welding windows 8 is to be used instead of the holding part 90 to exert pressure contact, a corresponding elastic element 91 can also be present in this case.

[0087] Furthermore, the embodiment according to Fig. 13 shows a possible modification of the embodiment according to Fig. 10, in which, on the one hand, an elastic element 91 is arranged between the holding part 90, in which, in comparison to Fig. 10, no welding windows are present, and the power semiconductor component 4. Accordingly, an elastic element 91 can also be present in the embodiment according to Fig. 10.

[0088] Fig. 14 shows a holding part 90 in which a plurality of elastic elements 91 are provided for applying pressure to a plurality of power semiconductor components (not shown in Fig. 14). This allows a uniform pressure to be applied to the individual power semiconductor components. The holding part 90 of the embodiment according to Fig. 14 can be mechanically coupled to the cooler 7 or the insulator 2 of the SMD circuit carrier 1 in the manner already described.

[0089] The SMD circuit carrier may also be of the previously described designs as shown by way of example in Figs. 8 and 9.

[0090] The method according to the invention is particularly suitable for power semiconductor component modules with a minimum current of 5 A or for a minimum voltage of 24 V. The method according to the invention is particularly suitable for this area of ​​power electronics, since the laser welding connection 16 allows the high temperatures caused by the high currents and voltages of the semiconductor components 4 and does not limit the performance and reliability of the circuit.

[0091] The semiconductor component 4 can be an active or passive semiconductor component. (Housed) discrete power semiconductor components are used as active and passive semiconductor components, which can be selected according to the circuit requirements and corresponding parameters. The semiconductor chips contained therein are designed to meet optimal performance and reliability requirements under the given cooling conditions. These are preferably standard semiconductor components with an electrical contact surface on the underside, designed for SMD technology.

[0092] REFERENCE MARKS LIST

[0093] 1 SM D-circuit carrier

[0094] 2 (first) insulator

[0095] 2a (first) conductor track structure

[0096] 3 Contact point

[0097] 4 Power semiconductor component

[0098] 4a electrically conductive base surface

[0099] 5 connecting element

[0100] 6 Coating

[0101] 7 coolers

[0102] 8 welding windows

[0103] 9 Holding part

[0104] 10 SMD circuit carriers

[0105] 11 Assembly film

[0106] 12 Adhesive

[0107] 13 placement machine

[0108] 14 Metallic carrier plate

[0109] 15 Equipment plate

[0110] 16 laser welding connection

[0111] 17 roll

[0112] 18 laser beam

[0113] 19 Fiber optic

[0114] 20 second insulator

[0115] 20a second conductor track structure

[0116] 21 Melting area

[0117] 22 fiber lasers

[0118] 23 Coupling area

[0119] 24 scanners

[0120] 25 screw

[0121] 26 Insulation material

[0122] 27 Frame 28 Edge area

[0123] 29 Snap connection

[0124] 90 holding part

[0125] 91 elastic element KB circular movement WB wobbling movement

Claims

GODPARENT SAYINGS 1. A method for producing an SMD power semiconductor component module, comprising the following steps: Providing an SMD circuit carrier (1, 10) provided with contact points (3) and insulation, Providing at least one discrete power semiconductor component (4) provided with electrically conductive connection elements (5), preferably connection legs, Arranging the at least one discrete power semiconductor component (4) provided with electrically conductive connection elements (5) on the side of the SMD circuit carrier (1, 10) provided with the contact points (3), wherein the connection elements (5) of the power semiconductor component (4) contact the contact points (3) of the SMD circuit carrier (1, 10), and Connecting the connection elements (5) to the respective associated contact points (3) by laser welding.

2. Method according to claim 1, characterized in that a printed circuit board, an IMS substrate or a lead frame is provided as the SMD circuit carrier (1).

3. Method according to claim 1 or 2, characterized in that the contact point (3) and / or the connection element (5) comprise or comprises copper or a copper alloy.

4. Method according to at least one of the preceding claims, characterized in that the connecting element (5) is designed to run parallel to the main extension surface of the SMD circuit carrier (1, 10) in the region of the connecting element (5) in which the laser welding takes place.

5. Method according to at least one of the preceding claims, characterized in that the connecting legs are designed in a step-like manner.

6. Method according to at least one of the preceding claims, characterized in that the laser welding connection is formed by a continuous melting area (21).

7. Method according to at least one of the preceding claims, characterized in that the laser welding connection is carried out by means of a wobbling laser beam. 8 Method according to at least one of the preceding claims, characterized in that the laser welding is carried out with an IR laser.

9. Method according to at least one of the preceding claims, characterized in that the at least one discrete power semiconductor component (4) provided with electrically conductive connection elements (5), preferably the plurality of power semiconductor components (4), is located between the SMD circuit carrier (1, 10) and a holding part (9, 90).

10. The method according to claim 9, characterized in that the at least one discrete power semiconductor component (4) provided with electrically conductive connection elements (5), preferably the plurality of power semiconductor components (4), is positioned and fixed on the holding part (9, 90) before the laser welding or the holding part (9, 90) is placed on the at least one discrete power semiconductor component (4) provided with electrical connection elements (5), preferably on the plurality of power semiconductor components (), before the laser welding for positional fixing.

11. Method according to claim 9 or 10, characterized in that the holding part (9) has welding windows (8) through which the laser welding takes place.

12. Method according to at least one of the preceding claims, characterized in that a pressure contact for electrical and thermal contacting is additionally generated between the at least one power semiconductor component (4) and the SMD circuit carrier (1, 10).

13. Method according to claim 12, characterized in that the pressure contact is generated via the holding part (9, 90) by clamping the arrangement of power semiconductor component (4) and SMD circuit carrier (1, 10) between the holding part (9, 90) and a counter bearing, preferably on the installation side.

14. Method according to claims 9 to 13, characterized in that an elastic element (91) is arranged between the at least one power semiconductor component (4) and the holding part (9, 90).

15. Method according to claim 14, characterized in that the elastic element (91) is a silicone foam pad.

16. Method according to claims 9 to 15, characterized in that the at least one power semiconductor component (4), preferably a plurality of power semiconductor components (4), is first positioned in a predetermined arrangement and / or orientation on a preferably self-adhesive mounting film (11), is fixed there, and the holding part (9) is fixed on the at least one power semiconductor component (4), preferably on the plurality of power semiconductor components (4), in the arrangement and / or orientation previously determined on the mounting film (11). Method according to at least one of the preceding claims, characterized in that a multilayer SMD circuit carrier (10) comprising at least a first and a second insulator (2, 20) and a first and a second conductor track structure (2a, 20a) is provided as the SMD circuit carrier (10), wherein the contact point (3) is located on the first conductor track structure (2a) or second conductor track structure (20a). Method according to claim 17, characterized in that the second insulator (20) with the second conductor track structure (20a) is arranged laterally to the semiconductor component (4).Method according to claim 18, characterized in that the contact point (3) is located on the second conductor track structure (20a), the second insulator (20) is angled to the second conductor track structure (20a), and the connection of the connection elements (5) to the respectively assigned contact points (3) is carried out by laser welding in the region of the second conductor track structure (20a) arranged parallel to the first insulator (2). Method according to at least one of the preceding claims, characterized in that the SMD circuit carrier (1, 10) comprises a cooling function, preferably in the form of a cooler (7). Method according to at least one of the preceding claims, characterized in that the power semiconductor component (4) is designed for a minimum current of 5 A or for a minimum voltage of 24 V.Method according to at least one of the preceding claims, characterized in that the power semiconductor component (4) is an active or passive semiconductor component. Method according to at least one of the preceding claims, characterized in that the power semiconductor component (4) has an electrically and thermally conductive base surface (4a), which is preferably contacted with the SMD circuit carrier (1, 10) by means of pressure contact. Method according to claim 23, characterized in that the electrically and thermally conductive base surface (4a) is provided with a coating of silver or a silver alloy. SMD power semiconductor component module, manufactured according to the method according to at least one of the preceding claims.

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