High-frequency power coupler for a power converter for an industrial process assembly, and method

Abstract

The invention relates to an HF power coupler (1) for coupling a plurality of HF input signals in order to form an HF output signal for outputting HF power to an industrial process assembly (1), preferably a plasma process assembly, gas laser excitation, or heating assembly, the HF power coupler (1) having: a. a plurality of HF inputs (11, 12, 13, 14, 15), b. an HF output (17) having a specified HF output impedance (88), c. an impedance matching line (20), and d. a coupling unit (19) having a specified coupling unit output impedance (81), the coupling unit (19) having: i. a common star point (10), ii. a respective connection for each of the HF inputs, and iii. a respective connecting line (41, 42, 43, 44, 45) extending from each of the connections of the HF inputs to the common star point (10), each connecting line having a connecting line reactance (21), wherein - the impedance matching line (20) is connected to the star point (10) of the coupling unit (19) and extends from the coupling unit (19) to the HF output (17) and has a specified length and a specified impedance between the aforementioned two ends, - the specified length differs from a ʎ / 4 length by a differential length (22) - the specified impedance differs from a calculated impedance by a differential impedance (26), and - the differential length (22) and the differential impedance (26) are each based on the reactance resulting from the connecting line reactances.

Description

[0001] High-frequency power coupler for a power converter for an industrial process arrangement and method

[0002] The invention relates to a high-frequency power coupler for coupling multiple RF input signals to a single RF output signal, for supplying RF power to an industrial process arrangement, preferably a plasma process arrangement, gas laser excitation, or heating arrangement. The invention further relates to an electrical power converter for an industrial process arrangement, preferably a plasma process arrangement, gas laser excitation, or heating arrangement, comprising such an RF power coupler. The invention further relates to a method for designing an impedance matching line of such a high-frequency power coupler.

[0003] In this application, "HF" stands for high frequency. High frequency here refers to a frequency of at least 1 MHz.

[0004] Preferably, this also refers to a frequency of no more than 100 MHz.

[0005] Such industrial process setups are often operated at very high power levels. Very high power here refers to an electrical output power of at least 20 kW at an RF output. These applications are also referred to as high-power applications.

[0006] A plasma process setup, especially for gas laser excitation, particularly for high-frequency RF applications, can be very complex and often has to meet high requirements, for example, regarding performance, efficiency, operational readiness / availability, and space requirements. This also requires, for example, the efficient transmission of high electrical RF power, which may necessitate precise electrical matching or adjustment.

[0007] Due to space constraints in such industrial processes, it is necessary to save space in the control cabinets to meet all customer requirements. Furthermore, there is a desire to accommodate more RF power converters and RF power couplers in a single cabinet, which leads to volume issues. An overly cramped design often results in insufficient mechanical stability and reduced resistance to electromagnetic interference because shielding is often inadequate and cables are routed too close together.

[0008] The invention is based on the objective of improving an RF power coupler of the type mentioned above, in particular making it more space-saving and at the same time improving its stability.

[0009] This problem is solved by an RF power coupler with the features according to claim 1. Further aspects are disclosed in the description and in dependent claims. In one aspect, an RF power coupler for coupling several RF input signals to an RF output signal, for supplying RF power to an industrial process arrangement, preferably a plasma process arrangement, gas laser excitation, or heating arrangement, is disclosed. The RF power coupler comprises: a. several RF inputs, b. an RF output with a predetermined RF output impedance, c. an impedance matching line, d. a coupling unit with a predetermined coupling unit output impedance, wherein the coupling unit comprises: i. a common neutral point, ii. one connection for each of the RF inputs, iii.Each connecting line extends from one of the terminals of the RF inputs to the common star point, with each connecting line exhibiting a connecting line reactance.

[0010] The impedance matching line is connected to the star point of the coupling unit and extends from the coupling unit to the RF output, having a predetermined length and impedance between these two ends.

[0011] This specified impedance is specifically designed to differ from the input and output impedances of the combiner.

[0012] The specified length differs from an Ä / 4 length by a difference length, and the specified impedance differs from a calculated impedance by a difference impedance, which results from the square root of the product of the input impedance of the high-frequency power coupler resulting from all inputs and the RF output impedance.

[0013] The difference length and the difference impedance are each non-zero and depend on the reactance resulting from the connecting line reactances.

[0014] In this revelation, "Ä" represents the wavelength of the high frequency. This wavelength depends on the material in which the wave propagates. In the case of an impedance matching line, this could be the material of the insulating layer. The insulating layer is described in more detail below. Instead of "Ä," the degree value "360°" is also frequently used in this context. "Ä / 4" then corresponds to "90°."

[0015] The term "coupling unit output impedance" refers to the impedance present at the output of the coupling unit. If all RF inputs have the same input impedance, e.g., 50 Ω, and the connecting lines have no or negligible reactance and no inherent impedance matching, then this coupling unit output impedance would be equal to the input impedance of the RF inputs divided by the number of RF inputs.

[0016] For example, with five RF inputs, each with an input impedance of 50 Q, the coupling unit output impedance would be 10 Q. In the case where the connecting lines from the RF input terminals to the star point have reactances, i.e.,

[0017] If the inductances are present, this value changes by the resultant of these connecting line reactances.

[0018] "Reactance" here refers to a reactance, i.e., a capacitive and / or inductive resistance. It has the property of causing a time shift between current and voltage, for example, in the case of a sinusoidal alternating voltage, i.e., a phase shift, as well as an unwanted upstream impedance transformation at both the inputs and the common output.

[0019] The term "star point" here refers to a connection point where several connecting lines are joined together in a star shape.

[0020] The "calculated impedance" is described as the impedance resulting from the square root of the product of the input impedance of the RF power coupler (resulting from all inputs) and the RF output impedance. This involves multiplying two impedances, for example, the input and output impedances of the impedance matching line. The square root of the resulting product is then taken. For the idealized case of an A / 4 line without attenuation and without reactance compensation, this yields an ideal impedance.

[0021] This compensation principle is applicable not only to an input region but also to an output region. Therefore, the following is disclosed: an RF power coupler for coupling multiple RF input signals to a single RF output signal, for supplying RF power to an industrial process arrangement, preferably a plasma process arrangement, gas laser excitation, or heating arrangement. The RF power coupler comprises: a. multiple RF inputs, b. an RF output with a predetermined RF output impedance, c. an impedance matching line, d. a coupling unit with a predetermined coupling unit output impedance, wherein the coupling unit comprises: i. a common neutral point, ii. one connection for each of the RF inputs.

[0022] The impedance matching line is connected to the star point of the coupling unit and extends from the coupling unit to the RF output, having a predetermined length and impedance between these two ends.

[0023] The RF output has an additional output connection unit, e.g. output connection line or output connection terminal with an output connection unit reactance.

[0024] This specified impedance is specifically designed to differ from the input and output impedances of the combiner.

[0025] The specified length differs from an Ä / 4 length by a difference length, and the specified impedance differs from a calculated impedance by a difference impedance, which results from the square root of the product of the input impedance of the high-frequency power coupler resulting from all inputs and the RF output impedance.

[0026] The difference length and the difference impedance are each non-zero and depend on the output junction reactance.

[0027] The compensation can also be applied to the output interconnect reactance and the input reactance resulting from the interconnect reactances. Therefore, the difference length and the difference impedance can each depend on the reactance resulting from the interconnect reactances and an output interconnect reactance.

[0028] In one aspect, the RF power coupler exhibits attenuation, particularly in the impedance matching section. The difference length and the differential impedance are also dependent on this attenuation. Attenuation here refers to a lossy, i.e., resistive, component in the RF power coupler, especially in the impedance matching section. This attenuation arises, for example, from resistance losses in the impedance matching section. Even if it is made of a highly conductive material, such as copper, losses are unavoidable. These losses lead to attenuation. The attenuation can be determined, for example, by the ratio of all input power to output power. It can be determined by measurement and / or simulation. If the difference length and the differential impedance are additionally adjusted based on this attenuation, a particularly low-reflection impedance matching can be achieved.In one aspect, the interconnection line reactances are designed as interconnection line inductances. If the interconnection lines each exhibit an inductive component, impedance matching and / or compensation measures in the coupling unit can be omitted. This can save space in the coupling unit. Furthermore, additional components, such as RF switching units, can be accommodated in the coupling unit. This can increase reliability.

[0029] In one aspect, the connection line reactances are designed as connection line capacities, e.g. as parasitic capacities.

[0030] In one aspect, the interconnection line reactances are designed as interconnection line impedances, whereby the interconnection line impedances essentially have reactive components.

[0031] In one respect, the difference in length is greater when the inductance resulting from the connecting line inductances is higher. This allows for particularly low-reflection impedance matching. At the same time, no impedance matching measures are necessary in the coupling unit. This can save space in the coupling unit.

[0032] In one respect, the differential impedance is greater when the inductance resulting from the connecting line inductances is higher. This allows for particularly low-reflection impedance matching. At the same time, no impedance matching measures are necessary in the coupling unit. This can save space in the coupling unit.

[0033] In one aspect, the difference length is greater when the damping is higher. This allows for particularly low-reflection impedance matching. At the same time, no impedance matching measures are necessary in the coupling unit. This can save space in the coupling unit.

[0034] In one aspect, the differential impedance is greater when the damping is greater. This allows for particularly low-reflection impedance matching. At the same time, no impedance matching measures are necessary in the coupling unit. This can save space in the coupling unit.

[0035] In one aspect, the inductance resulting from the connecting line inductances is in the range of 1 to 100 nH. Even if the connecting lines each exhibit such a significant inductive component, impedance matching and / or compensation measures in the coupling unit can be omitted. This can save space in the coupling unit. Furthermore, the impedance matching line can be significantly shortened. This saves additional space in the RF power coupler as a whole. Moreover, additional components, such as RF switching units, can be integrated into the coupling unit. This can increase reliability.

[0036] In one aspect, the difference length ranges from A / 40, which corresponds to 9°, to Ä / 9, which corresponds to 40°. This eliminates the need for impedance matching and / or compensation measures in the coupling unit, saving space. Furthermore, the impedance matching line can be significantly shortened, saving even more space in the RF power coupler as a whole.

[0037] In one respect, the coupling unit's output impedance lies in the range of the RF input impedance divided by the number of RF inputs. This allows the coupling unit to be built without impedance matching or compensation for reactances, particularly the inductances of the interconnected cables. This saves space.

[0038] In one aspect, the input impedance of the RF inputs is in the range of 50 Q + / - 5 Q. This allows RF amplifier arrangements with corresponding output impedances to be connected to these inputs with minimal reflection.

[0039] In one aspect, the RF output impedance is in the range of 50 Ω ± 5 Ω. This makes the RF power coupler ideally suited for use in an electrical power converter for an industrial process setup, preferably a plasma process setup, gas laser excitation setup, or heating setup. Standard connecting elements and measuring equipment, typically designed for this impedance, can be used. No additional impedance matching or special components are required, saving further space and costs.

[0040] In one aspect, the differential impedance is in the range of 1 Q to 10 Q. This can be achieved, for example, by widening the planar conductor tracks of the impedance matching line. This can then also reduce losses and may require fewer cooling measures.

[0041] In one aspect, the specified impedance is reduced by a differential impedance compared to the calculated impedance. This can be achieved, for example, by widening the planar conductor tracks of the impedance matching line. This can then also reduce losses and may necessitate fewer cooling measures.

[0042] In one aspect, the RF power coupler is designed for pulsed operation, where a load change of at least 1 kW occurs with a repetition frequency greater than or equal to 1 kHz, and in particular less than or equal to 500 kHz. Thus, the RF power coupler is very well suited for use in an electrical power converter for an industrial process arrangement, preferably a plasma process arrangement, gas laser excitation, or heating arrangement. 2024P00188WC

[0043] 7. In one aspect, the RF power coupler is designed for a power output of at least 1 kW at one, preferably at each, RF input. Preferably, the RF power coupler is designed for a power output of up to 10 kW at one, preferably at each, RF input. Since the RF power coupler is designed to integrate high power into a compact design, it can be installed in control cabinets or industrial plants in a space-saving manner. This is particularly advantageous when space is limited, but high RF power is still required. The power range of 1 kW or greater can cover a variety of RF applications, from small laboratory setups to large industrial applications such as plasma processes, gas lasers, or heating systems. This versatility can make the RF power coupler attractive for a wide range of applications.

[0044] In one aspect, the RF power coupler is designed for a high frequency in the range of at least 1 MHz, and preferably up to 100 MHz, more preferably in the range of 10 MHz to 30 MHz, particularly in the range of 13 MHz to 14 MHz and / or in the range of 26 MHz to 28 MHz, most preferably at 13.56 MHz or 27.12 MHz. The frequency range of 1 MHz or higher, and preferably up to 100 MHz, covers many industrial and scientific applications. These include, among others, plasma excitation, induction heating, and certain applications in high-frequency technology, such as the control of gas lasers. This makes the coupler usable in many different fields. The specific frequencies of 13.56 MHz and 27.12 MHz are common industrial ISM frequencies in many countries, where "ISM" stands for "Industry, Science, and Medicine."These frequencies are approved for use in industrial applications in many countries, allowing the RF power coupler to operate in many countries without additional frequency licenses. This can simplify deployment and reduce regulatory hurdles. Matching the coupler to these frequencies enables precise impedance matching and efficient power transfer. At these frequencies, it is possible to transmit high power with low losses, leading to improved overall system energy efficiency. These advantages make the RF power coupler not only versatile and adaptable but also particularly efficient and suitable for specific industrial applications requiring the aforementioned high power output.

[0045] In one aspect, the impedance matching cable is designed as a microstrip cable. Microstrip cables are flat conductive traces arranged on an insulating layer, also known as a dielectric. This design allows for a very compact construction, which can be particularly advantageous when space is limited in industrial applications, such as in control cabinets. Microstrip cables can be easily mounted on a printed circuit board (PCB), which can reduce manufacturing costs and production effort. The production of such cables is standardized, enabling fast and cost-effective manufacturing. The microstrip design can offer relatively low losses in high-frequency signals, thus enabling efficient transmission and distribution of RF energy.This can be important in applications within the aforementioned frequency ranges, where energy losses need to be minimized. A microstrip design can be engineered for very low antenna effect, meaning both very low RF energy radiation into the room and very low RF energy coupling into the transmission line. This can improve interference immunity.

[0046] In one aspect, the impedance matching line is arranged planarly on an insulating layer. A planar arrangement of the impedance matching line on an insulating layer allows for a flat and compact design that requires little space. This is particularly advantageous in space-constrained applications, such as in control cabinets or industrial equipment. Planar lines on insulating layers can be easily fabricated on printed circuit boards or other flat substrates. A planar arrangement on an insulating layer allows for relatively precise impedance control by adjusting the properties of the insulating layer and the geometry of the line. This enables accurate impedance matching, thereby reducing reflections and improving the efficiency of high-frequency transmission.Planar conductors applied to insulating layers can be effectively combined with cooling structures. Their flat design allows the conductor to be placed in contact with heat sinks or mounting plates for efficient heat dissipation, which can be crucial in high-power applications. These advantages make the planar arrangement of impedance matching conductors on an insulating layer a beneficial solution for precise, efficient, and robust transmission of high-frequency signals in various industrial applications.

[0047] In one aspect, the RF power coupler features an upper mounting plate, a middle mounting plate, and a lower mounting plate, with the middle mounting plate positioned between the upper and lower plates. This placement of the middle mounting plate between the upper and lower plates contributes to a particularly stable construction. This layered structure can give the coupler greater mechanical strength and resistance to vibrations and mechanical stresses commonly encountered in industrial environments. The middle mounting plate can act as a thermal buffer, distributing heat evenly between the upper and lower plates. This can promote uniform cooling, for example, when all three plates are used as cooling surfaces, which is particularly important in high-power applications to prevent overheating.The layered structure with the middle plate allows the upper and lower mounting plates to effectively shield the RF components from external electromagnetic interference. The middle plate provides an additional barrier, further improving the system's electromagnetic compatibility. The three-layer arrangement supports a modular design, allowing for easy addition or replacement of components. This can be advantageous, for example, when the coupler needs to be adapted for different applications or when specific parts need to be replaced during maintenance. This three-layer construction offers a combination of mechanical robustness, thermal management, and electrical shielding, which can be beneficial for the reliable and high-performance operation of the RF power coupler in demanding industrial environments.

[0048] In one aspect, the impedance matching line is positioned between the upper and middle mounting plates, and between the lower and middle mounting plates. This placement between the plates provides additional shielding against electromagnetic interference. This can reduce the risk of electromagnetic interference that could impair the performance of the impedance matching line and ensure more stable signal transmission. The contact of the impedance matching line with the adjacent mounting plates allows the heat generated during the transmission of the RF energy to be evenly transferred to and dissipated by the plates. This can support effective temperature management within the RF power coupler. The close coupling between the plates ensures that the impedance matching line remains stable and evenly positioned.This can help ensure that the impedance matching remains constant along the entire length of the line, thus reducing power losses during signal transmission. This arrangement of the impedance matching line can enable efficient use of space, increased mechanical and electrical stability, and simultaneously support temperature management within the assembly.

[0049] In one aspect, at least one of the mounting plates is designed as a cooling plate with a channel for circulating a coolant. The design of the cooling channels within the mounting plates not only contributes to heat dissipation but can also reinforce the structural integrity of the plates. This allows the mechanical properties of the mounting plates to be maintained while simultaneously improving cooling. Since cooling is achieved by the fluid in the channels, noisy, wear-prone, and failure-prone fans can often be eliminated. Furthermore, this reduces the risk of dust accumulation and / or dispersal, which is desirable in certain industrial environments, such as cleanrooms in the semiconductor industry.

[0050] In one aspect, the middle mounting plate is designed as a cooling plate with a channel for circulating a coolant. When positioned between the upper and lower plates, the middle mounting plate can act as a central cooling surface. The coolant in the channels can absorb heat from the surrounding components on both sides and efficiently dissipate it. This can ensure a uniform temperature distribution throughout the RF power coupler. The middle mounting plate's cooling function helps prevent heat buildup in the center of the assembly. The channels can dissipate heat directly, which can keep the operating temperature low and reduce the risk of thermally induced performance degradation.

[0051] In one aspect, both the upper and lower mounting plates are designed as cooling plates with a channel for coolant flow. The ability to route coolant through both plates increases heat dissipation capacity. This can support operation at higher power demands without component overheating. Using the mounting plates themselves as cooling surfaces allows for a space-saving design, eliminating the need for separate space for external heat sinks. This can simplify the integration of the RF power coupler into existing industrial systems.

[0052] In one aspect, an insulating layer is provided between the impedance matching line and one, or preferably several, mounting plates, or even all mounting plates. Here, "insulating layer" refers to an electrically insulating layer, not a thermally insulating layer. This insulating layer can positively influence the dielectric properties of the impedance matching line. This can enable more precise impedance control, thereby improving impedance matching to RF components and promoting smooth signal transmission. This insulating layer between the impedance matching line and the mounting plates can contribute to the safety, stability, and performance of the RF power coupler by providing electrical, mechanical, and thermal protection.

[0053] In one aspect, the insulating layer is made of PTFE. "PTFE" is an abbreviation for polytetrafluoroethylene. PTFE has a very high dielectric strength, which means it can function very well as an electrical insulator. It can effectively reduce the risk of short circuits and unwanted electrical connections between the impedance matching lead and the mounting plates. PTFE has a low dielectric loss factor, which can reduce energy losses in high-frequency signals. This can be used for 2024P00188WQ

[0054] 11. This contributes to ensuring that signal transmission over the impedance matching line remains efficient and the quality of the RF signals is maintained. PTFE is extremely temperature-resistant and remains stable over a wide temperature range. This allows the insulating layer to remain resilient even at high operating temperatures without losing its insulating properties, which can be particularly advantageous in high-power applications. PTFE is resistant to many chemicals and environmental influences. This protects it from corrosion and chemical reactions, which can increase the service life of the insulating layer and the surrounding components, even in demanding industrial environments. The dielectric constant of PTFE remains stable over a wide frequency range. This can facilitate precise impedance matching, as the electrical properties of the insulating layer do not change significantly with frequency.PTFE is relatively easy to process into thin layers and mold into various shapes. This can facilitate its integration as an insulating material in complex assemblies such as RF power couplers. Choosing PTFE as the insulating layer material can support reliable electrical insulation, stable high-frequency transmission, and high resistance to thermal and chemical stresses, thus improving the quality and longevity of the entire system.

[0055] One aspect is the ceramic insulating layer. Ceramic materials have very high dielectric strength, which allows them to act as highly effective insulators. They offer strong protection against electrical breakdowns, reducing the risk of short circuits between the impedance matching line and the mounting plates. Ceramic is extremely heat-resistant and retains its insulating properties even at very high temperatures. This makes it particularly suitable for applications where high operating temperatures may occur and can contribute to system stability. Ceramic materials exhibit low dielectric losses, which can help ensure efficient RF signal transmission. The low power dissipation ensures that energy transfer via the impedance matching line is not affected. The dielectric constant of ceramic remains stable even with changing temperatures and frequencies.This can facilitate precise impedance matching in the high-frequency range and ensure consistent performance of the RF power coupler. Ceramic is resistant to many aggressive chemicals and environmental influences. This makes it resistant to corrosion and ensures that the insulating layer retains its properties even in demanding industrial environments. Ceramic has high thermal conductivity compared to many other insulators. This allows for better heat dissipation, resulting in a more stable operating temperature for surrounding components. Choosing ceramic as the insulating layer material can offer a combination of excellent electrical insulation, high thermal and mechanical stability, and resistance to external influences, thus enhancing the reliability and durability of the RF power coupler.

[0056] In one aspect, the impedance matching cable is made of metal. Due to the high electrical conductivity of metal, less heat is generated during the transmission of high-frequency energy. This can help keep the cable's operating temperature low and reduce the need for complex cooling measures. Metals have high thermal conductivity, which allows the generated heat to be dissipated quickly. This can contribute to better temperature distribution and prevent certain areas from overheating. Using metal as the material for the impedance matching cable can enable reliable transmission of high-frequency signals, as metallic materials operate stably and with low loss even at high frequencies. This is advantageous for achieving a uniform impedance match.

[0057] One aspect of the impedance matching cable is its use of aluminum. Metallic materials, such as aluminum or copper, offer excellent electrical conductivity. This allows high-frequency signals to be transmitted with low resistance, which can increase signal transmission efficiency and reduce energy losses. Aluminum combines this advantage with the additional benefits of low weight, low cost, high corrosion resistance, and low emissions, which is particularly desirable in the semiconductor industry.

[0058] One aspect of the impedance matching cable is its use of copper. Metallic materials like copper offer exceptionally good electrical conductivity. This allows high-frequency signals to be transmitted with low resistance, which can increase signal transmission efficiency and reduce energy losses. Copper combines this advantage with the additional benefits of very good thermal conductivity.

[0059] In one aspect, the impedance matching cable has a meandering design. This allows for efficient use of space without unnecessarily increasing inductance. The meandering shape enables the cable to be housed in a small space. This is particularly useful when the physical length of the cable is critical for impedance matching, but available space is limited. The meandering design allows for fine-tuning of the cable's resonant characteristics to achieve precise matching at specific frequencies. This is especially advantageous in high-frequency applications where accurate cable tuning is essential. Due to its shape, a meandering cable can better absorb and compensate for certain mechanical stresses and vibrations. This allows for a more robust structure that withstands mechanical influences and maintains stability over a longer period.

[0060] In one aspect, the mounting plates are arranged parallel to each other and make contact with the impedance matching line on both sides via the insulating layer, thus providing cooling. This two-sided cooling allows the impedance matching line to handle higher electrical power without the risk of overheating. This can make the RF power coupler more resistant to power spikes and thermal loads. With this cooling method, additional external cooling devices such as fans or separate heat sinks can be reduced or eliminated, as the integrated plates already ensure effective heat dissipation. This saves space and simplifies the overall design.

[0061] In one aspect, the central mounting plate features a recess for routing the impedance matching cable. This recess allows for precise and secure routing of the impedance matching cable. This ensures the cable remains stable in place and preserves the system's mechanical structure, even under external influences. Integrating the cable into the recess allows for better utilization of vertical installation space. The cable can be routed through the plate without requiring additional width, enabling a more compact design. The recess also provides better protection for the cable against mechanical damage. The central plate acts as an additional physical barrier, safeguarding the sensitive impedance matching cable from shocks, vibrations, and other external influences.The recess allows for close contact between the conductor and the plate, facilitating heat transfer. This enables the plate to directly absorb heat from the impedance matching conductor and conduct it to a cooling system, thus promoting a more uniform temperature distribution. The precise positioning of the conductor by the recess ensures a stable electrical connection, contributing to the reliability of the high-frequency transmission. This allows for consistent impedance matching, reducing signal loss. The recess also provides clear routing for the conductor, simplifying installation. Furthermore, the impedance matching conductor remains easily accessible during maintenance without requiring disassembly of the entire assembly.This design of the center mounting plate with a recess offers a well-conceived solution for integrating the impedance matching line, reducing space requirements while simultaneously improving system stability and efficiency. Furthermore, the insulating layer between the impedance matching line and the center mounting plate is also located within the recess area, providing electrical isolation between the impedance matching line and the center mounting plate. This isolation ensures a stable electrical environment for the impedance matching line, which is crucial for maintaining a consistent impedance match. This contributes to smooth high-frequency transmission and helps reduce signal reflections, thereby increasing overall system efficiency. The insulating layer also provides additional protection when transmitting high voltages, such as those encountered in high-frequency applications.It can reduce the risk of high voltages arcing to the center mounting plate, which can increase operational reliability. The insulating layer can provide an additional physical barrier, protecting the impedance matching lead from direct mechanical stresses through the recess. This can reduce the risk of abrasion or damage that could result from movement or vibration. The insulating layer can also help regulate heat conduction between the impedance matching lead and the center mounting plate. This allows for more controlled heat dissipation and prevents overheating of the lead while maintaining electrical insulation.

[0062] In one aspect, one, and preferably several, mounting plate(s) has a cooling channel for conveying a coolant. The cooling channels in the mounting plates enable direct and uniform dissipation of the heat generated during the operation of the RF components. The coolant efficiently carries away the heat, thus maintaining the assembly temperature at a constant level. The integrated cooling channels significantly reduce the risk of overheating throughout the assembly. Even at high power levels and during extended periods of operation, this allows the components to operate within a safe temperature range. The ability to actively dissipate heat enables the system to operate stably even under high loads and demanding operating conditions. Constant cooling ensures that performance is not compromised by thermal effects.When cooling channels are arranged in several or all mounting plates, heat can be dissipated evenly across the entire system. This can reduce the formation of hotspots and ensure a balanced temperature distribution, which helps to distribute the load evenly across the components. Constant cooling reduces the thermal stress on the electrical and mechanical components. This can extend the lifespan of the components, as thermal cycling and material fatigue may be less pronounced. If the cooling channels are integrated directly into the mounting plates, the need for external cooling systems such as additional heat sinks or fans can be eliminated. This would save space and simplify the design, especially for compact assemblies. With cooling channels in multiple plates, the cooling capacity can be tailored to specific requirements.The flow rate and temperature of the coolant can be variably adjusted to ensure targeted cooling depending on the heat generation.

[0063] In one aspect, one, or more specifically several, and preferably all mounting plates are connected to a constant potential. Mounting plates at a constant potential can act as a shield, thereby reducing electromagnetic interference within the system. This can contribute to a more stable and interference-free transmission of the high-frequency signals. Connecting them to a constant potential ensures that the electrical potential of the plates remains uniform. This can create a stable electrical environment for the components and conductors in the RF power coupler, which can improve signal quality, reduce interference radiation, and minimize reflections. When all mounting plates are at the same potential level, voltage differences between the plates can be reduced or eliminated.This can reduce the risk of unwanted voltage flashovers or sparking, which could lead to damage.

[0064] In one aspect, one, or in particular several, preferably all mounting plates are connected to ground. Connecting the mounting plates to ground can further increase the electrical safety of the system. Potential leakage currents or electrical disturbances can be dissipated, which can reduce the risk of short circuits or uncontrolled voltages.

[0065] In one aspect, one, or more specifically several, and preferably all, of the mounting plate(s) can be connected to a metallic housing. Connecting the mounting plates to a metallic housing can create a closed shield that attenuates external electromagnetic interference and prevents interference radiation from escaping the system. This can improve the electromagnetic compatibility of the RF system. A metallic housing connected to the mounting plates can serve as a ground point. This allows electrical interference currents or overvoltages to be dissipated, which can increase the electrical safety of the system and protect sensitive components. The connection to a robust metallic housing can provide mechanical protection for the internal components. The housing can protect the plates and electronic components from physical influences such as shocks, vibrations, or mechanical stress.Metallic enclosures can exhibit good thermal conductivity, thus serving as an additional heat dissipation surface. When the mounting plates are directly connected to the enclosure, heat can be efficiently transferred from the plates to the enclosure and thus better distributed. Connecting the mounting plates to a common metallic enclosure ensures that all plates are at the same electrical potential. This reduces voltage differences between the plates, minimizing the risk of unwanted electrical effects such as flashovers. A metallic enclosure can also serve as a central grounding point for the entire system. Connecting the mounting plates to the enclosure facilitates system grounding and ensures reliable dissipation of electrical disturbances. The metallic enclosure provides protection against environmental factors such as moisture, dust, and chemicals.This can contribute to the longevity of the mounting plates and the integrated electronics, as they are protected from corrosion and wear. Connecting the mounting plates to the housing enables a compact and integrated design, where all components are housed securely and in a space-saving manner. This can facilitate the integration of the RF system into existing industrial plants.

[0066] In one aspect, coolant connections are provided for one, in particular several, and especially preferably all mounting plates. Using coolant connections directly on the mounting plates eliminates the need for additional external cooling devices. This can save space and simplify the design of the entire RF power coupler. Targeted cooling of each plate can prevent local overheating. This can contribute to a uniform temperature distribution throughout the assembly and prevent thermal stress points that could impair the performance and lifespan of the components.

[0067] In one aspect, an electrical power converter for an industrial process arrangement, preferably a plasma process arrangement, gas laser excitation, or heating arrangement, is disclosed. This power converter comprises: a. An RF power coupler as described in this disclosure, b. Several RF amplifier arrangements designed to be connected to the RF inputs of the RF power coupler.

[0068] An RF amplifier arrangement can also be designed as an RF generator arrangement.

[0069] The RF power coupler enables the aggregation of signals from multiple RF amplifier arrays and their combined transmission to the industrial process system. This ensures efficient transmission of high-frequency energy, thereby increasing the overall system performance. The combination of an RF power coupler and RF amplifier arrays provides clean and stable amplification of the RF signal. The power coupler helps the amplifiers operate efficiently and transmits the signal to the industrial process system without significant distortion. Integrating the RF amplifier arrays and the coupler into a single system reduces the required footprint. This is particularly advantageous when the power converter needs to be integrated into compact control cabinets or space-constrained industrial installations.Close coupling between the RF amplifier arrays and the RF power coupler can help reduce transmission losses. This allows more available energy to be utilized, which can improve the overall system efficiency. Since multiple RF amplifier arrays can be connected to the RF power coupler inputs, the system's power output can be flexibly adapted to the requirements of the specific application. This allows the power output to be increased or decreased depending on the process requirements. This design of an electrical power converter with an RF power coupler and multiple RF amplifier arrays can provide a versatile and efficient solution for demanding high-frequency industrial applications, offering advantages in adaptability, energy efficiency, and integration.

[0070] In one aspect, the problem is solved by a method for designing the impedance matching line of a high-frequency power coupler, as described here, whereby the difference length and the difference impedance are determined in an iterative procedure with the following steps:

[0071] - Difference length determination step, in which the difference length is determined as a function of the reactance resulting from the connecting line reactances, in particular the inductance resulting from the connecting line inductances;

[0072] - Differential impedance determination step in which the differential impedance is determined as a function of the impedance change resulting from the difference length;

[0073] - another difference length determination step and another difference impedance determination step and repeating these steps until a predetermined value for the fit is reached.

[0074] The development is explained in more detail below with reference to the advantageous embodiments shown in the figures. However, the development is not limited to any one of these embodiments. The figures show:

[0075] Fig. 1: an oblique view of a high-frequency power coupler;

[0076] Fig. 2: an oblique view of a high-frequency power coupler with housing parts removed;

[0077] Fig. 3: a cross-sectional view through a high-frequency power coupler without a housing;

[0078] Fig. 4: an oblique view of a high-frequency power coupler with housing parts removed; Fig. 5: a sectional view through part of a high-frequency power coupler;

[0079] Fig. 6: a schematic representation of an industrial process arrangement;

[0080] Fig. 7 shows a schematic representation of a coupling unit.

[0081] Fig. 8 shows a Smith chart and a corresponding equivalent circuit diagram of a power converter.

[0082] Fig 9a - 9f several transformation curves for different RF power coupler variants in comparison.

[0083] Fig. 1: shows an oblique view of a high-frequency power coupler 1. This RF power coupler is designed for coupling several RF input signals to a single RF output signal, for supplying RF power to an industrial process arrangement, preferably a plasma process arrangement, gas laser excitation, or heating arrangement. This RF power coupler comprises: a. several RF inputs 11, 12, 13, 14, 15, here configured as RF coaxial connectors, protruding from the housing 33; b. an RF output 7, here configured as a high-power RF connector, also in a coaxial configuration; c. a coupling unit 19, which here is arranged on a coupling unit circuit board 49; d. an impedance matching line 20, which extends from the coupling unit 19 to the RF output 7 and has a predetermined length and impedance between these two ends.

[0084] Fig. 1 further shows an upper mounting plate 23, a middle mounting plate 25 and a lower mounting plate 27, wherein the middle mounting plate 25 is arranged between the upper and the lower mounting plate and wherein the impedance matching line 20 is arranged between the upper mounting plate 23 and the middle mounting plate 25 and between the lower mounting plate 27 and the middle mounting plate 25.

[0085] The meandering shape of the impedance matching line 20 is clearly visible here.

[0086] Also shown are several fastening elements 35, in particular screws, with which, for example, the mounting plates 23, 25, 27 are connected to the housing 33.

[0087] Also shown are insulating layers 29, which are arranged between impedance matching line 20 and the mounting plates 23, 25, 27.

[0088] Also shown is a temperature sensor 37, which is arranged on one of the insulating layers 29. Several coolant channels 5, arranged in the upper mounting plate 23 and in the lower mounting plate 27 for the passage of coolant, are also shown.

[0089] Also shown are two coolant connections 8 for supplying and discharging coolant. The coolant connections 8 are connected to the coolant channels 5.

[0090] Also shown is a control connection 36 for control and data lines, e.g. for the measured signal from the temperature sensor 37.

[0091] Also shown is a recess 31 which has the middle mounting plate 25 for the routing of the impedance matching line 20.

[0092] Also shown is a cylinder 32, which provides an electrical connection of the impedance matching line 20 between the two layers of the impedance matching line 20.

[0093] Also shown are shielding spring contacts 34. These can be used to improve the electromagnetic properties of the RF power coupler.

[0094] Not shown, but conceivable, is an arrangement in which the impedance matching line 20 is guided at the edge of the middle mounting plate 25.

[0095] Fig. 2: shows an oblique view of the high-frequency power coupler 1 from Fig. 1 with at least partially removed housing parts, and without the upper mounting plate 23, so that the impedance matching line 20 on the insulating layer 29 is more clearly visible.

[0096] Here, the possible path of an impedance matching line 20" with a conventional A / 4 line length is also shown. The difference length 22, by which the actual impedance matching line 20 is shorter than A / 4, can thus also be schematically indicated. This difference length 22 depends on the connecting line reactance 21.

[0097] The depicted possible impedance matching line 20" with conventional A / 4 line length is also equipped with a calculated impedance, which is calculated from the square root of the product of the input impedance 99 of the high-frequency power coupler 1 resulting from all inputs 11, 12, 13, 14, 15 and the RF output impedance 88. The differential impedance 26, by which the conductor width is changed, can also be schematically indicated in this way.

[0098] In this and all subsequent figures, the same components have the same reference numbers.

[0099] Fig. 3 shows a cross-sectional view through the high-frequency power coupler 1 from Fig. 1 or Fig. 2 with at least some housing parts removed and without the upper mounting plate 23, so that the impedance matching line 20 on the insulating layer 29 is more clearly visible. The section plane passes through the lower mounting plate 27, the middle mounting plate 25, the insulating layer 29, the recess 31, the cylinder 32, and the impedance matching line 20. This clarifies the path of the impedance matching line 20. In particular, the transition from the position between the upper and middle mounting plates 23, 25 to the position between the lower and middle mounting plates 25, 27 by means of the recess 31 and the cylinder 32 is clearly visible. The cylinder 32 is made of metal, specifically copper. It serves to connect the impedance matching line 20 between the two layers. It is arranged insulated from the mounting plate.This therefore features recess 31, the diameter of which is correspondingly larger.

[0100] Also visible here is the coolant channel 5, which connects the two coolant connections 8 and is located in the lower mounting plate 27. A coolant 6, e.g., water, can be carried in it to dissipate the heat that may be generated by the impedance matching line 20 during operation. A coolant channel 5 can, of course, also be located in the upper and / or middle mounting plates 23, 25. In the present case, such a coolant channel 5 is indeed also provided in the upper mounting plate 23. However, the upper mounting plate 23 is not shown in this figure for the sake of clarity.

[0101] Fig. 4 shows an oblique view of the high-frequency power coupler 1 from Figs. 1-3 with at least some of the housing parts removed. In contrast to Fig. 3, the upper mounting plate 23 is shown here. Components that are not normally visible, such as the impedance matching line 20, the coolant channel 5, or the cylinder 32, are shown with dashed lines.

[0102] Fig. 5 shows a cross-sectional view through a portion of the high-frequency power coupler 1 from Figs. 1-4. The side view of the upper mounting plate 23, the middle mounting plate 25, and the lower mounting plate 27 is shown. Two insulating layers 29 are located between each of the mounting plates. The impedance matching line 20 is arranged between these insulating layers 29, thus running in two layers. The RF inputs 11, 12, 13, 14, and 15 are located on the same side of the housing 36 as the RF output 7. The impedance matching line 20 runs in a meandering path from the connection side of the housing to the opposite side, then changes position via the recess 31 and the cylinder 32, and in the second position also meanders back to the connection side of the housing 36. This design optimizes space utilization. The impedance matching line 20 runs on both sides of the middle mounting plate 25.It is further shown here how the insulating layer 29 is also arranged in the area of ​​the recess 31 between the impedance matching line 20 and the middle mounting plate 25, for electrical insulation of the impedance matching line 20 from the middle mounting plate 25.

[0103] Fig. 6 shows a schematic representation of an industrial process arrangement 100. The industrial process arrangement 100 includes an electrical power converter 4 as part of the industrial process arrangement 100. This is a gas laser excitation with a device connected to the power converter 4. The electrical power converter 4 includes: a. A power coupler 1, as described in this disclosure, b. Several RF amplifier arrangements 62, each connected to one of the RF inputs 11, 12, 13, 14, 15 of the high-frequency power coupler 1.

[0104] The RF output 7 of the high-frequency power coupler 1 is connected to the gas laser excitation arrangement 63 via a high-power interconnect 74. The high-power interconnect 74 is preferably a coaxial interconnect. These are manufactured with fixed impedances, preferably 50 Ω. For this reason, among others, the preferred output impedance of the high-frequency power coupler 1 is also set to 50 Ω. The RF power supplied by the power converter 4 is routed to an impedance matching device 64. This device typically has several reactances, such as inductance(s) or capacitance(s). These can each be partially or fully variable, i.e., adjustable, to match the input impedance of the load to the output impedance of the RF power coupler 1.

[0105] The gas laser excitation arrangement 63 has several discharge tubes 69 in which a plasma is generated using RF power. Upon recombination of the charged components of this plasma, the laser beam is produced by selecting a suitable gas, pressure, and mirror arrangement. This laser beam is then emitted at the laser outlet 68. Such a laser can be used in an EUV system. To generate and maintain the plasma in the discharge tubes 69, RF power is supplied to these tubes via electrodes. The RF power is transmitted from the impedance matching device 64 via a first connecting line 66, in particular an RF signal connecting line, to a first electrode arrangement 67, in particular an RF signal electrode arrangement.

[0106] The first connecting line 66 can have a first matching inductance 65, in particular an RF signal matching inductance, which can act as part of the impedance matching.

[0107] Opposite the first electrode arrangement 67, a second electrode arrangement 73, in particular a ground-side electrode arrangement, is arranged. This is connected to a ground terminal 72 via a second connecting line 70, in particular a ground-side connecting line. The second connecting line 70 can have an impedance matching inductance 71, in particular a ground-side impedance matching inductance, which can act as part of the impedance matching.

[0108] An electric RF field is built up between the first electrode arrangement 67 and the second electrode arrangement 73, which is used for plasma excitation.

[0109] The housing 33 of the RF power coupler 1 is connected to a ground terminal 72.

[0110] The housing of the gas laser excitation arrangement 63 is connected to a ground connection 72.

[0111] Fig. 7 shows a schematic representation of a coupling unit 19. The coupling unit 19 includes a coupling unit circuit board 49 on which the RF inputs 11, 12, 13, 14, 15 are arranged. These can be soldered to the coupling unit circuit board 49 as coaxial connectors. The coaxial connectors are shown in Figures 1 to 4. They protrude from the housing 33 in these figures.

[0112] The control connection 36 can also be located on the coupling unit circuit board 49. This is also shown in Figures 1 to 4. It also protrudes from the housing 33.

[0113] The RF inputs 11, 12, 13, 14, 15 are each connected to the star point 10 via connecting lines 41, 42, 43, 44, 45. The star point 10 is connected to the first endpoint of the impedance matching line 20 in the high-frequency power coupler 1. The second endpoint of the impedance matching line 20 is connected to the RF output 7, as also shown in Figures 1 to 4.

[0114] The connecting lines 41, 42, 43, 44, 45 can each be interrupted by RF switching units 51, 52, 53, 53, 55.

[0115] These RF switching units 51, 52, 53, 55 can, for example, be designed as RF relays. Semiconductor-based switching units, such as PIN diodes or transistors, are also conceivable.

[0116] These RF switching units 51, 52, 53, 55 can be used to disconnect individual connections during operation. This can be helpful, for example, if one of the amplifier assemblies 62 needs to be replaced while the other amplifier assemblies 62 remain in operation. In semiconductor manufacturing, for example, during plasma generation for semiconductor processes or EUV exposure, this can offer a significant advantage. The RF switching units 51, 52, 53, 55 can be controlled via signal paths connected to the control terminal 36. This can be done, in particular, via the coupling unit circuit board 49. This is shown in Fig. 7 as an example for the RF switching unit 51, 52.

[0117] Fig. 8 shows a Smith chart 80 and a corresponding equivalent circuit diagram of a power converter 4.

[0118] The RF amplifier arrangements 62 are shown here as RF signal sources 86, each with an output impedance 87. This output impedance 87 of an amplifier arrangement 62 is typically 50 Ω. An output impedance of 50 Ω corresponds to the industry standard for many high-frequency and amplifier systems. This facilitates the integration of the amplifier arrangement into existing systems, since many RF components, such as connectors, cables, and measuring instruments, are also designed for 50 Ω. This reduces unwanted reflections.

[0119] The Smith chart 80 is intended to illustrate the impedance matching by the RF power coupler 1. The Smith chart 80 and the equivalent circuit of the power converter 4 show: an impedance matching line input impedance 84 without line inductances, an impedance matching line input impedance 85 with line inductances, an impedance matching line output impedance 86 with a conventional A / 4 line, an impedance matching line output impedance 87 with a matched line length, an input impedance 99 of the RF power coupler 1 resulting from all inputs, and a predetermined RF output impedance 88.

[0120] The task is to transform the impedance of these 50 Q from the given RF output impedance 88 to the input impedance 99 resulting from all inputs. The better this is achieved, the lower the expected reflections in an industrial process arrangement 1.

[0121] Figure 8 shows that this is not possible with an A / 4 line for the impedance matching line 20 if a significant reactance resulting from the connecting line reactances 21 is present. This results in a point of 86 on the Smith chart. However, this problem can be solved by appropriately choosing the length and impedance of the impedance matching line 20. This is explained in more detail below with reference to Figures 9a to 9f.

[0122] Figures 9a-9f show different transformation curves in Smith charts. Figures 9b to 9d illustrate one embodiment of the procedural steps of this revelation. Figures 9e to 9f illustrate another possible embodiment of further procedural steps of this revelation.

[0123] All Smith charts in Figures 9a-9f are normalized to an input impedance 99 of the high-frequency power coupler 1 resulting from all inputs. For five inputs of 50 Ω each, this is, for example, 10 Ω. For eight inputs of 50 Ω each, it would be, for example, 6.25 Ω. This means that this input impedance 99 resulting from all inputs lies at the center of all Smith charts. In all Smith charts in Figures 9a-9f, the specified RF output impedance 88 is 50 Ω. The task is to transform the impedance from this 50 Ω of the specified RF output impedance 88 to the input impedance 99 resulting from all inputs. The better this is achieved, the lower the expected reflections in an industrial process arrangement 1.

[0124] Figure 9a shows this for idealized conditions. 'Idealized' means that there is no reactance resulting from the connecting line reactances 21, and no attenuation, or both would be negligibly small. The impedance matching line 20 would be an A / 4 line. The impedance transformation curve of the impedance matching line 20 for an A / 4 line is represented as a semicircle in the Smith chart. In this idealized case, such an A / 4 line is exactly the right choice. The impedance of such an A / 4 line is calculated from the square root of the product of the input impedance 99 of the high-frequency power coupler 1 resulting from all inputs and the specified RF output impedance 88. Thus, in this case, the impedance of the specified RF output impedance 88 is transformed to the input impedance 99 of the high-frequency power coupler 1 resulting from all inputs.

[0125] Figure 9b illustrates the case where the impedance matching line 20 is still the same A / 4 line with the same impedance, but the reactance resulting from the connecting line reactances 21 (here represented as inductances) is significant and no longer negligible. The attenuation is still negligibly small. The impedance 92b calculated in a simulation, which the high-frequency power coupler 1 would set, with an impedance transformation curve 97 for such an A / 4 line and an impedance transformation curve 98 for the inductance resulting from the connecting line inductances, now clearly no longer matches the input impedance 99 resulting from all inputs.

[0126] Figure 9c illustrates the case where the impedance matching line 20 has been shortened. The attenuation is still negligibly small. The shortening is already in the range of the described difference length 22. The impedance 92c calculated in a simulation, which the high-frequency power coupler 1 would set, with an impedance transformation curve 97 for such a shortened line length and an impedance transformation curve 98 for a reactance resulting from the connecting line reactances 21, now comes close to, but clearly still does not match, the input impedance 99 resulting from all inputs. Further measures are required for this.

[0127] Figure 9d illustrates the case where the impedance of the impedance matching line 20 has been changed relative to the impedance in Figure 9c by the described differential impedance 26. The simulation shows that after an initial adjustment of the differential impedance 26, the difference length 22 must also be adjusted again to approach the goal of transforming the impedance from the predetermined RF output impedance 88 to the input impedance 99 resulting from all inputs. Afterward, the differential impedance 26 must be adjusted again, followed by the difference length 22, and so on, until a satisfactory value is reached. The figure shown here is the impedance 92d calculated in a simulation, which the high-frequency power coupler 1 would set accordingly.

[0128] The entire process can be viewed as iterative. Figure 9d shows the final state of this process. The task of transforming the impedance from the 50 Q of the given RF output impedance 88 to the input impedance 99 resulting from all inputs has been achieved. A computational determination is also conceivable as an alternative to the iterative process, but more complex.

[0129] Figure 9e shows the case where the impedance matching line 20 has been modified compared to the impedance matching line 20 of Figure 9d by taking into account an actually determined attenuation. The impedance 92e calculated in a simulation, which the high-frequency power coupler 1 would set, with an impedance transformation curve 97 of such attenuation and an impedance transformation curve 98 of a reactance resulting from the connecting line reactances 21, again comes close to, but clearly does not yet match, the input impedance 99 resulting from all inputs. Further measures are required for this.

[0130] Figure 9f illustrates the case where the impedance of the impedance matching line 20 was further adjusted relative to the impedance in Figure 9e, specifically the described differential impedance 26 and the difference length 22. The simulation shows that after an initial adjustment of the differential impedance 26, the difference length 22 must also be adjusted again to approach the goal of transforming the impedance from the predetermined RF output impedance 88 to the input impedance 99 resulting from all inputs. Afterward, the differential impedance 26 must be adjusted again, followed by the difference length 22, and so on, until a satisfactory value is achieved.

[0131] The entire process can be viewed as iterative. Figure 9f shows the final state of this process. The task of transforming the impedance from the 50 Q of the given RF output impedance 88 to the input impedance 99 resulting from all inputs has been achieved again. Shown here is the impedance 92f calculated in a simulation, which the high-frequency power coupler 1 would set.

[0132] The features disclosed in the foregoing description, claims and drawings may be important, both individually and in combination, for the realization of the invention in its various embodiments.

Claims

27 Claims 1. High-frequency power coupler (1) for coupling several RF input signals to a single RF output signal, for supplying RF power to an industrial process arrangement (1), preferably a plasma process arrangement, gas laser excitation or heating arrangement, wherein the RF power coupler (1) comprises: a. several RF inputs (11, 12, 13, 14, 15), b. an RF output (17) with a predetermined RF output impedance (88), c. an impedance matching line (20), d. a coupling unit (19) with a predetermined coupling unit output impedance (81), wherein the coupling unit (19) comprises: i. a common star point (10), ii. one connection each for one of the RF inputs (11, 12, 13, 14, 15), iii. each a connecting line (41 , 42, 43, 44, 45) extending from each of the terminals of the RF inputs (11 , 12, 13, 14, 15) to the common star point (10), wherein the connecting lines (41 , 42, 43, 44, 45) each have a connecting line reactance (21), and • wherein the impedance matching line (20) is connected to the star point (10) of the coupling unit (19) and extends from the coupling unit (19) to the RF output (17) and has a predetermined length and impedance between these two ends, • where the specified length differs from a 1 / 4 length by a difference length (22), • wherein the specified impedance differs by a differential impedance (26) from a calculated impedance which is calculated from the square root of the product of the input impedance (99) of the high-frequency power coupler (1) resulting from all inputs (11, 12, 13, 14, 15) and the RF output impedance (88), • where the difference length (22) and the difference impedance (26) are each non-zero and depend on the reactance resulting from the connecting line reactances (21).

2. RF power coupler according to claim 1, wherein the RF power coupler (1) has attenuation, particularly in the area of ​​the impedance matching line (20), and the difference length (22) and the difference impedance (26) also depend on this attenuation.

3. RF power coupler according to one of the preceding claims, wherein the interconnection line reactances (21) are configured as interconnection line inductances.

4. RF power coupler according to claim 3, wherein the difference length (22) is greater when the inductance resulting from the connecting line inductances is greater.

5. RF power coupler according to one of the preceding claims, wherein the differential impedance (26) is larger when the inductance resulting from the connecting line inductances is larger.

6. RF power coupler according to one of the preceding claims, wherein the difference length (22) is greater when the attenuation is greater.

7. RF power coupler according to one of the preceding claims, wherein the differential impedance (26) is larger when the attenuation is greater.

8. RF power coupler according to one of the preceding claims, wherein the inductance resulting from the connecting line inductances (21) is in the range of 1 to 100 nH.

9. RF power coupler according to any one of the preceding claims 3 to 8, wherein the difference length (22) is in the range of Ä / 40 to Ä / 9.

10. RF power coupler according to one of the preceding claims, wherein the differential impedance (26) is in the range of 1 Q to 10 Q.

11. RF power coupler according to one of the preceding claims, wherein the predetermined impedance is reduced by a differential impedance (26) from the calculated impedance.

12. RF power coupler according to one of the preceding claims, wherein the RF power coupler (1) is designed for pulsed operation in which a load change of at least 1 kW occurs with a repetition frequency in the range of 1 kHz to 500 kHz.

13. RF power coupler according to one of the preceding claims, wherein the impedance matching line (20) is arranged planarly on an insulating layer (29).

14. RF power coupler according to one of the preceding claims, comprising an upper mounting plate (23), a middle mounting plate (25) and a lower mounting plate (27), wherein the middle mounting plate (25) is arranged between the upper and the lower mounting plate.

15. RF power coupler according to one of the preceding claims, wherein the impedance matching line (20) is arranged between the upper and middle mounting plates and between the lower and middle mounting plates.

16. RF power coupler according to one of the preceding claims, wherein at least one of the mounting plates (23, 25, 27) is designed as a cooling plate with a channel for passing a cooling fluid.

17. Electrical power converter (4) for an industrial process arrangement (100), preferably a plasma process arrangement, gas laser excitation or heating arrangement, comprising: a. An RF power coupler (1) according to one of the preceding claims, b. Several RF amplifier arrangements (62) designed to be connected to the RF inputs (11, 12, 13, 14, 15) of the RF power coupler (1).

18. Method for designing the impedance matching line (20) of a high-frequency power coupler (1) according to any one of the preceding claims 1-16, wherein the difference length (22) and the difference impedance (26) are determined in an iterative method with the following method steps: - Difference length determination step in which the difference length (22) is determined as a function of the reactance resulting from the connecting line reactances (21), in particular the inductance resulting from the connecting line inductances; - Differential impedance determination step in which the differential impedance (26) is determined as a function of the impedance change resulting from the difference length (22); - another difference length determination step and another difference impedance determination step and repeating these steps until a predetermined value for the fit is reached.

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