Semiconductor assembly having at least one semiconductor element

Abstract

The invention relates to a semiconductor component (2), in particular a power semiconductor component for a converter (50), having at least one semiconductor element (4), the at least one semiconductor element (4) being arranged in a housing (6), in particular a closed housing. In order to improve the recirculation capability of the semiconductor component (2), the invention proposes that the housing (6) is at least partially filled with a free-flowing material (30), which contains electrically insulating particles (44) and which is in direct contact with the at least one semiconductor element (4).

Description

Technical Field

[0001] The present invention relates to a semiconductor component, in particular a power semiconductor component for a converter, the semiconductor component having at least one semiconductor element.

[0002] Furthermore, the present invention also relates to a converter having at least one such semiconductor component.

[0003] In addition, the present invention relates to a method for manufacturing a semiconductor component, in particular a power semiconductor component for a converter, the semiconductor component having at least one semiconductor element.

[0004] Furthermore, the present invention also relates to the application of a free-flowing material containing electrically insulating particles for filling a semiconductor component housing. Background Art

[0005] Such semiconductor components are, for example, applied in converters. A "converter" refers, for example, to a rectifier, an inverter, a frequency converter or a DC-DC converter. Generally, such semiconductor components include a housing in which at least one semiconductor element is arranged. Such a semiconductor element can be, for example, a transistor or the like. Usually, a soft encapsulation compound, especially a silicone encapsulation compound, is provided inside the housing to protect at least one semiconductor element.

[0006] The published document WO 2022 / 033745 A1 describes a power module having at least one power unit, the power unit including at least one power semiconductor and a substrate, wherein at least one power unit is at least partially surrounded by a housing. The housing is filled with a soft encapsulation compound, especially a silicone encapsulation compound.

[0007] Environmental protection aspects have also become increasingly important in electronic development. In particular, improved recyclability has become the focus of attention. By eliminating the need for material connections (such as connections that can be produced by soldering, sintering or welding), both recyclability and repair costs are improved.

[0008] The published document EP 3 926 670 A1 describes a power semiconductor module having at least one power semiconductor element. In order to reduce the installation space required for the power semiconductor module and extend its service life, it is proposed that at least one power semiconductor element forms an electrically insulating and thermally conductive connection with a cooling element through a dielectric material layer, wherein the dielectric material layer is placed flat on the surface of the cooling element and forms a force-fitting connection with the cooling element by means of a first force acting perpendicular to the surface of the cooling element.

[0009] The published document WO 2018 / 046165 A1 describes a power module having semiconductor components that are contacted on the top and bottom, wherein the semiconductor components can be electrically contacted on the top by means of a lead frame matrix using contact pressure. Summary of the Invention

[0010] Soft encapsulation compounds are very difficult to remove, for example during the recycling process. Against this background, the object of the present invention is to improve the recyclability of semiconductor components.

[0011] According to the present invention, this object is achieved by means of a semiconductor component, in particular a power semiconductor component for a converter, having at least one semiconductor element, wherein the semiconductor element is arranged in a housing, in particular a closed housing, which housing is at least partially filled with a free-flowing material containing electrically insulating particles and in direct contact with at least one semiconductor element.

[0012] Furthermore, according to the present invention, this object is achieved by means of a converter having at least one such semiconductor component.

[0013] Additionally, according to the present invention, this object is also achieved by means of a method for manufacturing a semiconductor component, in particular a power semiconductor component for a converter, having at least one semiconductor element, wherein the at least one semiconductor element is arranged in a housing, and wherein the housing is at least partially filled with a free-flowing material containing electrically insulating particles such that the free-flowing material is in direct contact with at least one semiconductor element, and wherein, in a subsequent step, the housing is sealed.

[0014] Furthermore, according to the present invention, this object is achieved by means of the application of a free-flowing material containing electrically insulating particles for filling the housing of a semiconductor component in which at least one semiconductor element is arranged, wherein the filling is effected such that the free-flowing material is in direct contact with at least one semiconductor element.

[0015] The advantages and preferred embodiments described below for the semiconductor component can be transferred accordingly to the converter, the manufacturing method, and the application.

[0016] The present invention is based on the consideration of improving the recyclability of semiconductor components by replacing the commonly used soft encapsulation compound with a free-flowing material containing electrically insulating particles. At least one semiconductor element is arranged in the housing of the semiconductor component, and the housing is at least partially filled with the free-flowing material, so that the semiconductor element is in direct contact with the free-flowing material. In particular, the semiconductor element is at least partially surrounded by the free-flowing material. The free-flowing material can include, for example, quartz sand, carbonate sand, gypsum sand, silicate, but can also include organic flowable substances such as polymers and siloxanes. Due to its sandy structure, the free-flowing material can be removed significantly more easily, especially compared to the commonly used soft encapsulation compound. This free-flowing filler enables simple disassembly for repair, refurbishment or recycling. In addition, material- and energy-intensive manufacturing processes are saved.

[0017] Another embodiment proposes that the electrically insulating particles of the free-flowing material have a particle size in the range of 0.01 mm to 0.6 mm, especially 0.1 mm to 0.4 mm. In particular, the average particle size is in the range of 0.2 mm to 0.3 mm. Such a particle size minimizes the air gap and, for example, achieves sufficient insulation. In particular, the use of a free-flowing material with a bimodal or higher mixture can minimize the gap, which further improves the insulation effect.

[0018] Another embodiment proposes that the electrically insulating particles of the free-flowing material contain metal oxides. For example, the electrically insulating particles contain aluminum and / or titanium oxides, glass, mica and / or ceramic particles. Good insulation can be achieved by using these metal oxides. When using inorganic electrically insulating particles (such as alumina sand), enhanced explosion protection is imparted to the semiconductor component because significantly less, especially almost no, explosive gas is generated by the inorganic material, so no carbon dioxide or water is produced and it can better withstand pressure.

[0019] Another embodiment proposes that the electrically insulating particles of the free-flowing material have a sharply fractured surface, especially a serrated surface. Such a surface, especially compared to a spherical structure, results in an extended creepage distance.

[0020] Another embodiment proposes that the free-flowing material is filled with a meltable insulating material, especially wax. For this purpose, high-melting paraffin wax or other waxes, especially waxes with a melting point above 100 °C, are potential options. For example, the gaps are filled with a meltable insulating material, which infiltrates into the particle gaps when melted, expels air and hardens when cooled. This significantly increases the breakdown voltage of the module. In particular, meltable insulating materials such as wax are relatively fluid in the molten state and are easy to remove, for example, during the recycling process. In addition, paraffin wax or other waxes are biodegradable and / or reusable.

[0021] Another embodiment provides that the free-flowing material is filled with an insulating fluid. Such insulating fluids are, for example, fluorinated hydrocarbons such as 3M Novec. With this insulating fluid, a slurry can be formed, which can be simply removed during disassembly for repair, refurbishment or recycling, and the insulation effect is improved. In addition, the insulating fluid can be an electrically insulating gas that fills the gaps of the free-flowing material to achieve a higher insulation effect.

[0022] Another embodiment provides that the insulating fluid contains a phase change material, so that heat peaks can be buffered.

[0023] Another embodiment provides that a circuit carrier is arranged in the housing, wherein the semiconductor element has a force-locking connection to the circuit carrier, in particular by means of a pressure contact. Such a pressure contact can be designed, for example, as a busbar. Optionally, springs, screws and / or clamps can be used to achieve the force-locking connection of the semiconductor element. The circuit carrier can be a substrate, in particular a Direct Copper Bonded (DCB) substrate. This force-locking connection of the semiconductor element is detachable and can be easily removed during disassembly for repair, refurbishment or recycling, especially when used in combination with the free-flowing material filling.

[0024] Another embodiment provides that the housing includes a heat sink, and the circuit carrier is placed flat on the heat sink, wherein the circuit carrier has a force-locking connection to the heat sink. This force-locking connection can be achieved by squeezing between the objects and is easy to disassemble, for example, for recycling.

[0025] Another embodiment provides that the circuit carrier has a detachable and thermally conductive connection to the heat sink, in particular by means of an oil layer. This oil layer establishes a detachable connection between the circuit carrier and the heat sink and balances the roughness of the surfaces of the heat sink and the circuit carrier. In particular, the heat-conducting oil in the oil layer improves the thermal coupling effect between the circuit carrier and the heat sink.

[0026] Another embodiment provides that the semiconductor element has at least one contact on the side facing away from the circuit carrier, wherein the at least one contact is surrounded by a plastic frame, in particular a glued or pressed plastic frame. Such a plastic frame improves the insulation distance, especially for high-voltage power modules.

[0027] Another embodiment proposes that a metal contact element is arranged on at least one contact part of the semiconductor element, and the metal contact element is pressed by means of a pressure contact part to achieve a force-fitting contact with the semiconductor element. For example, the metal contact element is implemented as a small copper sheet or a small molybdenum sheet, and the metal contact element has a thickness in the range of 10 μm to 250 μm, especially in the range of 25 μm to 250 μm. The metal contact element acts as a pressure buffer to disperse pressure, such as the pressure from the pressure contact part, thereby preventing the occurrence of pressure peaks in the sensitive semiconductor element. This structure with a force-fitting connection pressure buffer is easy to disassemble, for example, for recycling. Description of the Drawings

[0028] Hereinafter, the present invention will be described and explained in more detail based on the embodiments shown in the figures.

[0029] The illustrations are as follows:

[0030] Figure 1 A schematic cross-sectional view showing a first embodiment of the semiconductor component is shown.

[0031] Figure 2 A schematic cross-sectional view showing a second embodiment of the semiconductor component is shown.

[0032] Figure 3 An enlarged schematic view showing a first embodiment of the free-flowing material is shown.

[0033] Figure 4 An enlarged schematic view showing a second embodiment of the free-flowing material is shown.

[0034] Figure 5 An enlarged schematic view showing a third embodiment of the free-flowing material is shown.

[0035] Figure 6 A schematic view of the converter is shown. Detailed Description of the Invention

[0036] The exemplary embodiments explained below are preferred implementation variants of the present invention. In these exemplary embodiments, the components of the described implementation variants each represent separate and independently considered features of the present invention, and they also each independently further improve the present invention, and thus can also be used alone or in combinations different from those shown as components of the present invention. In addition, the described embodiments can also be supplemented by other features of the present invention that have been described.

[0037] Identical reference signs in different figures have the same meaning.

[0038] Figure 1Shows a schematic cross-sectional view of a first embodiment of a semiconductor component 2 with a semiconductor element 4, wherein the semiconductor element is arranged in a closed housing 6. For example, the semiconductor element 4 is implemented as a vertical transistor, in particular as an IGBT (Insulated Gate Bipolar Transistor) or a vertical SiC-MOSFET (Silicon Carbide Metal Oxide Semiconductor Field Effect Transistor). The housing 6 includes a metal heat sink 8, a housing frame 10 with a plurality of pins 12, and a housing cover 14. The housing frame 10 and the housing cover 14 are made of plastic, for example, wherein the pins 12 are embedded or pressed into the housing frame 10. The heat sink 8 serving as the base plate is made of copper, aluminum, or their alloys, for example. The circuit carrier 16 is connected to the heat sink 8 in a planar manner. As an example, the circuit carrier 16 includes a dielectric material layer 18 that particularly contains alumina, aluminum nitride, or an organic electrical insulation and thermal conductivity material, and a metallization layer 20 that contains copper, gold, molybdenum, silver, or their alloys, for example. The dielectric material layer 18 can be connected to the heat sink by means of pressing or bonding. Optionally, the circuit carrier 16 can be implemented as a substrate, particularly as a direct copper bonding (DCB) substrate, and is welded to the heat sink 8, for example.

[0039] The semiconductor element 4 has a first power contact 22 (particularly a collector contact) and, on the opposite side, a second power contact 24 (particularly an emitter contact) and a control contact 26 (particularly a gate contact). The first power contact 22 of the semiconductor element 4 has a connection that mates with the material of the metallization layer 20 of the circuit carrier 16, for example. The material-mating connection between the semiconductor element 4 and the circuit carrier 16 can be achieved by means of welding and / or sintering, etc. The second power contact 24 and the control contact 26 located on the side of the semiconductor element 4 facing away from the circuit carrier 16 are respectively connected to the metallization layer 20 of the circuit carrier 16 through a wiring device 28, wherein the metallization layer 20 is connected to the pins 12 of the housing 6. In this way, the contacts 22, 24, 26 of the semiconductor element 4 are led out of the housing 6 and can be electrically conductively connected from the outside by means of the pins 12. The wiring device 28 is implemented as a bonding wire or a bonding tape, for example, and is connected particularly by means of ultrasonic wire bonding technology.

[0040] The housing 6 is completely filled with a free-flowing material 30, for example, which contains electrically insulating particles and is in direct contact with and partially surrounds the semiconductor element 4. The free-flowing material 30 can contain free-flowing sand, for example, which contains electrically insulating particles made of metal oxide (such as alumina). Additionally or alternatively, the free-flowing material 30 can contain other inorganic substances such as quartz sand, carbonate sand, gypsum sand, silicates, and organic flowable substances such as polymers, siloxanes. In particular, the electrically insulating particles of the free-flowing material 30 have a particle size in the range of 0.01 mm to 0.6 mm, especially in the range of 0.1 mm to 0.4 mm. The average particle size can be between 0.2 mm and 0.3 mm. In the semiconductor assembly 2, the free-flowing material 30 replaces the commonly used potting material, which is usually made of, for example, a silicon insulating material that is difficult to remove. After opening the housing 6, the free-flowing material 30 can be easily removed, enabling the components within the housing 6 to be freely recycled and repaired.

[0041] Optionally, the sand filling can be stratified or otherwise purified relative to the free-flowing material 30, where the electrically insulating particles have, for example, different densities for improved separability. The purpose of stratification can be, for example, to use a more cost-effective filling material in non-critical areas of the electric field or to achieve additional functions such as flame retardancy, arc quenching, or thermal buffering.

[0042] Figure 2 A schematic cross-sectional view of a variant of a second embodiment of the semiconductor assembly 2 is shown, where the semiconductor assembly has two semiconductor elements 4, for example, which are arranged in a closed housing 6. The housing 6 includes a metal heat sink 8, a housing frame 10, and a housing cover, which is not shown in Figure 2 for clarity. The circuit carrier 16, implemented as a DGB-substrate, for example, and having a dielectric material layer 18 with double-sided metallization 20, is placed on the heat sink 8. The heat sink has heat dissipation ribs 34 on the side facing away from the DCB-substrate. The oil layer 36 establishes a detachable and thermally conductive connection between the DCB-substrate and the heat sink. The heat-conducting oil in the oil layer 36 compensates for the surface roughness of the heat sink 8 and the circuit carrier 16, thereby improving the thermal coupling.

[0043] On the second power contact portion 24 of the semiconductor component 4, there are respectively metal contact elements 40. Additionally or alternatively, such metal contact elements 40 can be arranged between the circuit carrier 16 and the first power contact portion 22 of the semiconductor component 4. For example, the metal contact element 40 is implemented as a small copper sheet or a small molybdenum sheet, and the metal contact element has a thickness in the range of 25 μm to 250 μm. Alternatively, the metal contact element 40 can be connected to the corresponding semiconductor component 4 by material cooperation, such as by soldering or sintering. Optionally, the metal contact element 40 can be sprayed by means of a thermal spraying process, especially in the form of copper and / or molybdenum particles.

[0044] With the pressure contact portion 38, the pressure contact portion contacts the second power contact portion 24 of the semiconductor component 4 via the metal contact element 40, and the semiconductor component 4 has a force-fit and detachable connection with the metallization layer 20 of the circuit carrier 16. The pressure contact portion 38 is implemented as a bus bar in Figure 2 For example, these bus bars are made of copper or a copper alloy. Additionally or alternatively, the pressure contact portion 38 can have spring contacts. A force F perpendicular to the surface of the circuit carrier 16 is transmitted via the bus bar; this force fixes the semiconductor component 4. As Figure 1 shown, the housing 6 is filled with a free-flowing material 30, which contains electrically insulating particles, and the free-flowing material is in direct contact with the semiconductor components 4 and partially surrounds them. For example, the free-flowing material 30 contains quartz sand and / or alumina sand. Optionally, the free-flowing material 30 is completely or partially covered by a film in the area of the housing cover, and the film is pressed onto the free-flowing material 30, for example, through an elastic intermediate element (especially a polymer foam). Optionally, the elastic intermediate element is directly pressed onto the free-flowing material 30 to prevent cavities formed by the flowing of the free-flowing material. At the same time, in this way, re-compaction is achieved, the insulation effect is enhanced, and thus a positive impact on operational safety is produced.

[0045] Especially for high-voltage (HV) power modules, the second power contact portion 24 of the semiconductor component 4 is surrounded by a plastic frame 42 that is adhesively bonded or pressed, to improve the insulation distance. Optionally, the plastic frame 42 can be applied in a material-increasing manner, such as by a dispensing process or a 3D printing process. To prevent air bubbles from being generated when the free-flowing material 30 is added, for example, holes can be drilled in the pressure contact portion 38. In Figure 2 the further implementation of the semiconductor assembly 2 is in accordance with the implementation in Figure 1

[0046] Figure 3 ​Shows an enlarged schematic view of a first embodiment variant of the free-flowing material 30, which comprises sand having electrically insulating particles 44 with a spherical structure and a small particle size (ranging from 0.01 mm to 0.6 mm, in particular from 0.1 mm to 0.4 mm), which facilitates the addition of the material and reduces the likelihood of bubble formation. For example, the free-flowing material 30 comprises quartz sand, in particular fused sand. Further embodiments of the free-flowing material 30 correspond to the embodiments in Figure 1 and are in accordance with the embodiments therein.

[0047] Figure 4 Shows an enlarged schematic view of a second embodiment variant of the free-flowing material 30, which has electrically insulating particles 44 with a sharply fractured surface, ideally a serrated surface. Due to this surface characteristic, the creepage distance 46 is extended, especially compared to the spherical structure. In Figure 4 other embodiments of the free-flowing material 30 are in accordance with the embodiments in Figure 3 and are in accordance with the embodiments therein.

[0048] Figure 5 Shows an enlarged schematic view of a third embodiment variant of the free-flowing material 30, which is filled with a fusible insulating material, in particular wax. For this purpose, high-melting-point paraffin wax or other waxes with a melting point above 100 °C are options. Additionally or alternatively, the free-flowing material 30 is filled with an insulating fluid containing fluorocarbons (such as 3M Novec). The insulating fluid causes precipitate formation. The insulating fluid can be implemented as a phase change material to mitigate thermal peaks. In order to ensure improved partial discharge strength and thus extend the service life of the semiconductor component 2, the free-flowing material 30 can comprise a material with high partial discharge resistance, such as mica. In Figure 5 other embodiments of the free-flowing material 30 are in accordance with the embodiments in Figure 3 and are in accordance with the embodiments therein. Figure 5 In, at least some of the particles 44 of the free-flowing material 30 can have a sharply fractured surface, ideally a serrated surface, as shown in Figure 4 .

[0049] Figure 6 Shows a schematic view of a converter 50, which comprises a semiconductor component 2. The converter 50 can comprise a plurality of semiconductor components 2.

[0050] In summary, the present invention relates to a semiconductor component 2, in particular a power semiconductor component for a converter 50, which has at least one semiconductor element 4, wherein the at least one semiconductor element 4 is arranged in a housing 6, in particular a closed housing 6. In order to improve the recycling ability of the semiconductor component 2, the present invention proposes that the housing 6 is at least partially filled with a free-flowing material 30, which contains electrically insulating particles 44 and is in direct contact with the at least one semiconductor element 4.

Claims

1. A semiconductor component (2), in particular a power semiconductor component for a converter (50), having at least one semiconductor element (4), Among them, The at least one semiconductor element (4) is arranged in a housing (6), in particular a closed housing, wherein the housing (6) is at least partially filled with a free-flowing material (30), the free-flowing material comprising electrically insulating particles (44) and the free-flowing material being in direct contact with the at least one semiconductor element (4).

2. The semiconductor component (2) according to claim 1, Among them, The electrically insulating particles (44) of the free-flowing material (30) have a particle size in the range from 0.01 mm to 0.6 mm, in particular from 0.1 mm to 0.4 mm.

3. The semiconductor component (2) according to any one of claims 1 or 2, wherein, The electrically insulating particles (44) of the free-flowing material (30) comprise metal oxides.

4. The semiconductor component (2) according to any one of the preceding claims, Among them, The electrically insulating particles (44) of the free-flowing material (30) have a sharply fractured surface, in particular a serrated surface.

5. The semiconductor component (2) according to any one of the preceding claims, Among them, The free-flowing material (30) is filled with a fusible insulating material, in particular wax.

6. The semiconductor component (2) according to any one of claims 1 to 4, Among them, The free-flowing material (30) is filled with an insulating fluid.

7. The semiconductor component (2) according to claim 4, Among them, The insulating fluid comprises a phase change material.

8. The semiconductor component (2) according to any one of the preceding claims, Among them, A circuit carrier (16) is arranged in the housing (6), wherein the semiconductor element (4) has a force-locking connection to the circuit carrier (16), in particular by means of a pressure contact (38).

9. The semiconductor component (2) according to claim 8, Among them, The housing (6) comprises a heat sink (8), and the circuit carrier (16) is placed flat on the heat sink, wherein the circuit carrier (16) has a force-locking connection to the heat sink (8).

10. The semiconductor component (2) according to claim 9, Among them, The circuit carrier (16) has a detachable and thermally conductive connection to the heat sink (8), in particular by means of an oil layer (36).

11. The semiconductor component (2) according to any one of claims 8 to 10, Among them, The semiconductor element (4) has at least one contact (22, 24, 26) on the side facing away from the circuit carrier (16), wherein the at least one contact (22, 24, 26) is surrounded by a plastic frame (42), in particular a glued or pressed plastic frame (42).

12. The semiconductor component (2) according to claim 11, Among them, A metal contact element (40) is arranged on the at least one contact (22, 24, 26) of the semiconductor element (4), and the metal contact element is pressed by means of a pressure contact (38) to achieve a force-locking contact with the semiconductor element (4).

13. A converter (50) having at least one semiconductor component (2) according to any one of the preceding claims.

14. A method for manufacturing a semiconductor component (2), in particular a power semiconductor component for a converter (50), the semiconductor component having at least one semiconductor element (4), Among them, wherein the at least one semiconductor element (4) is arranged in a housing (6), wherein the housing (6) is at least partially filled with a free-flowing material (30) containing electrically insulating particles such that the free-flowing material (30) is in direct contact with the at least one semiconductor element (4), wherein the housing (6) is closed in an additional step.

15. The method according to claim 14, Among them, wherein the free-flowing material (30) is filled with a fusible insulating material, in particular wax.

16. The method according to claim 14, Among them, wherein the free-flowing material (30) is filled with an insulating fluid.

17. An application of a free-flowing material (30) containing electrically insulating particles for filling a housing (6) of a semiconductor component (2) in which at least one semiconductor element (4) is arranged, Among them, wherein the filling is effected such that the free-flowing material (30) is in direct contact with the at least one semiconductor element (4).

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