DE102023131882A1 - Cooling arrangement, electronic assembly, electrical power converter and method for assembling the same - Google Patents

Abstract

Cooling arrangement (7) for cooling an electrical unit (10), wherein the cooling arrangement comprises: a heat sink (5), a substrate (6), wherein the heat sink comprises: a cooling channel (35) through which coolant can flow in a predetermined flow direction, a cooling wall (50) on the side of the cooling channel facing the electrical unit (10) to be cooled, wherein the substrate is positively connected to the heat sink on the cooling wall and is designed such that the electrical unit can be mechanically firmly connected on its side facing away from the heat sink, wherein the cooling arrangement is designed such that, during operation, the coolant is guided through the cooling channel at a predetermined operating pressure which is above the ambient pressure applied to the substrate on the side of the electrical unit to be cooled, and wherein a distance (D) between the cooling channel (35) and the cooling wall (50) is selected to be so small that the heat sink cannot ensure sufficient dimensional stability and/or tightness at the predetermined operating pressure without the substrate positively connected to it, and the substrate and its The positive connection with the heat sink on the cooling wall is designed such that the cooling arrangement can ensure this sufficient dimensional stability and tightness, and the heat sink is of monolithic construction. Also disclosed are an electronic assembly with such a cooling arrangement, an electrical power converter with such an electronic assembly, and methods for assembling these devices.

Description

Field of the invention

The invention relates to a cooling arrangement for cooling an electrical unit, an electronic assembly, and an electrical power converter for an industrial process arrangement, preferably a plasma process arrangement or heating arrangement. Furthermore, the invention relates to a method for assembling such a cooling arrangement, electronic assembly, and such an electrical power converter.

The invention lies in the field of electrical power conversion for special power-intensive industrial processes prone to instability, such as plasma excitation, plasma coating processes, gas laser excitation, particle accelerators, charging and discharging devices for large batteries, such as flow batteries, melting of solids, heating and/or gasification of liquid substances using, for example, microwave energy or induction heating, or plasma torches. This can be a process for generating radiation, e.g. microwave radiation, X-rays or particle accelerators. What all these processes have in common is that they are designed to generate and accelerate charged atomic particles in a gas and/or plasma environment or liquid. What all these processes also have in common is that they have a high power consumption in the range of 1 kW or more, in particular 10 kW or more, preferably 100 kW or more. For the stated power range, frequencies ≥ 20 kHz, preferably ≥ 200 kHz, in particular ≥ 2 MHz, are generated internally or for external applications. Many of these processes also have very high requirements for the stability of the power supply because the processes are highly complex, such as semiconductor production using plasma processes and/or heating by electromagnetic fields. Typically, this involves converting power from a mains frequency in the range of approximately 50 Hz to 60 Hz to different frequencies that can be in the above-mentioned range. Conversion to direct current power, also known as DC power, is also conceivable. Even when converting to direct current power, a frequency in the above-mentioned range is often generated internally for the power signal, which is then rectified again according to the voltage, current and power requirements. This conversion of electrical power into other frequencies requires a large number of electronic components and assemblies, in particular power semiconductor components such as transistors or diodes, in particular PIN diodes, for example for switching RF power between different paths, designed for currents ≥ 10 A and voltages ≥ 400 V. These electronic components and assemblies generate heat losses during operation. The heat losses often arise in a very limited area of just a few mm ² , e.g. ≤ 8 mm ² . It is particularly challenging to dissipate this heat losses in order to protect the components and/or assemblies from destruction through overheating. Very large and material-intensive heat sinks are often provided for this purpose, and these are very expensive to manufacture.

In the prior art, the heat is dissipated by cooling using a cooling plate. When cooling with such a conventional cooling plate, the heat transfer from the electrical component, which may have a copper layer, to the cooling medium is achieved by applying a material such as thermal paste to the heat interface between two different materials, thereby dissipating the generated heat. However, such thermal interface material proves to be disadvantageous. On the one hand, it represents an additional heat transfer with thermal resistance, and on the other hand, it is subject to wear, which gradually deteriorates its effectiveness during operation. The surface area of the cooling plate is also increased, or the number and performance of the components are reduced in order to dissipate a greater amount of heat. Both options prove to be insufficient. Since the installation space in the housing of such a power supply is limited, expanding the cooling surface is not unlimited. Reducing the performance of the individual components is also not effective. Overall, inadequate cooling of the electrical components results in costs.

A particularly demanding area can be a process for plasma excitation, especially plasma processing, such as coating, e.g., PVD, CVD, or etching. Such processes are used in the manufacture of semiconductors such as microprocessor components and/or memory chips. Here, the requirements for reliability, durability, and process repeatability are particularly high. At the same time, the required power levels are also very high. Furthermore, the required output modulations, e.g., in modern electrical power converters with an RF amplifier array or pulsed high-voltage power supplies with pulse shaping, have recently increased steadily. One requirement for an RF amplifier array may, for example, be the ability to be pulsed with several different power levels, which is called multi-level pulsing (MLP). Another requirement for an RF amplifier array may, for example, be the ability to be frequency-adjustable, thus enabling rapid response to load changes. to be able to do what is called auto-frequency tuning (AFT). A further requirement can be, for example, the ability to provide a very high DC voltage, e.g. greater than or equal to 2 kV, in particular greater than or equal to 7 kV, in pulsed form, with pulse frequencies greater than or equal to 1 kHz, in particular greater than or equal to 10 kHz, particularly preferably greater than or equal to 200 kHz. With all of these requirements, the demands on power semiconductor components that are installed in the RF amplifier arrangement and used to generate the RF power also increase. In particular, the demand on these components to convert power that cannot be delivered to the load in certain conditions into heat also increases. These losses that are converted into heat can be ≥ 500 W, in particular ≥ 1 kW in some applications. This heat must be dissipated by the power semiconductor components, as otherwise they will be destroyed by overheating.

It is an object of the invention to provide a cooling arrangement, an electronic assembly and an electrical power converter in which an improved thermal coupling between the heat sink and an electrical unit to be cooled is made possible.

1. a) einen Kühlkörper,
2. b) ein Substrat,
3. c) wobei der Kühlkörper aufweist:
   • i) einen Kühlkanal, der in einer vorgesehenen Flussrichtung von Kühlmittel, insbesondere Kühlflüssigkeit, bevorzugt Kühlwasser, durchströmbar ist,
   • ii) eine Kühlwand an der der zu kühlenden elektrischen Einheit zugewandten Seite des Kühlkanals,
   • iii) und insbesondere auch eine Kühlmittelzuführung und eine Kühlmittelabführung, die beide mit dem Kühlkanal fluidisch verbunden sind, zur Zu- und Abführung des Kühlmittels,
4. d) wobei das Substrat formschlüssig mit dem Kühlkörper an der Kühlwand verbunden ist, und ausgelegt ist, dass auf seiner dem Kühlkörper abgewandten Seite die elektrische Einheit mechanisch fest verbunden werden kann,
5. e) wobei die Kühlanordnung ausgelegt ist, dass im Betrieb das Kühlmittel mit einem vorgegebenem Betriebsdruck, der über dem Umgebungsdruck liegt, der am Substrat auf der Seite der zu kühlenden elektrischen Einheit anliegt, durch den Kühlkanal geführt wird, und wobei
6. f) ein Abstand zwischen Kühlkanal und Kühlwand so klein gewählt ist, dass der Kühlkörper ohne das formschlüssig mit ihm verbundene Substrat bei dem vorgegebenen Betriebsdruck keine ausreichende Form-Stabilität und/oder Dichtheit sicherstellen kann, und
7. g) das Substrat und dessen formschlüssige Verbindung mit dem Kühlkörper an der Kühlwand so ausgelegt ist, dass die Kühlanordnung diese ausreichende Form-Stabilität und Dichtheit sicherstellen kann, und
8. h) der Kühlkörper monolithisch aufgebaut ist.

The stated object is achieved by a cooling arrangement according to claim 1. Preferred embodiments are disclosed in the description and in the dependent claims. The cooling arrangement is designed for cooling an electrical unit to be cooled, preferably a semiconductor device, wherein the cooling arrangement comprises:

1. a) a heat sink,
2. b) a substrate,
3. c) wherein the heat sink comprises:
   • i) a cooling channel through which coolant, in particular cooling liquid, preferably cooling water, can flow in a predetermined flow direction,
   • ii) a cooling wall on the side of the cooling channel facing the electrical unit to be cooled,
   • iii) and in particular also a coolant supply and a coolant discharge, both of which are fluidically connected to the cooling channel, for supplying and discharging the coolant,
4. d) wherein the substrate is positively connected to the heat sink on the cooling wall and is designed so that the electrical unit can be mechanically firmly connected on its side facing away from the heat sink,
5. e) wherein the cooling arrangement is designed such that, during operation, the coolant is guided through the cooling channel at a predetermined operating pressure which is above the ambient pressure applied to the substrate on the side of the electrical unit to be cooled, and wherein
6. f) a distance between the cooling channel and the cooling wall is chosen so small that the heat sink cannot ensure sufficient dimensional stability and/or tightness at the specified operating pressure without the substrate positively connected to it, and
7. g) the substrate and its positive connection with the heat sink on the cooling wall is designed in such a way that the cooling arrangement can ensure this sufficient dimensional stability and tightness, and
8. h) the heat sink is monolithic.

The distance between the cooling channel and the cooling wall is the shortest distance between the cooling wall and the inside of the cooling channel.

"Monolithic" construction here means "constructed from a homogeneous material." This can mean "constructed from a single element," e.g., copper or aluminum. However, this is not mandatory. It can also mean a metal alloy, i.e., a metal containing other metals or other elements. There are different processes for constructing a heat sink with cooling channels monolithically. This can be done, for example, by an additive manufacturing process, as is the case in EP1672690B1 : “micro heat sink”. The now more common term: “additive manufacturing process” is described there using the method of selective laser melting. However, “additive manufacturing process” can also include processes other than selective laser melting. It is characterized by the fact that the structure is applied gradually from the same material. The material can be melted during application. Lasers are currently suitable for this purpose in order to achieve particularly fine structures. For a heat sink made of copper, special lasers are required which have not been available on the market for very long. Also, at the time of development, there was a lack of experience with additively manufactured copper heat sinks and their properties for use in power converters.

An alternative manufacturing method for a monolithic heat sink is DE4315580A1 in which individual metal foils are at least partially structured by laser processing and/or punching and/or manufactured by electroplating processes and then Such a process is referred to as a “metal layer joining process”.

The structuring or manufacturing is preferably carried out in such a way that, after the layers have been joined together, closed channels are created through which a cooling medium can flow. The metal foils are preferably bonded together using a bonding process under high pressure and at high temperatures. For this purpose, oxide layers, for example, can be formed on the surfaces of the copper layers, which are then welded together, with the temperature preferably being selected high enough that the oxide layers melt but the metal foils do not. In this way, the metal foils bond to form a monolithic heat sink. If the metal foils are made of copper, for example, this is also referred to as "direct copper bonding," abbreviated to "DCB."

The metal foils preferably have a thickness of 0.4 mm or less, in particular 0.25 mm or less.

This allows for very effective heat dissipation.

The gap between the cooling channel and the cooling wall can also be realized with such a film. It can therefore have a thickness of 0.4 mm or less, in particular 0.25 mm or less.

This allows for particularly effective heat dissipation.

Preferably, all layers, i.e. both the substrate with the metal foil and metal foils are bonded together in one process.

This is particularly preferably done on both sides of the substrate.

The heat sink is preferably made of copper. Copper exhibits very good thermal and electrical conductivity. Disadvantages include the high cost, especially in additive manufacturing, the weight, and the diffusion of copper into the environment. However, these disadvantages can be overcome or offset by the fact that this heat sink arrangement can dissipate heat from the electrical unit much more effectively than all known heat sink arrangements. This allows it to have a volume more than three times smaller than conventional heat sink arrangements. This more than offsets the manufacturing costs.

A cooling channel structure is advantageous because it allows the cooling to be directed specifically to the areas of the heat sink that require particular cooling.

There are several ways to design the substrate and its positive connection to the heat sink on the cooling wall so that the cooling arrangement can ensure sufficient dimensional stability and tightness. The substrate can have a certain minimum thickness throughout. The substrate can be made thicker in places where the distance between the cooling channel and the substrate is particularly small, to ensure stability only there. However, the dimensional stability of the substrate is only one parameter. The strength of the positive connection between the substrate and the heat sink is also important. The more stable this can be designed, the thinner the substrate can be.

This characteristic: "designing the substrate and its positive connection to the heat sink on the cooling wall so that the cooling arrangement can ensure sufficient dimensional stability and tightness" is also easy to determine. Typical operating pressures of the coolant are known. They can, for example, be in the range of 3 bar to 5 bar.

To determine feature g), such an operating pressure can be applied to the cooling arrangement with the heat sink and substrate, and it can be checked whether the cooling arrangement remains tight and dimensionally stable. To determine feature f), the substrate can be removed from the heat sink, e.g., ground down, and then checked to see whether the heat sink changes shape or is or becomes leaky at the specified operating pressure.

1. a) der Kühlkanal dadurch gekennzeichnet, dass sein Querschnitt zumindest abschnittsweise eine geometrische Form aufweist, deren Breite, gemessen parallel zur Kühlwand, sich in Richtung der Kühlwand vermindert; und wobei
2. b) die geometrische Form des Querschnitts an der Kühlwand einen Abstand zum Substrat aufweist, der so ausgelegt ist, dass bei dem vorgegebenen Betriebsdruck des Kühlmittels der Kühlkörper ohne das formschlüssig mit ihm verbundene Substrat keine ausreichende Form-Stabilität und/oder Dichtheit sicherstellen kann.

In another aspect of the cooling arrangement,

1. a) the cooling channel is characterized in that its cross-section has, at least in sections, a geometric shape whose width, measured parallel to the cooling wall, decreases in the direction of the cooling wall; and wherein
2. b) the geometric shape of the cross-section on the cooling wall has a distance from the substrate which is designed in such a way that at the specified operating pressure of the coolant, the heat sink cannot ensure sufficient dimensional stability and/or tightness without the substrate being positively connected to it.

This allows the heat to be dissipated from the element to be cooled particularly effectively.

The narrowing width of the geometric shape toward the cooling wall provides two advantages. First, the coolant can be directed very close to the substrate, allowing for improved heat dissipation from the substrate. Second, sufficient heat sink material is directed to the substrate, allowing the heat to be effectively conducted to the other walls of the cooling channel. The heat sink material, such as copper, advantageously exhibits particularly good thermal conductivity.

This allows for particularly effective heat dissipation.

In a further aspect of the cooling arrangement, the heat sink is at least partially manufactured by means of an additive manufacturing process, in particular by means of selective laser melting, also called “selective laser melting” or “SLM” for short.

With a heat sink manufactured in this way, the heat dissipation of the element to be cooled can be carried out particularly effectively.

In a further aspect of the cooling arrangement, the heat sink is at least partially manufactured by means of a metal layer bonding process, in particular a DCB process.

With a heat sink manufactured in this way, the heat dissipation of the element to be cooled can be carried out particularly effectively.

• - eine Kühlmittelzuführung und eine Kühlmittelabführung, die beide mit dem Kühlkanal fluidisch verbunden sind, zur Zu- und Abführung des Kühlmittels an eine Kühleinheit, an der der Kühlkörper befestigbar ist, und wobei bei Befestigung eine erste fluidische Verbindung zwischen der Kühlmittelzuführung des Kühlkörpers und dem ersten Fluidport der Kühleinheit sowie insbesondere zusätzlich eine zweite fluidische Verbindung zwischen der Kühlmittelabführung des Kühlkörpers und dem zweiten Fluidport der Kühleinheit ausbildbar ist.

In a further aspect of the cooling arrangement, the heat sink comprises:

• - a coolant supply and a coolant outlet, both of which are fluidically connected to the cooling channel, for supplying and discharging the coolant to a cooling unit to which the heat sink can be fastened, and wherein, upon fastening, a first fluidic connection can be formed between the coolant supply of the heat sink and the first fluid port of the cooling unit and, in particular, additionally a second fluidic connection can be formed between the coolant outlet of the heat sink and the second fluid port of the cooling unit.

As will be explained in more detail later, this has advantages when connecting and installing the electrical unit to be cooled.

The stated object is also achieved by an electronic assembly comprising a cooling arrangement as described above and below and an electrical unit to be cooled, preferably a semiconductor arrangement, particularly preferably one or more power transistors, such as IGBTs or MOSFETs, which is mechanically firmly connected to the substrate. The electrical unit has at least one metal conductor structure that is positively connected to the substrate. The electrical unit further has at least one bare-die semiconductor component that is mechanically firmly attached to the conductor structure, in particular by soldering.

"Bare die" semiconductor components refer to "bare dies," also called "bare chips," "die," or "chips." These are integrated electronic components that are not conventionally housed in a plastic or ceramic package, but are processed without a housing. They are applied directly to the conductor structure of the substrate and can be electrically connected to surrounding components or conductor structures using bonding, e.g., wire bonding.

"Bonding" here refers to the connection of bare dies to other components or conductor structures. "Wire bonding" refers to a process step in which the terminals of a bare die are connected to the electrical terminals of other components or conductor structures using a thin wire, also called bonding wire. In contrast, the process of soldering the rear contacts of a bare die without wire is referred to as "chip bonding." Possible bare die semiconductor components can include: transistors, e.g., IGBTs, MOSFETs, especially LDMOS transistors; diodes, especially Schottky diodes; PIN diodes; LEDs; laser diodes; and control or driver circuits for the aforementioned components.

Connection pins can also be provided on the conductor structure. These can be connected to the conductor structure, for example, by ultrasonic bonding. Since bare-die semiconductor components can be designed very thin, they are also referred to here as a bare-die layer.

In one aspect of the electronic assembly, the electrical unit is connected to the substrate by at least one of the following: at least one solder joint, at least one weld joint, or sintering. This allows the thermal resistance to be reduced and cooling to be even more effective.

In one aspect of the electronic assembly, it includes a printed circuit board to which the electrical unit has a solid mechanical connection. This allows the assembly to be constructed even more compactly, thus enabling even more effective heat dissipation.

• - eine Elektronikbaugruppe, wie zuvor und nachfolgend beschrieben,

wobei der Kühlkörper eingerichtet ist zur Entwärmung der zu kühlenden elektrischen Einheit, bevorzugt einer Halbleiteranordnung, wobei der Kühlkörper lösbar an einer einen ersten Fluidport umfassenden Kühleinheit befestigt ist. Darüber hinaus ist der Kühlkörper lösbar an einer einen ersten Fluidport und insbesondere zusätzlich einen zweiten Fluidport umfassenden Kühleinheit befestigt. Bei Befestigung des Kühlkörpers an der Kühleinheit ist eine erste fluidische Verbindung zwischen der Kühlmittelzuführung des Kühlkörpers und dem ersten Fluidport der Kühleinheit sowie insbesondere zusätzlich eine zweite fluidische Verbindung zwischen der Kühlmittelabführung des Kühlkörpers und dem zweiten Fluidport der Kühleinheit ausgebildet. Der Kühlkörper ist vorzugsweise weiter derart ausgestaltet, dass bei Befestigung des Kühlkörpers an der Kühleinheit zugleich eine fluiddichte Abdichtung der ersten fluidischen Verbindung und insbesondere auch der zweiten fluidischen Verbindung erfolgt.The solution to the problem is also achieved by an electrical power converter for an industrial process arrangement, preferably a plasma process arrangement or heating arrangement, comprising:

• - an electronic assembly as described above and below,

wherein the heat sink is configured to dissipate heat from the electrical unit to be cooled, preferably a semiconductor device, wherein the heat sink is detachably attached to a cooling unit comprising a first fluid port. Furthermore, the heat sink is detachably attached to a cooling unit comprising a first fluid port and, in particular, additionally a second fluid port. When the heat sink is attached to the cooling unit, a first fluidic connection is formed between the coolant supply of the heat sink and the first fluid port of the cooling unit, and, in particular, an additional second fluidic connection is formed between the coolant discharge of the heat sink and the second fluid port of the cooling unit. The heat sink is preferably further configured such that, when the heat sink is attached to the cooling unit, a fluid-tight seal is simultaneously formed between the first fluidic connection and, in particular, also between the second fluidic connection.

The heat sink enables detachable fastening of the cooling arrangement in a cooling unit. The cooling unit is designed to supply coolant to the heat sink and to discharge coolant. The heat sink can, for example, be configured such that, when the heat sink is fastened in the cooling unit, fluid-tight fluidic connections can be formed between the heat sink and the cooling unit. It is possible to remove the cooling arrangement, together with the electrical unit to be cooled, which is attached to the cooling arrangement, from the cooling unit as needed. This is advantageous, in particular from the point of view of maintenance and repair. According to the embodiments of the development, the electrical unit could, for example, be removed from the cooling unit together with the cooling arrangement.

The electrical power converter can be designed, in particular, to generate an RF output power. RF output power here refers to an output power in the range of 1 kW or more, in particular 10 kW or more, preferably 100 kW or more, at frequencies ≥ 20 kHz, preferably ≥ 200 kHz, in particular ≥ 2 MHz.

As mentioned at the beginning, such a power converter is particularly dependent on very powerful and reliable cooling, which can be achieved particularly well with such a cooling arrangement.

In EP3317966B1 An arrangement with a printed circuit board for cooling on a metallic cooling plate is described. The printed circuit board has a bottom layer, with the bottom layer being a metallic layer that serves as a reference ground. However, the heat transfer from the printed circuit board to the cooling plate is not optimal. The printed circuit board often does not lie flat on the cooling plate. To counteract the lack of heat transfer caused by this disadvantage, thermal paste is used. However, this is disadvantageous in the manufacturing process and can age, which can further deteriorate the heat transfer. This disadvantage has been overcome through development.

In one aspect of the development, the semiconductor arrangement comprises two power semiconductor components, in particular transistors, each having a first and a second power terminal and a control terminal. Both power semiconductor components, in particular transistors, are connected by one of their power terminals to form a series circuit, with a direct current or direct voltage being connected to the remaining power terminals. This can be done, for example, directly or via a filter or an inductor. Control electronics can also be provided, which are connected to the control terminals of the power semiconductor components, and the control electronics are designed to control the power semiconductor components, in particular transistors, such that they can generate RF power, for example by switching the transistors from a first conducting state to a second conducting state, wherein the conductivity of the two states is different. Such an arrangement can be operated very efficiently, e.g., in Class D, Class F, or Class F-1 operation. Such operation generates less power loss than, for example, Class A or Class B operation. In combination with the very good cooling by means of the described power electronic unit, an even further improved supply of the industrial processes can be achieved, for example by allowing them to be operated at higher power.

In one aspect, the two power semiconductor components, in particular transistors, can each be connected by their first power terminal to a common connection point, in particular a ground connection point, wherein the power semiconductor components, in particular transistors, are in particular of the same design and are arranged on the multilayer printed circuit board. Cooling can thus be further improved. sert and the performance yield can be further increased.

In one aspect, one of the two power semiconductor components, in particular transistors, can be connected by its first power terminal to the other power semiconductor component, in particular transistor, with its second power terminal at a common connection point. The power semiconductor components, in particular transistors, are particularly similarly designed and arranged on the multilayer printed circuit board. This allows cooling to be further improved and power efficiency to be further increased.

In one aspect, a power transformer with a primary winding and a secondary winding can be arranged on the circuit board, wherein the primary winding is connected to the at least one power terminal of the power semiconductor components, in particular transistors. The primary winding and the secondary winding of the power transformer can each be designed as planar conductor tracks arranged in different layers of the circuit board. The circuit board can have a thermal connection to the cooling unit. This allows cooling to be further improved and the power output to be further increased.

In one aspect, the thermal connection to the cooling unit may comprise a thermally conductive compensation layer, the first surface of which is firmly connected to the first surface of the circuit board. Furthermore, the thermal connection may alternatively or additionally comprise a connection layer, the first surface of which is firmly connected to the second surface of the thermally conductive compensation layer, and the second surface of which is firmly connected to the cooling unit.

The cooling unit can have heat-distributing characteristics. It can be electrically conductive or insulating.

By firmly connected we mean that the connection is firm and permanent, such as gluing, welding, soldering or pressing and preferably only removable with high heat and/or mechanical pressure.

In particular, the connection can be designed with a form-fitting design. This prevents air pockets and ensures good heat conduction.

The thermally conductive leveling layer is designed to conduct heat from the circuit board toward the cooling unit. It can compensate for unevenness caused, for example, by conductor tracks, windings, or contact pads on the underside of the circuit board and provide a homogeneous and flat surface toward the cooling unit.

The thermally conductive compensating layer can consist of a prepreg or unreinforced adhesive. The insulating circuit board and the heat spreader can be joined by heating and pressing a prepreg between them. "Prepreg" is a common material name, short for "preimpregnated." This term typically refers to pre-impregnated, usually flat, sheet-like textile semi-finished products with a thermoplastic or thermosetting matrix, such as unidirectional layers of threads, fabrics, or scrims, often with perpendicularly arranged threads.

Prepregs are cured under heat and pressure to produce components. They are prefabricated, for example, in sheet form or wound on rolls. The term "prepreg" encompasses not only unidirectionally reinforced or flat semi-finished products, but also other preforms of essentially any shape, consisting, in the broadest sense, of a fiber-filled, uncured thermoset matrix. The matrix is in a partially cross-linked state and is pasty to solid, but can be liquefied again by heating.

Prepregs are machine-processable and are therefore frequently used in automated processes. They produce consistent, high-quality products. Advantages include their low undulation and high fiber volume fraction. Curing at high temperatures enables short cycle times in further processing. Processing requires significant investment, e.g., for autoclaves, placement robots, and refrigerated storage. Such prepregs are generally used to join several printed circuit boards together to form a multilayer circuit board. To ensure a secure and long-lasting joint, the materials to be joined should have very similar properties regarding their expansion when heated. However, this is not necessarily the case for the printed circuit board and the heat spreader, especially if the heat spreader is made of ceramic. This initially spoke against such a joint.

However, ceramics exhibit very good thermal conductivity and, at the same time, very good electrical insulating properties, as well as low dielectric losses when isolating high-frequency signals with high voltages. Contrary to expectations, tests have shown that, even with small dimensions, a safe and long-lasting joining of materials with different properties, such as ceramic with FR-4 and/or ceramic with PTFE material, is possible. "Small dimensions" here means a bonding area of less than 400 ^cm² and/or with a maximum length of 20 cm.

The bonding layer may comprise a resin-based adhesive. It may be thinner than the thermally conductive compensating layer.

The connecting layer may comprise an adhesive film.

Together, the two layers can form a solid connection with good heat conduction to the cooling unit.

This allows the electrical unit, for example, to be mechanically firmly connected to the cooling arrangement. One aspect of the development is to create the connection between the electrical unit to be cooled and the cooling arrangement using as few additional materials and as thinly as possible. During the considerations, simulations, and tests for this development, it became clear that this is particularly possible when the cooling arrangement, through which fluid flows, is firmly connected, in particular by a material bond, to the electrical unit to be cooled. This can be achieved, for example, by a soldered connection, sintering, pressing, or "direct copper bonding" (DCB). "Mechanically firmly connected" here can mean "can only be removed by destruction." In other words, using connection means that cannot be removed even with tools without destroying either the electrical unit to be cooled or the cooling arrangement, or both components. In this case, too, it would be possible to remove the electrical unit together with the cooling arrangement from the cooling unit, for example for maintenance purposes. By mechanically attaching the electrical unit to be cooled to the cooling arrangement, an improved thermal coupling between the electrical unit to be cooled and the heat sink and a better heat transfer from the electrical unit to be cooled to the heat sink can be achieved.

The electronic assembly, which includes the cooling arrangement and the electrical unit mechanically connected to the substrate, can, for example, be inserted into and removed from the cooling unit as a whole. This allows access to the electrical unit to be cooled.

The electrical power converter can further comprise: a cooling unit for supplying the heat sink, which has a coolant supply and a coolant discharge, with coolant, in particular coolant liquid, preferably cooling water. The cooling unit can have a first flow channel and a second flow channel. Furthermore, the cooling unit can have a first fluid port fluidically connected to the first flow channel, and in particular a second fluid port fluidically connected to the second flow channel. The cooling unit can be configured such that the cooling arrangement can be detachably fastened to the cooling unit and that, when the heat sink is fastened to the cooling unit, a first fluidic connection can be formed between the coolant supply of the heat sink and the first fluid port of the cooling unit, and a second fluidic connection can be formed between the coolant discharge of the heat sink and the second fluid port of the cooling unit. Furthermore, the heat sink can in particular be configured such that, when the heat sink is fastened to the cooling unit, a fluid-tight seal between the first fluidic connection and the second fluidic connection is simultaneously created.

The cooling unit can be designed, for example, to supply coolant to a single cooling arrangement, but it can also be designed, for example, to supply coolant to a plurality of cooling arrangements and to discharge the coolant again after flowing through the heat sinks. This creates a cooling system that allows access to the units to be cooled when needed.

The electrical power converter may comprise a cooling device comprising a cooling unit as described above and a heat sink detachably connected to the cooling unit as described above.

• - eine Leiterplatte,
• - weitere elektronische Bauteile,

wobei die weiteren elektronischen Bauteile und die elektrische Einheit auf oder an einer Leiterplatte angeordnet sind und mit elektrischen Kontakten verbunden sind.The electrical power converter may further comprise:

• - a circuit board,
• - other electronic components,

wherein the further electronic components and the electrical unit are arranged on or at a printed circuit board and are connected by electrical contacts.

Furthermore, the invention relates to a method for assembling a cooling arrangement as described above and below, wherein at least a part of the heat sink is applied to the substrate by means of metallization of the substrate, in particular by means of direct-bonded copper.

Direct-Bonded-Copper is a process used in the assembly and connection technology provides a structure that enables a tight thermal connection between electronic components via copper. This is particularly important in power electronics for improved heat dissipation. A copper foil can be bonded to the substrate, e.g., a ceramic substrate, under pressure and high temperature. Possible ceramic materials include: aluminum oxide ceramic, beryllium oxide ceramic, aluminum nitride ceramic, and sapphire.

Other metallization processes are known, for example, under the term “insulated metal substrate”.

In one aspect of the method for assembling the cooling arrangement, the heat sink can be manufactured by means of an additive manufacturing method, in particular by means of selective laser melting, also called 'SLM', in that the part of the heat sink which was applied to the substrate by means of metallization of the substrate, in particular direct-bonded copper, is further built up by means of the additive manufacturing method.

In one aspect of the method for assembling the cooling arrangement, the heat sink can be manufactured by means of a metal layer bonding method, in particular a DCB method.

In one aspect of the method for assembling the cooling arrangement, the method step of applying and producing the heat sink can be carried out in one step during the assembly of the cooling arrangement.

• - Zusammenbau einer Kühlanordnung wie zuvor und nachfolgend beschrieben,
• - formschlüssiges Verbinden einer Leiterstruktur aus Metall mit dem Substrat, und
• - mechanisch festes Anbringen zumindest eines Bare-Die-Halbleiterbausteins auf der Leiterstruktur, insbesondere durch Löten.

Furthermore, the invention relates to a method for assembling an electronic assembly, in particular an electronic assembly as described above and below, comprising the following steps:

• - Assemble a cooling arrangement as described above and below,
• - positive connection of a metal conductor structure to the substrate, and
• - mechanically fixed attachment of at least one bare-die semiconductor component to the conductor structure, in particular by soldering.

Furthermore, the invention relates to a method for assembling an electrical power converter for an industrial process arrangement, preferably a plasma process arrangement or heating arrangement, in particular as described above or below, starting from a cooling arrangement described above and below for dissipating heat from an electrical unit to be cooled, preferably a semiconductor arrangement, and a cooling unit. The heat sink has a cooling channel, a coolant supply fluidically connected to the cooling channel, and a coolant discharge fluidically connected to the cooling channel. The cooling unit comprises a first fluid port and a second fluid port. The method comprises a step of releasably attaching the cooling arrangement to the cooling unit, wherein, upon attachment of the heat sink to the cooling unit, a first fluidic connection is formed between the coolant supply of the heat sink and the first fluid port of the cooling unit, and a second fluidic connection is formed between the coolant discharge of the heat sink and the second fluid port of the cooling unit. Upon attachment of the heat sink to the cooling unit, a fluid-tight seal is simultaneously formed between the first fluidic connection and the second fluidic connection.

The electrical power converter can be used in particular for power conversion for special power-intensive industrial processes prone to instability, such as plasma excitation, plasma coating processes, gas laser excitation, particle accelerators, charging and discharging devices for large batteries, such as flow batteries, melting of solids, heating and/or gasification of liquid substances using, for example, microwave energy or induction heating. What all these processes have in common is that they are designed to generate and accelerate charged atomic particles in a gas and/or plasma environment or liquid. The electrical power converter can be designed in particular for high power consumption in the range of 1 kW or more, in particular 10 kW or more, preferably 100 kW or more. For loads of this type, very high demands exist on the stability of the power supply because the processes are highly complex, such as semiconductor production using plasma processes and/or heating by electromagnetic fields. Typically, this involves converting power from a mains frequency in the range of approximately 50 Hz to 60 Hz to different frequencies, which can range from 1 kHz to 200 MHz. Conversion to direct current power, also known as DC power, is also conceivable. This conversion of electrical power to other frequencies requires a variety of electronic components and assemblies, particularly power semiconductor devices such as transistors or diodes designed for currents ≥ 10 A and voltages ≥ 400 V. These electronic components and assemblies generate significant heat losses during operation. Efficiently dissipating this heat always presents a major challenge, one that is successfully addressed using the devices and methods described.

The electrical power converter is preferably designed to excite a plasma process, in particular a plasma process for semiconductor production.

Particularly preferably, such an electrical power converter will improve the properties of a power supply system having LDMOS transistors as the element to be cooled, as disclosed, for example, in DE 10 2013 226 537A1 , EP 3 317 964 B1 , EP3 317 965 B1 The power handling capacity of LDMOS transistors in such power supply systems often reaches its limits because they overheat, even though neither their maximum voltage nor their maximum current carrying capacity has been reached. This means that with a cooling improvement as described above and below, such power supply systems can be operated much more reliably.

Particularly preferably, such an electrical power converter will improve the properties of a power supply system that provides very high voltages at its output, in particular voltages greater than or equal to 1 kV, particularly preferably greater than or equal to 2 kV, in particular greater than or equal to 4 kV. This is particularly preferred if these are also provided in pulsed form, as in, for example, EP 4 235 737 A1 as a “high power generator.” Since the switching elements described there must switch on even when a voltage is applied to their power terminals, these switching operations are particularly lossy. EP 4 235 737 A1 A very complex cooling process is described, which can be improved with the devices and/or processes described here.

The patent publications DE 10 2013 226 537A1 , EP 3 317 964 B1 , EP3 317 965 B1 and EP 4 235 737 A1 are incorporated in their entirety by reference into this application.

Preferably, the coolant supply and coolant discharge of the heat sink are arranged on the side of the heat sink facing away from the electrical unit to be cooled. This makes it possible, for example, to fluidically contact the heat sink on the side of the heat sink facing away from the electrical unit to be cooled.

According to a preferred embodiment, the heat sink can be releasably attached to the cooling unit by means of at least one fastening means, preferably at least one screw. The at least one fastening means can preferably be designed to form the fluidic connections between the heat sink and the cooling unit in such a way that a fluid-tight seal is achieved.

It is advantageous if the fluid-tight seal between the first fluidic connection and the second fluidic connection can be established with at least one fastening means accessible from the side of the first cooling wall. The "first" cooling wall is the aforementioned cooling wall on the side of the cooling channel facing the electrical unit to be cooled. The fact that the at least one fastening means is accessible from the side of the first cooling wall facilitates, for example, handling of the heat sink when inserting and removing it from the cooling unit.

According to a preferred embodiment, the heat sink can be pressed against the cooling unit by means of the at least one fastening means such that liquid-tight fluidic connections can be formed between the first fluid port of the cooling unit and the coolant supply of the heat sink, and between the second fluid port of the cooling unit and the coolant discharge of the heat sink. For example, the at least one fastening means can be configured such that, when the heat sink is attached to the cooling unit, a contact force can be generated that presses the first and second fluid ports of the cooling unit against the coolant supply and discharge of the heat sink.

As previously described, a cooling device is defined here as comprising a cooling unit as described above and a heat sink detachably connected to the cooling unit as described above. It is advantageous if the cooling device further comprises a first sealing element which is designed to form the first fluidic connection in a liquid-tight manner when the heat sink is fastened to the cooling unit. By means of the first sealing element, for example, a fluid-tight first fluidic connection can be formed when the heat sink is fastened to the cooling unit. For example, the sealing element can be deformed when the heat sink is pressed against the cooling unit such that the connection between the first cooling port and the coolant supply is sealed. The first sealing element is preferably a first sealing ring which surrounds the first fluid port.

Further preferably, the cooling device comprises a second sealing element which is designed to form the second fluidic connection in a liquid-tight manner when the heat sink is attached to the cooling unit. By means of the second sealing element, for example, a fluid-tight second fluidic connection can be formed when the heat sink is attached to the cooling unit. Preferably, the second sealing element is a second sealing ring surrounding the second fluid port.

According to a preferred embodiment, the heat sink is configured such that, when the heat sink is attached to the cooling unit, a cooling flow can be formed from the first fluid port for the coolant supply via the cooling channel and the coolant discharge to the second fluid port. In this way, the heat sink can be supplied with coolant, for example, from the cooling unit.

The heat sink is preferably made of metal, preferably copper. Copper's high thermal conductivity enables effective heat dissipation from the electrical unit to be cooled.

The element to be cooled, in particular the semiconductor arrangement, can comprise a power semiconductor component, wherein the power converter is designed such that the power semiconductor component can be operated in switching or amplifier mode at a frequency of 10 kHz or more and can generate an electrical power loss ≥ 500 W.

The heat sink preferably has a cooling channel through which coolant, in particular cooling liquid, preferably cooling water, can flow in a predetermined flow direction. The cooling channel can preferably have a first cooling wall on the side of the cooling channel facing the electrical unit to be cooled. A plurality of cooling pins can further preferably be arranged in the cooling channel or in a partial region of the cooling channel, which cooling pins extend, in particular from the first cooling wall, into the cooling channel. The plurality of cooling pins can further preferably comprise at least one cooling pin of a first category, which is oriented in a first inclination direction that is inclined obliquely relative to a perpendicular to the first cooling wall. The cooling pins of the plurality of cooling pins can further preferably be arranged such that one cooling pin of the plurality of cooling pins does not intersect any other cooling pin of the plurality of cooling pins.

Such a device is described, for example, in the German patent application with the official file number 10 2023 123 660.1 , filed on September 1, 2023, entitled: “Heat sink with pressure loss-optimized arrangement of cooling pins within the cooling channel,” which is incorporated in its entirety by reference into this patent application.

At least some of the cooling pins can be designed conically in such a way that the cooling channel formed by them has the property already mentioned above, namely that its cross-section has, at least in sections, a geometric shape whose width, measured parallel to the cooling wall, decreases in the direction of the cooling wall.

In the heat sink, a plurality of cooling pins can further preferably be arranged in the cooling channel or in a partial region of the cooling channel, said cooling pins extending from the first cooling wall into the cooling channel. A cooling pin is understood to be a cooling element whose length is greater than the average width or the average diameter of the cooling element. In particular, a cooling pin can be designed, for example, with a cylindrical or tapered geometry. The directional extension of the cooling pin can preferably be represented by a center line of the cooling pin. According to an exemplary embodiment, to determine such a center line, for example, a line could be drawn through the centers of the cross sections along the cooling pin. The center line of a cooling pin can, for example, be designed as a straight line, but it can also, for example, be slightly curved or slightly kinked.

More preferably, cooling pins of the first category can be oriented at an angle to a perpendicular to the first cooling wall. "An angled" here means that the cooling pins of the first category are neither parallel nor perpendicular to the first cooling wall. It has been found that the angled arrangement of the cooling pins allows for particularly good coolant flow and improved thermal contact between the cooling pin and the coolant.

Furthermore, the cooling pins of the plurality of cooling pins can be arranged such that no cooling pin intersects any other cooling pin of the plurality of cooling pins. This non-overlapping arrangement of the cooling pins in the cooling channel or in a portion of the cooling channel results in improved flow through the cooling channel and a reduction in pressure loss. The pressure required to convey the coolant through the cooling channel has proven to be particularly low in the development described here.

Preferably, each cooling pin of the plurality of cooling pins is arranged such that coolant can flow around it all around. This enables high heat transfer from the cooling pins to the coolant.

It is advantageous if the cooling pins of the plurality of cooling pins are arranged such that one cooling pin of the plurality of cooling pins does not touch any other cooling pin of the plurality of cooling pins. In this way A gap is created between the cooling pins. This facilitates flow through the cooling channel and reduces pressure loss.

The cooling pins are preferably rod-shaped. The cooling pins are also preferably substantially cylindrical. The rod-shaped or cylindrical design of the cooling pins creates a large contact surface for heat transfer from the cooling pins to the coolant. The cooling pins preferably thicken on the side facing the cooling wall, so that the cross-section of a cooling channel formed by them has, at least in sections, a geometric shape whose width, measured parallel to the cooling wall, decreases toward the cooling wall. The advantages of this have already been described above.

Preferably, the cooling pins have a round or oval cross-section. This can further reduce flow resistance.

It is advantageous if the cooling channel has a second cooling wall on the side opposite the first cooling wall. The "first cooling wall" here generally refers to the cooling wall facing the substrate and the electrical unit to be cooled.

According to a preferred embodiment, the cooling pins of the plurality of cooling pins extend continuously from the first cooling wall to the second cooling wall. In this way, heat can be supplied to the cooling pins from both the first cooling wall and the second cooling wall. This achieves improved heat dissipation.

Preferably, the first cooling wall is arranged substantially parallel to the second cooling wall. The parallel alignment of the first cooling wall and the second cooling wall ensures a homogeneous flow through the cooling channel with turbulent flow conditions inside.

It is advantageous if the cooling channel has a substantially constant cross-section across the entire heat sink. This results in a constant coolant flow velocity throughout the cooling channel. This is advantageous with a local dependence of the flow velocity, which leads to a desired turbulent system.

Preferably, the cooling channel has a substantially rectangular cross-section. It is also advantageous if the cooling channel is configured as a substantially cuboid-shaped cooling channel. Such geometries simplify the formation of flat contact surfaces for thermally connecting the electrical units to be cooled.

It is advantageous if the heat sink is a micro heat sink and the electrical unit to be cooled is an electronic component. According to this embodiment, a separate micro heat sink can be provided for each electronic component. This enables heat dissipation that is individually tailored to the respective electronic component. Preferably, the electrical unit to be cooled is an electronic circuit component. The term "micro heat sink" is used, for example, in EP1672690B1 explained.

According to a preferred embodiment, the heat sink has an inlet, wherein coolant can be supplied via the inlet at a first end of the cooling channel. Further preferably, the heat sink has an outlet, wherein coolant can be discharged via the outlet at a second end of the cooling channel, wherein the second end of the cooling channel is arranged opposite the first end of the cooling channel. This allows coolant to flow through the entire heat sink.

The heat sink is preferably made of metal. Metals generally have high thermal conductivity. According to a preferred embodiment, the heat sink is made of copper. Copper is a metal with very high thermal conductivity and is therefore preferred for the construction of heat sinks. According to an alternative preferred embodiment, the heat sink is made of another material or a combination of metals, e.g., molybdenum, stainless steel, or nickel.

Preferably, the cooling pins of the heat sink are manufactured using an additive manufacturing process, in particular selective laser melting, also abbreviated to "SLM." Using such additive manufacturing processes, the cooling pins can be applied to the first cooling wall of the heat sink in virtually any orientation. Even with additive manufacturing, certain restrictions must be observed in the structure, for example, on the inside, such as the installation angle, which should in particular be less than 45°, which would otherwise be impossible to achieve without a support structure.

According to a preferred embodiment, the electrical unit is mechanically and thermally connected to the heat sink.

Preferably, the electrical unit is connected to the heat sink by at least one of the following: by at least one solder connection by at least one welded joint, or by sintering. For example, if the heat sink is firmly soldered to the electrical unit to be cooled, the soldering enables improved thermal coupling. Improved thermal coupling between the heat sink and the electrical unit to be cooled can also be achieved, for example, by means of a welded joint or by sintering.

Further preferably, the electrical unit is connected to the heat sink by means of a layer of thermal paste. In this case, too, it may be advantageous to be able to remove the heat sink from the cooling unit if necessary.

According to a preferred embodiment, the electronic assembly described above comprises a printed circuit board to which the electrical unit has a fixed mechanical connection. This fixed mechanical connection can be achieved, for example, by soldering electrical connections of the electrical unit to the printed circuit board. In this embodiment, the printed circuit board, the electrical unit, and the heat sink form a structural unit that can, for example, be inserted as a whole into the cooling unit.

The electronic assembly preferably comprises a plurality of electrical units to be cooled, which have a fixed mechanical connection to the circuit board, as well as a plurality of heat sinks. The electronic assembly with the plurality of heat sinks can be inserted in its entirety into the cooling unit. The cooling unit preferably has a plurality of recesses designed to accommodate the plurality of heat sinks. The fact that the electronic assembly is removable from the cooling unit facilitates maintenance, for example.

Preferably, the cooling unit has at least one receiving device for at least one fastening means.

According to a preferred embodiment, the heat sink can be attached by means of at least one fastening means accessible from the side of the first cooling wall, which engages with the at least one receiving device. If the at least one fastening means engages with the at least one receiving device on the side of the cooling unit, the heat sink can thus be attached to the cooling unit, for example.

According to a further preferred embodiment, the fluid-tight seal of the first fluidic connection and the second fluidic connection can be established with at least one fastening means that is accessible from the side of the electrical unit to be cooled. If the at least one fastening means is accessible from the side of the electrical unit to be cooled, the insertion and removal of the heat sink into the cooling unit can be facilitated.

It is advantageous if the cooling unit has a mount for the heat sink into which the heat sink can be inserted. This allows, for example, a precise fixation of the heat sink in the cooling unit.

According to a preferred embodiment, the cooling unit is designed to supply coolant to a plurality of heat sinks and to remove coolant from the plurality of heat sinks.

Preferably, the cooling unit has a plurality of receptacles into which a plurality of heat sinks can be inserted. This makes it possible, for example, to insert an electronic assembly comprising a plurality of heat sinks in its entirety into the receptacles of the cooling unit.

Preferably, the cooling unit is made entirely or partly of metal or entirely or partly of plastic.

According to a preferred embodiment, grooves are provided within the cooling unit into which pipes can be pressed. The pipes can, for example, comprise a first flow channel for supplying coolant and a second flow channel for discharging coolant.

Preferably, the pipe walls consist entirely or predominantly of a material, preferably copper, that has a higher thermal conductivity than other areas of the cooling unit. The high thermal conductivity of the pipe walls can, for example, further improve the heat dissipation of the electrical unit to be cooled.

According to a preferred embodiment, the cooling unit comprises a distribution unit having the first fluid port and the second fluid port. The distribution unit is preferably designed to supply at least one heat sink with coolant and to discharge the returning coolant.

According to a preferred embodiment, the cooling unit comprises a support unit. The distribution unit can be inserted into the support unit.

Preferably, the carrier unit consists entirely or partially of metal, preferably of aluminum.

It is advantageous if the distribution unit is designed as a cooling insert, which is made of a material with higher thermal conductivity than other areas of the cooling unit, preferably copper. For example, the cooling insert can be in thermal contact with the heat sink, so that the heat dissipation of the heat sink is improved by the thermal contact with the cooling insert. This saves costs and weight, as the entire support unit does not have to be manufactured from the more expensive and usually heavier material, such as copper.

Preferably, a cooling flow can be formed within the cooling device from the first fluid port for the coolant supply via the cooling channel and the coolant discharge to the second fluid port. This cooling flow can be used, for example, to dissipate the heat generated by the electrical unit to be cooled.

Preferably, the cooling unit is designed to supply coolant, in particular cooling liquid, preferably cooling water, to the heat sink via the first fluid port and to discharge coolant from the heat sink via the second fluid port.

Further advantageous embodiments are described in more detail below with reference to several exemplary embodiments shown in the drawings, to which the invention is not, however, limited.

• 1 zeigt eine Elektronikbaugruppe mit einer Kühlanordnung.
• 2 zeigt einen Längsschnitt durch Kühlanordnung und Kühleinheit.
• 3 zeigt eine Darstellung einer Leiterplatte mit zwei an der Leiterplatte angeordneten Kühlanordnungen.
• 4 zeigt einen elektrischen Leistungsumwandler für eine Industrieprozessanordnung, vorzugsweise Plasmaprozessanordnung oder Erwärmungsanordnung.
• 5 zeigt eine mögliche Ausgestaltung eines mittels additivem Verfahren hergestellten Kühlkörpers.
• 6a - 6d zeigen unterschiedliche Ausführungsformen von Kühlkanälen im Kühlkörper.

They show schematically:

• 1 shows an electronic assembly with a cooling arrangement.
• 2 shows a longitudinal section through the cooling arrangement and cooling unit.
• 3 shows a representation of a printed circuit board with two cooling arrangements arranged on the circuit board.
• 4 shows an electrical power converter for an industrial process arrangement, preferably a plasma process arrangement or heating arrangement.
• 5 shows a possible design of a heat sink manufactured using an additive process.
• 6a - 6d show different designs of cooling channels in the heat sink.

In the following description of preferred embodiments of the present development, like reference numerals designate like or comparable components.

1 shows an electronic assembly 24 with a cooling arrangement 7 and with an electrical unit 10 to be cooled, which is preferably a semiconductor arrangement.

• - eine Leiterstruktur 11a, 11b 11c, zusammen bezeichnet als Metallisierung 11,
• - einen 3-poligen Halbleiter-Baustein 12, der insbesondere ein Transistor sein kann,
• - weitere zu kühlende 2-polige Halbleiter-Bausteine 13a, 13b, z.B. Dioden,
• - Bonding-Drähte 29 zum Verbinden der Anschlüsse der Halbleiter-Bausteine 12, 13a, 13b untereinander oder mit der Leiterstruktur 11a, 11b 11c .

The cooling arrangement 7 comprises a heat sink 5 and a substrate 6 positively connected to it. The heat sink 5 has a cooling channel 35 through which coolant can flow in a predetermined flow direction. The heat sink 5 further has a cooling wall 50 on the side of the cooling channel 35 facing the electrical unit 10 to be cooled. The substrate 6 is positively connected to the heat sink 5 at the cooling wall 50. On the side facing away from the heat sink 5, the electrical unit 10 is mechanically firmly connected to the substrate. The electrical unit 10 has:

• - a conductor structure 11a, 11b 11c, together referred to as metallization 11,
• - a 3-pin semiconductor component 12, which may in particular be a transistor,
• - further 2-pole semiconductor components 13a, 13b to be cooled, e.g. diodes,
• - Bonding wires 29 for connecting the terminals of the semiconductor components 12, 13a, 13b to each other or to the conductor structure 11a, 11b 11c .

The 3-terminal semiconductor component 12 can be designed as a bare die layer 14. This allows for very direct thermal coupling. It can be connected to the conductor structure 11c in a form-fitting and secure manner, e.g., by a solder joint. This results in a particularly low and stable thermal resistance.

One or more, in particular all, of the 2-terminal semiconductor components 13a, 13b to be cooled can be designed as a bare die layer 14. This allows for very direct thermal coupling. They can be connected to the conductor structure 11c in a form-fitting and secure manner, e.g., by a solder joint. This results in a particularly low and stable thermal resistance. The 3-terminal semiconductor component 12 and the 2-terminal semiconductor components 13a, 13b are collectively referred to as semiconductor components.

These semiconductor components can be power semiconductor devices, e.g., transistors and/or diodes for switching and conducting very high power, a very high current, and/or a very high voltage. The power can be, for example, 10 kW or more. The voltage can be, for example, 400 V or more, in particular 1 kV or more. The current can be, for example, 10 A or more, in particular 50 A or more. The switching frequency can be, for example, 10 kHz or more, preferably 100 kHz or more, in particular 1 MHz or more.

In 1 A bare-die layer 14 can be seen, which can comprise one or more semiconductor components. The semiconductor components are firmly connected on their underside to the conductor structures 11a, 11b, 11c of the metallization 11, which is applied to the top side of the substrate 6. The bare-die semiconductor elements and the metallization 11 can be connected to one another, for example, by means of at least one soldered connection, in particular a silver solder connection, at least one welded connection, by sintering, or a comparable process. Such a positive connection exhibits very good and stable heat transfer.

The substrate 6 can preferably be a ceramic substrate. Examples of suitable ceramic materials include aluminum oxide ceramic, beryllium oxide ceramic, aluminum nitride ceramic, and sapphire. The metallization 11 can be applied to the substrate 6 using a bonding process, for example, using direct-bonded copper. In this process, a copper foil can be bonded to the substrate, for example, the ceramic substrate, under pressure and at high temperature. Alternatively, metallization processes such as IMB (Insulated Metal Substrate) or AMB (Active Metal Brazed) could be considered. Such a positive connection exhibits very good and stable heat transfer.

A metallization 9 is also applied to the side of the substrate 6 facing away from the bare die layer 14. The metallization 9 can also be applied to the substrate 6 using a previously mentioned bonding method, for example, using direct-bonded copper. The heat sink 5 is firmly connected to the metallization 9. Such a positive connection exhibits very good and stable heat transfer.

In the 1 In the example shown, the heat sink 5 is manufactured using a metal layer bonding process. Individual metal foils 27 μm, preferably copper foils, are structured at least partially by laser processing and/or punching and/or manufactured using electroplating processes and then joined together. The structuring or manufacturing is carried out in such a way that, after the layers have been joined together, closed cooling channels 35 are created through which a cooling medium can flow. By means of a cooling channel structure, the coolant can be directed specifically to the areas of the heat sink 5 that particularly require cooling. The metal foils are preferably bonded together using a bonding process under high pressure and at high temperature. For this purpose, oxide layers, for example, can be formed on the surfaces of the copper layers, which are then welded together, wherein the temperature is preferably selected high enough that the oxide layers melt but the metal foils do not. The metal foils thus bond to form a monolithic heat sink. If the metal foils are made of copper, for example, this is also referred to as direct copper bonding, abbreviated to DCB. The 27 gm metal foils preferably have a thickness of 0.4 mm or less, especially 0.25 mm or less.

For the production of 1 There are different possibilities for the structure shown. According to a first possibility, the production of the substrate 6 provided with metallizations 9 and 11 and the heat sink 5 each takes place in separate steps. Subsequently, the heat sink 5 is firmly connected to the metallization 9, for example by means of a bonding process, in particular by means of direct copper bonding. In this way, the metallization 9 can be part of the heat sink 5, in particular of the monolithic heat sink. Other, less preferred, methods of connecting the heat sink 5 to the metallization can be, for example: soldering, welding, or sintering.

According to a second, alternative manufacturing method, all layers, i.e. both the metallizations 9, 11 of the substrate 6 and the metal foils 27g-m from which the heat sink 5 is formed, are bonded together in a bonding process under high pressure and at high temperature, preferably by means of direct copper bonding and direct bonded copper.

Further preferably, the metallization 11 is also applied to the top side of the substrate 6 in the same step. The metallization 11 can then be formed into the conductor structures 11a, 11b, 11c, for example, by an etching process.

The cooling arrangement 7 is designed such that, during operation, the coolant is guided through the cooling channel 35 at a predetermined operating pressure which is higher than the ambient pressure applied to the substrate on the side of the electrical unit 10 to be cooled. A distance D between the cooling channel 35 and the cooling wall 50 is selected to be so small that the heat sink 5, without the substrate 6 positively connected to it, does not have sufficient dimensional stability and/or However, the substrate 6 and its positive connection with the heat sink 5 on the cooling wall 50 are designed such that the cooling arrangement 7 can ensure this sufficient dimensional stability and tightness. The heat sink 5 has a monolithic construction.

In particular, the distance D may be equal to or less than or equal to the thickness of the metallization 9 and/or less than or equal to 50 µm.

The cooling channel 35 is characterized in that its cross section Q has, at least in sections, a geometric shape F whose width B, measured parallel to the cooling wall 50, decreases in the direction of the cooling wall 50. The geometric shape F of the cross section Q on the cooling wall 50 has, at least in sections, a distance D from the substrate 6 which is designed to be so small that, at the predetermined operating pressure of the coolant, the heat sink 5 cannot ensure sufficient dimensional stability and/or tightness without the substrate 6 being positively connected to it.

As an alternative to the 1 In contrast to the illustrated production of the heat sinks 5, 19 using a metal layer bonding process, the heat sink 5 can be produced using an additive process, for example, using selective laser melting. Additive manufacturing processes are characterized by the fact that the structure is gradually applied from the same material. The material can be melted during application. To produce such a heat sink, for example, the metallization applied to the side of the respective substrate facing away from the bare die layer 14 can be further built up using an additive manufacturing process.

In 2 A cooling device is shown in longitudinal section. The cooling device comprises a heat sink 5, which is designed to cool an electrical unit 10 attached to the heat sink 5. The electrical unit 10 to be cooled can, in particular, be a semiconductor device.

The heat sink 5, which is in 3 also shown as a heat sink 85, is detachably connected to a cooling unit 22. In the example shown in the figures, the cooling unit 22 comprises a distribution unit 20 which is designed to supply the heat sink 5, 85 with coolant. In addition, the cooling unit 22 comprises a carrier unit 21 into which the distribution unit 20 is inserted. The cooling unit 22 has a receptacle 23 into which the heat sink 5, 85 can be detachably inserted. The heat sink 5, 85 is then fastened to the cooling unit 22 by means of at least one fastening means 15, preferably by means of one or more screws. The cooling unit 22 has at least one receiving device 16 for the at least one fastening means 15. In order to separate the heat sink 5 from the cooling unit 22 again, the at least one fastening means 15 is first released. The heat sink 5 can then be removed from the receptacle 23 of the cooling unit 22 together with the electrical unit 10 to be cooled mounted thereon.

Preferably, the electrical unit 10 is mechanically and thermally connected to the heat sink 5, 85. The electrical unit 10 can be connected to the heat sink 5, 85, for example, by means of one or more soldered connections. Another possibility is to connect the electrical unit 10 to the heat sink 5, 85, for example, by sintering. Alternatively, it is possible to weld the electrical unit 10 to the heat sink 5, 85. As a further, albeit less advantageous, alternative, the electrical unit 10 could also be connected to the heat sink 5, 85 by means of a layer of thermal paste. One aspect of the invention, however, lies in implementing the connection between the electrical unit 10 to be cooled and the heat sink 5, 85 with as few additional materials and as thinly as possible. During the considerations, simulations, and tests for this invention, it became clear that this is particularly possible when the heat sink through which fluid flows is firmly connected, in particular by a material bond, to the electrical unit 10 to be cooled. This can be achieved, for example, by soldering, sintering, pressing, or "direct copper bonding," abbreviated to "DCB." "Permanent" here can mean "can only be removed by destructive means." That is, by means of a connection that cannot be removed even with tools without destroying either the electrical unit 10 to be cooled or the heat sink 5, 85, or both components. It was further recognized that such a solution will only be feasible if a new solution can be found for replacing the printed circuit board together with electronic components, and in particular with the electrical unit 10 to be cooled attached to it. This has been achieved with the proposed heat sink 5.

The heat sink 5, 85 and the electrical unit 10, which is mechanically firmly connected to the heat sink 5, together form an electronic assembly 24. This electronic assembly 24 can be inserted into the receptacle 23 of the cooling unit 22 and removed again from this receptacle 23.

The cooling unit 22 is designed to supply coolant to the heat sink 5 attached to the cooling unit 22 and to discharge the coolant again to be discharged after the coolant has flowed through the heat sink 5, 85. Within the cooling unit 22, a first flow channel 25 can be seen, via which coolant can be supplied to the heat sink 5, 85. Within the cooling unit 22, a second flow channel 30 can be seen, via which the coolant can be discharged. The heat sink 5, 85 has a cooling channel 35 through which the coolant can flow. At a first end of the cooling channel 35, a coolant supply 40 is provided, and at the second end of the cooling channel 35 opposite the first end, a coolant discharge 45 is provided. The coolant supply 40 and the coolant discharge 45 are fluidically connected to the cooling channel 35.

The cooling unit 22 comprises a first fluid port 41, which is fluidically connected to the first flow channel 25, and a second fluid port 46, which is fluidically connected to the second flow channel 30. When the heat sink 5 is inserted and subsequently secured in the receptacle 23, a first fluid connection is formed between the first fluid port 41 and the coolant supply 40, and a second fluid connection is formed between the second fluid port 46 and the coolant discharge 45.

To seal the first fluidic connection, a first sealing ring 42 is arranged in a groove 43 between the cooling unit 22 and the heat sink 5, wherein the sealing ring 42 completely surrounds the first fluid port 41. Likewise, a second sealing ring 44 is provided on the second fluid port 46, which completely surrounds the second fluid port 46 and is arranged in a groove 43 between the cooling unit 22 and the heat sink 5. When the at least one fastening means 15 is attached, for example when tightening the at least one screw, the heat sink 5 is pressed against the first fluid port 41 and the first sealing ring 42 as well as against the second fluid port 46 and the second sealing ring 44. As a result of this pressing, a liquid-tight first fluidic connection and a liquid-tight second fluidic connection are formed between the cooling unit 22 and the heat sink 5.

As in 2 As shown, a cooling flow 36 can be formed within the cooling device. The coolant flows from the first flow channel 25 via the first fluid port 41 and the coolant supply 40 into the cooling channel 35. The coolant flows through the cooling channel 35 and is discharged again via the coolant discharge 45, the second fluid port 46 and the second flow channel 30.

The heat sink 5 has a first cooling wall 50 on the side facing the electrical unit 10 to be cooled. On the side of the heat sink 5 facing away from the electrical unit 10 to be cooled, the cooling channel 35 is delimited by a second cooling wall 55, which is opposite the first cooling wall 50. Preferably, the second cooling wall 55 is formed parallel to the first cooling wall 50.

The electronic assembly 24 may be part of a power electronic unit, such as that used in DE 10 2023 131 877.2 described.

In the 2 In the example shown, the electrical unit 10 comprises an array of transistors 60, which can be designed, in particular, as bare-die semiconductor components. The heat generated during operation of the transistors 60 is dissipated via the coolant flowing in the cooling channel 35.

To improve the thermal exchange between the coolant flowing through the cooling channel 35 and the heat sink 5, a plurality of cooling pins 65 can be arranged inside the cooling channel 35, extending from the first cooling wall 50 and/or from the second cooling wall 55 into the cooling channel 35. Coolant flows around the cooling pins 65 and ensures improved thermal coupling between the heat sink 5 and the coolant.

In 2 It can also be seen that the electrical unit 10, together with the heat sink 5 arranged underneath, is arranged within a first recess 70 of a printed circuit board 75.

In a variety of technical applications, particularly in the field of power electronics, there is a need to detach an electrical unit to be cooled, for example a semiconductor element or a semiconductor arrangement, from the rest of the assembly when necessary. To enable detachable attachment of the electrical unit to be cooled to the heat sink, the electrical units to be cooled are often detachably attached to the associated heat sinks, for example using thermal paste. This results in the disadvantage of comparatively low thermal coupling between the electrical unit to be cooled and the heat sink. This disadvantage can be avoided by the features explained here.

In 3 the arrangement of the electrical unit 10 to be cooled within the first recess 70 of the printed circuit board 75 can be clearly seen. 3 The circuit board 75 is shown, which is arranged on the cooling unit 22. Within the first recess 70 of the circuit board 75, the electrical unit 10 is arranged together with the associated heat sink 5 in the Longitudinal section shown. The heat sink 5 is inserted into the receptacle 23 of the cooling unit 22.

In addition to the electrical unit 10 to be cooled, 3 Another electrical unit 80 can be seen together with a further heat sink 85 arranged underneath. The further electrical unit 80 is arranged within a further recess 90 provided in the circuit board 75, and the associated further heat sink 85 is inserted into a further receptacle 92 of the cooling unit 22. The further heat sink 85 has a further cooling channel 95 through which coolant flows. In addition, electrical connection terminals 105 can be seen on the further electrical unit 80 to be cooled, which are provided for forming electrical connections between the further electrical unit 80 to be cooled and the circuit board 75. The electrical unit 10 also has electrical connection terminals for connection to the circuit board 75, which are in 3 but are not shown.

In this document, an electrical connection refers specifically to a high-quality, low-resistance, and low-inductance connection. It should preferably have a contact resistance of 0.2 Ω or less and preferably a contact inductance of 5 nH or less.

In this document, a “thermal connection” refers in particular to a high-quality thermal connection with a low thermal resistance.

The requirement arises from a predictable power dissipation, e.g., in a semiconductor component, and the system thermal resistance Rth_sys from the bare die to the cooling liquid. The system thermal resistance Rth_sys is calculated as the sum of all thermal resistances. The first important thermal resistance, which cannot be influenced by the cooling arrangement, is the thermal resistance between the bare die or chip and the bare die cooling surface. It is specified by the manufacturer as Rth_J/C (junction/case). It depends on the cooling surface of the semiconductor component and, for currently common transistors, is between 0.7 K/W and 0.8 K/W.

As previously mentioned, modern plasma process applications, particularly in the production of semiconductors such as computer or memory chips, place high demands on electrical power converters. These demands can often only be met if the semiconductor component(s) are designed to absorb significant power losses. This can, for example, be greater than or equal to 1 kW. To achieve this, a system thermal resistance of less than or equal to 0.15 K/W, measured from bare die or chip to coolant, should preferably be achieved. After extensive simulations and tests, it was determined that this can be achieved with the present power electronics component. Further improvements are not excluded and are always welcome.

The 3 The cooling unit 22 shown is designed to supply coolant to a plurality of heat sinks and to discharge the coolant again after flowing through the heat sinks. In the example of 3 The cooling unit 22 is designed to supply coolant to both the heat sink 5 and the additional heat sink 85 and then to remove it from both the heat sink 5 and the additional heat sink 85. The cooling unit 22 is designed, in particular, to distribute the coolant evenly among the various heat sinks.

The additional heat sink 85 is also fluidically connected to the cooling unit 22 when it is fastened in the additional receptacle 92. In the sectional view of 3 It can be seen that the further cooling channel 95 is connected via the further coolant discharge 100 and the further second fluid port 102 to the second flow channel 30, via which the coolant is discharged.

The 3 The printed circuit board 75 shown, together with the electrical units 10 and 80 to be cooled and the heat sinks 5 and 85 fastened to the printed circuit board 75, forms a structural unit which, in its entirety, can be placed on the cooling unit 22 and also removed again, i.e. which can be detachably connected to the cooling unit 22. When this structural unit is placed on the cooling unit 22, the heat sinks 5, 85 attached to the electrical units 10, 80 to be cooled are inserted into the associated receptacles 23, 92 of the cooling unit 22. The heat sinks 5, 85 are then fastened to the cooling unit 22 by means of the at least one fastening means 15, wherein when the heat sinks 5, 85 are fastened to the cooling unit 22, fluidic connections for supplying and discharging coolant are formed between the respective heat sinks 5, 85 and the cooling unit 22. The cooling unit 22 is designed to supply all heat sinks 5, 85 of the structural unit evenly with coolant and to discharge the coolant again after flowing through the heat sinks 5, 85.

4 shows an industrial process arrangement 1, preferably a plasma process arrangement or heating arrangement.

• - einen elektrischen Leistungsumwandler 4,
• - eine Last 2, vorzugsweise einen Plasmaprozess oder Erwärmungsprozess, z.B. einen Induktions- oder Mikrowellen-Erwärmungsprozess, wobei die Last 2 mit dem elektrischen Leistungsumwandler 4 elektrisch verbunden ist, so dass der elektrische Leistungsumwandler 4 die Last 2 mit der benötigten elektrischen Leistung versorgen kann,
• - optional eine zusätzliche Anpassungseinheit 3, die zwischen Leistungsumwandler 4 und die Last 2 geschaltet ist.

The industrial process arrangement 1 has:

• - an electrical power converter 4,
• - a load 2, preferably a plasma process or heating process, e.g. an induction or microwave heating process, wherein the load 2 is electrically connected to the electrical power converter 4 so that the electrical power converter 4 can supply the load 2 with the required electrical power,
• - optionally an additional adaptation unit 3, which is connected between the power converter 4 and the load 2.

• - einen Kühlkörper 5, und einen weiteren Kühlkörper 85, wie zuvor und nachfolgend beschrieben,
• - eine Kühleinheit 22, die wie zuvor und nachfolgend beschrieben eine oder mehrere Verteilereinheiten 20 und eine Trägereinheit 21 aufweist,
• - eine Leiterplatte 75,
• - eine elektrische Einheit 10, bevorzugt eine Halbleiteranordnung, vorzugsweise aufweisend ein Leistungshalbleiterbauelement,
• - weitere elektronische Bauteile 8a, 8b, 8c,

wobei die weiteren elektronischen Bauteile 8a, 8b, 8c und die elektrische Einheit 10 auf oder an einer Leiterplatte 75 angeordnet sind und mit elektrischen Kontakten verbunden sind,
wobei die elektrische Einheit 10 mit dem Kühlkörper 5,85 eine feste, insbesondere stoffschlüssige, Verbindung aufweist.The power converter 4 has:

• - a heat sink 5, and another heat sink 85, as described above and below,
• - a cooling unit 22 comprising one or more distribution units 20 and a support unit 21 as described above and below,
• - a circuit board 75,
• - an electrical unit 10, preferably a semiconductor device, preferably comprising a power semiconductor component,
• - other electronic components 8a, 8b, 8c,

wherein the further electronic components 8a, 8b, 8c and the electrical unit 10 are arranged on or at a printed circuit board 75 and are connected to electrical contacts,
wherein the electrical unit 10 has a fixed, in particular material-locking, connection with the heat sink 5,85.

In 5 A possible embodiment of the heat sink 5 is shown. This can preferably be manufactured using an additive process. The cooling channel 35 of the heat sink 5 is shown here together with the plurality of cooling pins 65 arranged within the cooling channel 35. The cooling channel 35 is delimited by the first cooling wall 50 facing the first unit 10 to be cooled, the second cooling wall 55 arranged opposite the first cooling wall 50, and by the side walls 111, 116. Preferably, the cooling channel 35 has a substantially rectangular flow cross-section. Further preferably, the cross-section of the cooling channel 35 is substantially constant over the entire length of the cooling channel 35. The flow direction of the coolant within the cooling channel 35 is in 4 represented by the arrow 121. As can be seen from the 4 As can be seen from the coordinate system shown, the cooling channel 35 is flowed through by the coolant in the z-direction.

The plurality of cooling pins 65 extends from the first cooling wall 50 into the interior of the cooling channel 40. According to the 4 In the embodiment shown, the cooling pins 65 extend into the cooling channel 35, but do not extend as far as the second cooling wall 55, so that there is a distance between the ends of the cooling pins 65 facing away from the first cooling wall 50 and the second cooling wall 55. According to an alternative preferred embodiment of the invention, which is shown in 4 is not shown, it can be provided that the plurality of cooling pins 65 extend continuously from the first cooling wall 50 to the second cooling wall 55. In this case, each cooling pin of the plurality of cooling pins 65 is arranged within the cooling channel 35 such that it does not intersect any other cooling pin of the plurality of cooling pins 65. As a result, coolant can flow around each of the cooling pins 65 all around.

The plurality of cooling pins 65 includes cooling pins 125 of a first category, which are aligned in a first inclination direction 130. The first inclination direction 130 is inclined obliquely relative to a direction 135 perpendicular to the first cooling wall 50. Furthermore, the plurality of cooling pins 65 includes cooling pins 140 of a second category, which are aligned in a second inclination direction 145. The second inclination direction 145 is inclined obliquely relative to the direction 135 perpendicular to the first cooling wall 50, wherein the second inclination direction 145 differs from the first inclination direction 130.

The cooling pins 65 arranged within the cooling channel are preferably manufactured by means of an additive manufacturing process, preferably by means of selective laser melting.

Such a device is described, for example, in the German patent application with the official file number 10 2023 123 660.1 , filed on September 1, 2023, entitled: “Heat sink with pressure loss-optimized arrangement of cooling pins within the cooling channel.”

6a - 6d show different embodiments of cooling channels 35 with a cross section Q in a heat sink 5 with a cooling wall 50.

The determination of the distance D is shown in each case.

6a shows a heat sink 5 with cooling channels 35 with a cross section Q as in 1 .

6b shows a heat sink 5 with cooling channels 35 with oval cross-section Q.

6c shows a cooling channel 35 with cooling channels 35 with star-shaped cross-section Q. Here, with different orientation of the cross-section Q clearly shows how the distance D can be determined along the shortest route.

6d shows a heat sink 5 with cooling channels 35 with a trapezoidal cross-section Q, as can be created in the design with cooling pins 65.

The features disclosed in the above description, the claims and the drawings may be important both individually and in any combination for the realization of the invention in its various embodiments.

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1672690B1 [0008, 0102]
• DE 4315580A1 [0009]
• EP 3317966B1 [0042]
• DE 10 2013 226 537A1 [0075, 0077]
• EP 3 317 964 B1 [0075, 0077]
• EP 3 317 965 B1 [0075, 0077]
• EP 4 235 737 A1 [0076, 0077]
• DE 10 2023 123 660.1 [0088, 0175]
• DE 10 2023 131 877.2 [0154]

Claims (24)

A cooling arrangement (7) for cooling an electrical unit (10), preferably a semiconductor device, wherein the cooling arrangement (7) comprises: a) a heat sink (5), b) a substrate (6), c) wherein the heat sink (5) comprises: i) a cooling channel (35) through which coolant can flow in a predetermined flow direction, ii) a cooling wall (50) on the side of the cooling channel (35) facing the electrical unit (10) to be cooled, d) wherein the substrate (6) is positively connected to the heat sink (5) at the cooling wall (50) and is designed such that, on its side facing away from the heat sink (5), the electrical unit (10) can be mechanically firmly connected, e) wherein the cooling arrangement (7) is designed such that, during operation, the coolant is guided through the cooling channel (35) at a predetermined operating pressure that is higher than the ambient pressure applied to the substrate on the side of the electrical unit (10) to be cooled, and wherein f) a distance (D) between the cooling channel (35) and the cooling wall (50) is selected to be so small that the heat sink (5) cannot ensure sufficient dimensional stability and/or tightness at the specified operating pressure without the substrate (6) positively connected to it, and g) the substrate (6) and its positive connection to the heat sink (5) on the cooling wall (50) are designed such that the cooling arrangement (7) can ensure this sufficient dimensional stability and tightness, and h) the heat sink (5) is constructed monolithically. Cooling arrangement (7) according to Claim 1 , wherein a) the cooling channel (35) is characterized in that its cross section (Q) has, at least in sections, a geometric shape (F), the width (B), measured parallel to the cooling wall (50), decreasing in the direction of the cooling wall (50); and wherein b) the geometric shape (F) of the cross section (Q) on the cooling wall (50) has, at least in sections, a distance (D) from the substrate (6) which is designed such that, at the predetermined operating pressure of the coolant, the heat sink (5) cannot ensure sufficient dimensional stability and/or tightness without the substrate (6) being positively connected to it. Cooling arrangement (7) according to one of the preceding claims, characterized in that the heat sink (5, 85) is at least partially manufactured by means of an additive manufacturing process, in particular by means of selective laser melting. Cooling arrangement (7) according to one of the preceding claims, characterized in that the heat sink (5, 85) is at least partially manufactured by means of a metal layer bonding process, in particular a DCB process. Cooling arrangement (7) according to one of the preceding claims, characterized in that the heat sink (5, 85) has: - a coolant supply (40) and a coolant discharge (45), both of which are fluidically connected to the cooling channel (35), for supplying and discharging the coolant to a cooling unit (22) to which the heat sink can be fastened, and wherein, upon fastening, a first fluidic connection can be formed between the coolant supply (40) of the heat sink (5, 85) and the first fluid port (41) of the cooling unit (22) and, in particular, additionally a second fluidic connection can be formed between the coolant discharge (45) of the heat sink (5, 85) and the second fluid port (46) of the cooling unit (22). An electronic assembly (24) comprising a cooling arrangement (7) according to one of the preceding claims and an electrical unit (10, 80) to be cooled, which is mechanically firmly connected to the substrate (6), wherein i) the electrical unit (10, 80) comprises at least one conductor structure (11a, 11b, 11c) made of metal, which is positively connected to the substrate (6), and ii) the electrical unit (10, 80) comprises at least one bare-die semiconductor component (12, 13a, 13b) which is mechanically firmly attached, in particular by soldering, to the conductor structure (11a, 11b, 11c). Electronic assembly (24) according to Claim 6 , characterized in that the electrical unit (10, 80) is connected to the substrate (6) by at least one of the following: by at least one soldered connection, by at least one welded connection, by sintering. Electronic assembly (24) according to one of the Claims 6 or 7 , further comprising a circuit board (75) to which the electrical unit (10, 80) has a fixed mechanical connection. Electrical power converter (4) for an industrial process arrangement (1), preferably a plasma process arrangement or heating arrangement, comprising: - a cooling arrangement (7) according to one of the preceding claims, - an electrical unit (10), preferably a semiconductor arrangement, preferably comprising a power semiconductor component, wherein the electrical unit (10) is arranged on the substrate on the side facing away from the heat sink (5) and is connected thereto by a fixed, in particular or material-locking connection, and wherein the heat sink (5, 85) is designed to dissipate heat from the electrical unit (10, 80) to be cooled, preferably the semiconductor arrangement, wherein - the heat sink (5, 85) is detachably fastened to a cooling unit (22) comprising a first fluid port (41), - when the heat sink (5, 85) is fastened to the cooling unit (22), a first fluidic connection is formed between the coolant supply (40) of the heat sink (5, 85) and the first fluid port (41) of the cooling unit (22), - when the heat sink (5, 85) is fastened to the cooling unit (22), a fluid-tight seal of the first fluidic connection is simultaneously effected. Electrical power converter (4) according to Claim 9 , characterized in that the cooling arrangement (7) can be detachably fastened to the cooling unit (22) by means of at least one fastening means (15), preferably at least one screw. Electrical power converter (4) according to Claim 9 or 10 , characterized in that the fluid-tight seal of the first fluidic connection can be produced with at least one fastening means (15) which is accessible from the side of the first cooling wall (50). Electrical power converter (4) according to one of the preceding Claims 9 until 11 , characterized in that the cooling arrangement (7) is designed such that when the heat sink (5, 85) is attached to the cooling unit (22), a cooling flow (36) can be formed from the first fluid port (41) to the coolant supply (40) via the cooling channel (35, 95). Electrical power converter (4) according to one of the preceding Claims 9 until 12 , characterized in that the electrical power converter (4) is designed to excite a plasma process, in particular a plasma process for semiconductor production. Electrical power converter (4) according to one of the preceding Claims 9 until 13 , characterized in that the heat sink (5, 85) has a cooling channel (35) through which coolant, in particular cooling liquid, preferably cooling water, can flow in a provided flow direction, wherein the cooling channel (35) has in particular a first cooling wall (50) on the side of the cooling channel (35) facing the electrical unit to be cooled, wherein in the cooling channel (35) or in a partial region of the cooling channel (35) a plurality of cooling pins (65) are arranged, which extend, in particular from the first cooling wall (50), into the cooling channel (35), wherein the plurality of cooling pins (65) comprises at least one cooling pin (125) of a first category, which is oriented in a first inclination direction (130) which is inclined obliquely relative to a perpendicular (135) to the first cooling wall (50), wherein the cooling pins of the plurality of cooling pins (65) are preferably arranged such that one cooling pin of the plurality of Cooling pins (65) do not intersect any other cooling pin of the plurality of cooling pins (65). Electrical power converter (4) according to one of the preceding Claims 9 until 14 , characterized in that the electrical unit (10) has at least one LDMOS transistor, preferably two identical LDMOS transistors. Electrical power converter (4) according to one of the preceding Claims 9 until 15 , characterized in that the electrical power converter (4) is designed to generate a high voltage greater than or equal to 1 kV, in particular greater than or equal to 2 kV, preferably with a pulsed high voltage. Electrical power converter (4) according to one of the preceding Claims 9 until 16 , further comprising a circuit board (75) to which the electrical unit (10, 80) has a fixed mechanical connection. Electrical power converter (4) for an industrial process arrangement (1), preferably a plasma process arrangement or heating arrangement, in particular according to one of the preceding Claims 9 until 17 , with a cooling unit (22) for supplying the heat sink (5, 85), which has a coolant supply (40) and a coolant discharge (45), with coolant, wherein the cooling unit (22) has: - a first flow channel (25) and a second flow channel (30); - a first fluid port (41) which is fluidically connected to the first flow channel (25), - a second fluid port (46) which is fluidically connected to the second flow channel (30), wherein the cooling unit (22) is designed such that - the heat sink (5, 85) can be detachably fastened to the cooling unit (22), - when the heat sink (5, 85) is fastened to the cooling unit (22), a first fluid connection is formed between the coolant supply (40) of the heat sink (5, 85) and the first fluid port (41) of the cooling unit (22) and, in particular, additionally a second fluid connection is formed between the coolant discharge (45) of the heat sink (5, 85) and the second fluid port (46) of the cooling unit (22) bar, - when the heat sink (5, 85) is attached to the cooling unit (22), a fluid-tight seal of the first fluidic connection and in particular additionally of the second fluidic connection is simultaneously effected. Method for assembling a cooling arrangement (7) according to one of the preceding Claims 1 until 5 , wherein at least a part of the heat sink (5) is applied to the substrate (6) by means of metallization of the substrate (6), in particular by means of direct-bonded copper. Method for assembling a cooling arrangement (7) according to Claim 19 , wherein the heat sink is produced by means of an additive manufacturing process, in particular by means of selective laser melting (SLM), in that the part of the heat sink (5) which was applied to the substrate (6) by means of metallization of the substrate (6), in particular direct-bonded copper, is further built up by means of the additive manufacturing process. Method for assembling a cooling arrangement (7) according to Claim 19 , wherein the heat sink (5) is applied by means of a metal layer bonding process. Method for assembling a cooling arrangement (7) according to Claim 21 , wherein during the assembly of the cooling arrangement (7) the process step of applying the heat sink (5) and metallizing the substrate (6) takes place in one step. Method for assembling an electronic module (24), in particular according to one of the Claims 6 until 8 , comprising the following steps: - Assembling a cooling arrangement according to one of the Claims 19 until 22 , - positively connecting a conductor structure (11a, 11b, 11c) made of metal to the substrate (6), and - mechanically firmly attaching at least one bare-die semiconductor component (12, 13a, 13b) to the conductor structure (11a, 11b, 11c), in particular by soldering. Method for assembling an electrical power converter (4) for an industrial process arrangement (1), preferably a plasma process arrangement or heating arrangement, in particular according to one of the preceding Claims 9 until 18 , starting from: - a cooling arrangement (7) for cooling an electrical unit (10, 80) to be cooled, according to one of the Claims 1 until 5 , wherein the heat sink (5, 85) comprises a cooling channel (35, 95), a coolant supply (40) fluidically connected to the cooling channel (35, 95), and a coolant discharge (45) fluidically connected to the cooling channel (35, 95), and - a cooling unit (22) comprising a first fluid port (41) and a second fluid port (46), wherein the method comprises: - releasably fastening the heat sink (5, 85) to the cooling unit (22), wherein upon fastening the heat sink (5, 85) to the cooling unit (22), a first fluidic connection is established between the coolant supply (40) of the heat sink (5, 85) and the first fluid port (41) of the cooling unit (22), and in particular a second fluidic connection is established between the coolant discharge (45) of the heat sink (5, 85) and the second fluid port (46) of the cooling unit (22) wherein, when the heat sink (5, 85) is fastened to the cooling unit (22), a fluid-tight seal of the first fluidic connection, and in particular of the second fluidic connection, is simultaneously effected.

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