Plasma process supply system and power combiner for coupling HF signals for plasma process systems

Abstract

A power combiner (1) for coupling HF signals, particularly configured for a plasma process supply system and a plasma process system, wherein the power combiner (1) is configured for a predetermined operating frequency range having frequencies in the range of 2 MHz to 200 MHz, particularly in the range of 10 MHz to 50 MHz, and is configured for output power of 2 kW or more, preferably 4 kW or more, and the power combiner comprises e) a plurality of inputs (In1 to In4) configured for connecting HF power amplifier stages (AS1 to AS4), f) a main output (OUT), g) a plurality of coupling elements, particularly in the form of inductors (L1 to L4), each coupling element connecting one input (In1 to In4) to the main output (OUT), and h) a balanced circuit (B) connecting the inputs (In1 to In4) to each other, iii) an energy absorber, particularly in the form of resistors (R1 to R4), a fixed characteristic impedance, and The system comprises a balanced circuit (B) having balanced transmission lines (W1~W4) with a length of n*λ / 2, which is TIFF2026516036000010.tif5150.

Description

Technical Field

[0001] The present invention relates to a power combiner for combining HF signals, configured particularly for a plasma process supply system and a plasma process system, for powers of 2 kW or more, preferably 4 kW or more, and for frequencies in the range of 2 MHz to 200 MHz, particularly in the range of 10 MHz to 50 MHz.

[0002] The present invention further relates to an HF power amplifier unit having such a power combiner, and to a plasma process supply system and a plasma process system.

[0003] The present invention also includes a method of supplying a load, particularly a plasma process.

Background Art

[0004] A plasma process supply system is configured to supply plasma process equipment. Plasma process equipment refers to a configuration in which plasma is generated and maintained to start and continue a process. This can be gas laser excitation. In particular, it can be a plasma process apparatus. Such plasma process equipment allows materials, especially their surfaces, to be subjected to treatments such as coating, etching, or activation. Such plasma process equipment is found, for example, in the production of architectural glass, solar power modules, displays, microcontrollers, or semiconductor components such as semiconductor memory chips. Because these are high-precision processes, the requirements for such plasma process equipment, and by extension the plasma process supply system that powers them, are very high in terms of measurement and control accuracy, reliability, continuous operation, and efficiency. Such plasma process supply systems are often configured for power of 2 kW or more, preferably 4 kW or more, and for frequencies in the range of 2 MHz to 200 MHz, particularly 10 MHz to 50 MHz. Such plasma process supply systems often have one or more radio frequency signal sources configured to supply the required power in bulk and control it according to the process specifications. In addition, plasma process supply systems often have one or more impedance matching circuits configured to match the impedance at the output of a radio frequency signal source to the impedance at the input of the plasma process.

[0005] The output power of radio frequency signal sources, particularly HF power amplifier stages with transistor amplifiers, is currently limited to several hundred watts to several kilowatts by the transistors available. Therefore, to achieve higher output power, multiple radio frequency signal sources must be interconnected using a power combiner. The power combiner should minimize losses as much as possible over a wide bandwidth. Such power combiners are particularly necessary for radio frequency signal sources used in plasma process supply systems. As the demands for accuracy and stability in the measurement and control of plasma process supply systems constantly increase, the corresponding demands on the power combiners used are also constantly increasing.

[0006] At the same time, the inputs of power combiners to which radio frequency signal sources can be connected should be isolated from each other as much as possible to avoid mutual supply of radio frequency signal sources and uneven distribution of reflected output power. If the amplitude, phase, or internal impedance of the radio frequency signal sources connected to the power combiner are unequal, a push-pull signal detrimental to the radio frequency signal sources will be generated. In addition, or alternatively, if the reflected power is unevenly distributed, the phase and / or amplitude of individual amplifiers, as well as the load impedance, may fluctuate. This can lead to excessive stress on the amplifiers under the heaviest loads.

[0007] For this reason, the inputs of a power combiner are usually connected via a so-called balanced circuit. Such a balanced circuit may have, for example, resistors and / or capacitors. The inputs are often interconnected via balanced circuits, particularly a common star point.

[0008] A power combiner for such a process is known, for example, from the German Utility Model No. 202016008958 (DE202016008958U1).

[0009] A drawback of such power combiners is that they are only suitable for limited power outputs. This is because the number of radio frequency signal sources that can be placed around them is limited by the available space. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] German Utility Model No. 202016008958 (DE202016008958U1) Specification [Overview of the project] [Problems that the invention aims to solve]

[0011] Therefore, the present invention aims to provide a power combiner that is suitable for higher output. [Means for solving the problem]

[0012] This objective is achieved by the power combiner described in independent claim 1. Advantageous further developments of the present invention arise from the dependent claims and / or the detailed description of the invention.

[0013] According to the present invention, a power combiner is proposed that is configured for a predetermined operating frequency range for coupling HF signals in the range of 2 MHz to 200 MHz, particularly in the range of 10 MHz to 50 MHz, and that is configured for an output power of 2 kW or more, preferably 4 kW or more. The power combiner is configured a) Multiple inputs configured to connect HF power amplifier stages, b) Main output and, c) A plurality of coupling elements configured as inductors, each coupling element connecting one input to the main output, d) A balanced circuit that connects the inputs to each other, i) An energy absorber configured in particular as a resistor, ii) Fixed characteristic impedance, and

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[0014] The "operating frequency range" refers to the frequency range in which a power combiner and any HF power amplifier stages that can be connected to it operate, i.e., their design purpose. This can be a very narrow bandwidth operating frequency range, for example, 13.54 MHz to 13.58 MHz, or a slightly wider bandwidth, for example, 13.06 MHz to 14.06 MHz. In either case, the center frequency is 13.56 MHz. The operating frequency range is usually specified as the nominal frequency range by the power combiner manufacturer. This is specified differently depending on the application area of ​​the power combiner. If the power combiner is part of an HF power amplifier unit, it is also configured for at least this operating frequency range.

[0015] Here, λ generally refers to the wavelength of the radio frequency signal at the center frequency of the operating frequency range within the corresponding transmission line, i.e., in this case, within the balanced transmission line.

[0016]

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[0017] An energy absorber can be a component suitable for extracting electrical energy from a power combiner and converting it into heat, similar to a resistor. However, this component may also be configured to convert at least partially the energy so that this portion can be reused at a later time.

[0018] The coupling element can be, for example, an inductor or a coupling line having a predetermined length of, for example, λ / 4. For example, if all of the plurality of coupling elements are inductors, they can advantageously always have the same inductance value and, in particular, can have the same structure. The plurality of HF power amplifier stages - often generate so much heat that they need to be cooled by a cooling unit and / or - carry very high currents and voltages that would mutually interfere by radiating high-frequency electromagnetic fields due to high-power generation, and thus often cannot be arranged very close to each other.

[0019] One solution is to arrange the HF power amplifier stages further apart from each other and / or shield them appropriately. In either case, the outputs of the HF power amplifier stages can then only be arranged at a certain distance from each other. Thus, they have a disadvantageous distance for the power combiner.

[0020] If the inputs of the power combiner are far apart, the length of the balanced line from the balanced circuit to the star point increases and may deviate from the theoretically ideal 0 mm. Such a long balanced line between the balanced circuit and the star point can cause unwanted coupling with phase distortion. This deteriorates the matching between the coupling and the input. Attempts to compensate for these couplings using a balanced circuit or an attenuator have not been successful so far and / or have resulted in undesirable power losses, and in addition to the loss of efficiency in these power outputs, often result in undesirably high heat generation.

[0021] However, in such a configuration, the balanced line of the described configuration, particularly of the described length, can bring great advantages.

[0022] The coupling elements can be arranged so that they have little or no influence on each other. Here, the term "little influence" refers to an influence that is so small that it is not important according to the physical laws.

[0023] In particular, the fixed characteristic impedance of a balanced transmission line can be made equal to the characteristic impedance at the corresponding input.

[0024] In particular, the fixed characteristic impedance of a balanced transmission line can be equal to an integer multiple of the characteristic impedance at the corresponding input.

[0025] In particular, the fixed characteristic impedance of a balanced transmission line can be equal to an integer divisor of the characteristic impedance at the corresponding input.

[0026] The fixed characteristic impedance of a balanced transmission line can be equal to 25Ω, 50Ω, or 100Ω, in particular.

[0027] By using such a balanced transmission line with a length of n*λ / 2 in the balanced circuit of a power combiner, it is possible to avoid deterioration in the matching between the power combiner's coupling and its inputs.

[0028] In a further embodiment, the length of the balanced transmission line of the power combiner can serve to bridge the distance between the inputs of the power combiner, particularly over long distances.

[0029] A wide distance refers to a distance greater than or equal to λ / 16.

[0030] This makes it possible to provide a power combiner that operates efficiently and functions accurately, even with long distances between individual components.

[0031] The ability to select from different lengths of individual balanced transmission lines allows for flexible selection of the distances between the individual components of the power combiner. This means that the possible implementations of the power combiner can be configured and used with great flexibility.

[0032] Furthermore, the balanced circuit of the power combiner may have an additional capacitor. This capacitor can be connected in series or parallel to the energy absorber of the balanced circuit, particularly configured as a resistor. This makes it possible to increase the decoupling bandwidth.

[0033] Furthermore, a balanced transmission line having a length of n*λ / 2 can be configured at least partially as a coaxial cable or microstrip line. In particular, the portion configured as a coaxial cable or microstrip line can be longer than the remaining portion of the balanced transmission line in this context. This avoids interference that could be transmitted from the balanced transmission line to other assemblies such as HF power amplifier stages, or conversely, interference that could be transmitted from other assemblies such as HF power amplifier stages to the balanced transmission line.

[0034] Furthermore, the power combiner may have a capacitor that connects the output to ground. This capacitor, in particular, can be used as a low-pass filter that filters out unwanted harmonics, together with a coupling element configured as an inductor.

[0035] An additional capacitor connected to ground before the inductor can also be used. Using this, a so-called pi circuit can be created, consisting of two capacitors and one inductor, which can then function as a low-pass filter.

[0036] The power combiner can be placed on a cooling unit. The cooling unit can be a fluid-cooled cooling unit. This cooling unit may have at least one channel through which a fluid flows. In this regard, the cooling unit can be made of, for example, copper.

[0037] A cooling unit can be configured at least partially as a cooling plate. A cooling unit can be composed of multiple components of different materials. Examples of such cooling units are disclosed and described in detail in the following publications: International Publication No. 2019 / 072894 (WO2019 / 072894A1), International Publication No. 2013 / 068004 (WO2013 / 068004A1), and International Publication No. 2014 / 207185 (WO2014 / 207185A1). This means that a power combiner can be used for the high power output described in this disclosure, since process heat generated by components of a balanced circuit, particularly energy absorbers configured as resistors, can be directly discharged through a fluid located within the cooling unit. However, the power combiner can be distributed in particular across multiple cooling units, preferably multiple cooling units spaced apart from each other as described above.

[0038] Furthermore, coupling elements configured particularly as inductors, energy absorbers configured particularly as resistors, and capacitors that may be conceivable in power combiners can be arranged on a printed circuit board. The printed circuit board can be, for example, a printed circuit board formed from a material called FR-4. Such configurations of components on a printed circuit board can be easily manufactured and allow for simple contact between components.

[0039] In particular, the printed circuit board material can be a polytetrafluoroethylene-based material, also known as PTFE material. This material is especially preferable due to its low dielectric constant and low loss.

[0040] The designation FR-4 represents a class of flame-retardant and fire-resistant composite materials consisting of epoxy resin and glass fiber fabric. The abbreviation FR stands for "flame-retardant."

[0041] Polytetrafluoroethylene (PTFE) materials, also abbreviated as PTFE, are several times more expensive than FR-4, but their particularly low losses in this frequency range make them suitable for use in HF circuit boards. Because this material has a lower dielectric constant and higher dielectric strength against high electric fields, circuit boards can be constructed to be thinner.

[0042] In one embodiment, the coupling element has a fixed characteristic impedance and,

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[0043] In a further embodiment, the power combiner is - The first power combiner section, - May have a second power combiner section, - The two power combiner sections have fixed characteristic impedances, and

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[0044] In particular, the heat-generating portion of the power combiner, i.e., the portion through which the aforementioned high power flows, can be cooled by the cooling unit described in this disclosure. Balanced lines, which generally do not generate much heat, can be freely routed.

[0045] One, in particular several, preferably all, of these power combiner components may, in further embodiments, have the following: - In particular, multiple coupling elements configured as inductors for connecting one input to the main output, and / or -Energy absorbers configured as resistors, especially multiple energy absorbers. In this way, most power combiners can be mounted on a printed circuit board as described above. Balanced lines can be routed from one part of the power combiner to another.

[0046] Even in this manner, the heat-generating parts of the power combiner, that is, the parts through which the aforementioned high power flows, particularly the coupling elements, can be cooled by the cooling unit described in this disclosure.

[0047] For this purpose, an HF power amplifier stage can be connected to the input of the power combiner to complement it and form an HF power amplifier unit. This HF power amplifier unit represents a functional unit for combining multiple HF power sources and can supply its output power to other consumers or processes. The connected HF power amplifier stage can be, for example, an HF transistor amplifier.

[0048] In a further embodiment, the HF power amplifier unit may have two additional heat sink sections. -The first HF power amplifier stage, in particular the first group of HF power amplifier stages, is located on the first heat sink section. - The second HF power amplifier stage, in particular the second group of HF power amplifier stages, is located on the second heatsink section. - The two heat sink sections are spaced apart from each other, and the balanced circuit connects the outputs of the HF power amplifier stage, and the balanced line connects the HF power amplifier stage of the first heat sink section to the HF power amplifier stage of the second heat sink section.

[0049] In a further embodiment, the HF power amplifier unit may have two additional cooling units. -The first HF power amplifier stage, in particular the first group of HF power amplifier stages, is located on the first cooling unit. - The second HF power amplifier stage, in particular the second group of HF power amplifier stages, is located on the second cooling unit. - The two cooling units are positioned at a distance from each other, a balanced circuit connects the outputs of the HF power amplifier stages, and a balanced line connects the HF power amplifier stage of the first cooling unit to the HF power amplifier stage of the second cooling unit.

[0050] In this way, high power for the plasma process described herein can be generated particularly well. The HF power amplifier stages can be distributed across multiple cooling units or heat sink sections. This allows for very good heat dissipation. In addition, the HF power amplifier stages interfere with each other less due to their spacing.

[0051] A cooling unit and / or a heatsink section, or both, can be placed between the two HF power amplifier stages. Thus, the cooling unit and / or heatsink section can provide shielding to these two HF power amplifier stages, further improving signal quality and reliability.

[0052] The spacing can be measured at the shortest distance between the two cooling units and / or heatsink sections and be at least 10 mm, and in particular at least 20 mm.

[0053] As described above, a power combiner can be divided into multiple power combiner sections. Each power combiner section can be placed on a cooling unit or heat sink section, depending on which group of HF power amplifier stages it is assigned to, i.e., which power outputs it is configured to combine. This also makes it possible to effectively cool the power combiner sections.

[0054] The term “heat sink section” refers to a part of a cooling unit. A cooling unit can be configured as at least partially a cooling plate. A cooling unit can be composed of multiple parts made of different materials. Examples of such cooling units are disclosed and described in detail in the following publications: International Publication No. 2019 / 072894 (WO2019 / 072894A1), International Publication No. 2013 / 068004 (WO2013 / 068004A1), and International Publication No. 2014 / 207185 (WO2014 / 207185A1).

[0055] The above objectives can also be achieved by a plasma process supply system having at least one HF power amplifier unit as described above and an impedance matching circuit connected downstream thereof. This makes it possible to use the power combiner described above in a particularly advantageous manner, ensuring high reliability and stability of the system.

[0056] The above objectives can also be achieved by a plasma process system having a plasma process supply system as described above and a plasma process apparatus connected to an impedance matching circuit.

[0057] This makes it possible to use the power combiner described above in a particularly advantageous manner, ensuring high reliability and stability of the system.

[0058] The above objective can also be achieved by supplying a load, particularly a plasma process apparatus, using the power amplifier unit described above and an impedance matching circuit connected particularly downstream thereof, and more preferably connected to a plasma process apparatus, in which, - The HF power signal from the HF power amplifier stage is supplied to the input of the power combiner. -These HF power signals are combined at the output of a power combiner. - The balanced current is a balanced line between inputs,

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[0059] In this way, the objective can be achieved in a particularly advantageous manner.

[0060] Preferred exemplary embodiments of the present invention are schematically shown in the drawings and will be described in more detail below with reference to the figures in the drawings. [Brief explanation of the drawing]

[0061] [Figure 1a] An embodiment of a power amplifier unit having two cooling units is shown. [Figure 1b] An embodiment of a power amplifier unit having two cooling units is shown. [Figure 2] This shows an embodiment of a power amplifier unit having three cooling units. [Figure 3] This shows an embodiment of a power amplifier unit having four cooling units. [Figure 4a] An embodiment of a power amplifier unit having two cooling units is shown. [Figure 4b] An embodiment of a power amplifier unit having two cooling units is shown. [Figure 5] A schematic diagram of the power amplifier unit is shown. [Figure 6] This shows a plasma process system that includes a plasma process supply system. [Modes for carrying out the invention]

[0062] Figures 1a and 1b show two embodiments of the power amplifier unit 10 according to the present invention. Each power amplifier unit 10 comprises a power combiner 1, two HF power amplifier stages AS1 and AS2, and two cooling units CP1 and CP2. The power combiner 1 comprises two coupling elements configured as two inputs In1 and In2, a main output OUT, inductors L1 and L2, and a balanced circuit B. The HF power amplifier stages AS1 and AS2 are connected to inputs In1 and In2, with the first HF power amplifier stage AS1 connected to the first input In1 and the second HF power amplifier stage AS2 connected to the second input In2. The inductors L1 and L2 connect inputs In1 and In2 to the main output OUT, with the first inductor L1 connecting to the first input In1 and the second inductor L2 connecting to the second input In2 to the main output OUT. The inductors L1 and L2 and the HF power amplifier stages AS1 and AS2 are located on cooling units CP1 and CP2.

[0063] The first HF power amplifier stage AS1 and the first inductor L1 are located on the first cooling unit CP1. The second HF power amplifier stage AS2 and the second inductor L2 are located on the second cooling unit CP2.

[0064] Balanced circuit B connects the two inputs In1 and In2 of power combiner 1. In Figure 1a, balanced circuit B has two energy absorbers configured as resistors R1 and R2, and two balanced lines W1 and W2 having a length of n*λ / 2. Both inputs In1 and In2 of power combiner 1 are connected to a common star point S via the two resistors R1 and R2 and the two balanced lines W1 and W2.

[0065] In Figure 1b, the balanced circuit B has two energy absorbers configured as resistors R1 and R2, and a balanced transmission line W1 having a length of n*λ / 2. The two inputs In1 and In2 are interconnected via the two resistors R1 and R2 and the balanced transmission line W1.

[0066] In Figures 1a and 1b, both resistors R1 and R2 of the balanced circuit B are located on one of the two cooling units CP1 and CP2, respectively. The first resistor R1 is located on the first cooling unit CP1 and is connected in each case to the first input In1. The second resistor R2 is located on the second cooling unit CP2 and is connected in each case to the second input In2.

[0067] In contrast to the power combiner 1 in Figure 1a, the power combiner 1 in Figure 1b has a capacitor C that connects the main output OUT to ground GND.

[0068] If the energy absorber is configured as a resistor, its value can, advantageously, be equal to the characteristic impedance at the corresponding input.

[0069] In particular, the fixed resistor acting as an energy absorber can be equal to an integer multiple of the characteristic impedance at the corresponding input.

[0070] In particular, the resistance acting as an energy absorber can be equal to an integer fraction of the characteristic impedance at the corresponding input.

[0071] The resistance of the energy absorber can be equal to 25Ω, 50Ω, or 100Ω, in particular.

[0072] Figure 2 shows one embodiment of the power amplifier unit 10 according to the present invention. The power amplifier unit 10 is substantially identical to the embodiment in Figure 1a and has a third HF power amplifier stage AS3 and a third cooling unit CP3. In addition to the components described in Figure 1a, the power combiner 1 has a third input In3 and a third coupling element configured as an inductor L3. In this embodiment, the balanced circuit B includes a third balanced line W3 having a length of n*λ / 2 and a third energy absorber configured as a resistor R3. The third HF power amplifier stage AS3 is connected to the third input In3. The third inductor L3 is used to connect the third input In3 to the main output OUT. The third HF power amplifier stage AS3, the third inductor L3, and the third resistor R3 of the balanced circuit B are located on the third cooling unit CP3. Balanced circuit B connects three inputs In1 to In3 to a common star point S via resistors R1 to R3 and balanced lines W1 to W3 having a length of n*λ / 2. In this regard, the first resistor R1 and the first balanced line W1 are connected to the first input In1, the second resistor R2 and the second balanced line W2 are connected to the second input In2, and the third resistor R3 and the third balanced line W3 are connected to the third input In3.

[0073] Figure 3 shows another embodiment of the power amplifier unit 10 according to the present invention. This power amplifier unit 10 is substantially identical to the embodiment in Figure 2 and has a fourth HF power amplifier stage AS4 and a fourth cooling unit CP4. In addition to the components described in Figures 1a and 2, the power combiner 1 has a fourth input In4 and a fourth coupling element configured as an inductor L4. In this embodiment, the balanced circuit B includes a fourth balanced line W4 having a length of n*λ / 2 and a fourth energy absorber configured as a resistor R4. The fourth HF power amplifier stage AS4 is connected to the fourth input In4. The fourth inductor L4 is used to connect the fourth input In4 to the main output OUT. The fourth HF power amplifier stage AS4, the fourth inductor L4, and the fourth resistor R4 of the balanced circuit B are located on the fourth cooling unit CP4. Balanced circuit B connects four inputs In1 to In4 to a common star point S via resistors R1 to R4 and balanced lines W1 to W4 having a length of n*λ / 2. In this regard, the first resistor R1 and the first balanced line W1 are connected to the first input In1, the second resistor R2 and the second balanced line W2 are connected to the second input In2, the third resistor R3 and the third balanced line W3 are connected to the third input In3, and the fourth resistor R4 and the fourth balanced line W4 are connected to the fourth input In4.

[0074] Figures 4a and 4b show further embodiments of the power amplifier unit 10 according to the present invention. Each power amplifier unit 10 comprises a power combiner 1, four HF power amplifier stages AS1 to AS4, and two cooling units CP1 and CP2. The power combiner 1 comprises four inputs In1 to In4, a main output OUT, four coupling elements configured as inductors L1 to L4, and a balanced circuit B. The HF power amplifier stages AS1 to AS4 are connected to inputs In1 to In4. The inductors L1 to L4 connect inputs In1 to In4 to the main output OUT.

[0075] In Figure 4a, the four inputs In1 to In4 are directly connected to the main output OUT via four inductors L1 to L4.

[0076] In Figure 4b, the first two inputs In1 and In2 are interconnected via the first two inductors L1 and L2 to form the first output O1, and the second two inputs In3 and In4 are interconnected via the second two inductors L3 and L4 to form the second output O2. The two outputs O1 and O2 are then connected to the main output OUT.

[0077] The four inductors L1 to L4 and the four HF power amplifier stages AS1 to AS4 are arranged on two cooling units CP1 and CP2. The first two inductors L1 and L2 and the first two HF power amplifier stages AS1 and AS2 are arranged on the first cooling unit CP1. The HF power amplifier stages AS1 and AS2 and the components of the first power combiner section 1a, namely the coupling elements configured here as inductors L1 and L2 and the energy absorbers configured here as resistors R1 and R2, together form the first HF power amplifier stage device AU1. The second two inductors L3 and L4 and the second two HF power amplifier stages AS3 and AS4 are arranged on the second cooling unit CP2. The HF power amplifier stages AS3 and AS4 and the components of the second power combiner section 1b, namely the coupling elements configured here as inductors L3 and L4 and the energy absorbers configured here as resistors R3 and R4, together form the second HF power amplifier stage device AU2.

[0078] The balanced circuit B comprises four energy absorbers configured as resistors R1 to R4, and a balanced transmission line W1 having a length of n*λ / 2. The four inputs In1 to In4 are interconnected by the balanced circuit B. Thus, the first two inputs In1 and In2 are interconnected via the first two resistors R1 and R2 located on the first cooling unit CP1. In this regard, the first resistor R1 is connected to the first input In1, and the second resistor R2 is connected to the second input In2. Similarly, the second two inputs In3 and In4 are interconnected via the second two resistors R3 and R4 located on the second cooling unit CP2. In this regard, the third resistor R3 is connected to the third input In3, and the fourth resistor R4 is connected to the fourth input In4. The balanced transmission line W1 interconnects all four inputs In1 to In4.

[0079] In this way, two, and especially more than two, HF power amplifier stage units AU1 and AU2 can be interconnected. When more than two HF power amplifier stage units AU1 and AU2 are interconnected, as shown in Figures 2 and 3, more than two HF power amplifier stages can be used to interconnect multiple balanced lines in a star configuration.

[0080] Individual, and especially multiple, and especially preferably all, HF power amplifier stage units AU1, AU2 may have more than two HF power amplifier stages AS1, AS2. Accordingly, they may then have more than two components of power combiner sections 1a, 1b, namely more than two coupling elements configured here as inductors L1, L2, and more than two energy absorbers configured here as resistors R1, R2.

[0081] Figure 4b also shows possible connection configurations between the two outputs O1 and O2 of the two HF power amplifier stage devices AU1 and AU2 and the main output OUT.

[0082] In this case, the first output O1 of the first HF power amplifier stage AU1 is connected to the first transmission line device TL1. The first transmission line device TL1 includes a first signal conductor SL1 and a first reference conductor BL1. The second output O2 of the second HF power amplifier stage AU2 is connected to the second transmission line device TL2. The second transmission line device TL2 includes a second signal conductor SL2 and a second reference conductor BL2.

[0083] The two signal conductors SL1 and SL2 are configured to transmit the output signals of the HF power amplifier stages AU1 and AU2, respectively. The two reference conductors BL1 and BL2 represent the reference potential for the two signal conductors SL1 and SL2 and are electrically connected to a potential that cannot be altered relative to the reference ground. In this case, this potential is the reference ground GND itself.

[0084] Two transmission line devices TL1 and TL2 are both connected to a coupling line device TLC. The coupling line device TLC has a coupling signal line SLC and a coupling reference line BLC. The coupling signal line SLC is configured to transmit the combined output signals of two HF power amplifier stage devices AU1 and AU2, i.e., the sum of the output signals of the two HF power amplifier stage devices AU1 and AU2. The coupling reference conductor BLC represents the reference potential of the coupling signal conductor SLC and is electrically connected to a potential that cannot be changed with respect to the reference ground. In this case, this potential is the reference ground GND itself. The coupling line device TLC is connected to the main output OUT of the power amplifier unit 10.

[0085] In this case, the two transmission line devices TL1 and TL2 can be configured as a microstrip line MSL.

[0086] In this case, the coupling line device (TLC) can also be configured as a microstrip line (MSL). Other embodiments for carrying HF power signals are also possible, such as coaxial cables.

[0087] Figure 5 shows a further embodiment of the power amplifier unit 10 according to the present invention. The power amplifier unit 10 is very similar to the power amplifier unit 10 of Figure 4b, except from a different perspective, and the connection configuration between the two outputs O1 and O2 of the two HF power amplifier stage devices AU1 and AU2 and the main output OUT is configured as a coaxial line CXL. A description of the two transmission line devices TL1 and TL2, the two signal conductors SL1 and SL2, the two reference conductors BL1 and BL2, the coupling line device TLC, the coupling signal line SLC, and the coupling reference conductor BLC can be found in the description of Figure 4b.

[0088] The two cooling units CP1 and CP2 may each have heat sink sections CS1 and CS2. Although the multiple heat sink sections CS1 and CS2 are arranged on a common cooling plate, they may be locally spaced apart from each other (not shown in the figure). For example, the first heat sink section CS1 may be placed on the first side of the cooling unit, and the second heat sink section CS2 may be placed on the rear side of the same cooling unit.

[0089] In contrast to the power amplifier unit 10 in Figure 4b, the power amplifier unit 10 here has two combiner printed circuit boards, PCB1 and PCB2.

[0090] The first combiner printed circuit board PCB1 is placed on the first heat sink section CS1, and therefore, in this embodiment, also on the first cooling unit CP1. The second combiner printed circuit board PCB2 is placed on the second heat sink section CS2, and therefore, in this embodiment, also on the second cooling unit CP2. Furthermore, the power amplifier unit 10 has the power combiner 1 shown in Figure 4b. Of these, four HF power amplifier stages AS1 to AS4 are shown, each divided into HF power amplifier stage devices AU1 and AU2. Inductors L1 to L4, a main output OUT, and four coupling elements configured as a balanced circuit B are also shown. The balanced circuit B comprises four energy absorbers configured as resistors R1 to R4, and a balanced line W1 having a length of n*λ / 2.

[0091] The first two HF power amplifier stages AS1 and AS2 are located on the first amplifier printed circuit board PCB12. The first two HF power amplifier stages AS1 and AS2 are located together with the first amplifier printed circuit board PCB12 on the first heat sink section CS1, and therefore, in this embodiment, also on the first cooling unit CP1. The second two HF power amplifier stages AS3 and AS4 are located on the second amplifier printed circuit board PCB34. The second two HF power amplifier stages AS3 and AS4 are located together with the second amplifier printed circuit board PCB34 on the second heat sink section CS2, and therefore, in this embodiment, also on the second cooling unit CP2.

[0092] The first synthesizer printed circuit board PCB1 can also be combined with the first amplifier printed circuit board PCB12 to form a common printed circuit board.

[0093] The second synthesizer printed circuit board PCB2 can also be combined with the second amplifier printed circuit board PCB34 to form a common printed circuit board.

[0094] This simplifies production, reduces the number of cable connections between printed circuit boards, and makes the entire system more reliable.

[0095] The first two inductors L1 and L2 and the first two resistors R1 and R2 are arranged on the first combiner printed circuit board PCB1. The second two inductors L3 and L4 and the second two resistors R3 and R4 are arranged on the second combiner printed circuit board PCB2.

[0096] Figure 6 shows a plasma process system 17 having a plasma process supply system 12.

[0097] The plasma process supply system 12 includes a power amplifier unit 10 having a power combiner 1. These can be configured as described above.

[0098] The plasma process supply system 12 also includes an impedance matching circuit 11.

[0099] The main output OUT of the power combiner 1 is connected to the input of the impedance matching circuit 11. The output terminal of the impedance matching circuit 11 is connected to the load, in this case the plasma process equipment in the plasma chamber 13.

[0100] Plasma chamber 13 is located here. - A substrate 15 is processed by plasma 16, for example, by coating or etching, -In order to ignite and maintain the plasma 16, HF power is coupled to the electrode 14 which is connected to the plasma chamber 13, It holds.

[0101] The impedance matching circuit 11 is configured to convert the input impedance of the plasma process at its output to the output impedance of the power amplifier unit 10. Embodiments of such plasma process systems and / or impedance matching circuits are described, for example, in the following published applications: German Patent Publication No. 102009001355 (DE102009001355A1), German Patent Publication No. 102011007597 (DE102011007597A1), German Patent Publication No. 102011007598 (DE102011007598A1), International Publication No. 2021 / 209390 (WO2021 / 209390A1), and International Publication No. 2021 / 255250 (WO2021 / 255250A1).

Claims

1. A power combiner (1) for coupling HF signals, particularly configured for a plasma process supply system and a plasma process system, wherein the power combiner (1) is configured for a predetermined operating frequency range having frequencies in the range of 2 MHz to 200 MHz, particularly in the range of 10 MHz to 50 MHz, and is configured for an output power of 2 kW or more, preferably 4 kW or more. The aforementioned power combiner is a) Multiple inputs (In1 to In4) configured to connect the HF power amplifier stages (AS1 to AS4), b) Main output (OUT), c) A plurality of coupling elements configured as inductors (L1 to L4), each coupling element connecting one input (In1 to In4) to the main output (OUT), d) A balanced circuit (B) that connects the inputs (In1 to In4) to each other, i) An energy absorber configured in particular as resistors (R1 to R4), ii) Fixed characteristic impedance, and, [Math 1] A balanced transmission line (W1 to W4) having a length of n*λ / 2, A balanced circuit (B) having, A power combiner (1) is provided with the following:

2. The power combiner (1) according to claim 1, wherein the balanced circuit (B) may have an additional capacitor.

3. The power combiner (1) according to claim 1 or 2, wherein the balanced lines (W1 to W4) having a length of n*λ / 2 have at least partially coaxial cables or microstrip lines, and in particular, the portion configured as a coaxial cable or microstrip line is longer than the remaining portion of the balanced lines.

4. The power combiner (1) according to any one of claims 1 to 3, wherein the power combiner has a capacitor (C) that connects the main output (OUT) to ground (GND).

5. The power combiner (1) according to any one of claims 1 to 4, wherein the power combiner (1) is disposed on at least one cooling unit (CP1 to CP4), for example, a fluid-cooled cooling plate.

6. The power combiner (1) according to any one of claims 1 to 5, wherein the coupling element of the power combiner (1), which is particularly configured as an inductor (L1 to L4), and the energy absorber of the balance circuit (B), which is particularly configured as a resistor (R1 to R4), are arranged on a printed circuit board, particularly a combiner printed circuit board (PCB1, PCB2).

7. - The first power combiner section (1a), - The second power combiner section (1b), It has, - The two power combiner sections (1a, 1b) have a fixed characteristic impedance, and [Math 2] A power combiner (1) according to any one of claims 1 to 6, connected to a balanced line (W1) having a length of n*λ / 2.

8. One, in particular, multiple, preferably all, power combiner sections (1a, 1b) - In particular, a plurality of coupling elements configured as inductors (L1 to L4) for connecting one input (In1 to In4) to the main output (OUT), - In particular, an energy absorber configured as a resistor (R1 to R4), especially multiple energy absorbers, A power combiner (1) according to claim 7, having the following features.

9. An HF power amplifier unit (10) having a power combiner (1) according to any one of claims 1 to 8, wherein an HF power amplifier stage (AS1 to AS4), for example an HF transistor amplifier, is connected to the inputs (In1 to In4) of the power combiner (1).

10. It has two additional cooling units (CP1, CP2), - The first HF power amplifier stage (AS1), in particular the first group of HF power amplifier stages (AS1, AS2), is arranged on the first cooling unit (CP1), - The second HF power amplifier stage (AS3), in particular the second group of HF power amplifier stages (AS3, AS4), is located on the second cooling unit (CP1). - The HF power amplifier unit (10) according to claim 9, wherein the two cooling units (CP1, CP2) are arranged at a distance from each other, the balanced circuit (B) connects the outputs of the HF power amplifier stages (AS1, AS2, AS3, AS4), and the balanced line (W1) connects the HF power amplifier stages (AS1, AS2, AS3, AS4) of the first cooling unit (CP1) to the HF power amplifier stages of the second cooling unit (CP2).

11. It has two additional heatsink sections (CS1, CS2), - The first HF power amplifier stage (AS1), in particular the first group of HF power amplifier stages (AS1, AS2), is arranged on the first heat sink section (CS1), - The second HF power amplifier stage (AS3), in particular the second group of HF power amplifier stages (AS3, AS4), is located on the second heatsink section (CS2). - The HF power amplifier unit (10) according to claim 9, wherein the two heat sink sections (CS1, CS2) are spaced apart from each other, the balanced circuit (B) connects the outputs of the HF power amplifier stages (AS1, AS2, AS3, AS4), and the balanced line (W1) connects the HF power amplifier stages (AS1, AS2, AS3, AS4) of the first heat sink section (CS1) to the HF power amplifier stages of the second heat sink section (CS2).

12. A plasma process supply system (12) comprising at least one HF power amplifier unit (10) and an impedance matching circuit (11) connected downstream thereof, as described in any one of claims 9 to 11.

13. A plasma process system (17) comprising a plasma process supply system (12) according to claim 12, and a plasma process apparatus connected to the impedance matching circuit (11).

14. A method for supplying a load, particularly a plasma process, using a power amplifier unit (10) according to any one of claims 9 to 11 and an impedance matching circuit (11) connected particularly downstream thereof, and more preferably connected to a plasma process apparatus, -HF power signals from the HF power amplifier stages (AS1 to AS4) are supplied to the inputs (In1 to In4) of the power combiner. - These HF power signals are combined at the main output (OUT) of the power combiner (1), - A balanced current flows through the balanced line (W1) between the inputs (In1 to In4), and the balanced line (W1) is, [Math 3] A method having a length of n*λ / 2 and a fixed characteristic impedance.

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