Power supply system for supplying a plasma or gas laser process, and method for operating such a power supply system

Abstract

The invention relates to a method for operating a power supply system (2), the power supply system (2) having a power converter (3) which generates an HF power signal and is connected to a load (6) in order to supply power to a plasma or gas laser process, the power converter (3) comprising at least one amplifier stage (40) which is designed as a balanced amplifier having a first and a second amplifier unit (42a, 43a) which each have the following components: i. a base-load amplifier (103) configured to provide a base-load amplifier power; ii. a peak-load amplifier (104) configured to provide a peak-load amplifier power; and iii. a power coupler (107) for combining the base-load amplifier power and the peak-load amplifier power at the output of the respective first and second amplifier unit to form an amplifier output power (Pout), the method comprising the following method steps: - in order to generate a power increase above the continuous-operation power of the power supply system (2), an amplitude and / or phase relationship between the base-load amplifier (103) and the peak-load amplifier (104) of at least one of the first and second amplifier units is set in such a way that the amplifier output power (Pout) of the amplifier unit is greater than a continuous-operation power of the amplifier unit (42a, 43a).

Description

[0001] Power supply system for supplying a plasma or gas laser process and method for operating such a power supply system

[0002] The invention relates to a method for operating a power supply system, wherein the power supply system comprises a power converter generating a high-frequency power signal (RF power signal) which is connected to a load for supplying power to a plasma or gas laser process. The invention further relates to a power supply system comprising a power converter designed to generate a high-frequency power signal for supplying power to a plasma or gas laser process and which is connectable to a load for this purpose.

[0003] Power supply systems, especially systems that generate power at frequencies > 1 MHz and particularly < 200 MHz and especially < 90 MHz, are used, for example, for laser excitation or in plasma coating systems. Such power supply systems often employ multiple amplifiers to generate the overall power output of the system.

[0004] In such a power supply system, sudden changes in the required power can occur, for example, if an arc occurs in the plasma chamber and the supplied power must be abruptly reduced as a result. Conversely, igniting a plasma may require a different power than operating a plasma process. When the plasma state changes, the load impedance also changes. This, too, results in a sudden load change. Impedance matching often cannot be performed quickly enough, so power is reflected from the load. This reflected power should be kept away from the amplifiers and amplifier paths, if possible, to prevent damage to the power supply system. While it is known to use circulators to absorb the reflected power, this is not always the case.However, in the aforementioned frequency range, such circulators are very large due to the need for very large inductances and / or magnetic fields and can no longer be used practically.

[0005] When sudden load changes or changes in the required power occur, the output power must be controlled. This can be achieved, for example, by varying the input power of an amplifier. However, this also changes the efficiency of the amplifier. At low output powers, the amplifier operates in the so-called back-off region. This is the region in which the amplifier only provides a portion of its maximum possible output power. In this back-off region, the efficiency of the amplifier decreases. Depending on the load being driven, the transistor used in the amplifier must therefore dissipate significantly more power. This causes it to heat up considerably. With a mismatch, this behavior changes. Depending on the load angle or reflection coefficient, the transistor heats up either in the back-off or saturation region.This means that controlling the output power via the input power is only possible to a limited extent in the case of impedance mismatch. To prevent the transistor from overheating, it has often been recommended to limit the maximum output power. However, reducing the maximum output power does not solve this problem, as critical temperatures occur at low power levels, not just high ones, when there is a large impedance mismatch and an unfavorable load angle.

[0006] Igniting a plasma or gas laser typically requires more power than the subsequent operation of the ignited plasma or gas laser. Therefore, it is known to apply the full operating power to the plasma system at an increased voltage to achieve the fastest possible plasma ignition. Such systems frequently employ so-called balanced amplifiers. A balanced amplifier typically has two amplifier paths, each delivering an amplifier path output signal to a phase-shifting coupler unit. The phase-shifting coupler unit has an output terminal and an isolation terminal and is configured to combine the amplifier path output signals based on their amplitude and / or phase relationship, delivering power to the output terminal and / or the isolation terminal.The amplifier paths are typically operated with a mutual phase shift of 90°. Such balanced amplifiers and their characteristics are also described, for example, in the following publication: Alexander Alt et al.: “Analysis of high power LDMOS amplifiers for industrial applications under mismatch conditions”, published in 2014 IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications (PAWR), Electronic ISBN: 978-1-4799-2778-4. There, the term “balanced amplifier” is used as an alternative to “balanced amplifier”.

[0007] For suitable balanced amplifiers designed for operation with a gas laser or plasma, the output power across the complex load plane is essentially flat, i.e., essentially constant. Power peaks or surges, also known as "peaking," are difficult to generate. Only by selecting a higher DC supply voltage can pseudo-peaking be achieved. The briefly higher DC supply voltage allows for the generation of higher ignition power. However, generating a higher DC supply voltage for the power surge, also called a "power peak," is very complex.

[0008] With unbalanced amplifiers, especially those without a coupler, an impedance at which power amplification occurs can be selected by choosing a suitable cable length between the amplifier and the plasma chamber or discharge chamber. Unbalanced amplifiers have numerous other disadvantages, which is why they are being used less and less frequently in plasma or laser applications.

[0009] One method for igniting such a plasma or gas laser system with a balanced amplifier is described, for example, in DE 10 2022 108 631 A1. There, the term "balanced amplifier" is used as an alternative designation. 1The term 'balanced amplifier' is also used. For ignition and operation, the phase relationship between the amplifier paths is changed during ignition operation compared to the phase relationship during plasma processing or laser excitation operation. The method described there works very well in many systems, but not with satisfactory reliability in all systems.

[0010] Against this background, the task arises to enable reliable ignition of a plasma or a gas laser and also to enable reliable and efficient operation of a power supply system with highly fluctuating, for example pulsed, power output.

[0011] To solve the problem, a method for operating a power supply system according to claim 1 is proposed. This relates to a method for operating a power supply system, wherein the power supply system comprises a power converter generating a high-frequency power signal, which is connected to a load for supplying power to a plasma or gas laser process, wherein the power converter comprises at least one amplifier stage having:

[0012] - a first amplifier path comprising a first amplifier unit,

[0013] - a second amplifier path comprising a second amplifier unit, wherein the first amplifier path is configured to output a first amplifier path output signal and the second amplifier path is configured to output a second amplifier path output signal having a phase shift relative to the first amplifier path output signal, which is not equal to, in particular greater than, 0°, wherein the amplifier paths are connected to a phase-shifting coupler unit configured to couple the output signals of the amplifier paths to a high-frequency power signal, wherein the first and second amplifier units each comprise: i. a base-load amplifier configured to provide base-load amplifier power; ii. a peak-load amplifier configured to provide peak-load amplifier power; and iii.a power coupler for combining the base load amplifier power and the peak load amplifier power at the output of the respective first or second amplifier unit to form an amplifier output power, wherein the method comprises the following process steps:.

[0014] - To generate a power boost above a continuous operating power of the power supply system, in particular to ignite a plasma or gas laser, an amplitude and / or phase relationship between the base load amplifier and the peak load amplifier of at least one of the first and second amplifier units is changed.

[0015] The phrase "one of the first and second amplifier units is modified" here can particularly mean: "one of the first and second amplifier units is set in such a way that the amplifier output power of this amplifier unit is greater than the continuous operating power of this amplifier unit".

[0016] "Continuous operating power" refers to the power rating for which the system or unit is designed during normal operation and to which it can be set, or is set, by an operator during normal operation. Normal operation can be operation with a continuous output power or with a pulsed output power. In pulsed operation, the continuous operating power can be the power rating of a single pulse. Therefore, in multilevel pulse operation, several continuous operating power ratings can be provided, for example, one power rating for each pulse level.

[0017] The increased power output is therefore not intended for normal operation, but only for special operation, particularly for short periods, e.g., for ignition. "Short period" here refers to the time range within which a plasma typically ignites. This can depend on the characteristics of the plasma process setup. Such a value might, for example, be at most 1 ms.

[0018] The method for achieving a power boost can also be used for operating states other than ignition. For example, when pulsing the amplifier output power, such as in multi-level pulsing, one of the pulses can be operated with this power boost.

[0019] Since the power loss is generally higher in this type of power boost operation than in normal operation, this power boost operation is not advantageous for continuous operation.

[0020] In one aspect, the power boost is achieved by adjusting the amplitude and / or phase relationship between the base load amplifier and the peak load amplifier in such a way that the load impedance for the base load amplifier and / or the load impedance for the peak load amplifier changes in such a way that the resulting amplifier output power of this amplifier unit is greater than the continuous operating power of this amplifier unit.

[0021] In one aspect, during normal operation, especially for maintaining a plasma or operating a gas laser, the first and second amplifier units are operated with an amplifier output power that is less than or equal to the continuous operating power of this amplifier unit.

[0022] A phase-shifting coupler unit is understood to be a unit comprising a coupler and, optionally, a phase-shifting network for one or more amplifier paths, wherein the input signals of the coupler unit, in normal operation, have a phase relationship to each other that is neither 0° nor 180°, and in particular is greater than 0° and less than 180°. For example, the input signals may be phase-shifted by 90°. A coupler unit whose input signals, in fully coupled operation, have a phase offset of 0° or 180° to each other is not understood as a phase-shifting coupler unit in this disclosure, since here the input signals are merely added without any further phase offset. The phase-shifting coupler unit can be a 90° hybrid coupler. This fulfills the requirements in an improved manner with reduced component count.A phase-shifting coupler unit is also understood to be a unit designed to return reflected power, which is conducted from the load through the coupler to the amplifier units, to the amplifier units with different phases. For example, in the case of a mismatch, a 90° hybrid coupler, to whose input terminals two amplifier units with the same impedance are connected, will distribute the reflected power to the two amplifier units with a 90° phase shift.A phase-shifting coupler unit is also understood to be a unit that has a first input impedance at its first input terminal and a second input impedance at its second input terminal, and that is designed such that the input impedances are equal when no reflected power is passed through the coupler unit to the input terminals, and that they are unequal when reflected power is passed through the coupler unit to the input terminals.

[0023] The coupler unit can be designed to forward the power reflected from its output terminal to its input terminals with a phase shift, thus directing it to the amplifier units in the amplifier paths. The input impedances at the coupler unit can then change, and in particular, can differ. This can result in the output impedance of the first amplifier unit having a different value than the output impedance of the second amplifier unit. This, in turn, can affect the characteristics of the coupler unit in such a way that it directs the power of one amplifier unit to the other, causing the amplifier units to interfere with each other. The output impedance of the amplifier units can become negative. Under certain load conditions, this can lead to the first amplifier unit in the first amplifier path supplying power to the second amplifier unit in the second amplifier path.These characteristics led to past recommendations against using a phase-shifting coupler unit. There were concerns that it would drive the amplifier units into unstable states and / or cause the transistors to overheat.

[0024] A common cause of instability, particularly when maintaining the plasma or operating the gas laser, lies in the very rapid change in the load's impedance, such as that of the plasma process. This load change occurs so quickly that neither an impedance matching network connected between the power supply system and the load nor the power control system can react to it fast enough. The rapid load change produces reflected power, which is reflected back into the amplifier units. As described above, this reflection alters the amplifier units' impedance. Consequently, after the rapid load change, the amplifier units no longer deliver the same power as before the change.In a power supply system with a phase-shifting coupler unit, especially with a 90° hybrid coupler, the change in power per change in the load state is much smaller than in a power supply system without such a coupler unit or with non-phase-shifting characteristics. Therefore, a power supply system with a phase-shifting coupler unit behaves more stably.

[0025] Examples of the design of such a phase-shifting coupler unit are disclosed, for example, in WO 2017 / 001598 A1, WO 2005 / 027258 A1, WO 2011 / 110654 A1, EP 1 699 107 A1, DE 20 2010 016 850 U1 or DE 20 2010 016732 U1. These disclosures are hereby incorporated in full into the present application by reference.

[0026] In one aspect, a first and a second amplifier unit are provided as part of the two amplifier paths. Both the first and second amplifier units have a design with two different sub-amplifiers, referred to here as the base-load amplifier and the peak-load amplifier. The first and second amplifier units are configured such that the base-load amplifier essentially provides a base load of the amplifier output power. The peak-load amplifier can be active at a low power level during base-load operation, in which the output power is mainly provided by the base-load amplifier, or the peak-load amplifier can be inactive. The power coupler provided as part of the first and second amplifier units combines the base-load amplifier power and the peak-load amplifier power at the output of the respective first and second amplifier units to produce a single amplifier output power.Preferably, the first and second amplifier units, i.e., the two combinations of base load amplifier and peak load amplifier, are each designed as Doherty amplifiers.

[0027] In one aspect, the first and second amplifier units are identical.

[0028] It has been found that the power supply system exhibits significantly lower power dissipation in case of impedance mismatch than known power supply systems. This can be attributed to the fact that the base-load amplifier and the peak-load amplifier of the first and second amplifier units can each operate in a high-efficiency operating range, particularly during normal operation. This increases the efficiency of the first and second amplifier units compared to a conventional push-pull amplifier, especially a Class AB amplifier. Due to the reduced power dissipation, the first and second amplifier units heat up less, particularly during normal operation, thereby increasing the lifespan of the amplifier units, especially their transistors, and consequently the overall reliability of the power supply system.Furthermore, the variation in load power is almost independent of the load angle.

[0029] To generate the power boost above the continuous operating power of the power supply system, the amplitude and / or phase relationship between the base-load amplifier and the peak-load amplifier of at least one amplifier unit is modified compared to normal operation, so that the amplifier output power of the respective amplifier unit is greater than its continuous operating power. In the first and second amplifier units, the base-load amplifier and the peak-load amplifier are combined by the power coupler in such a way that they mutually modulate the load. By changing the phase relationship between the base-load amplifier and the peak-load amplifier, the direction of the load modulation can be set. By changing the amplitude relationship between the base-load amplifier and the peak-load amplifier, the magnitude of the load modulation can be set.Load modulation can pull the base-load amplifier and / or the peak-load amplifier into a load range where the amplifiers provide an output power greater than their continuous operating power. While this does have some adverse effects, it does increase the power dissipation of the amplifiers. This is acceptable for short periods, such as one or more microseconds. However, the maximum achievable output power may be limited by the DC power supply to the base-load and peak-load amplifiers. This limitation can be overcome by providing a buffer capacitor or other suitable energy storage device.

[0030] The described method thus enables reliable ignition of a plasma or gas laser and also allows reliable and efficient normal operation with highly fluctuating, for example pulsed, power output.

[0031] In one aspect, it is provided that, to generate the power boost, the amplitude and / or phase relationship between the base-load amplifier and the peak-load amplifier of both the first and second amplifier units is modified, particularly briefly, specifically adjusted such that the amplifier output power of both amplifier units is greater than the continuous operating power of the respective amplifier unit. Such a design allows for particularly flexible adjustment of the power boost above the continuous operating power of the power supply system. In another aspect, it is provided that, to generate the power boost, the amplitude and / or phase relationship is adjusted such that the load impedance of the base-load amplifier deviates from normal operation, specifically that the load impedance of the base-load amplifier is lower than in normal operation.In such an operating state, the respective amplifier unit can generate a higher output power with lower efficiency.

[0032] One aspect of the design is that, to generate the power boost, the phase relationship between the base-load amplifier and the peak-load amplifier is set to a phase difference other than 90°, preferably deviating by at least 10° from 90°, and particularly preferably by at least 20° from 90°, for example, to 120° or 60°. Setting the phase relationship between the base-load amplifier and the peak-load amplifier within this range has proven advantageous for generating the power boost. During normal operation, the phase relationship can be set to a phase difference of less than or equal to 90°. Therefore, the phase difference for generating the power boost can be increased.

[0033] One aspect of the design is that, to generate the power boost, the amplitude relationship between the base-load amplifier and the peak-load amplifier is set to a factor of at least 1.2, and in particular at least 1.4. For example, the amplitude of the base-load amplifier relative to the amplitude of the peak-load amplifier can be set to a value greater than or equal to 3 dB. Alternatively, the amplitude of the peak-load amplifier relative to the amplitude of the base-load amplifier can be set to a value greater than or equal to 3 dB. Such an amplitude relationship has proven advantageous for generating the power boost. During normal operation, the amplitude relationship can be set to a value of essentially 0 dB.

[0034] One aspect of the design is that the power supply system includes one or more buffer capacitors configured to store sufficient energy to provide the short-term power boost. Conventional DC power supplies limit the achievable output power by restricting current, voltage, and / or power. For short periods in the range of 1 ps to 1 ms, the increased power demand can be met by one or more buffer capacitors. Another aspect of the design is that the power supply system includes a signal generation device that provides signals to the first and second amplifier units for generating the high-frequency power signal, the signal provided in normal operating mode being different from the signal provided for generating the power boost.Therefore, the signal supply device makes it possible to control the first and second amplifier units in such a way that, particularly briefly, either a power boost above the continuous operating power is generated, or in normal operation an amplifier output power is provided that is less than or equal to the continuous operating power.

[0035] Preferably, the signal generation device is configured to provide signals for generating the high-frequency power signal during normal operation of the first and second amplifier units within a predetermined power range such that the base-load amplifier power is greater than the peak-load amplifier power at least in a portion of this range. In this power range, which can also be referred to as the base-load range, the base-load amplifier can thus supply the majority of the amplifier output power. The base-load amplifier preferably operates in a high-efficiency range. The peak-load amplifier provides only a small amount of power or none at all in this range, so it is not necessary for the peak-load amplifier to also operate in an efficient range within this power range.Preferably, the base-load amplifier power is greater than the peak-load amplifier power in the lower part of the specified power range. This allows low power levels to be covered solely or primarily by the base-load amplifier without the peak-load amplifier needing to be active or provide high power.

[0036] In one aspect, it is provided that the peak-load amplifier and the base-load amplifier each have an amplifying transistor with an input terminal, e.g., a gate terminal. In another aspect, it is provided that a bias voltage at the input terminal of the transistor is adjustable for at least one of the two amplifiers, and that during operation, the bias voltage for the base-load amplifier is different from that of the peak-load amplifier. In yet another aspect, it is provided that a bias current at the input terminal of the transistor is adjustable for at least one of the two amplifiers, and that during operation, the bias current for the base-load amplifier is different from that of the peak-load amplifier. A bias voltage, in this context, is understood to be a voltage that changes very slowly or not at all compared to the input signal and is designed to maintain the transistor in a predetermined conductivity state at its output terminals.A bias current, as used here, is understood to be a current that changes very slowly or not at all compared to the input signal and is configured to maintain the transistor in a predetermined conductivity state at its output terminals. A typical gate bias arrangement is disclosed, for example, in WO 2017 / 001594 A1. WO 2017 / 001594 A1 is hereby incorporated in its entirety into the present application by reference.

[0037] In one aspect, the base-load amplifier is configured as an essentially linear amplifier, and the peak-load amplifier as an essentially non-linear amplifier. The base-load amplifier behaves essentially linearly, particularly in a power range where its power output is greater than its power output; that is, its output signal is proportional to its input signal. The peak-load amplifier, on the other hand, can be configured such that its output signal is not proportional to its input signal. The aforementioned bias voltage and / or bias current settings can be used for this purpose.

[0038] In one aspect, the peak-load amplifier and / or the base-load amplifier are designed as a push-pull power amplifier. Specifically, the peak-load amplifier and / or the base-load amplifier each have two identical transistors. In particular, the two identical transistors are housed in a common package. In another aspect, the peak-load amplifier and / or the base-load amplifier are designed as a planar power amplifier, specifically in a design such as that described, for example, in WO 2017 / 001602 A1. WO 2017 / 001602 A1 is hereby incorporated in its entirety into the present application by reference.

[0039] One aspect of the design is that the base-load amplifier is configured as either a Class B or Class AB amplifier, and the peak-load amplifier is configured as a Class C amplifier. In the Class B or Class AB configuration, the base-load amplifier can comprise two transistors arranged in a push-pull configuration. In a Class B amplifier, each transistor conducts for 180° of a oscillation period. A Class B amplifier can achieve an efficiency of up to 78.5%, but exhibits some distortion due to the switching transition between the two transistors. In a Class AB amplifier, however, each transistor conducts for more than 180° of a oscillation period, thus providing an overlap region in which both transistors conduct.Class AB amplifiers sacrifice some of the efficiency of a Class B amplifier but achieve improved linearity. A Class C amplifier has one or more transistors that conduct for less than 180° of the oscillation period, for example, approximately 120°. Class C amplifiers exhibit high signal distortion but can achieve high efficiency, for example, around 80%. The previously mentioned bias voltage and / or bias current settings can be used to adjust these amplifier classes.

[0040] In one aspect, the peak-load amplifier is designed – during normal operation – to provide peak-load amplifier power only when a predetermined base-load amplifier power is exceeded. The aforementioned bias voltage and / or bias current at the input of the peak-load amplifier's amplifying transistor can be used for this purpose. This design offers the advantage that the base-load amplifier alone provides the amplifier output power within a base-load range. Therefore, the behavior of the first and second amplifier units within the base-load range can be essentially controlled by the base-load amplifier. Only when a higher power than the base load is supplied does the peak-load amplifier become active and provide peak-load amplifier power in addition to the base-load amplifier power. Thus, the peak-load amplifier can, in particular, cover power surges.

[0041] One aspect is that the peak load amplifier - in normal operation - is designed to change the output impedance of the peak load amplifier so that it is high-impedance when a predetermined base load amplifier power is undershot.

[0042] In one aspect, it is provided that the power supply system has a signal supply device configured to provide signals to the first and second amplifier units for generating the high-frequency power signal in such a way that an output signal of the peak load amplifier has a phase shift relative to an output signal of the base load amplifier, and / or the first and second amplifier units include a phase-shifting splitter configured to provide signals to the base load amplifier and the peak load amplifier for generating the high-frequency power signal in such a way that an output signal of the peak load amplifier has a phase shift relative to an output signal of the base load amplifier.The phase shift between the output signals of the peak load amplifier and the base load amplifier makes it possible to use a power coupler as part of the first and second amplifier units, which is designed to shift the phase.

[0043] In one aspect, the signal generation device or phase-shifting splitter is designed so that the phase offset, particularly during normal operation, is adjustable, especially to a value of 90° or n*180° + 90°. Examples of the design of such a phase-shifting splitter are disclosed, for example, in WO 2017 / 001598 A1.

[0044] In one aspect, the splitter is equipped with an adjustable phase shifter so that the adjustability of the phase during operation can be controlled, e.g., with electronic means such as transistors, especially to achieve power amplification.

[0045] In one aspect, the power coupler is designed as a phase-shifting power coupler. This allows the phase-shifting power coupler to combine two output signals from the base-load amplifier and the peak-load amplifier with a phase offset in a phase-correct manner. The phase-shifting power coupler can include an impedance converter and / or a quarter-wave transmission line, particularly one arranged between the output of a base-load amplifier and a peak-load amplifier and the output of the first or second amplifier unit. The power coupler can be constructed from discrete components, particularly from a combination of inductance(s) and capacitor(s), and most preferably from a network with two capacitors connected to ground and an inductor connected between the other two terminals of the capacitors and connected to the input or output of the power coupler.The inductor can be implemented as a planar inductor on a circuit board. One or both capacitances can be at least partially determined by the capacitance of the planar inductor to ground. Impedance matching can be achieved via the impedance converter, which increases the efficiency of the first and second amplifier stages.

[0046] One aspect is that the power coupler increases the output impedance at its output relative to the output impedance of the base load amplifier when the base load amplifier is operated in overdrive.

[0047] In one aspect, it is stipulated that the base-load amplifier has a higher output impedance when operated in the linear range than when operated in overdrive. In another aspect, it is stipulated that the peak-load amplifier has a higher output impedance when the base-load amplifier is operated in the linear range than when the base-load amplifier is operated in overdrive.

[0048] One aspect of the design is that the phase shift of the second amplifier path output signal relative to the first amplifier path output signal is adjustable. Adjusting the phase allows the output power of the power converter to be controlled. Furthermore, it is possible to increase the output power to generate the power boost above the continuous operating power. The phase adjustment between the first and second amplifier path output signals can be achieved by a signal generation device configured to provide signals to the first and second amplifier units for generating the high-frequency power signal, or by an adjustable splitter connected to the first and second amplifier units.

[0049] One aspect of the design is that the amplifiers and / or amplifier units each incorporate one or more transistors, particularly LDMOS or GaN transistors. LDMOS stands for "laterally diffused metal oxide semiconductor." When used in amplifiers or amplifier units to generate power suitable for plasma processes, these LDMOS transistors have proven to be significantly more reliable than comparable conventional MOSFETs. This can be attributed to their much higher current handling capability. LDMOS transistors allow for the construction of amplifiers, amplifier units, and power supply systems with a very similar or even identical topology, suitable for use at frequencies spanning several decades in the range of 1 MHz to 200 MHz, preferably in the range of 1 MHz to 90 MHz. These are frequencies commonly used in plasma processes and for gas laser excitation.Conventional MOSFETs often encounter problems when operated at these frequencies in plasma processes if too much power supplied to the plasma process is reflected back. Therefore, the generated power often had to be limited to prevent the reflected power from exceeding a critical threshold. This meant that the plasma processes could not always be reliably ignited or operated within the desired power range. Furthermore, complex adjustable impedance matching circuits and combiners were required to overcome these drawbacks. LDMOS transistors are particularly advantageous when significant reflected power is expected, as is the case, for example, when powering plasma processes. In conjunction with the aforementioned phase-shifting coupler unit, the advantage of LDMOS transistors lies in their ability to handle much higher levels of reflected power.This reduces the requirements for additional impedance matching networks connected between the power supply system and the load, and can save on component and control costs for these impedance matching networks. Examples of the design of a phase-shifting power coupler and an amplifier with LDMOS transistors are disclosed, for example, in WO2015 / 091468 A1. This disclosure is hereby incorporated in its entirety into the present application by reference.

[0050] One aspect of the design involves multiple amplifier stages, with each pair of amplifier paths connected directly to a 90° hybrid coupler, without the need for any intermediate coupling devices. This configuration allows for higher power output.

[0051] In one aspect, the power supply system is configured such that, in the event of a load mismatch, power reflected from the load is at least partially routed via the coupler unit and at least one power coupler to at least one of the base-load amplifiers and one of the peak-load amplifiers, at least partially reflected by these amplifiers, and then returned via the at least one power coupler to the coupler unit, which at least partially dissipates this returned power into a resistor. Preferably, a larger proportion of the power is reflected by the base-load amplifier than by the respective peak-load amplifier.

[0052] In one aspect, it is provided that several of the amplifier stages disclosed herein are connected in parallel and the output terminals of these parallel amplifier stages are interconnected via a power coupler cascade or multiple combiner. Examples of such a power coupler cascade or multiple combiner are disclosed, for example, in WO 2011 / 110652 A1, WO 2017 / 001595 A1, DE 102011 086 557 A1, EP 1 701 376 A1, and DE 10 2023 111 812 A1. These disclosures are hereby incorporated in full into the present application by reference.

[0053] To solve the aforementioned problem, a power supply system is further proposed, comprising a power converter designed to generate a high-frequency power signal for powering a plasma or gas laser process and capable of being connected to a load for this purpose, wherein the power converter includes at least one amplifier stage comprising:

[0054] - a first amplifier path comprising a first amplifier unit,

[0055] - a second amplifier path, comprising a second amplifier unit, wherein the first amplifier path is for outputting a first

[0056] The amplifier path is configured to output a first amplifier path output signal, and the second amplifier path is configured to output a second amplifier path output signal having a phase shift relative to the first amplifier path output signal, which is not equal to, in particular greater than, 0° and not equal to, in particular less than, 180°, wherein the amplifier paths are connected to a phase-shifting coupler unit designed to couple the output signals of the amplifier paths to a high-frequency power signal, wherein the first and second amplifier units each comprise: i. a base-load amplifier configured to provide base-load amplifier power; ii. a peak-load amplifier configured to provide peak-load amplifier power; and iii. a power coupler for combining the base-load amplifier power and the peak-load amplifier power at the output of the respective first and second amplifier units.second amplifier unit to an amplifier output power, with the power supply system configured.

[0057] - for generating a power boost above the continuous operating power of the power supply system, in particular for igniting a plasma or gas laser, wherein an amplitude and / or phase relationship between the base load amplifier and the peak load amplifier of at least one of the first and second amplifier units is changed, in particular briefly, and in particular is adjustable such that the amplifier output power of this amplifier unit is greater than a continuous operating power of this amplifier unit; and, preferably

[0058] - for normal operation, in particular for maintaining a plasma or operating a gas laser, in which the first and second amplifier units can be operated with an amplifier output power that is less than or equal to the continuous operating power of this amplifier unit.

[0059] A phase shift between the base-load amplifier and the peak-load amplifier can be achieved using a phase shifter. Examples of possible designs for such a phase shifter are described below.

[0060] Also disclosed is a plasma system comprising a. a power supply system as described above and below, b. a load, in particular configured as a plasma or gas laser process,

[0061] • wherein the power supply system includes a power converter that can be connected to a power supply network,

[0062] • where the power converter is connected to the load,

[0063] • wherein, in particular, an impedance matching network is arranged between the load and the power converter.

[0064] Alternatively or in addition to the advantageous embodiments explained above, the advantageous embodiments and features explained in connection with the device according to the invention can be used in the method.

[0065] Further details and advantages of the development will be explained below with reference to the exemplary embodiments shown in the figures. These show:

[0066] Fig. 1 shows a plasma system with a detailed view of the amplifier arrangement according to an exemplary embodiment in a block diagram;

[0067] Fig. 2 shows a plasma system with a detailed view of the power supply system according to an exemplary embodiment in a block diagram;

[0068] Fig. 3 shows a DDS module in a block diagram;

[0069] Fig. 4 shows an embodiment of an amplifier unit of the power supply system according to Fig. 1 or 2:

[0070] Fig. 5 shows an alternative embodiment of an amplifier stage for the power supply system according to Fig. 1 or 2;

[0071] Figure 1 shows a plasma system 1 comprising a power supply system 2. The power supply system 2, in turn, has a power converter 3, which can be connected to a power supply network 4. The power converter 3 has an amplifier stage 40. The power generated at the output of the power converter is supplied via an impedance matching network 5 to a load 6, which can, for example, be a plasma chamber in which a plasma is generated for plasma processing. In particular, a workpiece can be etched or a layer of material can be deposited onto a substrate. The load 6 can also be a gas laser excitation.

[0072] A comparable power supply system and a method for exciting a plasma are disclosed, for example, in DE 102013226 537 A1. In this power supply system, two amplifier paths are connected to a phase-shifting coupler unit, which couples the output signals of the amplifier paths to a high-frequency power signal. The advantage of using a phase-shifting coupler unit is that the two amplifier paths connected to the coupler unit "see" different impedances in the event of a mismatch. "Seeing" different impedances means that an amplifier path is connected to an impedance at its output. Since power is reflected back to the amplifier path depending on the impedance, the person skilled in the art says that the amplifier path can "see" the impedance.Because the amplifier paths see different impedances, the transistors of the amplifiers and / or amplifier units heat up differently in case of impedance mismatch, unlike in in-phase combinations. The warmer of the two transistors heats up less, even without supply voltage regulation, compared to using conventional combiners. Furthermore, in case of impedance mismatch, power is not returned to the amplifier paths but can be dissipated into an absorption resistor.

[0073] The lower part of Figure 1 shows a detailed view of amplifier stage 40. Amplifier stage 40 features:

[0074] - a first amplifier path 42, comprising a first amplifier unit 42a and

[0075] - a second amplifier path 43, comprising a second amplifier unit 43a.

[0076] An output network 45, 46 is optionally provided at the output of each of the amplifier paths 42, 43.

[0077] The first amplifier path 42 is configured to output a first amplifier path output signal, and the second amplifier path 43 is configured to output a second amplifier path output signal.

[0078] The second amplifier path output signal has a phase shift relative to the first amplifier path output signal, which is not equal to, in particular greater than, 0°.

[0079] The amplifier paths 42, 43 are connected to a phase-shifting coupler unit 47.

[0080] The phase-shifting coupler unit 47 is designed to couple the output signals of the amplifier paths 42 and 43 into a high-frequency power signal. The first amplifier unit 42a and the second amplifier unit 43a each comprise the following components:

[0081] • a baseload amplifier 103, which is configured to provide a baseload amplifier power;

[0082] • a peak load amplifier 104, which is configured to provide peak load amplifier power; and

[0083] • a power coupler 107 for combining the base load amplifier power and the peak load amplifier power at the output of the respective first amplifier unit 42a or second amplifier unit 43a to form an amplifier output power P ou t.

[0084] This phase relationship shift can be achieved, for example, by the signal supply device 99. In that case, a signal influencer 102 would be designed as a phase shifter, typically implemented digitally, i.e., in digital hardware and / or software.

[0085] This phase relationship shift can also be achieved, for example, by an analog signal influencer 102 designed as a phase shifter. This can be provided within the amplifier unit 42a, 43a.

[0086] To generate a power boost above the continuous operating power of the power supply system 2, the amplitude and / or phase relationship between the base-load amplifier 103 and the peak-load amplifier 104 is adjusted such that a load impedance 106 for the base-load amplifier 103 and / or a load impedance 108 for the peak-load amplifier 104 changes such that the resulting amplifier output power Pout of the amplifier unit 42a, 43a is greater than the continuous operating power of the amplifier unit 42a, 43a. The load impedances 106, 108 are shown in Fig. 1 and Fig. 5 only for amplifier unit 43a, but they also apply analogously to amplifier unit 43a. Further details on the power converter 3 and the amplifier stage 40 are described below in connection with Figs. 2, 4, and 5.

[0087] Figure 2 shows a schematic representation of the power supply system 2 with further details. The power supply system 2 includes a power converter 3 that generates an output power which can be supplied to the load 6, for example, a plasma process or a laser excitation. An impedance matching network 5 can be arranged between the load 6 and the power converter 3.

[0088] Generating a power boost above the continuous operating power of the power supply system by changing the amplitude and / or phase relationship between the base-load amplifier and the peak-load amplifier can produce the higher output power required to ignite a plasma or gas laser. This ignition often requires a short-term power boost exceeding the system's rated power.

[0089] By adjusting the amplitude and phase relationship, the system can flexibly respond to different requirements, such as sudden changes in load or switching between ignition and operating modes.

[0090] The ability to control the amplitude and phase relationship allows for optimization of the efficiency of the amplifier units by operating them in ranges where they can achieve higher power output with less loss.

[0091] By adjusting the phase relationship, the system can become more stable against rapid load changes, as the effects of reflected power can be better controlled.

[0092] The power supply system 2 comprises a digital-to-analog converter (DAC) 31 for generating an analog output signal. The generation of the analog signal will be explained below with reference to the illustration in Fig. 3. A logic circuit unit 32 is associated with the digital-to-analog converter 31. In particular, sequences of digital values ​​are supplied to the DAC 31 from the logic circuit unit 32, from which the DAC 31 generates the analog output signal. The DAC 31 and the logic circuit unit 32 can be integrated in a so-called direct synthesis device (DDS device) 33, which can also be referred to as a direct digital synthesizer. According to the exemplary embodiment, the logic circuit unit 32 comprises:

[0093] • a signal data storage device in which signal data values ​​for generating the analog signal shape are stored,

[0094] • an amplitude data storage device in which amplitude data values ​​are stored to influence the amplitude of the analog signals,

[0095] • a multiplier for multiplying the signal data values ​​by the amplitude data values ​​and

[0096] • a counter that ensures that signal data values ​​are read from the signal data memory and fed to the multiplier at a predetermined rate.

[0097] Both the signal data storage 34 and the amplitude data storage 35 can be configured as so-called look-up tables (LUTs).

[0098] As shown in Fig. 2, the generated analog signal is fed to a first amplifier stage 40, and in particular to a splitter 41. The splitter 41 can be designed as a hybrid coupler that splits the analog signal into two phase-shifted signals, in particular into two signals phase-shifted by 90°, with each signal output by the splitter 41 being fed to an amplifier path 42, 43. The first amplifier path 42 has at least one first amplifier unit 42a. The second amplifier path 43 has at least one second amplifier unit 43a. The amplifier units 42a, 43a are designed here as Doherty amplifiers, the construction of which will be discussed below. The power supply to the amplifier paths 42, 43, and thus to the amplifier units 42a, 43a, is provided by a power supply 44.At the output of amplifier paths 42, 43, an output network 45, 46 is optionally provided, which matches the output impedance of the respective amplifier unit 42a, 43a to the input impedance of a phase-shifting coupler unit 47 and simultaneously filters out unwanted overtones. In the phase-shifting coupler unit 47, the output signals of amplifier paths 42, 43 are coupled phase-dependently to form an output signal, which is ultimately fed to the load 6 via an optional impedance matching network 5. Preferably, the phase-shifting coupler unit 47 is a 90° hybrid coupler. In this respect, the first amplifier stage 40 is designed as a balanced amplifier.

[0099] The output power at the output of the coupler unit 47 can be measured by appropriate measuring instruments 48. The dashed line 49 indicates that the measuring instruments 48 are connected to a voltage regulator 50, which in turn controls the power supply 44. In particular, the measuring instruments 48 can also measure the power delivered to the load 6 and the power reflected by the load 6. From these values, a reflection coefficient or the magnitude of a reflection coefficient can be determined, which can then be used to control the voltage regulation.

[0100] The illustration in Fig. 4 shows a first embodiment of the two amplifier units 42a, 43a from Fig. 2. The amplifier units 42a, 43a are designed here as Doherty amplifiers, each comprising the following components:

[0101] ■ a baseload amplifier 103, which is configured to provide a baseload amplifier power;

[0102] ■ a peak load amplifier 104, which is configured to provide peak load amplifier power; and

[0103] • a power coupler 107 for combining the base load amplifier power and the peak load amplifier power at the output of the respective first or second amplifier unit 42a, 43a to a single amplifier output power P ou t.

[0104] The performance Pj nAt the input of the first and second amplifier units 42a and 43a, respectively, a phase-shifting splitter 101 splits the signal into two paths with a phase shift, here a phase shift of 90°. Figure 4 shows the functional elements of the phase-shifting splitter 101 as separate elements: splitter 101 and signal influencer 102. This signal influencer 102 can be configured as a phase shifter. Additionally or alternatively, this signal influencer 102 can be configured as an amplitude influencer, i.e., for example, a signal amplifier or attenuator. However, the phase-shifting splitter 100 can also be configured as a hybrid coupler, in particular a 90° hybrid coupler. Due to the introduced phase shift, the output signal of the peak-load amplifier 104 also exhibits a phase shift relative to the output signal of the base-load amplifier 103. These output signals are combined by the power coupler 107.The power coupler 107 is also shown here as a combination of a phase-shifting impedance inverter 105, for example an Ä / 4 line, and an impedance converter 116.

[0105] The first and second amplifier units 42a, 43a are configured such that the base load amplifier 103 essentially provides a base load of the amplifier output power P ou t provides. The peak load amplifier 104 can operate in a base load mode in which the amplifier output power P ouThe power is primarily supplied by the base-load amplifier 103, which may be active at a low power level, or the peak-load amplifier 104 may be inactive, i.e., high-impedance. The base-load amplifier 103 may be configured as a class-B or class-AB amplifier, while the peak-load amplifier 104 is configured as a class-C amplifier. The peak-load amplifier 104 may be designed such that its transistor(s) are conducting for only a fraction of half a signal period. In this respect, the peak-load amplifier 104 is configured to provide the peak-load amplifier power only when a predetermined base-load amplifier power is exceeded.

[0106] Figure 5 shows a further embodiment of an amplifier stage 40 comprising a first amplifier path 42 with a first amplifier unit 42a and a second amplifier path 43 with a second amplifier unit 43a. The two amplifier units 42a, 43a are coupled to each other via a phase-shifting coupler unit 47. This is configured here as a 3dB-90° hybrid coupler. The two amplifier units 42a, 43a, in particular their base-load amplifier 103 and peak-load amplifier 104, are controlled by a signal generation device 99. This device is preferably configured to provide signals for generating the high-frequency power signal in a predetermined power range such that the base-load amplifier power is greater than the peak-load amplifier power at least in a part of the predetermined power range, preferably in a lower part of the predetermined power range.

[0107] The power supply system comprising amplifier stage 40 is configured such that, in the event of a mismatch of the load 6, power reflected from the load 6 is at least partially directed via the coupler unit 47 and at least one power coupler 107 to at least one of the base-load amplifiers 103 and peak-load amplifiers 104. The power is reflected at least at this base-load amplifier 103 or peak-load amplifier 104 and returned via the power coupler 107 to the coupler unit 47. This unit is connected to an absorption resistor 110, which absorbs this returned power.

[0108] To ensure both reliable ignition of the plasma or gas laser and reliable and efficient operation after ignition, even with highly fluctuating, for example pulsed, power output, special provisions have been made in the power supply system according to the embodiments described above. As already explained above with reference to Figures 1 to 5, the power supply system 2 is configured to supply the first and second amplifier units 42a, 43a with an amplifier output power P during normal operation, particularly for maintaining a plasma or operating a gas laser. 0U to operate t which is less than or equal to the continuous operating power of the respective amplifier unit 42a, 43a.

[0109] In addition, it is provided that the power supply system 2 is also configured to generate a power boost above the continuous operating power of the power supply system 2, in particular for igniting a plasma or gas laser, wherein an amplitude and / or phase relationship between the base load amplifier 103 and the peak load amplifier 104 of at least one of the first and second amplifier units 42a, 43a is changed, in particular briefly, and in particular is adjustable such that the amplifier output power P ou t of the amplifier unit 42a, 43a is greater than the continuous operating power of the respective amplifier unit 42a, 43a.

[0110] In a Doherty amplifier, the respective peak-load amplifier 104 modulates the load impedance of the base-load amplifier 104. To generate the power boost, the phase and / or amplitude relationship between the base-load amplifier 103 and the peak-load amplifier 104 can be changed, thereby briefly influencing the load impedance so that the overall amplifier generates an output power exceeding its continuous operating power. This may reduce efficiency, but this is acceptable for short periods. For example, the phase relationship in one or both amplifier units 42a, 43a can be set to a phase difference greater than 90°, preferably greater than 100°, and particularly preferably greater than 110°, for example, 120°.

[0111] Under normal operating conditions, the phase relationship is usually 90°, so it is increased to generate the power boost.

[0112] Alternatively or additionally, the amplitude relationship in one or both amplifier units 42a, 43a can be set to a value greater than or equal to 3dB.

[0113] This amplitude relationship shift can be achieved, for example, by the signal supply device 99. In that case, a signal influencer 102 would be designed as an amplitude influencer, typically implemented digitally, i.e., in digital hardware and / or software.

[0114] This amplitude relationship shift can also be achieved, for example, by an analog signal influencer 102, designed as an amplitude influencer. This can be provided within the amplifier unit 42a, 43a.

[0115] The signal influencer 102 can be designed to be switched on and off.

[0116] The signal influencer 102 can be designed to be adjustable, in particular by means of an electrical signal.

[0117] The time period for generating the power boost can range from 2 microseconds to 100 microseconds.

[0118] Since two of these Doherty amplifiers are interconnected with a 3dB coupler in the present power supply system, it is possible to combine the ability to provide a power boost with highly efficient normal operation with a balanced amplifier, i.e., cable length independence.

[0119] The linear operation of the base-load amplifier enables efficient amplification at low power levels. This means it is capable of delivering a constant output power with minimal distortion and losses, which is essential for normal operation. A linear amplifier can ensure high signal quality because the gain is proportional to the input power. This is particularly advantageous for reducing signal distortion and ensuring clear and precise performance.

[0120] The non-linear peak load amplifier can be specifically designed to deliver high peak power levels that exceed normal operating conditions. This makes it possible to efficiently meet short-term power demands, such as those encountered when firing plasmas or gas lasers.

[0121] The combination of a linear base-load amplifier and a non-linear peak-load amplifier enables the system to efficiently meet both low and high power requirements. This increases the system's flexibility to cope with varying operating conditions.

[0122] Since the base-load amplifier can operate linearly and within a high efficiency range, power loss during normal operation can be reduced. The non-linear amplifier can be selectively activated only when needed, resulting in a further reduction in overall system power loss.

[0123] By strategically using two different amplifier types, heat generation and thus the stress on the components can be reduced. The base-load amplifier can operate efficiently, while the peak-load amplifier is only activated when needed, which increases the lifespan of the amplifier units.

[0124] Class B and Class AB amplifiers can offer high efficiency compared to other amplifier types. Class B amplifiers, in particular, can achieve efficiency levels of up to 78.5%, resulting in lower power loss and better heat dissipation. This can be advantageous for normal operation where constant power output is required.

[0125] Class AB amplifiers offer improved linearity compared to Class B amplifiers. This means they produce less distortion, resulting in better signal quality, especially at low power levels supplied by the base load amplifier.

[0126] A Class-C amplifier can deliver high output power, especially at higher frequencies. This configuration is ideal for applications requiring short-term power surges, such as firing plasmas or gas lasers.

[0127] Since a Class C amplifier is only active for a portion of the signal period, it can provide high power when needed, while remaining inactive during normal system operation. This allows for targeted use of peak loads without unnecessarily burdening the base-load amplifier. Combining the two amplifier types can improve heat dissipation within the system. The base-load amplifier can operate efficiently, while the peak-load amplifier is only activated when required, which can reduce overall system heat generation and extend component lifespan.

[0128] The ability to control the phase of the output signals allows for more stable system operation. This is particularly advantageous in applications with rapid load changes, as adjusting the phase helps minimize reflections and instabilities. The capacity to regulate the output signal phase contributes to system reliability, especially in applications with rapidly fluctuating impedance. This can help reduce the impact of reflected power, which could destabilize the system.

[0129] The use of discrete components such as inductors and capacitors can enable a cost-effective and modular design of the power coupler. This can reduce manufacturing and material costs compared to more complex integrated solutions. Discrete components can be selected to exhibit low power losses at the intended frequencies and loads. This can contribute to the overall energy efficiency of the system.

Claims

Patent claims:

1. Method for operating a power supply system (2), wherein the power supply system (2) comprises a power converter (3) generating a high-frequency power signal, which is connected to a load (6) for supplying power to a plasma or gas laser process, wherein the power converter (3) comprises at least one amplifier stage (40) comprising: - a first amplifier path (42), comprising a first amplifier unit (42a), - a second amplifier path (43), comprising a second amplifier unit (43a), wherein the first amplifier path (42) is used to output a first The amplifier path (42, 43) is configured to output a second amplifier path output signal which has a phase shift relative to the first amplifier path output signal, which is not equal to, in particular greater than, 0°, the amplifier paths (42, 43) being connected to a phase-shifting coupler unit (47) designed to couple the output signals of the amplifier paths (42, 43) to a high-frequency power signal, the first and second amplifier units (42a, 43a) each comprising: i. a base-load amplifier (103) configured to provide base-load amplifier power; ii. a peak-load amplifier (104) configured to provide peak-load amplifier power; and iii.a power coupler (107) for combining the base load amplifier power and the peak load amplifier power at the output of the respective first or second amplifier unit (42a, 43a) to a single amplifier output power (P. ou t) wherein the procedure comprises the following procedural step: - To generate a power boost above a continuous operating power of the power supply system (2), an amplitude and / or phase relationship between the base load amplifier (103) and the peak load amplifier (104) of at least one of the first and second amplifier units (42a, 43a) is changed, in particular briefly, in particular adjusted such that the amplifier output power (Pout) of this amplifier unit (42a, 43a) is greater than a continuous operating power of this amplifier unit (42a, 43a).

2. Method according to claim 1, characterized in that the power amplification is achieved by adjusting the amplitude and / or phase relationship between the base load amplifier (103) and the peak load amplifier (104) such that the load impedance (106) for the base load amplifier (103) and / or the load impedance (108) for the peak load amplifier (104) changes such that the resulting amplifier output power (P) ou t) of the amplifier unit (42a, 43a) is greater than the continuous operating power of this amplifier unit (42a, 43a).

3. Method according to one of the preceding claims, characterized in that in normal operation, in particular for maintaining a plasma or operating a gas laser, the first and second amplifier unit (42a, 43a) are operated with an amplifier output power (Pout) that is less than or equal to the continuous operating power of this amplifier unit (42a, 43a).

4. Method according to one of the preceding claims, characterized in that the coupler unit (47) is designed such that it forwards the power reflected to its output terminal in a phase shift to its input terminals and thus forwards it to the amplifier units in the amplifier paths.

5. Method according to one of the preceding claims, characterized in that, to generate the power boost, an amplitude and / or phase relationship between the base load amplifier (103) and the peak load amplifier (104) of both the first amplifier unit (42a) and the second amplifier unit (43a) is changed, in particular briefly, and in particular adjusted such that the amplifier output power (P ou t) of both amplifier units (42a, 43a) is greater than the continuous operating power of each amplifier unit (42a, 43a).

6. Method according to one of the preceding claims, characterized in that, to generate the power boost, an amplitude and / or phase relationship between the base load amplifier (103) and the peak load amplifier (104) of both the first amplifier unit and the second amplifier unit is changed, in particular briefly, and in particular adjusted such that the amplifier output power of both amplifier units (42a, 43a) is greater than a continuous operating power of the respective amplifier unit.

7. Method according to one of the preceding claims, characterized in that, to generate the power boost, the amplitude and / or phase relationship is adjusted such that the load impedance (106) of the base load amplifier (103) deviates from normal operation, in particular the load impedance (106) of the base load amplifier (103) is lower than in normal operation.

8. Method according to one of the preceding claims, characterized in that, to generate the power boost, the phase relationship between the base load amplifier (103) and the peak load amplifier (104) is set to a phase difference other than 90°, preferably deviating by at least 10° from 90°, particularly preferably deviating by at least 20° from 90°, for example to 60° or 120°.

9. Method according to one of the preceding claims, characterized in that, to generate the power increase, the amplitude relationship between the base load amplifier (103) and the peak load amplifier (104) is set to a factor of at least 1.2, in particular at least 1.

4.

10. Method according to one of the preceding claims, characterized in that, for generating the power boost, the power supply system has one or more buffer capacitor(s) which is / are configured to be able to store sufficient energy to provide the short-term power boost.

11. Method according to one of the preceding claims, characterized in that the power supply system (2) has a signal provision device (99) which provides signals to the first and second amplifier unit (42a, 43a) for generating the high-frequency power signal, wherein the signal provided for the normal operating mode differs from the signal provided for generating the power boost.

12. Method according to one of the preceding claims, characterized in that the peak load amplifier (104) and the base load amplifier (103) each have an amplifying transistor with an input terminal, wherein a bias voltage is applied to the input terminal of the transistor at least in one of the Both amplifiers are adjustable, and the bias voltage in operation is different for the base load amplifier than for the peak load amplifier.

13. Method according to one of the preceding claims, characterized in that the base load amplifier (103) is configured as a substantially linear amplifier and the peak load amplifier (104) is configured as a substantially non-linear amplifier.

14. Method according to one of the preceding claims, characterized in that the base load amplifier (103) is configured as a class B amplifier or as a class AB amplifier and the peak load amplifier (104) is configured as a class C amplifier.

15. Method according to one of the preceding claims, characterized in that the peak load amplifier (104) - in normal operation - is configured to provide the peak load amplifier power only when a predetermined base load amplifier power is exceeded.

16. Method according to one of the preceding claims, characterized in that the peak load amplifier (104) is configured in normal operation to change the output impedance of the peak load amplifier (104) such that it is high-impedance when a predetermined base load amplifier power is undershot.

17. Method according to one of the preceding claims, characterized in that the power supply system (2) comprises a signal provision device (99) configured to provide signals to the first and second amplifier units (42a, 43a) for generating the high-frequency power signal such that an output signal of the peak load amplifier (104) has a phase shift relative to an output signal of the base load amplifier (103), and / or the first and second amplifier units (42a, 43a) comprise a phase-shifting splitter (100) configured to provide signals to the base load amplifier (103) and the peak load amplifier (104) for generating the high-frequency power signal such that an output signal of the The peak load amplifier (104) has a phase shift relative to an output signal of the base load amplifier (103).

18. Power supply system (2) comprising a power converter (3) designed to generate a high-frequency power signal for powering a plasma or gas laser process and connectable to a load (6) for this purpose, wherein the power converter (3) comprises at least one amplifier stage (40) comprising: - a first amplifier path (42), comprising a first amplifier unit (42a), - a second amplifier path (43), comprising a second amplifier unit (43a), wherein the first amplifier path (42) is used to output a first The amplifier path output signal is configured, and the second amplifier path (43) is configured to output a second amplifier path output signal having a phase shift relative to the first amplifier path output signal, which is not equal to, in particular greater than, 0° and not equal to, in particular less than, 180°, wherein the amplifier paths (42, 43) are connected to a phase-shifting coupler unit (47) configured to couple the output signals of the amplifier paths (42, 43) to a high-frequency power signal, wherein the first and second amplifier units (42a, 43a) each comprise: i. a base-load amplifier (103) configured to provide base-load amplifier power; ii. a peak-load amplifier (104) configured to provide peak-load amplifier power; and iii.a power coupler (107) for combining the base load amplifier power and the peak load amplifier power at the output of the respective first or second amplifier unit (42a, 43a) to a single amplifier output power (P. ou t) wherein the power supply system (2) is configured to generate a power boost above a continuous operating power of the power supply system (2), in particular to ignite a plasma or gas laser, wherein an amplitude and / or phase relationship between the base load amplifier (103) and the peak load amplifier (104) of at least one of the first and second amplifier units (42a, 43a) is changed, in particular briefly, and in particular is adjustable such that the amplifier output power (Pout) of this amplifier unit (42a, 43a) is greater than a continuous operating power of this amplifier unit (42a, 43a).

19. Plasma system (1) comprising a. a power supply system (2) according to claim 18, b. a load (6), in particular configured as a plasma or gas laser process, • wherein the power supply system (2) includes a power converter (3) which can be connected to a voltage supply network (4), • wherein the power transformer (3) is connected to the load (6), • wherein in particular a connection exists between the load (6) and the power transformer (3). impedance matching network (5) is arranged.

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