METHOD FOR MANUFACTURING A POWER MODULE AND POWER MODULE - Patent application

Abstract

A method for manufacturing a power module (10) includes providing a first plate (11), providing a second plate (12), arranging a first number N of power semiconductor bodies (13-18) on the first plate (11), additively manufacturing the first number N of flexible structures (23-28) or providing the first number N of additively manufactured flexible structures (23-28), and forming a stack comprising the first plate (11), the first number N of power semiconductor bodies (13-18), the first number N of flexible structures (23-28), and the second plate (12).

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a power module, a method for manufacturing a flexible structure, and a power module. [Background technology]

[0002] The power module includes a power semiconductor body located between a first plate and a second plate. Between the second plate and the power semiconductor body, for example, a spring is arranged. Pressure can be applied to achieve good electrical contact between the second plate and the first surface of the power semiconductor body via the spring. The spring is designed to fit the first surface of the power semiconductor body. However, such a spring cannot be easily miniaturized to fit a smaller power semiconductor body.

[0003] US 6,320,268 refers to a power semiconductor module having a semiconductor chip which is contacted by pressure: the contact element has two flat contact surfaces between which a spring element is located.

[0004] US Patent Application Publication No. 2020 / 0152595 relates to a spring electrode for a pressure contact power semiconductor module.

[0005] US Patent Application Publication No. 2019 / 0229030 relates to a power module and a method for manufacturing a power module.

[0006] China Patent No. 108281405 relates to a power device module and a method for fabricating the same. Summary of the Invention [Problem to be solved by the invention]

[0007] What is needed is a method for manufacturing a power module, a method for manufacturing a flexible structure, and a power module. [Means for solving the problem]

[0008] According to one embodiment, a method for manufacturing a power module includes providing a first plate, providing a second plate, arranging a first number N of power semiconductor bodies on the first plate, additively manufacturing the first number N of flexible structures or providing the first number N of additively manufactured flexible structures, and forming a stack comprising the first plate, the first number N of power semiconductor bodies, the first number N of flexible structures, and the second plate.

[0009] Advantageously, the first number N of flexible structures can be designed to fit power semiconductor bodies having a first surface with a small or large area. Additive manufacturing is a versatile tool for manufacturing the first number N of flexible structures with a suitable diameter and suitable flexibility.

[0010] Additive manufacturing may also be called 3-D printing or 3D printing. According to a further embodiment, the additive manufacturing is carried out using one of the following techniques: Fused Deposition Modeling (abbreviated as FDM), Selective Laser Sintering (abbreviated as SLS), Selective Laser Melting (abbreviated as SLM), Electron Beam Melting (abbreviated as EBM), additive manufacturing of metal structures, or another additive manufacturing technique.

[0011] According to one embodiment, a method for manufacturing a flexible structure includes additively manufacturing a first number N of flexible structures. The first number N of flexible structures are configured for a power module.

[0012] The method for manufacturing a flexible structure described in the present disclosure is exemplarily suitable for a method for manufacturing a power module, and therefore the features and advantages described in relation to the method for manufacturing a flexible structure can be used for the method for manufacturing a power module, and vice versa.

[0013] According to one embodiment, the power module comprises a stack comprising a first plate, a first number N of power semiconductor bodies, a first number N of flexible structures and a second plate.

[0014] According to a further embodiment, the first number N of flexible structures are manufactured by additive manufacturing. Thus, the first number N of flexible structures are implemented as a first number N of additively manufactured flexible structures.

[0015] Advantageously, the first number N of flexible structures allows pressure to be applied from the second plate to the first number N of power semiconductor bodies both in the case of small power semiconductor bodies and in the case of large power semiconductor bodies.

[0016] In one example, the flexible structures are realized as deformable structures. Thus, the first number N of flexible structures are manufactured as the first number N of deformable structures.

[0017] Parts, such as flexible structures, created by additive manufacturing can be distinguished from parts made by other techniques, such as metalworking (e.g., milling, turning, threading, grinding, machining, welding, brazing, wire drawing, etc.), and injection molding. Parts made by additive manufacturing can be recognized by checking the internal structure of the part and / or the surface of the part. Parts made by additive manufacturing typically have a higher degree of roughness of the surface, and an internal structure with cavities or porosity that can be seen using an optical or electron microscope (e.g., looking at the surface or cross section of the part).

[0018] In one example, exactly one flexible structure of the first number N of flexible structures is arranged between one of the first number N of power semiconductor bodies and the second plate. The flexible structure comprises or consists of a number P of parts. The number P is less than 10 or less than 5. The number P is for example 1 or 2. A flexible structure realized by additive manufacturing is therefore assembled from much fewer parts compared to a flexible structure that is not produced by additive manufacturing but is formed by many individual parts assembled together.

[0019] The above-mentioned method for manufacturing a power module and the method for manufacturing a flexible structure are exemplarily suitable for a power module, and therefore the features and advantages described in relation to the power module can be used for the method for manufacturing a power module and the method for manufacturing a flexible structure, and vice versa.

[0020] In one example, the first number N of flexible structures are 3D printed parts. The first number N of flexible structures are, for example, printed directly onto a plate, such as onto a second plate, as a single part unit. Advantageously, many small parts can be avoided that are later assembled together.

[0021] According to a further embodiment, the power module incorporates a flexible structure realized as a 3D printed press pin. The power module may be implemented as a pressure contact power module. The 3D printed press pin realizes a 3D printed height compensator.

[0022] According to further embodiments, the device comprises series-connected modules, for example with fault tolerance, for example in high voltage direct current applications (HVDC applications for short) or in flexible AC transmission systems (FACTS for short). The power module comprises press pins with height compensation made possible by additive manufacturing, which may be called 3D printing. Advantageously, the power module can be manufactured at low cost. The power module is implemented as a high current power module with SiC chips. The power module also realizes a rigid pressure contact for high currents, for example with a robust package for HVDC applications with small SiC chips. The proposed springs of the power module can be scaled down to fit the small SiC chips. The cost of the proposed power module can be reduced due to the low number of parts and the low number of assembly processes.

[0023] According to further embodiments, the second plate can be implemented as a top emitter plate or a top emitter / source plate. The 3D printed height compensator allows for a single-piece spring array (e.g., Inconel 718 or high-strength Cu alloy) directly above the second plate (or preform) with precise alignment to the chip location. The second plate or metal preform can be realized with a 3D printed spring structure for uniform pressure distribution and can close the arcing gap after chip failure, for example with short circuit failure mode capability, SCFM for short. This increases the power cycling capability or product life. The second plate supports or carries an array of 3D printed springs aligned to the SiC chip location. Alternatively, a top metal preform is attached to the 3D printed height compensator for each individual SiC chip. The power module can be implemented as a bipolar and / or metal oxide semiconductor module (bipolar / MOS module for short). The power semiconductor body is manufactured, for example, as an insulated gate bipolar transistor, IGBT for short.

[0024] The present disclosure includes several embodiments of power modules and methods for manufacturing the power modules. All features described with respect to one of the embodiments are also disclosed herein with respect to the other embodiments, even if the respective feature is not explicitly mentioned in the context of a particular embodiment.

[0025] The accompanying drawings are included to provide a further understanding. In the drawings, elements of the same structure and / or function may be referenced by the same reference numerals. It should be understood that the embodiments shown in the drawings are illustrative representations and are not necessarily drawn to scale. [Brief description of the drawings]

[0026] [Figure 1] 1A-1D are cross-sectional views of a power module according to different embodiments; [Diagram 2] 1A-1D are cross-sectional views of a power module according to different embodiments; [Diagram 3] 1A-1D are cross-sectional views of a power module according to different embodiments; [Figure 4] 1A-1D are cross-sectional views of a power module according to different embodiments; [Figure 5A] 1 shows a flexible structure according to different embodiments; [Figure 5B] 1 shows a flexible structure according to different embodiments; [Figure 6] 1 is a cross-sectional view of an apparatus according to one embodiment. [Figure 7A] 1A-1D illustrate a method for making a power module according to different embodiments. [Figure 7B] 1A-1D illustrate a method for making a power module according to different embodiments. [Figure 7C] 1A-1D illustrate a method for making a power module according to different embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] FIG. 1 shows a cross-sectional view of a power module 10 according to an embodiment. The power module 10 comprises a first plate 11 and a second plate 12, and a first number N of power semiconductor bodies 13-18. The first plate 11 can be referred to as a base plate. The second plate 12 can be referred to as an upper emitter plate or an emitter plate. Moreover, the power module 10 comprises a first number N of flexible structures 23-28. In FIG. 1, the power module 10 is shown before a stack is formed. After the stack is formed, the first number N of power semiconductor bodies 13-18 are attached to the first plate 11, the first number N of flexible structures 23-28 are attached to the first number N of power semiconductor bodies 13-18, and the second plate 12 is attached to the first number N of flexible structures 23-28. The stack of power modules 10 has the following order: first plate 11 / first number N of power semiconductor bodies 13-18 / first number N of flexible structures 23-28 / second plate 12.

[0028] The power semiconductor body 13 has a first surface 19 and a second surface 20. The first surface 19 of the power semiconductor body 13 is oriented towards the second plate 12, whereas the second surface 20 of the power semiconductor body 13 is oriented towards the first plate 11. The first plate 11 is made from a homogeneous material, for example a metal such as copper or molybdenum. The second plate 12 is made from a homogeneous material, for example a metal such as copper or molybdenum.

[0029] The first number N of flexible structures 23-28 have, for example, a cylindrical shape. The first number N of flexible structures 23-28 are manufactured as porous or hollow structures by additive manufacturing. The first number N of flexible structures 23-28 are manufactured by additive manufacturing on the second plate 12. The first number N of flexible structures 23-28 are manufactured by additive manufacturing using a conductive material, for example a metal or a metal alloy. The metal alloy is, for example, a Cu alloy, for example a CuNiSi alloy. The first number N of flexible structures 23-28 thus realize both a spring function and an electrical function.

[0030] The first number N of power semiconductor bodies 13-18 are manufactured using silicon or a wide band gap semiconductor, for example silicon carbide, SiC for short, as a substrate. The area of ​​one of the first number N of semiconductor bodies 13-18 is 100 mm 2 Less than or equal to 50 mm 2 Less than or 25mm 2 The power semiconductor body 13 can be referred to as a power semiconductor device or a power semiconductor chip. For example, one of the first number N of flexible structures 23-28 is porous or hollow or has some microstructure that allows flexibility in the direction from the first plate 11 to the second plate 12.

[0031] In the example shown in FIG. 1, the first number N of flexible structures 23-28 are attached to the second plate 12 before forming the stack. Thus, the first number N of flexible structures 23-28 are manufactured on the second plate 12. Also, before forming the stack or in one of the first processes for forming the stack, the first number N of power semiconductor bodies 13-18 are attached to the first plate 11, for example by means of a material not shown, such as an adhesive or a solder. The first number N of flexible structures 23-28 are, for example, attached to or oriented towards the center of the first surfaces 19 of the first number N of power semiconductor bodies 13-18.

[0032] Advantageously, the first number N of flexible structures 23-28 are configured to compensate for height differences of the first number N of power semiconductor bodies 13-18. The height differences may be due to thickness variations of the first number N of power semiconductor bodies 13-18 and / or to thickness variations of the material fixing the first number N of power semiconductor bodies 13-18 to the first plate 11. The power module 10 is height tolerant. The first number N of flexible structures 23-28 allow for a certain movement distance.

[0033] The power module 10 achieves homogenous pressure distribution for the multi-chip. The power module 10 is designed as a high current and robust package for HVDC applications. The flexible structure 23 has a diameter that fits the power semiconductor body 13 even if the power semiconductor body 13 is small, e.g., has an area of ​​5 mm x 5 mm. As shown in FIG. 1, the power module 10 includes a 3D printed conductive spring array that realizes a first number N of flexible structures 23-28.

[0034] FIG. 2 is a cross-section of a power module 10 according to an embodiment that is a further development of the embodiment shown in FIG. 1. The power module 10 includes a first number N of conductive parts 33-38. The conductive part 33 couples one end of the flexible structure 23 to the other end of the flexible structure 23. Thus, after mounting and forming the stack, the first surface 19 of the power semiconductor body 13 is electrically connected with the second plate 12 via the conductive part 33. As a result, the first number N of conductive parts 33-38 electrically connect the first number N of semiconductor bodies 13-18 to the second plate 12. The first number N of conductive parts 33-38 are arranged in the stack and provide a conductive path from the second plate 12 to the power semiconductor bodies 13-18. The first number N of conductive parts 33-38 are made of metal, for example copper.

[0035] The first number N of flexible structures 23-28 can be made from conductive materials (as shown in FIG. 1) or from non-conductive materials (as shown in FIG. 2). The first number N of flexible structures 23-28 are manufactured by additive manufacturing using non-conductive materials. Non-conductive materials include materials that are not conductive or have a low electrical conductivity.

[0036] The first number N of flexible structures 23-28 is manufactured, for example, by using an austenitic nickel-chromium based alloy or an austenitic chromium based superalloy, for example an Inconel alloy or an Inconel alloy 718. Inconel is a trademark of Special Metals Corporation, New Hartford, New York, USA. Inconel alloys are provided by Special Metals Corporation. The first number N of flexible structures 23-28 can be made from Inconel alloys and Inconel alloy 718 by additive manufacturing. Inconel generally has a low electrical conductivity.

[0037] As shown in FIG. 2, the power module 10 includes a 3D printed spring array with additional current paths. Advantageously, additive manufacturing allows single-piece springs (e.g., Inconel 718, Cu alloy) to be placed directly on the second plate 12 (or preforms as shown below) at precise locations. The part count of the compression power module press pin is reduced. Smaller springs are possible due to smaller chip sizes (e.g., SiC or other wide bandgap semiconductors). The power module 10 results in a reduced part count (e.g., 10-20 times fewer parts) and cost of the compression power module press pin kit. Spring materials, sizes, geometries and properties can be optimized.

[0038] In one embodiment, the first number N of flexible structures 23-28 are made from a conductive material and the power module 10 includes a first number N of conductive parts 33-33. Thus, the first number N of conductive parts 33-33 provide additional electrical paths from the first number N of power semiconductor bodies 13-18 to the second plate 12.

[0039] FIG. 3 is a cross section of a power module 10 according to an embodiment that is a further development of the embodiment shown in FIG. 1 and FIG. 2. The first number N of flexible structures 23-25 ​​are realized as springs 29. Thus, each flexible structure of the first number N of flexible structures 23-25 ​​is made as a spring 29. The power module 10 additionally comprises a first number N of preforms 43-45. The first number N of preforms 43-45 are located between the first number N of power semiconductor bodies 13-15 and the first number N of flexible structures 23-25. The first number N of flexible structures 23-25 ​​are arranged on the first number N of preforms 43-45. For example, the first number N of flexible structures 23-25 ​​are made on the first number N of preforms 43-45. The first number N of preforms 43-45 are designed to fit onto the first number N of power semiconductor bodies 13-15. For example, the lateral extension of the embodiments 43-45 is smaller than the surface 19 of the power semiconductor bodies 13-15. The embodiments 43-45 may each be formed as a pedestal. The height of the embodiments 43-45 may be smaller than the height of the flexible structures 23-28.

[0040] The stack further comprises a first number N of preforms 43-45. The stack is formed such that the stack comprises a first plate 11, a first number N of power semiconductor bodies 13-15, a first number N of preforms 43-45, a first number N of flexible structures 23-25, and a second plate 12. The stack of the power module 10 has the order of the first plate 11 / the first number N of power semiconductor bodies 13-15 / the first number N of preforms 43-45 / the first number N of flexible structures 23-25 / the second plate 12.

[0041] The first number N of preforms 43-45 are made from a conductive material, such as metal. The first number N of flexible structures are manufactured on the first number N of preforms by additive manufacturing.

[0042] In FIG. 3 the power module 10 is shown before forming the stack. A first number N of power semiconductor bodies 13-18 are attached to a first plate 11. The stack is formed in such a way that a first number N of flexible structures 23-28, already attached or fabricated on a first number N of preforms 43-45, are attached to a first surface 19 of the first number N of semiconductor bodies 13-18. A second plate 12 is attached to the first number N of flexible structures 23-28. In FIG. 3 a preform 43 with 3D printed spring structures is shown. The preform 43 carries a height compensator.

[0043] In one example (e.g., when the first number N of flexible structures 23-25 ​​are formed from a non-conductive material), the first number N of conductive portions 33-35 are arranged in the stack to electrically connect the second plate 12 to the first number N of semiconductor bodies 13-15 or the first number N of preforms 43-45.

[0044] FIG. 4 is a cross-section of a power module 10 according to an embodiment that is a further development of the embodiment shown in FIGS. 1 to 3. As shown in FIG. 4, a first number N of preforms 43 to 45 are fitted to a first number N of power semiconductor bodies 13 to 15. The first number N of preforms 43 to 45 are attached to first surfaces 19 of the first number N of power semiconductor bodies 13 to 18. The first number N of flexible structures 23 to 28 are attached to the second plate 12. Thus, for example, the first number N of flexible structures 23 to 28 are fabricated on the second plate 12.

[0045] Thus, a stack is formed by attaching the second plate 12 on one side with the first number N of flexible structures 23-28 to the stack of the first number N of preforms 43-45 on the other side, the first number N of power semiconductor bodies 13-18 and the first plate 11. The second plate 12 includes bumps or ridges on which the first number N of flexible structures 23-28 are attached. In FIG. 4, the second plate 12 carries a 3D printed spring structure. The second plate 12 thus supports a height compensator. The power module 10 of FIGS. 1-4 can be mounted in a pressure-fitted power module or a pressure-fitted module in a hermetically sealed ceramic housing (not shown).

[0046] Fig. 5A is a flexible structure 23 according to an embodiment that is a further development of the above embodiment. The flexible structure 23 is realized as a spring 29. A first number N of flexible structures 23-28 are manufactured as the spring 29 by additive manufacturing. The spring 29 has the form of a group including a coil (for example as shown in Figs. 3, 4 and 5B) and a stack of spring washers 51-56 (for example as shown in Fig. 5A).

[0047] The spring 29 has the form of a stack of a second number M of spring washers 51-56. The second number M is, for example, greater than 1 or greater than 10. A single spring washer 51 is also shown in FIG. 5A. The spring washer 51 is not flat and therefore has a spring effect. The spring washer 51 can also be implemented as a Belleville washer, a cup-shaped spring washer, a conical spring washer, a Belleville washer, a curved Belleville spring, a Waver washer and / or a wave spring. The flexible structure 23 is manufactured by additive manufacturing. The spring 29 is therefore not realized from several single separate spring washers. Instead, the flexible structure 23 is made as a single piece. In FIG. 5A, a spring 29 with a rounded shape and a spring 29 with corners and edges are shown.

[0048] 5B is a cross-section of a flexible structure 23 according to an embodiment that is a further development of the above embodiment. The flexible structure 23 is realized as a coil 30. Optionally, the flexible structure 23 has a first end plate 31 configured to be attached to the second plate 12. Also, optionally, the flexible structure 23 includes a second end plate 32 configured to be connected to the first surface 19 of the power semiconductor body 13 or to the preform 43.

[0049] In Figures 5A and 5B an example of one flexible structure 23 is shown. The other flexible structures of the first number N of flexible structures 23-28 are realized like the flexible structure 23. Other designs that can be realized by additive manufacturing can be used for the production of the first number N of flexible structures 23-28.

[0050] FIG. 6 is a cross-section of a device 70 according to an embodiment that is a further development of the above embodiment. The device 70 comprises a third number L of power modules 10, 71. The power modules 10, 71 can be realized like the power module 10 shown in FIGS. 1 to 4. The further power module 71 comprises a further first plate 11' and a further second plate 12', a further number N of power semiconductor bodies 13' and a further number of flexible structures 23'. The first number N may be equal to or different from the further number. The third number L of power modules 10, 71 form a stack. The third number L is greater than 1 or greater than 4. A fixing layer 72 fixes the power module 10 to the adjacent power module 71. The fixing layer 72 may be a solder or an adhesive.

[0051] Figure 7A shows an embodiment of a method for producing a power module 10, which is a further development of the above embodiment. The method includes a first providing process 101, a second providing process 102, a placement process 103, an additive manufacturing process 104, and a stack forming process 105. In one example, the processes are performed in the order shown in Figure 7A and described above. Alternatively, the chronological order of some operations is interchanged.

[0052] In a first providing process 101, a first plate 11 is provided. In a second providing process 102, a second plate 12 is provided. In an arranging process 103, a first number N of power semiconductor bodies 13-18 are attached to the first plate 11, for example by solder or adhesive. In an additive manufacturing process 104, a first number N of flexible structures 23-28 are produced by additive manufacturing. In a stack forming process 105, a stack is formed comprising the second plate 12, the first number N of flexible structures 23-28, the first number N of power semiconductor bodies 13-18 and the first plate 11.

[0053] The additive manufacturing process 104 is for example realized such that a first number N of flexible structures 23-28 are manufactured by additive manufacturing on the second plate 12. Alternatively, the additive manufacturing process 104 is realized such that a first number N of flexible structures 23-28 are manufactured by additive manufacturing on a first number N of power semiconductor bodies 13-18.

[0054] Fig. 7B shows a further embodiment of a method for manufacturing a power module 10, which is a further development of the above-mentioned embodiment. According to Fig. 7B, the method comprises a third providing process 106. In the third providing process 106, a first number N of preforms 33-38 are provided. Furthermore, the method comprises an attaching process 107. In the attaching process 107, the first number N of preforms are attached to first surfaces of the first number N of power semiconductor bodies 13-18.

[0055] In an additive manufacturing process 104, a first number N of flexible structures 23-28 are manufactured by additive manufacturing on the second plate 12. Thus, the second plate 12 and the first number N of flexible structures 23-28 are attached to a stack comprising the first number N of preforms 43-45, the first number N of power semiconductor bodies 13-18 and the first plate 11 in a stack formation process 105, as shown in Figure 4.

[0056] Alternatively, the first number N of flexible structures 23-28 are manufactured on the first number N of preforms 43-45 as shown in Fig. 3. After these processes, a stack is formed by a stack formation process 105, in which the first number N of preforms 43-45 together with the first number N of flexible structures 23-28 are first attached to the first surfaces 19 of the first number N of power semiconductor bodies 13-18, and then the second plate 12 is attached to the first number N of flexible structures 23-28.

[0057] FIG. 7C shows another embodiment of a method for manufacturing a power module 10, which is a further development of the above embodiment. The method comprises providing a fastening process 108, in which a first number N of conductive parts 33-38 are provided and attached to the first number N of flexible structures 23-33. Further processes can be performed as described above. The method comprises providing a first number N of conductive parts arranged in a stack for connecting the second plate to the first number N of semiconductor bodies or the first number N of preforms. The first number N of conductive parts 33-38 are made by additive manufacturing or another process. The additive manufacturing is performed using different materials for the first number N of flexible structures 23-28 and the first number N of conductive parts 33-38. The first number N of flexible structures 23-28 are made, for example, by multi-metal printing, which is performed in a single step. The first number N of flexible structures 23-28 are for example fabricated using additive manufacturing as a first step and electroplating as a second step.

[0058] Optionally, the method includes arranging a third number M of power modules 10, 71 on top of each other, for example as shown in FIG.

[0059] Methods such as those shown in Figures 7A-7C can be combined. The timeline is shown in Figures 7A-7C. The timeline of the processes can be changed.

[0060] The power module 10 realizes a pressure contact power module with 3D printed springs / height compensators for homogenous pressure distribution between multiple parallel power semiconductor bodies 13-18 or chips. The power semiconductor bodies 13-18 or chips are made from wide band gap semiconductors such as Si or SiC. The springs / height compensators are 3D printed on a common second plate 12 aligned to the chip positions. Alternatively, the springs / height compensators are 3D printed on top metal preforms 43-45 (e.g. Mo, Cu, Al) and then inserted with the preforms 43-45 during assembly. The springs 29 are made, for example, from Inconel by 3D printing / additive manufacturing combined with additional conductive paths. Alternatively, the springs 29 are made from conductive high strength Cu alloys by 3D printing to achieve both mechanical and electrical functions.

[0061] While the present disclosure is susceptible to various modifications and alternative forms, details of which have been shown by way of example in the drawings and have been described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.

[0062] The embodiments shown in Figures 1-7C above represent exemplary embodiments of the improved power module and the method for manufacturing the power module. Therefore, they do not constitute an exhaustive list of all embodiments of the improved power module and the method. The actual power module and the method may differ from the illustrated embodiments, for example, in terms of arrangement, devices, processes, and layers. [Explanation of symbols]

[0063] Reference sign 10 Power Module 11,11' First plate 12,12' Second plate 13~18, 13' Power semiconductor body 19 First Surface 20 Second Surface 23~28, 23' flexible structure 29,29' Spring 30 Coil 31,32 End plate 33~38 Conductive part 43~45 Preform 51~56 Spring washer 70 equipment 71 Power Module 72 Fixed layer 101 First Delivery Process 102 Secondary Delivery Process 103 Placement Process 104 Additive Manufacturing Processes 105 Stack Formation Process 106 The third provision process 107 Installation Process 108 Fixation Process

Claims

1. A method for manufacturing a power module (10), comprising the steps of: Providing a first plate (11); Providing a second plate (12); - arranging a first number N of power semiconductor bodies (13-15) on said first plate (11); Providing a first number N of preforms (43-45); Providing a first number N of flexible structures (23-25); forming a stack comprising, in this order, the first plate (11), the first number N of power semiconductor bodies (13-15), the first number N of preforms (43-45), the first number N of flexible structures (23-25) and the second plate (12); Including, said first number N of flexible structures (23-25) being additively manufactured on said first number N of preforms (43-45); the first number N is greater than 1; the first number N of flexible structures (23-25) are configured to compensate for height differences of the first number N of power semiconductor bodies (13-15); Additively manufacturing said first number N of flexible structures (23-25) as springs (29).

2. The method of claim 1, wherein the spring (29) has the form of a coil (30) or a stack of spring washers (51-56).

3. The method according to claim 1 or 2, wherein said first number N of flexible structures (23-25) are additively manufactured as porous or hollow structures.

4. The method according to any one of claims 1 to 3, wherein said first number N of flexible structures (23-25) are additively manufactured by using a non-conductive material.

5. A method for manufacturing a power module (10), comprising: Providing a first plate (11); Providing a second plate (12); - arranging a first number N of power semiconductor bodies (13-15) on said first plate (11); Providing a first number N of preforms (43-45); Providing a first number N of flexible structures (23-25); forming a stack comprising, in this order, the first plate (11), the first number N of power semiconductor bodies (13-15), the first number N of preforms (43-45), the first number N of flexible structures (23-25) and the second plate (12); Including, said first number N of flexible structures (23-25) being additively manufactured on said first number N of preforms (43-45); the first number N is greater than 1; the first number N of flexible structures (23-25) are configured to compensate for height differences of the first number N of power semiconductor bodies (13-15); A method of additively manufacturing said first number N of flexible structures (23-25) by using an austenitic nickel-chromium based alloy.

6. The method according to any one of claims 1 to 3, wherein said first number N of flexible structures (23-25) are additively manufactured by using an electrically conductive material which is a metal or a metal alloy.

7. A method for manufacturing a power module (10), comprising: Providing a first plate (11); Providing a second plate (12); - arranging a first number N of power semiconductor bodies (13-15) on said first plate (11); Providing a first number N of preforms (43-45); Providing a first number N of flexible structures (23-25); forming a stack comprising, in this order, the first plate (11), the first number N of power semiconductor bodies (13-15), the first number N of preforms (43-45), the first number N of flexible structures (23-25) and the second plate (12); Including, said first number N of flexible structures (23-25) being additively manufactured on said first number N of preforms (43-45); the first number N is greater than 1; the first number N of flexible structures (23-25) are configured to compensate for height differences of the first number N of power semiconductor bodies (13-15); The method further comprises providing a first number N of conductive parts (33-35) arranged in the stack for connecting the second plate (12) to the first number N of power semiconductor bodies (13-15) or the first number N of preforms (43-45).

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