Manufacturing method for SMD power semiconductor component module and SMD power semiconductor component module

Abstract

The present invention relates to a method for manufacturing an SMD power semiconductor component module, the method comprising the steps of: providing an SMD circuit carrier (1, 10) with contacts (3) and an insulating material; providing at least one discrete power semiconductor component (4) with electrically conductive connecting elements (5), preferably connecting legs; arranging the at least one discrete power semiconductor component (4) with the electrically conductive connecting elements (5) on the side of the SMD circuit carrier (1, 10) that is provided with the contacts (3), the connecting elements (5) of the power semiconductor component (4) being in contact with the contacts (3) of the SMD circuit carrier (1, 10); and connecting the connecting elements (5) to the respectively assigned contacts (3) by laser welding.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an SMD power semiconductor component module, in which at least one discrete power semiconductor component with electrically conductive connecting elements is mounted on an SMD circuit carrier with contacts of SMD design, the mechanical fastening and the electrical contact being made on the same side of the SMD circuit carrier. Furthermore, the present invention relates to an SMD power semiconductor component module manufactured using the method according to the invention. [Background technology]

[0002] (Technical background) Currently, discrete SMD power semiconductor components are widely used as SMD components. They are soldered to SMD circuit carriers (e.g., printed circuit boards (PCBs) or IMS substrates) using a soft soldering process. In this process, all three contacts of the component—the collector, emitter, and gate—are soldered to the power lines of the SMD circuit carrier. As the performance of power semiconductor chips increases, so does the amperage. This means that newer power semiconductor chips have higher current carrying capacity. Higher currents in these components result in higher contact temperatures, which reduces the reliability of the application. Therefore, the current carrying capacity of a power semiconductor component is determined by the type of contact connection in the power semiconductor component. This means that the current must be reduced or limited as necessary to ensure the required reliability of the circuit. This is particularly important when power circuits are built using SMD components on circuit carriers. SMD components, in contrast to PCBs, can also provide advanced cooling functions for the circuit. In this case, the small copper cross section of the connecting legs and the additional ohmic resistance due to the soft solder connections create losses that impair the economical utilization of the current carrying capacity of the chip or reduce the reliability of the circuit.

[0003] (Publicly Published Prior Art) The method according to the preamble of claim 1 is known from DE 102013213448 (B4), in which a power semiconductor is attached to a substrate on its upper side, the lower side of which is connected to a heat sink, and the electrical connection between the power semiconductor and the contacts of the substrate is made by soldering in a reflow process.

[0004] A heat sink module for electronic semiconductor devices is known from EP 2 458 632 A1, in which multiple electronic semiconductor devices are fixed to a finned heat sink using a fastening frame, leaf springs, and fastening screws. The fastening frame determines the precise alignment of the individual semiconductor devices. The connection legs of the electronic semiconductor devices extend vertically through the printed circuit board and are connected to the PCB on the side opposite the heat sink module by wave welding or point-to-point welding. Thus, the mechanical fastening surface and the electrical connection surface of the electronic semiconductor devices are located on different sides of the printed circuit board.

[0005] German Patent Application Publication No. 102019205772 A1 discloses a power module with packaged power semiconductors for controllably supplying electrical power to consumers. A heat sink with a cooling surface is arranged on the underside of a printed circuit board for cooling purposes. The power semiconductors are directly fastened to the heat sink and protrude through through-holes that are required in the circuit board. The power semiconductors' connection elements are electrically connected to the connection surface of the printed circuit board facing away from the heat sink. Soldering, specifically split-head soldering, as well as welding are listed as possible connections. However, this is not an SMD power semiconductor component, since the power semiconductors are directly fastened to the heat sink. Because the power semiconductors are directly fastened to the top side of the heat sink, they must be provided with insulation on their underside. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] German patent number 102013213448 (B4) [Patent Document 2] European Patent Application Publication No. 2 458 632(A1) [Patent Document 3] German Patent Application Publication No. 102019205772(A1) Summary of the Invention [Problem to be solved by the invention]

[0007] (Object of the present invention) The object of the present invention is to provide a method by which high current carrying SMD power semiconductor component modules can be manufactured using simple manufacturing techniques. [Means for solving the problem]

[0008] (Achievement of the objective) This object is achieved by the features of claim 1. Advantageous embodiments of the method according to the invention are set forth in the dependent claims. An SMD power semiconductor component module according to the invention is taught in claim 25.

[0009] The method according to the present invention for manufacturing an SMD power semiconductor device module comprises: providing an SMD circuit support with contacts and insulation; Providing at least one discrete power semiconductor component with an electrically conductive connecting element; placing the at least one discrete power semiconductor component with electrically conductive connection elements on a side of the SMD circuit support that has the contacts, the connection elements of the power semiconductor component contacting the contacts of the SMD circuit support; and connecting the connecting elements to the assigned contacts by laser welding.

[0010] Preferably, power semiconductor components having electrical contacts on the underside (ie without insulating material) are used in the method according to the invention.

[0011] Preferably, the SMD circuit carrier is provided with a cooling function.

[0012] Preferably, a printed circuit board, a so-called IMS board or lead frame is provided as the SMD circuit carrier. An IMS board is a conductor track structure on an insulator. A lead frame is a metal grid (e.g., a perforated grid) of conductor tracks. The lead frame may be thermally insulated and / or equipped with a cooling structure or heat sink or cooling layer.

[0013] Thus, during the method according to the present invention, the power semiconductor component is fastened in an SMD design to the SMD circuit support on the same side where the component's connection elements are electrically connected to the SMD circuit support. Therefore, the mechanical fastening surfaces and the electrical contact surfaces are identical or at least parallel to each other on the same side of the SMD circuit support. This significantly simplifies the assembly of the SMD power semiconductor component module. Furthermore, the current carrying capacity of the SMD power semiconductor component module is significantly increased because the connection elements are connected to their assigned contacts by laser welding instead of soldering. During laser welding, the connection elements and contacts melt in the corresponding areas of the laser beam, thereby creating a tight connection between the joining partners. Thus, a single metal connection can be formed using laser welding. As a result, this type of material-bonded connection, in contrast to a soldered connection, offers the advantage that the SMD power semiconductor component module can be operated at a higher amperage. Additionally, the connection according to the present invention also allows the SMD power semiconductor component module to be operated at higher temperatures compared to those possible with a soldered connection. Furthermore, compared to soldered connections, more sustainable operation is possible under high load cycle conditions, which allows for high reliability of SMD power semiconductor component modules. Furthermore, power semiconductor component modules can be operated at the maximum capacity of the power semiconductor components, i.e., without any "limitations."

[0014] The contacts (between the contacts and the connecting elements) are standard contacts for soldering connections, in which the contacts and / or the connecting elements are made of copper or a copper alloy. Consequently, the method according to the invention can be applied to conventional semiconductor components (e.g. TO263; D 2The present invention can be applied to SMD components on IMS substrates (e.g., printed circuit boards, PCBs, DCB substrates, IMS substrates, lead frames) or circuit carriers (e.g., printed circuit boards, PCBs, DCB substrates, IMS substrates, lead frames). This is particularly advantageous when power circuits are built using SMD components on IMS substrates. In contrast to PCBs, SMD components can also provide advanced cooling functions for the circuit. In this case, the small copper cross-sections of the connecting elements and the additional ohmic resistance of their conventional soft soldering would impair the economical utilization of the chip's current capacity or result in losses that reduce the reliability of the circuit. This can be effectively avoided by the present invention.

[0015] The contacts and / or connecting elements may be pre-tin plated.

[0016] It is advantageous if the connecting elements in the region where laser welding is carried out are designed to extend parallel to a main extension plane of the SMD circuit carrier.

[0017] Preferably, the connection elements are so-called connection legs with particularly small connection cross sections, where the method according to the invention is particularly advantageous, since the ohmic resistance resulting from a laser welded connection is lower compared to that resulting from a soldered connection.

[0018] Preferably, the laser welding connection of the power semiconductor component can be limited to the area of the connection legs only, and preferably no laser welding connection is provided in the area of further contact areas on the underside of the power semiconductor component with the SMD circuit carrier.

[0019] On the one hand, the connecting legs run parallel to the connection surface in the area to be welded and / or are preferably designed in a stepped manner to fit the overall height of the array, which on the other hand has the advantage that the laser beam can be coupled into the area to be welded from above unobstructed and uniformly.

[0020] Studies have shown that it is particularly advantageous if the laser welded connection is formed by a continuous melt zone, as the narrow connecting legs allow for a uniform energy input over a small contact area, thereby establishing an effective and stable contact.

[0021] Alternatively or additionally, it is particularly advantageous if the laser welded connection is formed using an oscillating laser beam, which also increases the bonding area of the laser beam and thereby prevents localized overmelting, which can result in holes.

[0022] Laser welding is preferably carried out using an IR laser, which has proven to be very advantageous since it initially forms oxides (e.g., copper oxide) on the surface of the weld, which reduces the reflectivity of the laser beam and thus increases its coupling and energy.

[0023] According to a further embodiment, the at least one discrete power semiconductor component, preferably the plurality of power semiconductor components, with electrically conductive connecting elements may be located between the SMD circuit support and a holding part.

[0024] According to a specific embodiment of the method of the present invention, the at least one discrete power semiconductor component, preferably the plurality of power semiconductor components, equipped with electrically conductive connecting elements may first be positioned and fixed on the holder before laser welding. In this case, the holder acts as a transfer part. Here, the discrete power semiconductor component or the plurality of discrete power semiconductor components may already be fixed on the holder in a specific arrangement, for example, a circular or star-shaped arrangement. This may also be the final arrangement for a predetermined specific application. In a useful embodiment, the holder may remain on the power semiconductor component module to be manufactured so that the power semiconductor components are firmly stabilized in their position during subsequent laser welding. The holder also functions as a mechanical bearing for the entire arrangement.

[0025] In another embodiment of the present invention, at least one discrete power semiconductor component or a plurality of discrete power semiconductor components may be gripped by a gripper and placed on a power semiconductor component module to be manufactured in a specific arrangement, for example, a circular or star-shaped arrangement. A holding part is then used to fix each power semiconductor component in place only during laser welding. The holding part may then be removed again. In this case, the holding part only serves as a temporary holder during laser welding.

[0026] The power semiconductor component may be fixed to the holder by gluing it on the top side of the power semiconductor component, for example by means of adhesive dots.

[0027] Advantageously, the holding part has a welding window for performing laser welding. This allows the laser beam to be advantageously coupled in from above. At the same time, other areas of the SMD circuit carrier are protected or shielded from the effects of the laser beam. In particular, this shielding allows welding residues to be held there. In addition, the presence of the welding window makes it possible to introduce insulating material or a molding compound over the welding point (provided that the entire volume formed or at least limited by the holding part can be poured out).

[0028] Furthermore, pressure contacts for electrical and thermal contact in SMD power semiconductor component modules can be established between at least one power semiconductor component and the SMD circuit support via a holding part by clamping the arrangement of the power semiconductor component and the circuit support between the holding part and a counter-bearing, preferably located on the installation side. The latter can be, for example, a heat sink located on the underside of the SMD circuit support or a counter-bearing located on the installation side (e.g., a housing part on which the power semiconductor module is installed during use). Furthermore, the use of a holding part for clamping each power semiconductor component makes it unnecessary, for example, to adapt the shape or shape of the power semiconductor component itself for press-fitting. The power semiconductor component does not need to be adapted itself; it simply needs to rest on the conductor track structure of the SMD circuit support, which is located on the insulator. The pressure contact can be achieved, for example, by screwing the holding part to the heat sink or by pressing the holding part against the SMD circuit support. The pressure contact ensures that electrical and thermal contact is established between the power semiconductor component and the SMD circuit carrier, thereby ensuring good electrical and thermal contact in the event of temperature fluctuations or mechanical influences.

[0029] According to a further useful embodiment, an elastic element may be arranged between the at least one power semiconductor component and the holding part, which ensures that the power semiconductor components are pressed onto the SMD circuit carrier with the same or at least similar force. In addition, this embodiment makes it possible to establish a pressure contact by clamping with the holding part even when there is a height difference due to different heights of the power semiconductor components.

[0030] The elastic element is usefully a silicone foam pad.

[0031] At least one power semiconductor component, preferably a plurality of power semiconductor components, may first be arranged in a predetermined arrangement and / or orientation on a preferably adhesive mounting foil and fixed thereto, and a holder may then be fixed onto the at least one power semiconductor component, preferably a plurality of power semiconductor components, in the previously determined arrangement and / or orientation on the mounting foil. Thus, the method according to the invention allows for pre-assembly, e.g., on an industrial scale, of arrays of power semiconductor components before the array is transferred to a holder and used as a transfer part or removed by a gripper. For example, such arrays and / or orientations of a plurality of power semiconductor components may be provided on a supply roll for the manufacturing process.

[0032] The foil is removed from the holder to be used as a transfer part after the power semiconductor component has been fixed to the holder.

[0033] Preferably the foil is an adhesive foil.

[0034] The method according to the invention also allows the design of power semiconductor device modules with low-inductance interconnect levels, which allow particularly fast switching. In particular, as an SMD circuit carrier forming part of the method according to the invention, a multilayer SMD circuit carrier may also be manufactured, which includes at least first and second insulators and first and second conductor track structures, and the contacts may be located on the first conductor track structure or the second conductor track structure. Structures with three or more insulator or insulating material layers may also be manufactured.

[0035] The method according to the invention also makes it possible to arrange a second insulator with a second conductor track structure laterally relative to the semiconductor component, where again laser welding of the connection elements of the power semiconductor component to the laterally arranged second conductor track structure can be carried out by the method according to the invention.

[0036] In particular, the contact may be located on a second conductor track structure, the second insulator with which the second conductor track structure is angled, the first conductor track structure being angled accordingly or to the second insulator, and the second insulator being continuous with the first conductor track structure, wherein said contact is located in a region of the second conductor track structure that is arranged parallel to the first insulator.

[0037] To achieve this cooling function, it is useful to provide a cooler, preferably in the form of a heat sink, below the SMD circuit carrier for heat dissipation. Specifically, the heat sink may be made of aluminum, preferably pure aluminum, due to its high thermal conductivity. These cooling devices and conditions allow the semiconductor chips contained in the semiconductor component to meet optimal performance and reliability requirements.

[0038] Particularly advantageously, semiconductor components can be designed for a minimum amperage of 5 A or a minimum voltage of 24 V. The method according to the invention is particularly suitable for this field of power electronics, since the laser welded connections can tolerate the high temperatures resulting from the high amperage and voltage of the semiconductor components, and therefore do not limit the performance and reliability of the circuit.

[0039] The semiconductor components may be active or passive. (Packaged) discrete power components are used as active and passive semiconductor components, which may be selected according to the requirements of the circuit based on corresponding parameters. The semiconductor chips contained in these semiconductor components are designed to meet optimal performance and reliability requirements under given cooling conditions. Additional (passive) circuit components may be welded or pressure-welded.

[0040] The semiconductor component may have an electrically and thermally conductive base surface that can be brought into pressure contact with the SMD circuit carrier or a conductor track structure arranged on the SMD circuit carrier. For this purpose, for example, a peripheral frame of the holder may be pressed against the edge region of the insulator. In particular, the holder may have at least one pressing protrusion that engages with a corresponding recess on the edge region of the insulator, or vice versa. In particular, the respective parts may be designed to latch or snap into position. The pressure contact may be reliably and permanently established with the required pressure or pressing force by pressing or latching or snapping.

[0041] Advantageously, the electrically and thermally conductive base surface of the semiconductor component can be provided with a silver or silver alloy coating, which ensures not only good thermal contact but also a permanent ohmic contact, which ensures good electrical conduction, and which ensures good heat dissipation and therefore proper cooling.

[0042] The coating made of silver or a silver alloy may have a thickness of 0.1 μm to 0.5 μm, in particular 0.1 μm to 0.3 μm.

[0043] The invention further relates to an SMD power semiconductor component module manufactured by a method according to at least one of claims 1 to 24. [Brief explanation of the drawings]

[0044] [Figure 1] FIG. 1 shows a highly simplified schematic diagram of a number of power semiconductor components provided in a particular arrangement and / or orientation on a mounting foil. [Figure 2] FIG. 2 shows a highly simplified schematic view of the transfer of power semiconductor components arranged on a mounting foil in a corresponding arrangement and / or orientation to a holding part, which in this example functions as a transfer part. [Figure 3]FIG. 3 shows a highly simplified schematic diagram of laser welding for connecting connection elements of a power semiconductor component to contacts of an SMD circuit carrier in the form of a lead frame. [Figure 4] FIG. 4 shows a highly simplified schematic diagram of the array shown in FIG. 3 after completion. [Figure 5] FIG. 5 shows a highly simplified schematic diagram of the laser during the execution of the laser weld connection. [Figure 6] FIG. 6 shows a highly simplified schematic view of the melting zone in the region of the contacts of the connection element of the power semiconductor component and the SMD circuit carrier in a first embodiment. [Figure 7] FIG. 7 shows a highly simplified schematic view of a melting area in the region of a connection element of a power semiconductor component and a contact of an SMD circuit carrier in a further embodiment. [Figure 8] FIG. 8 shows a highly simplified schematic diagram of a further embodiment of an SMD power semiconductor component module manufactured using the method according to the invention in the region of a power semiconductor component in the form of a lead frame with two insulators. [Figure 9] FIG. 9 shows a highly simplified schematic diagram of a further embodiment of an SMD power semiconductor component module manufactured using the method according to the invention in the region of a power semiconductor component in the form of a lead frame with two insulators. [Figure 10] FIG. 10 shows a highly simplified schematic diagram of the arrangement shown in FIG. 4 with the retainers latched or pressed onto the insulator. [Figure 11] FIG. 11 shows a highly simplified schematic diagram of a further embodiment of an SMD power semiconductor component module manufactured using the method according to the invention in the region of the power semiconductor component with a retaining feature applied after laser welding has been carried out to establish the pressure contact. [Figure 12]FIG. 12 shows a highly simplified schematic view of a further embodiment of an SMD power semiconductor component module manufactured using the method according to the invention in the region of the power semiconductor component module using elastic elements between the holder and the power semiconductor component to establish a pressure contact. [Figure 13] FIG. 13 shows a highly simplified schematic view of an arrangement according to FIG. 10, which additionally uses elastic elements and holding parts which are not provided as transfer parts. [Figure 14] FIG. 14 shows a highly simplified schematic diagram of a holding part for ensuring pressure contact of a plurality of power semiconductor components arranged on an SMD circuit carrier. DETAILED DESCRIPTION OF THE INVENTION

[0045] Description of the invention using exemplary embodiments The invention will now be explained in more detail with reference to exemplary embodiments in the drawings.

[0046] 1 shows a number of power semiconductor components 4, the underside of which is not insulated, provided on a mounting foil 11 which is removed from a roll 17 in a mounting machine 13 and rewound onto another roll 17 on which the power semiconductor components 4 are arranged. The power semiconductor components 4 are discrete power semiconductor components having connection elements 5 in the form of connection legs. Typically, each power semiconductor component 4 comprises one connection leg for each of the collector, emitter and gate of the power semiconductor component 4. The mounting machine 13 comprises, for example, a metallic support plate 14, which allows for electrostatic discharge of the power semiconductor components 4.

[0047] The mounting foil 11 is preferably a single-sided adhesive foil.

[0048] Thus, in the process of mounting the power semiconductor components 4 on the mounting foil 11, the arrangement and / or orientation of the power semiconductor components 4 may be determined, since the power semiconductor components 4 are provided as needed for later use. This arrangement and / or orientation is then the arrangement and / or orientation of the power semiconductor components 4 relative to or between each other, which have already been pre-assembled as part of the provision of a plurality of power semiconductor components 4. For example, this may be a ring-shaped arrangement or a star-shaped arrangement. This allows for large-scale pre-assembly of groups of power semiconductor components. The grouped power semiconductor components may also be provided with the mounting foil 11 in the form of a roll.

[0049] According to the method of the present invention, the assembly of power semiconductor components 4 arranged on a mounting foil 11 is transferred to a holding part 9 arranged and fixed on the mounting foil 11. This is done on an equipment plate 15. The mounting foil 11 is provided on the equipment plate 15 with the power semiconductor components 4 located thereon. An adhesive 12 is applied to the top side of each power semiconductor component 4, and then a holding part 9 is applied to the top side of each power semiconductor component 4 that is provided with the adhesive 12. This permanently connects the holding part 9 to the pre-assembled array of power semiconductor components 4. The mounting foil 11 is then removed. The holding part 9 comprises a separate welding window 8. Preferably, the holding part 9 is a plastic plate or a plate-like part of a component for subsequent application.

[0050] 3 shows the contacting of a power semiconductor component 4, which is already connected to a holding part 9, to an SMD circuit carrier 1 in the form of a lead frame by means of a laser welded connection. Note that FIG. 3 shows only a partial area of the holding part 9 that is provided in the manufacturing process.

[0051] The lead frame not only comprises an insulator 2 but also, located on the insulator 2, conductor track structures 2a or contacts 3 for contacting the connection elements 5 of the power semiconductor components 4. The conductor track structures of the lead frame may be drilled, etched or laser cut. Each power semiconductor component 4 has an electrically conductive base surface 4a on which a coating 6 is provided. The coating 6 is preferably made of silver or a silver alloy. The coating made of silver or a silver alloy may have a thickness of 0.1 μm to 0.5 μm, in particular 0.1 μm to 0.3 μm.

[0052] A cooler 7 for dissipating heat energy generated during operation of the power semiconductor component 4 is disposed on the underside of the insulator 2 .

[0053] Instead of an 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 board may also be used.

[0054] The arrangement of power semiconductor components 4 and the associated holding parts 9 is aligned with the SMD circuit carrier 1 so that the connection elements 5 of the power semiconductor components 4 lie on the contacts 3 of the SMD circuit carrier 1. Here, the connection elements 5 of the power semiconductor components 4 are preferably designed in a stepped manner and extend parallel to the main extension plane of the SMD circuit carrier 1 in the contact areas of the contacts 3.

[0055] The contacts 3 and the connecting elements 5 are made of a material including copper or a copper alloy. The connecting elements 5 of the power semiconductor component 4 may be provided with a Sn-Ag coating (not shown). The latter is generally provided as a soldering aid to avoid copper oxidation during the soldering process, which normally occurs.

[0056] In the context of the method according to the invention, the contact between the connection element 5 and the contact 3 is established by a laser welded connection 16 rather than by soldering.

[0057] During the method according to the present invention, a power semiconductor component 4 of SMD design is fastened to the SMD circuit carrier 1 on the same side where the component's connection element 5 electrically contacts the SMD circuit carrier 1. Therefore, the mechanical fastening and electrical contact surfaces are identical or at least parallel to each other on the same side of the SMD circuit carrier 1. Because the connection elements 5 are connected to their assigned contacts 3 using laser-welded connections 16 instead of soldered connections, the current carrying capacity of the manufactured SMD power semiconductor component module is significantly increased. During laser welding, the connection elements and contacts melt in the corresponding areas of the laser beam, thereby creating a tight connection between the mating partners. In contrast to soldering, laser welding forms a single metal connection. This type of material-bonded connection, as opposed to a soldered connection, offers the advantage that the SMD semiconductor component module can be operated at a higher amperage. Additionally, the connection according to the present invention also allows the SMD power semiconductor component module to operate at higher temperatures than would be possible with a soldered connection. Furthermore, compared to a soldered connection, a more sustainable operation under high load cycle conditions is possible. This allows for high reliability of SMD power semiconductor component modules. Ultimately, the power semiconductor component module can be operated at the maximum capacity of its power semiconductor components, i.e., without any "limitations."

[0058] Due to the arrangement of the holding part 9 on the upper side, in which the welding window 8 is formed, the laser beam 18 can be advantageously coupled in from above. At the same time, other areas of the SMD circuit carrier 1 are protected or shielded from the influence of the laser beam 18, in particular from welding residues. Furthermore, the welding window 8 makes it possible to introduce an insulating material 26 (e.g., in the form of an insulating drop in FIG. 4) into the area of the laser weld or, for example, in the form of a molding compound by completely casting a cavity at least partially defined by the holding part 9, as shown in FIG. 10.

[0059] According to another useful embodiment of the method according to the invention, at least one power semiconductor component, preferably several power semiconductor components, may be removed by a gripper (not shown) from the desired arrangement of the provided article (e.g. the correspondingly mounted mounting foil 11) and placed on the SMD circuit carrier. In such a procedure, as shown in Fig. 3, the holding element 9 is used for locally fixing the power semiconductor component 4 during the laser welding process. In this case, the holding element 9 is not used as a transfer element but only for fixing during laser welding.

[0060] As shown in FIG. 4, a pressure contact may be established between the power semiconductor component 4 and the SMD circuit carrier 1 by means of a holding part 9 for electrical and thermal contact. This may be achieved by the holding part 9 and the SMD circuit carrier 1 clamping the power semiconductor component 4 together, as shown in FIG. 4. This may be achieved, for example, by screwing the holding part 9 to the cooler 7 using a screw 25. For simplicity's sake, only one screw 25 is shown in FIG. 4. The entire arrangement including the holding part 9, the power semiconductor component 4, the SMD circuit carrier 1, and the cooler 7 may be placed, for example, in a bearing cover of an electrical device (e.g., an electric motor). A specific electrical consumer or electrical component (e.g., a motor coil) may be directly connected to the SMD power semiconductor component module thus prepared.

[0061] Alternatively, the retaining part 9 may be pressed against the SMD circuit carrier 1 to establish the pressure contact. For this purpose, for example, a peripheral frame 27 of the retaining part 9 may be pressed against an edge region 28 of the insulator 2. The pressure contact may be reliably and permanently established with the required pressure by a pressing or latching or snapping connection. In particular, a latching or snapping fit of the parts may also be provided (see FIG. 10 ). The press and / or latching connection is designated by the reference numeral 29. In particular, the retaining part 9 may have at least one protrusion (not shown in FIG. 10 ) which engages or latches or snaps into a corresponding recess (also not shown in FIG. 10 ) on the edge region 28 of the insulator 2, or vice versa. The pressure contact may be reliably and permanently established with the required pressure or pressing force by a pressing or latching or snapping connection.

[0062] Figure 5 shows a highly simplified schematic diagram of an embodiment and operating mode of a laser used to create the laser welded connection 16. Preferably, this is a so-called fiber laser 22, in which the laser beam 18 is provided via an optical fiber 19. A scanner 24 may be used to move the laser beam 18 depending on the required application. The scanner 24 may ensure, for example, that the laser beam 18 performs a circular movement (KB) about a central axis, as shown in Figure 5. Alternatively or additionally, the laser beam 18 may perform an oscillating movement (WB), also as shown in Figure 5.

[0063] 5 shows in snapshots an example of the coupling surface 23 of the laser beam 18 during the circular motion KB and the oscillating motion WB. Preferably, the laser is an IR laser.

[0064] The laser focus has a diameter in the range of 20 to 50 μm, particularly 30 to 40 μm. The melted region 21 produced by the laser beam 18 is at least substantially continuous, for example, in the shape of a dot or a circle. The diameter of the melted region 21 is in the range of 60 to 100 μm, preferably 70 to 90 μm.

[0065] Figure 6 shows a highly simplified schematic diagram of a laser welded connection 16 having at least a substantially circular shaped melted area 21. In the diagram shown in Figure 6, the at least substantially dot-shaped or substantially circular shape of the melted area 21 is due to the substantially circular cross section of the laser beam 18.

[0066] In another embodiment shown in Figure 7, melted areas 21 are also provided that are at least approximately dot-shaped or circular, however the latter is due to a specific motion of the laser beam 18, namely a circular motion KB (see Figure 5), which may be superimposed with a swinging motion WB.

[0067] 8 shows a highly simplified schematic diagram of a power semiconductor component module with a low-inductance structure, comprising a multilayer SMD circuit carrier 10 in the form of a multilayer lead frame manufactured according to the method of the invention. The multilayer SMD circuit carrier 10 shown in FIG. 8 comprises a first insulator 2 with a perforated or milled conductor track structure 2a and contacts 3 assigned to a cooler 7, and a second insulator 20 with a corresponding perforated or milled conductor track structure 20a located on the first insulator 2. The connecting elements 5 of the power semiconductor components 4 contact the contacts 3 of the conductor track structure 2a. This corresponding structure allows particularly fast switching operations of the electrical circuit.

[0068] 9 shows a highly simplified schematic diagram of a further variant of a power semiconductor component module that can be produced according to the method of the invention, again in the form of a multilayer SMD circuit carrier 1 in the form of a multilayer leadframe, comprising a first insulator 2 with a conductor track structure 2a connected to a cooler 7, and an angled second insulator 20 with a second conductor track structure 20a located on the first insulator 2. Each connection element 5 of the power semiconductor component 4 is in contact with a contact 3 of the second conductor track structure 20a of the second insulator 20 by a laser welded connection 16.

[0069] In the power semiconductor component module shown in FIGS. 8 and 9, instead of the SMD circuit carrier 10 in the form of a multilayer lead frame, a multilayer printed circuit board or a multilayer IMS board may also be used.

[0070] Otherwise, the two above-described embodiments of the power semiconductor component module correspond to the power semiconductor component module of Figure 4. The two embodiments shown in Figures 8 and 9 also comprise, in the ready-to-use state, a holding part 9 arranged on the upper side, by means of which a pressure contact can be established in the manner already described with reference to Figure 4.

[0071] In the embodiment shown in FIG. 11 , in contrast to the embodiment shown in FIG. 4 , the pressure contact is applied to the power semiconductor component 4 by a holding part 90 that does not have a through-hole for the laser beam. In this embodiment, laser welding of the connection element 5 of the power semiconductor component 4 is performed before the holding part 90 is attached. The laser welding may be performed, for example, using a holding part 9 that has a welding window 8 that is temporarily provided to fix the power semiconductor component 4 during laser welding and then removed again. As a result, the holding part 90 shown in FIG. 11 does not require a welding window. Furthermore, the embodiment shown in FIG. 11 corresponds to the embodiment of the present invention shown in FIG. 4 .

[0072] 12 shows a further embodiment of the present invention, in which an elastic element 91 is inserted between the holding part 90 and each power semiconductor component 4 to apply a controlled pressure to the power semiconductor component 4 to ensure a pressure contact. The elastic element 91 is preferably a silicone foam pad. The elastic element 91 allows a uniform contact pressure to be applied to the multiple power semiconductor components 4 via the holding part 90.

[0073] Likewise, it is also conceivable that if a retaining part 9 with a welding window 8 is used instead of the retaining part 90 to apply the pressure contact, a corresponding elastic element 91 may also be present.

[0074] Furthermore, the embodiment shown in Figure 13 shows a possible variant of the embodiment shown in Figure 10, in which an elastic element 91 is arranged between the holding part 90, which, unlike in Figure 10, does not have a welding window, and the power semiconductor component 4. Thus, in the embodiment shown in Figure 10, an elastic element 91 may also be present.

[0075] 14 shows a retaining part 90 provided with a plurality of elastic elements 91 for applying pressure to a plurality of power semiconductor components (not shown in FIG. 14). This allows uniform pressure to be applied to the individual power semiconductor components. The retaining part 90 of the embodiment shown in FIG. 14 may be mechanically coupled to the cooler 7 or insulator 2 of the SMD circuit carrier 1 in the manner described above.

[0076] The SMD circuit carrier of the above-described embodiment may be any of those illustrated in FIGS.

[0077] The method according to the present invention is particularly suitable for power semiconductor device modules with a minimum amperage of 5 A or a minimum voltage of 24 V. The method according to the present invention is particularly suitable for this field of power electronics because the laser welded connection 16 can tolerate the high temperatures generated by the high amperage and voltage of the semiconductor components 4 and therefore does not limit the performance and reliability of the circuit.

[0078] The semiconductor components 4 may be active or passive semiconductor components. (Packaged) discrete power semiconductor components are used as active and passive semiconductor components, which may be selected according to the requirements of the circuit based on corresponding parameters. The semiconductor chips contained in these semiconductor components are designed to meet optimal performance and reliability requirements under given cooling conditions. Preferably, they are standard semiconductor components for SMD technology with electrical contacts on the underside. [Explanation of symbols]

[0079] 1 SMD circuit support 2 (first) insulator 2a (first) conductor track structure 3. Contact points 4. Power semiconductor components 4a Conductive base surface 5. Connection Elements 6. Coating 7 Cooler 8 Welding window 9 Holding part 10 SMD circuit support 11 Mounting foil 12 Adhesive 13 Placement machine 14 Metal support plate 15 Equipment Plate 16 Laser welded connections 17 rolls 18 Laser beam 19 Optical Fiber 20 Second insulator 20a Second conductor track structure 21 Melting Zone 22 Fiber laser 23 Bonding surface 24 Scanner 25 screws 26 Insulating materials 27 frames 28 Edge area 29 Latch Connection 90 Holding part 91 Elastic Elements KB circular motion WB rocking motion

Claims

1. 1. A method for manufacturing an SMD power semiconductor component module, comprising: Providing an SMD circuit support (1, 10) with contacts (3) and insulation; Providing at least one discrete power semiconductor component (4) with an electrically conductive connecting element (5), preferably a connecting leg; a step of placing the at least one discrete power semiconductor component (4) with an electrically conductive connecting element (5) on the side of the SMD circuit support (1, 10) that has the contacts (3), the connecting element (5) of the power semiconductor component (4) being in contact with the contacts (3) of the SMD circuit support (1, 10); and b. connecting said connecting elements (5) to said respectively assigned contacts (3) by laser welding.

2. 2. The method according to claim 1, wherein the SMD circuit carrier (1) is a printed circuit board, an IMS board or a lead frame.

3. 3. The method according to claim 1 or 2, wherein the contacts (3) and / or the connecting elements (5) comprise copper or a copper alloy.

4. 4. The method according to claim 1, wherein the connecting element (5) is designed to extend parallel to a main extension plane of the SMD circuit carrier (1, 10) in the area of the connecting element (5) where the laser welding is performed.

5. The method according to any one of claims 1 to 4, wherein the connecting legs are designed in a stepped manner.

6. The method according to any one of claims 1 to 5, wherein the laser welded connection is formed by a continuous melted area (21).

7. The method according to any one of claims 1 to 6, wherein the laser weld connection is made by means of an oscillating laser beam.

8. The method according to any one of claims 1 to 7, wherein the laser welding is performed using an IR laser.

9. 9. The method according to claim 1, wherein the at least one discrete power semiconductor component (4), preferably the plurality of power semiconductor components (4), provided with an electrically conductive connecting element (5) are located between the SMD circuit support (1, 10) and a holding part (9, 90).

10. 10. The method according to claim 9, wherein the at least one discrete power semiconductor component (4), preferably the plurality of power semiconductor components (4) with electrically conductive connecting elements (5) is placed and fixed on the holding part (9, 90) before laser welding, or the holding part (9, 90) is placed on the at least one discrete power semiconductor component (4), preferably the plurality of power semiconductor components (4) with electrically conductive connecting elements (5) before laser welding in order to fix its position.

11. 11. The method according to claim 9 or 10, wherein the holding part (9) has a welding window (8) for performing the laser welding.

12. The method according to any of the preceding claims, further comprising establishing a pressure contact for electrical and thermal contact between the at least one power semiconductor component (4) and the SMD circuit carrier (1, 10).

13. 13. The method according to claim 12, wherein the pressure contact is established via the holding part (9, 90) by clamping the arrangement of power semiconductor components (4) and SMD circuit carriers (1, 10) between the holding part (9, 90) and a counter-bearing preferably located on the installation side.

14. The method according to any of claims 9 to 13, wherein an elastic element (91) is arranged between the at least one power semiconductor component (4) and the holding part (9, 90).

15. 15. The method according to claim 14, wherein said elastic element (91) is a silicone foam pad.

16. 16. The method according to any of claims 9 to 15, wherein the at least one power semiconductor component (4), preferably a plurality of power semiconductor components (4), are first arranged in a predetermined arrangement and / or orientation on a preferably adhesive mounting foil (11) and fixed therein, and the holding part (9) is fixed on the at least one power semiconductor component (4), preferably a plurality of power semiconductor components (4) in the predetermined arrangement and / or orientation on the mounting foil (11).

17. 17. The method according to claim 1, wherein a multilayer SMD circuit carrier (10) is provided as the SMD circuit carrier (10), comprising at least first and second insulators (2, 20) and first and second conductor track structures (2a, 20a), and wherein the contacts (3) are located on the first conductor track structure (2a) or the second conductor track structure (20a).

18. 18. The method of claim 17, wherein the second insulator (20) with the second conductor track structure (20a) is arranged laterally with respect to the semiconductor component (4).

19. said contacts (3) being located on said second conductor track structure (20a), the second insulator (20) with the second conductor track structure (20a) is angled; 19. The method according to claim 18, wherein the step of connecting the connection elements (5) to the respectively assigned contacts (3) is performed by laser welding in areas of the second conductor track structure (20a) arranged parallel to the first insulator (2).

20. The method according to any of the preceding claims, wherein the SMD circuit carrier (1, 10) is provided with a cooling function, preferably in the form of a cooler (7).

21. The method according to any of the preceding claims, wherein the power semiconductor component (4) is designed for a minimum amperage of 5A or a minimum voltage of 24V.

22. The method according to any of the preceding claims, wherein the power semiconductor component (4) is an active or passive semiconductor component.

23. 23. The method according to any one of claims 1 to 22, wherein the power semiconductor component (4) has an electrically and thermally conductive base surface (4a) that is brought into contact with the SMD circuit carrier (1, 10), preferably by pressure contact.

24. 24. The method according to claim 23, wherein the electrically and thermally conductive base surface (4a) comprises a coating of silver or a silver alloy.

25. An SMD power semiconductor component module, characterized in that it is manufactured by the method according to any one of claims 1 to 24.

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