RF power amplifier unit for coupling RF signals for a plasma process supply system and a plasma process system

Abstract

The invention relates to an RF power amplifier unit (10) for coupling RF signals, in particular for a plasma process supply system, said unit comprising a) a first RF power amplifier stage arrangement (AU1), b) a second RF power amplifier stage arrangement (AU2), c) a first and a second transmission line arrangement (TL1, TL2) each connected to the output of the two RF power amplifier stage arrangements (AU1, AU2), d) a coupling line arrangement (TLC) designed to transmit the sum of the output powers of the two RF power amplifier stage arrangements (AU1, AU2), wherein e) the two transmission line arrangements (TL1, TL2) are each connected to the coupling line arrangement (TLC) in order to be able to transmit the output powers of the first and second RF power amplifier stage arrangements (AU1, AU2) to the coupling line arrangement (TLC), f) a measuring device (M1) designed to determine a variable that describes the power output by the RF power amplifier stage arrangements and / or the RF power amplifier unit, said measuring device being positioned on at least one of the transmission and / or coupling line arrangements (TL1, TL2, TLC).

Description

[0001] RF power amplifier unit for coupling RF signals for a plasma process supply system and a plasma process system

[0002] The present invention relates to an RF power amplifier unit for coupling RF signals, in particular for a plasma process supply system and a plasma process system, designed for powers > 2 kW, preferably > 4 kW and frequencies in the range from 2 MHz to 200 MHz, in particular in the range from 10 MHz to 50 MHz.

[0003] The present invention further relates to a plasma process supply system and a plasma process system.

[0004] It also includes a method for supplying a load, in particular a plasma process.

[0005] A plasma process supply system is configured to supply a plasma process assembly. A plasma process assembly is an assembly in which a plasma is generated and maintained to start and maintain a process. This can involve gas laser excitation. In particular, it can be a plasma processing assembly. With such a plasma processing assembly, materials, and in particular their surfaces, can be processed, for example, by coating, etching, or activating them. Such plasma processing assemblies are used, for example, in the manufacture of architectural glass, photovoltaic modules, displays, semiconductor components such as microcontrollers or semiconductor memory chips, etc.Since these are high-precision processes, the demands on such plasma process arrangements and consequently also on the plasma process supply systems that supply them with electrical power are extremely high, with regard to measurement and control accuracy, reliability, continuous operation, efficiency, etc. Such a plasma process supply system is often designed for power levels > 2 kW, preferably > 4 kW, and frequencies in the range of 2 MHz to 200 MHz, particularly in the range of 10 MHz to 50 MHz. Such a plasma process supply system often has one or more high-frequency signal sources designed to jointly provide this required power and to regulate it according to the process specifications.

[0006] In addition, a plasma process supply system often includes one or more impedance matching circuits designed to match the impedance at the output of the high-frequency signal source(s) to the impedance at the input of the plasma process.

[0007] The output power of high-frequency signal sources, especially RF power amplifier stages with transistor amplifiers, is limited by currently available transistors to a few hundred watts to a few kW. To achieve higher output power, multiple high-frequency signal sources must therefore be interconnected. This interconnection can be implemented in RF power amplifier units.

[0008] The RF power amplifier units should have the lowest possible losses at a wide bandwidth. High-frequency signal sources for plasma process supply systems, in particular, require such RF

[0009] Power amplifier units. As the demands on measurement and control accuracy, as well as stability, of plasma process supply systems continue to increase, the corresponding requirements for the RF power amplifier units used in them are also constantly growing. At high power levels, RF power amplifier units often require a lot of space. Furthermore, the problem of interference from unwanted emissions increases.

[0010] A power combiner for such processes is known, for example, from DE 20 2016 008 958 Ul.

[0011] The disadvantage of such a power combiner is that it is only suitable for a limited power output. This is due to the limited space available for the number of high-frequency signal sources that can be arranged around it.

[0012] The present invention is therefore based on the object of providing an RF power amplifier unit which reliably combines several RF power amplifier stages in a limited space and at high power levels and monitors the output power using a measuring device.

[0013] This object is achieved by an RF power amplifier unit according to independent claim 1. Advantageous developments of the invention emerge from the subclaims and / or the description. According to the present invention, an RF power amplifier unit for coupling RF signals, designed for powers > 2 kW, preferably > 4 kW and frequencies in the range from 2 MHz to 200 MHz, in particular in the range from 10 MHz to 50 MHz, is proposed, comprising: a) a first RF power amplifier stage arrangement with a first output impedance arranged on a first heat sink section, b) a second RF power amplifier stage arrangement with a second output impedance arranged on a second heat sink section,c) A first transmission line arrangement connected to the output of the first RF power amplifier stage arrangement and designed to transmit the output power of the first RF power amplifier stage arrangement and designed for a first line impedance equal to the output impedance of the first RF power amplifier stage arrangement, d) A second transmission line arrangement connected to the output of the second RF power amplifier stage arrangement and designed to transmit the output power of the second RF power amplifier stage arrangement and designed for a second line impedance equal to the output impedance of the second RF power amplifier stage arrangement, e) A coupling line arrangement designed to transmit the sum of the output powers of the first and second RF power amplifier stage arrangements and designed for a coupling line impedance, wherein the coupling line impedance is dependent on the first and second line impedances,wherein f) the first and second transmission line arrangements are each connected to the coupling line arrangement in order to be able to transfer the output powers of the first and second RF power amplifier stage arrangements to the coupling line arrangement, g) a measuring device designed to determine a quantity describing the power output by the RF power amplifier stage arrangements and / or the RF power amplifier unit, arranged on at least one of the transmission and / or coupling line arrangements.

[0014] RF power amplifier stage arrangement refers to an arrangement that may include several RF power amplifier stages, coupling elements and energy absorbers.

[0015] An energy absorber can be a component capable of extracting electrical energy from the power combiner and converting it into heat, for example, like a resistor. It is also conceivable, however, that this component is designed to at least partially convert the energy and make it available again at another location.

[0016] A coupling element can be, for example, an inductor or a coupling line with a predetermined length, e.g., a quarter-wavelength. If the multiple coupling elements are all inductors, for example, they can advantageously always have the same inductance value, in particular, they can be of identical construction. The multiple coupling elements can be arranged such that they hardly influence each other, or in particular, do not influence each other at all. "Hardly" here means such a small influence that it is insignificant according to the laws of physics.

[0017] A heat sink section refers to a part of a cooling unit. The cooling unit can be designed at least partially as a cooling plate. The cooling unit can be composed of several parts made of different materials. Examples of such a cooling unit are disclosed and described in detail in the following published applications: WO 2019 / 072894 A1, WO 2013 / 068004 A1, WO 2014 / 207185 A1.

[0018] This provides an RF power amplifier unit that reliably interconnects the output power of two RF power amplifier stage arrangements in a confined space and, with the aid of a measuring device, monitors the power of the RF power amplifier stage arrangement and / or the output power of the RF power amplifier unit. Furthermore, arranging the RF power amplifier stage arrangements on heat sink sections can achieve a shielding effect. This can prevent disruptive effects such as unwanted radiation. Another reason for this may be that the RF power amplifier stages often cannot be arranged very close to one another because they frequently generate so much heat that they require cooling units, and / or their high power generation results in such high currents and voltages that they would negatively influence each other by radiating high-frequency fields.

[0019] One solution is to arrange the RF power amplifier stages further apart and / or to shield them appropriately. In both cases, the outputs of the RF power amplifier stages can then only be arranged further apart. This creates a disadvantageous distance for the power combiner. This disadvantage can be overcome by advantageous interconnection with the previously described transmission line arrangements and the coupling line arrangement.

[0020] In a further aspect of the RF power amplifier unit, the following relationship to the first and second line impedance can apply to the coupling line impedance: ZC' = 1 / (1 / Z1'+1 / Z2') with

[0021] ZC': coupling line impedance,

[0022] ZI': first line impedance and

[0023] Z2': second line impedance.

[0024] In this way, interference caused by reflections can be further reduced and the measurement and thus the control can be further improved.

[0025] In another aspect of the RF power amplifier unit, the first and second line impedances may be equal.

[0026] In this way, interference caused by reflections can be further reduced and the measurement and thus the control can be further improved.

[0027] In another aspect of the RF power amplifier unit, the first and second line impedances may each be twice the coupling line impedance.

[0028] In this way, interference due to reflections can be further reduced, and the measurement and thus the control are further improved. In a further aspect, the RF power amplifier unit can further comprise: a) one, in particular a plurality of, further RF power amplifier stage arrangement(s), each with a further output impedance arranged on a respective further heat sink section, and b) one, in particular a plurality of, further transmission line arrangement(s), connected to the respective output of the further RF power amplifier stage arrangement(s) and each designed to transmit the output power of the further RF power amplifier stage arrangement(s) and designed for further line impedance(s) equal to the output impedance of the further RF power amplifier stage arrangement(s),wherein c) the coupling line arrangement is designed to transmit the sum of the output powers of the first and second and further RF power amplifier stage arrangements and is designed for a coupling line impedance, wherein the coupling line impedance is dependent on the first, second and further line impedance, and wherein d) the further transmission line arrangement(s) are each connected to the coupling line arrangement in order to be able to transfer the output power(s) of the further RF power amplifier stage arrangement to the coupling line arrangement.

[0029] In this way, the advantages of the invention can be achieved even at higher power levels.

[0030] In a further aspect of the RF power amplifier unit, the following relationship to the first, second and further line impedances can apply to the coupling line impedance: ZC' = 1 / (1 / Zl'+1 / Z2'+1 / Zn') with

[0031] ZC': coupling line impedance,

[0032] ZI': first line impedance,

[0033] Z2': second line impedance and

[0034] Zn': further line impedances.

[0035] For ne H applies. This means that n can be a natural number, i.e. n = 1, 2, 3, 4, . . . The number n indicates the number of line impedances. For n = 3 as an example, the further line impedances Zn' result in a third line impedance Z3' and the following applies: ZC' = 1 / (1 / Z1'+1 / Z2'+1 / Z3'). For n = 4 as an example, the further line impedances Zn' result in a third line impedance Z3' and a fourth line impedance Z4', the following applies: ZC' = 1 / (1 / Z1'+1 / Z2'+1 / Z3'+1 / Z4'). This can be continued in this way for larger numerical values ​​of n.

[0036] The number of line impedances results from the number of transmission line arrangements of the RF power amplifier unit.

[0037] In this way, interference caused by reflections can be further reduced even at higher power levels, and the measurement and thus the control is further improved.

[0038] In a further aspect of the RF power amplifier unit, the further line impedance(s) may be equal to the first and / or second line impedance.

[0039] In this way, interference caused by reflections can be further reduced even at higher power levels, and the measurement and thus the control is further improved.

[0040] In a further aspect of the RF power amplifier unit, the further line impedance(s) may each be N times as large as the coupling line impedance with N = number of the first, second and n-th transmission line arrangements.

[0041] In this way, interference caused by reflections can be further reduced even at higher power levels, and the measurement and thus the control is further improved.

[0042] In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, transmission line arrangements can have:

[0043] - a signal conductor designed to transmit the respective output signal of the RF power amplifier stage arrangements,

[0044] - a reference conductor electrically connected to a potential that is constant relative to the reference ground, especially to the reference ground. This further reduces interference due to radiation, further improving measurement and thus control.

[0045] In a further aspect of the RF power amplifier unit, the coupling line arrangement may comprise:

[0046] - a coupling signal conductor designed to transmit the combined output signals of the RF power amplifier stage arrangements,

[0047] - a coupling reference conductor which is electrically connected to a potential which is invariable with respect to the reference ground, in particular to the reference ground.

[0048] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0049] In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, transmission line arrangements can be designed as a microstrip line.

[0050] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0051] In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, transmission line arrangements can be designed as a coaxial line.

[0052] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0053] In a further aspect of the RF power amplifier unit, the coupling line arrangement can be designed as a microstrip line.

[0054] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0055] In a further aspect of the RF power amplifier unit, the coupling line arrangement can be designed as a coaxial line.

[0056] In this way, interference due to radiation can be further reduced, and measurement and thus control are further improved. In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, transmission line arrangements can be connected by their connection, in particular by their signal connection, to the respective RF power amplifier stage arrangement(s) by means of a pin, which can in particular be part of the respective transmission line arrangements.

[0057] This makes production easier and allows for very reliable and accurate measurements.

[0058] In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, RF power amplifier stage arrangement(s) can be arranged on printed circuit boards, which in turn are arranged on the respective heat sink sections and in particular the transmission line arrangements are connected to electrical contacts of these printed circuit boards.

[0059] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0060] In a further aspect of the RF power amplifier unit, the heat sink sections can each be arranged on a separate cooling unit.

[0061] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0062] In another aspect of the RF power amplifier unit, the heat sink sections may be arranged to surround a space surrounding them.

[0063] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0064] In a further aspect of the RF power amplifier unit, the coupling line arrangement can be arranged within a space surrounded by the heat sink sections.

[0065] This further reduces interference due to radiation, and measurement and thus control are further improved. In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, transmission line arrangements can be arranged predominantly within a space surrounded by the heat sink sections.

[0066] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0067] In a further aspect of the RF power amplifier unit, the measuring device may be arranged within a space surrounded by the heat sink section.

[0068] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0069] In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, RF power amplifier stage arrangement(s) can be arranged outside a space surrounded by the heat sink sections.

[0070] In this way, interference caused by radiation can be further reduced and the measurement and thus the control can be further improved.

[0071] In a further aspect of the RF power amplifier unit, several, particularly preferably all, RF power amplifier stage arrangement(s) can be constructed identically and, in particular, can be arranged line-symmetrically to the coupling line arrangement.

[0072] This improves the reliability of the RF power amplifier unit because identical parts can be used.

[0073] In a further aspect of the RF power amplifier unit, the cooling unit(s) can be designed, in particular embodied, as fluid-cooled cooling unit(s), in particular cooling plate(s), e.g. for cooling with air, a liquid or a combination of both.

[0074] This can improve the reliability of the RF power amplifier unit, as the RF power amplifier unit does not heat up as much, and temperature-sensitive components remain operational longer. In a further aspect of the RF power amplifier unit, one, in particular several, particularly preferably all, RF power amplifier stage arrangements can have several amplifier stages, the outputs of which are connected to the inputs of a power combiner section, which has:

[0075] - several inputs and one output,

[0076] - several coupling elements, in particular inductors, which each connect the inputs to the output of the power combiner part,

[0077] - an energy absorber, in particular a resistor, which connects the inputs of the power combiner part, in particular a plurality of energy absorbers, in particular resistors, which connect the inputs of the power combiner part, in particular in a star shape.

[0078] In this way, interference caused by reflections can be further reduced even at higher power levels, and the measurement and thus the control is further improved.

[0079] In a further aspect of the RF power amplifier unit, the RF power amplifier unit may comprise a power combiner, comprising:

[0080] - several power combiner parts,

[0081] - several further transmission line arrangement(s), each connected to an output of the power combiner parts,

[0082] - a coupling line arrangement and

[0083] - especially a balancing line.

[0084] In this way, interference caused by reflections can be further reduced even at higher power levels, and the measurement and thus the control is further improved.

[0085] A compensating line can be a line with a fixed characteristic impedance and a length of n* / 2 with ne N.

[0086] Such a balancing line is described, for example, in DE 10 2023 111 812.9, filed on May 5, 2023, which is incorporated into this application in its entirety by reference. Such a balancing line can be used to prevent cross-feeding of the RF power amplifier stages used as RF signal sources and to prevent uneven distribution of reflected output power. Unequal amplitudes, phases, or internal impedances of the RF power amplifier stages connected to the power combiner result in a push-pull signal that is harmful to the RF signal sources. Additionally or alternatively, unequal distribution of the reflected power can change the phases and / or amplitudes as well as the load impedance of the individual RF power amplifier stages. This can lead to excessive stress on the most heavily loaded RF power amplifier stage.To avoid this, the compensation line can be connected to the inputs of a power combiner.

[0087] The compensation line can also be designed as a compensation circuit with additional elements such as resistors.

[0088] In particular, the specified characteristic impedance of the compensating line can be equal to the characteristic impedance at the corresponding input.

[0089] The specified characteristic impedance of the compensation line can in particular be equal to an integer multiple of the characteristic impedance at the corresponding input.

[0090] The specified characteristic impedance of the compensation line can in particular be equal to an integer divisor of the characteristic impedance at the corresponding input.

[0091] The specified characteristic impedance of the compensating line can in particular be equal to 25 Q, 50 Q or 100 Q.

[0092] Here, "n" generally refers to the wavelength of the high-frequency signals within the corresponding line, i.e., within the compensating line, at a frequency within the operating frequency range, specifically the center frequency of the operating frequency range. "n" N means that n can be a natural number, i.e., n = 1, 2, 3, 4, . . .

[0093] An 'operating frequency range' refers to a frequency range within which the power combiner and the RF power amplifier stages connected to it are operated, i.e. for which they are designed.

[0094] This can be a very narrowband operating frequency range, e.g., 13.54 MHz - 13.58 MHz, or a somewhat broader one, e.g., 13.06 MHz to 14.06 MHz. In both cases, the center frequency would be 13.56 MHz. The operating frequency range is usually specified by the manufacturer of a power combiner as the nominal frequency range. This will vary depending on the power combiner's application. If a power combiner is part of an RF power amplifier unit, it is also designed for at least this operating frequency range.

[0095] The problem is also solved by a plasma process supply system comprising at least one RF power amplifier unit as described above and a downstream impedance matching circuit. Thus, a power combiner as described above can be used particularly advantageously and ensures exceptional system reliability and stability.

[0096] The object is also achieved by a plasma process system comprising a plasma process supply system as described above and a plasma process arrangement which is connected to the impedance matching circuit.

[0097] For example, a power combiner as described above can be used particularly advantageously and ensure particular reliability and stability of the system.

[0098] The object is also achieved by a method for supplying a load, in particular a plasma processing arrangement with a previously described power amplifier unit and in particular with an impedance matching circuit connected downstream thereof, which in turn is particularly preferably connected to a plasma processing arrangement, wherein a) a first output power is generated by a first RF power amplifier stage arrangement, b) a second first output power is generated by a second RF power amplifier stage arrangement, c) the first output power is transmitted by a first transmission line arrangement and d) a second output power is transmitted by a second transmission line arrangement e) to a coupling line arrangement, f) which transmits the coupled output powers of the first and second RF power amplifier stage arrangements to an output of the power amplifier unit,and a) a quantity describing the power delivered by the RF power amplifier stage arrangements and / or the RF power amplifier unit is determined at one of the transmission and / or coupling line arrangements using a measuring device, and g) the load is supplied with these coupled output powers.

[0099] In this way, the task can be solved particularly advantageously.

[0100] Preferred embodiments of the invention are illustrated schematically in the drawings and are explained in more detail below with reference to the figures of the drawing.

[0101] They show:

[0102] Fig. 1 is a schematic view of a first embodiment of an RF power amplifier stage unit according to the invention

[0103] Fig. 2 is a schematic view of a second embodiment of an RF power amplifier unit according to the invention

[0104] Fig. 3 is a schematic circuit diagram of an embodiment of an RF power amplifier unit according to the invention

[0105] Fig. 4 shows a further embodiment of an RF power amplifier unit according to the invention

[0106] Fig. 5 shows a plasma process system with an RF power amplifier stage unit according to the invention.

[0107] Fig. 1 shows an embodiment of an RF power amplifier unit 10 according to the invention. The RF power amplifier unit 10 has two RF power amplifier stage arrangements AU1, AU2, two cooling units CP1, CP2, two heat sink sections CS1, CS2, two printed circuit boards PCB1, PCB2, two transmission line arrangements TL1, TL2, a measuring device M1 and a coupling line arrangement TLC. The first RF power amplifier stage arrangement AU1 is arranged on the first printed circuit board PCB1. Via this first printed circuit board PCB1, the first RF power amplifier stage arrangement AU1 is also arranged on the first heat sink section CS1. The first heat sink section CS1 is part of the first cooling unit CP1. The second RF power amplifier stage arrangement AU2 is arranged on the second printed circuit board PCB2. Via this second printed circuit board PCB2, the second RF power amplifier stage arrangement AU2 is also arranged on the second heat sink section CS2.The second heat sink section CS2 is part of the second cooling unit CP1.

[0108] The two cooling units CPI, CP2 are arranged in such a way that they surround a room VI.

[0109] The first transmission line arrangement TL1 connects the first RF power amplifier stage arrangement AU1 to the coupling line arrangement TLC and has a first signal conductor SL1 and a first reference conductor BL1. The second transmission line arrangement TL2 connects the second RF power amplifier stage arrangement AU2 to the coupling line arrangement TLC and has a second signal conductor SL2 and a second reference conductor BL2. The coupling line arrangement TLC has a coupling signal conductor SLC and a coupling reference conductor BLC.

[0110] The two signal conductors SL1, SL2 are designed to transmit the respective output signals of the RF power amplifier stage arrangements AU1, AU2. The two reference conductors BL1, BL2 represent the reference potential to the two signal conductors SL1, SL2 and are electrically connected to a potential that is constant relative to the reference ground. This potential can also be the reference ground itself.

[0111] The two transmission line arrangements TL1, TL2 are combined and connected to the coupling line arrangement TLC. The coupling signal line SLC is designed to transmit the combined output signals of the two RF power amplifier stage arrangements AU1, AU2. The coupling reference conductor BLC represents the reference potential of the coupling signal conductor SLC and is electrically connected to a potential that is constant with respect to the reference ground. This potential can also be the reference ground itself. The measuring device M1 is integrated into the coupling line arrangement TLC and is designed here to determine the combined power of the two RF power amplifier stage arrangements AU1, AU2. The measuring device M1 can, for example, comprise at least one directional coupler or a current sensor and a voltage sensor.Via the at least one directional coupler, the measuring device M1 can measure the power of the RF signal transmitted from the RF power supply unit 10 toward the impedance matching circuit 11 or load. Preferably, the measuring device M1 can also measure the power of an RF signal reflected back at the impedance matching circuit 11 toward the RF power supply unit 10. The power of the RF signal transmitted from the RF power supply unit 10 toward the impedance matching circuit 11 can also be determined via the current sensor and the voltage sensor. The power of an RF signal reflected by the impedance matching circuit 11 can also be detected by the current sensor and the voltage sensor.

[0112] A typical measuring device Ml is shown, for example, in one of the following publications: WO2019 / 185424 Al, WO2013 / 143537 Al, US2009 / 0140722 Al, US2006 / 0232265 Al, DE 20 2011 051 371 Ul.

[0113] Fig. 2 shows a further embodiment of an RF power amplifier unit 10 according to the invention. The RF power amplifier unit 10 is constructed very similarly to the RF power amplifier unit 10 from Fig. 1. However, it has an additional third RF power amplifier stage arrangement AUn. This third RF power amplifier stage arrangement AUn is arranged on a third heat sink section CSn. The third heat sink section CSn is part of a third cooling unit C3. The third RF power amplifier arrangement AUn is combined with the first and second RF power amplifier arrangements AU1, AU2 via a third transmission line arrangement TLn and connected to the coupling power arrangement TLC. The third transmission line arrangement TLn has the same structure as the two transmission line arrangements TL1, TL2 from Fig. 1. In contrast to the embodiment in Fig.1, the RF power amplifier unit in this embodiment does not have any printed circuit boards. The RF power amplifier stage arrangements AU1, AU2, AUn are arranged directly on the cooling units CP1, CP2, CPn. Furthermore, the first cooling unit CP1 has a first heat sink section CS1.

[0114] More detailed descriptions of the individual components, which are also mentioned in Fig. 1, can be found in the description of Fig. 1.

[0115] Overall, the RF power amplifier unit 10 in this embodiment is designed to combine the output signals of the three RF power amplifier stage arrangements AU1, AU2, AUn and to transmit the combined power further via the coupling power arrangement TLC.

[0116] Fig. 3 shows a further embodiment of a power amplifier unit 10 according to the invention. The power amplifier unit 10 comprises a power combiner 1, four RF power amplifier stages AS1-AS4, and two cooling units CP1, CP2. The power combiner 1 comprises four inputs Inl-In4, a main output OUT, four coupling elements configured as inductors L1-L4, and a compensating circuit B. The RF power amplifier stages AS1-AS4 are connected to the inputs Inl-In4. The inductors Ll-L4 connect the inputs Inl-In4 to the main output OUT.

[0117] The first two inputs Inl, In2 are connected to a first output O1 via the first two inductors L1, L2, and the second two inputs In3, In4 are connected to a second output O2 via the second two inductors L3, L4. The two outputs O1, O2 are then connected to the main output OUT.

[0118] The four inductors L1-L4 and the four RF power amplifier stages AS1-AS4 are arranged on the two cooling units CP1, CP2. The first two inductors LI, L2 and the first two RF power amplifier stages AS1, AS2 are arranged on the first cooling unit CP1. The RF power amplifier stages AS1, AS2 and the components of a first power combiner section 1a, namely the coupling elements designed here as inductors LI, L2 and the energy absorbers designed here as resistors RI, R2, together form a first RF power amplifier stage arrangement AU1. The second two inductors L3, L4 and the second two RF power amplifier stages AS3, AS4 are arranged on the second cooling unit CP2.The RF power amplifier stages AS3, AS4, and the components of a second power combiner part lb, namely the coupling elements designed here as inductors L3, L4 and the energy absorbers designed here as resistors R3, R4 together form a second RF power amplifier stage arrangement AU2.

[0119] The compensation circuit B has four energy absorbers designed as resistors R1-R4 and a compensation line W1 with a length n* / 2. The four inputs Inl-In4 are connected to one another using the compensation circuit B. For this purpose, the first two inputs Inl, In2 are connected to one another via the first two resistors RI, R2, arranged on the first cooling unit CP1. The first resistor RI is connected to the first input Inl and the second resistor R2 is connected to the second input In2. Likewise, the second two inputs In3, In4 are connected to one another via the second two resistors R3, R4, arranged on the second cooling unit CP2. The third resistor R3 is connected to the third input In3 and the fourth resistor R4 is connected to the fourth input In4. The compensation line W1 then connects all four inputs Inl-In4 to one another.

[0120] In this way, two, or in particular more than two, RF power amplifier stage arrangements AU1, AU2 can be connected to each other. If more than two RF power amplifier stage arrangements AU1, AU2 are connected to each other, several compensating lines can be connected in a star configuration.

[0121] Individual, in particular several, particularly preferably all, RF power amplifier stage arrangements AU1, AU2 can also have more than two RF power amplifier stages AS1, AS2. Accordingly, these can then also have more than two components of the power combiner parts 1a, 1b, i.e., more than two coupling elements configured here as inductors LI, L2, and more than two energy absorbers configured here as resistors RI, R2.

[0122] Fig. 3 also shows a possible connection arrangement of the two outputs 01, 02 of the two RF power amplifier stage arrangements AU1, AU2 with the main output OUT.

[0123] The first output O1 of the first RF power amplifier stage arrangement AU1 is connected to a first transmission line arrangement TL1. The first transmission line arrangement TL1 has a first signal conductor SL1 and a first reference conductor BL1. The second output O2 of the second RF power amplifier stage arrangement AU2 is connected to a second transmission line arrangement TL2. The second transmission line arrangement TL2 has a second signal conductor SL2 and a second reference conductor BL2.

[0124] The two signal conductors SL1, SL2 are designed to transmit the respective output signals of the RF power amplifier stage arrangements AU1, AU2. The two reference conductors BL1, BL2 represent the reference potential to the two signal conductors SL1, SL2 and are electrically connected to a potential that is constant relative to the reference ground. In this case, this potential is the reference ground GND itself.

[0125] The two transmission line arrangements TL1, TL2 are combined and connected to a coupling line arrangement TLC. The coupling line arrangement TLC has a coupling signal line SLC and a coupling reference line BLC. The coupling signal line SLC is designed to transmit the combined output signals of the two RF power amplifier stage arrangements AU1, AU2. The coupling reference conductor BLC represents the reference potential of the coupling signal conductor SLC and is electrically connected to a potential that is constant relative to the reference ground. In this case, this potential is the reference ground GND itself. The coupling line arrangement TLC is connected to the main output OUT of the power amplifier unit 10.

[0126] In this case, the two transmission line arrangements TL1, TL2 are designed as microstrip lines MSL.

[0127] Fig. 4 shows an embodiment of a power amplifier unit 10 according to the invention. The power amplifier unit 10 is very similar to the power amplifier unit 10 in Fig. 3, only in a different view, and the connection arrangement of the two outputs O1, O2 of the two RF power amplifier stage arrangements AU1, AU2 to the main output OUT is implemented as a coaxial line CXL. The descriptions of the two transmission line arrangements TL1, TL2, the two signal conductors SL1, SL2, the two reference conductors BL1, BL2, the coupling line arrangement TLC, the coupling signal line SLC, and the coupling reference conductor BLC can be found in the description of Fig. 3.

[0128] The two cooling units CP1, CP2 can each have a heat sink section CS1, CS2. It is also conceivable for multiple heat sink sections CS1, CS2 to be arranged on a common cooling plate, but spatially spaced from one another (not shown in the figures). For example, the first heat sink section CS1 can be arranged on a first side of a cooling unit, and the second heat sink section CS2 can be arranged on the rear side of the same cooling unit.

[0129] In contrast to the power amplifier unit 10 in Fig. 3, the power amplifier unit 10 here has two combiner circuit boards PCB1, PCB2. The first combiner circuit board PCB1 is arranged on the first heat sink section CS1 and thus, in this embodiment, also on the first cooling unit CP1. The second combiner circuit board PCB2 is arranged on the second heat sink section CS2 and thus, in this embodiment, also on the second cooling unit CP2. The power amplifier unit 10 also has the power combiner 1 from Fig. 3. This shows the four RF power amplifier stages AS1-AS4, each divided into the RF power amplifier stage arrangements AU1, AU2. Also shown are the four coupling elements embodied as inductors L1-L4, the main output OUT, and the compensation circuit B. The compensation circuit B comprises the four energy absorbers embodied as resistors R1-R4 and the compensation line W1 of length n* / 2.

[0130] The first two RF power amplifier stages AS1, AS2 are arranged on a first amplifier circuit board PCB12. The first two RF power amplifier stages AS1, AS2 are arranged with this first amplifier circuit board PCB12 on the first heat sink section CS1 and thus, in this embodiment, also on the first cooling unit CP1. The second two RF power amplifier stages AS3-AS4 are arranged on a second amplifier circuit board PCB34. The second two RF power amplifier stages AS3-AS4 are arranged with this second amplifier circuit board PCB12 on the second heat sink section CS2 and thus, in this embodiment, also on the second cooling unit CP2. The first combiner circuit board PCB1 can also be combined with the first amplifier circuit board PCB12 to form a common circuit board.The second combiner board (PCB2) can also be combined with the second amplifier board (PCB34) to form a single board. This simplifies manufacturing and reduces the number of cable connections between boards, making the overall system more reliable.

[0131] The first two inductors L1, L2 and the first two resistors R1, R2 are arranged on the first combiner circuit board, PCB1. The second two inductors L3, L4 and the second two resistors R3, R4 are arranged on the second combiner circuit board, PCB2.

[0132] Fig. 5 shows a plasma process system 17 with a plasma process supply system 12.

[0133] The plasma process supply system 12 comprises a power amplifier unit 10 with a power combiner 1. These can be designed as previously described.

[0134] The plasma process supply system 12 also has an impedance matching circuit 11.

[0135] 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 a plasma processing arrangement in a plasma chamber 13.

[0136] The plasma chamber 13 has:

[0137] - a substrate 15 that is processed by the plasma 16, e.g. coated or etched,

[0138] - an electrode 14 with which the RF power is coupled into the plasma chamber 13 in order to ignite and maintain the plasma 16.

[0139] The impedance matching circuit 11 is designed to transform 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 patent applications: DE 10 2009 001 355 A1, DE 10 2011 007 597 A1, DE 10 2011 007 598 A1, WO 2021 / 209390 A1, WO 2021 / 255250 A1.

Claims

1. RF power amplifier unit (10) for coupling RF signals, in particular for a plasma process supply system and a plasma process system, the RF power amplifier unit (10) being designed for powers > 2 kW, preferably > 4 kW and frequencies in the range from 2 MHz to 200 MHz, in particular in the range from 10 MHz to 50 MHz, comprising: a) a first RF power amplifier stage arrangement (AU1) with a first output impedance (ZI) arranged on a first heat sink section (CS1), b) a second RF power amplifier stage arrangement (AU2) with a second output impedance (Z2) arranged on a second heat sink section (CS2),c) A first transmission line arrangement (TL1) connected to the output of the first RF power amplifier stage arrangement (AU1) and designed to transmit the output power of the first RF power amplifier stage arrangement and designed for a first line impedance (ZI') equal to the output impedance (ZI) of the first RF power amplifier stage arrangement (AU1), d) A second transmission line arrangement (TL2) connected to the output of the second RF power amplifier stage arrangement (AU2) and designed to transmit the output power of the second RF power amplifier stage arrangement (AU2) and designed for a second line impedance (Z2') equal to the output impedance (Z2) of the second RF power amplifier stage arrangement, e) A coupling line arrangement (TLC) designed to transmit the sum of the output powers of the first and second RF power amplifier stage arrangements (AU1, AU2) and designed for a coupling line impedance (ZC'),wherein the coupling line impedance (ZC') is dependent on the first and second line impedance (ZI', Z2'), wherein f) the first and second transmission line arrangements (TL1, TL2) are each connected to the coupling line arrangement (TLC) in order to couple the output powers of the first and second RF, power amplifier stage arrangement (AU1, AU2) to the coupling line arrangement (TLC), g) a measuring device (Ml) designed to determine a variable describing the power delivered by the RF power amplifier stage arrangements and / or the RF power amplifier unit, arranged on at least one of the transmission and / or coupling line arrangements (TL1, TL2, TLC).

2. RF power amplifier unit (10) according to the preceding claim 1, wherein the following relationship to the second and first line impedance (Z2', ZI') applies to the coupling line impedance (ZC'): ZC' = (ZI' 1 +Z2' 1 ) 1 .

3. RF power amplifier unit (10) according to one of the preceding claims, wherein the second and first line impedances (Z2', ZI') are equal.

4. RF power amplifier unit (10) according to one of the preceding claims, wherein the second and first line impedances (Z2', ZI') are each twice as large as the coupling line impedance (ZC').

5. RF power amplifier unit (10) according to one of the preceding claims, wherein the RF power amplifier unit (10) further comprises: a) one, in particular a plurality of further RF power amplifier stage arrangement(s) (AUn) each having a further output impedance (Zn) arranged on a respective further heat sink section (CSn), and b) one, in particular a plurality of further transmission line arrangement(s) (TLn), connected to the respective output of the further RF power amplifier stage arrangement(s) (AUn) and each designed to transmit the output power of the further RF power amplifier stage arrangements (AUn) and designed for further Line impedance(s) (Zn') equal to the output impedance (Zn) of the further RF power amplifier stage arrangement(s), wherein c) the coupling line arrangement (TLC) is designed to transmit the sum of the output powers of the first and the second and the further RF power amplifier stage arrangements (AU1, AU2, AUn) and designed for a coupling line impedance (ZC'), wherein the coupling line impedance (ZC') is dependent on the first, the second and the further line impedance (ZI', Z2', Zn'), and wherein d) the further transmission line arrangement(s) (TLn) are each connected to the coupling line arrangement (TLC) in order to be able to transfer the output power(s) of the further RF power amplifier stage arrangement (AUn) to the coupling line arrangement (TLC) 6. RF power amplifier unit (10) according to one of the preceding claims, wherein the following relationship to the first, second and further line impedances (Zn', Z2', ZI') applies to the coupling line impedance (ZC'): ZC' = (ZI' 1 +Z2' 1 4-Zn' 1 ) 1 .

7. RF power amplifier unit (10) according to one of the preceding claims, wherein the further line impedance(s) is / are equal to the second and / or the first line impedance (Z2', ZI').

8. RF power amplifier unit (10) according to one of the preceding claims, wherein the further line impedance(s) (Z2', ZI') is / are each N times as large as the coupling line impedance (ZC') with N = number of first, second and n-th transmission line arrangements (TL1, TL2, TLn).

9. RF power amplifier unit (10) according to one of the preceding Claims, wherein one, in particular several, particularly preferably all, transmission line arrangement(s) (TL1, TL2, TLn) comprises / comprising: - a signal conductor (SL1, SL2, SLn) designed to transmit the respective output signal of the RF power amplifier stage arrangements (AU1, AU2, AUn), - a reference conductor (BL1, BL2, BLn) which is electrically connected to a potential which is invariable with respect to the reference ground, in particular to the reference ground (GND).

10. RF power amplifier unit (10) according to one of the preceding claims, wherein the coupling line arrangement (TLC) comprises: - a coupling signal conductor (SLC) designed to transmit the combined output signals of the RF power amplifier stage arrangements (AU1, AU2, AUn), - a coupling reference conductor (BLC) which is electrically connected to a potential which is invariable with respect to the reference ground, in particular to the reference ground (GND).

11. RF power amplifier unit (10) according to one of the preceding claims, wherein one, in particular several, particularly preferably all, transmission line arrangement(s) (TL1, TL2, TLn) is / are designed as a microstrip line (MSL).

12. RF power amplifier unit (10) according to one of the preceding claims, wherein one, in particular several, particularly preferably all, transmission line arrangement(s) (TL1, TL2, TLn) is / are designed as a coaxial line (CXL).

13. RF power amplifier unit (10) according to one of the preceding claims, wherein the coupling line arrangement (TLC) is designed as a microstrip line (MSL).

14. RF power amplifier unit (10) according to one of the preceding claims, wherein the coupling line arrangement (TLC) is designed as a coaxial line (CXL).

15. RF power amplifier unit (10) according to one of the preceding claims, wherein one, in particular several, particularly preferably all, Transmission line arrangement(s) (TL1, TL2, TLn) is / are connected with its connection, in particular with its signal connection, to the respective RF power amplifier stage arrangement(s) (AU1, AU2, AUn) by means of a pin which is / are in particular part of the respective transmission line arrangements (TL1, TL2, TLn).

16. RF power amplifier unit (10) according to one of the preceding claims, wherein one, in particular several, particularly preferably all, RF power amplifier stage arrangement(s) (AU1, AU2, AUn) is / are arranged on printed circuit boards (PCB1, PCB2, PCBn), which in turn are arranged on the respective heat sink sections (CS1, CS2, CSn) and in particular the transmission line arrangements (TL1, TL2, TLn) are connected to electrical contacts of these printed circuit boards (PCB1, PCB2, PCBn).

17. RF power amplifier unit (10) according to one of the preceding claims, wherein the heat sink sections (CS1, CS2, CSn) are each arranged on a separate cooling unit (CP1, CP2, CPn).

18. RF power amplifier unit (10) according to one of the preceding claims, wherein the heat sink sections (CS1, CS2, CSn) are arranged such that they surround a space (VI) surrounding them.

19. RF power amplifier unit (10) according to one of the preceding claims, wherein the coupling line arrangement (TLC) is arranged within a space (VI) surrounded by the heat sink sections (CS1, CS2, CSn).

20. RF power amplifier unit (10) according to one of the preceding claims, wherein one, in particular several, particularly preferably all, transmission line arrangement(s) (TL1, TL2, TLn) is / are arranged for its predominant part within a space (VI) surrounded by the heat sink sections (CS1, CS2, CSn).

21. RF power amplifier unit (10) according to one of the preceding claims, wherein the measuring device (Ml) is arranged within a space (VI) surrounded by the heat sink sections (CS1, CS2, CSn).

22. RF power amplifier unit (10) according to one of the preceding claims, wherein one, in particular several, particularly preferably all, RF power amplifier stage arrangement(s) (AU1, AU2, AUn) is / are arranged outside a space (VI) surrounded by the heat sink sections (CS1, CS2, CSn).

23. RF power amplifier unit (10) according to one of the preceding claims, wherein several, particularly preferably all, RF power amplifier stage arrangement(s) (AU1, AU2, AUn) are constructed identically and are arranged in particular line-symmetrically to the coupling line arrangement (TLC).

24. RF power amplifier unit (10) according to one of the preceding claims, wherein the cooling unit(s) (CP1, CP2, CPn) is / are designed, in particular constructed, as fluid-cooled cooling unit(s), in particular cooling plate(s), e.g. for cooling with air, a liquid or a combination of both.

25. RF power amplifier unit (10) according to one of the preceding claims, wherein one, in particular several, particularly preferably all, RF power amplifier stage arrangement(s) (AU1, AU2, AUn) has / have several amplifier stages (AS1, AS2, AS3, AS4) which are connected with their outputs to the inputs of a power combiner part (la, lb) which has: - several inputs and one output, - several coupling elements, in particular inductors, which each connect the inputs to the output of the power combiner part (la, lb), - an energy absorber, in particular a resistor, connecting the inputs of the power combiner part (la, lb).

26. RF power amplifier unit (10) according to one of the preceding claims, comprising a power combiner (1), which comprises: - several power combiner parts (la, lb), - several further transmission line arrangement(s) (TL1, TL2), each connected to an output of the power combiner parts (la, lb), - a coupling line arrangement (TLC) and - in particular a balancing line (Wl).

27. Plasma process supply system (12) comprising at least one RF power amplifier unit (10) according to one of the preceding claims, and an impedance matching circuit (11) connected downstream thereof.

28. Plasma process system (17) comprising a plasma process supply system (12) according to claim 27 and a plasma process arrangement connected to the impedance matching circuit (11).

29. Method for supplying a load, in particular a plasma process, with a power amplifier unit (10) according to one of the preceding claims 1 to 26, and in particular with an impedance matching circuit (11) connected downstream thereof, which in turn is particularly preferably connected to a plasma process arrangement, wherein a) a first output power is supplied from a first RF Power amplifier stage arrangement (AU1) is generated, b) a second first output power is generated by a second RF power amplifier stage arrangement, c) the first output power is transmitted from a first transmission line arrangement (TL1) and d) a second output power is transmitted from a second transmission line arrangement (TL2) e) to a coupling line arrangement (TLC), f) which transmits the coupled output powers of the first and second RF power amplifier stage arrangements (AU1, AU2) to an output of the power amplifier unit (10), and g) a quantity describing the power delivered by the RF power amplifier stage arrangements (AU1, AU2) and / or the RF power amplifier unit (10) is determined at one of the transmission and / or coupling line arrangements (TL1, TL2, TLC) using a measuring device (Ml), and h) the load is supplied with these coupled output powers.

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