Energy re-feeding module, switching circuit and implementation structure, plasma processing system and method for generating rectangular voltage output pulse for plasma sub-processing load

Abstract

An energy re-feeding module (15) for a switching circuit (101) having a switching unit (24) configured to be connectable to a DC voltage source (V1) and to provide, at its output (OUT), one or a combination of the following features: iv) a high voltage value, v) a high voltage rise value with reduced oscillation and / or overshoot, vi) a high current value to a capacitive load, in particular a plasma sub-processing load (12), the energy re-feeding module (15) comprises: c. A rectifying circuit (14) configured to connect its positive terminal on the DC side to the positive connection of the DC voltage source (V1) and to connect its negative terminal on the DC side to the negative connection of the DC voltage source; and d. A transformer (TF1) comprising: i. A primary winding (18) configured to be connected in series between the switching unit (24) and the output (OUT) and configured to have a sufficiently low stray inductance and parasitic resistance to cause one or a combination of the following characteristics:-a high voltage value,-a high voltage rise value,-a high current value; and ii. A secondary winding (19) connected to the AC side of the rectifying circuit (14).

Description

Technical Field

[0001] The invention relates to an energy re-feeding module, a switching circuit comprising such an energy re-feeding module, a switching implementation structure comprising at least one such switching circuit, a plasma system comprising such a switching circuit and / or such a switching implementation structure, and a method for generating rectangular voltage output pulses. Background Art

[0002] Some plasma processing applications, such as etching or layer deposition, require high voltage (HV), high frequency (HF), rectangular, asymmetric, pulsed voltage supplies. The voltage values ​​often greatly exceed the voltage handling capabilities of a single semiconductor switch, especially when high frequency operation is required. Therefore, connecting these switches in series is often the only feasible solution. Series connection requires voltage balancing means. These are not easy to achieve in HF operation.

[0003] Most plasma applications present a load which contains capacitive elements. The pulse-by-pulse charging and discharging process of this load capacitance generates significant power losses. Other problems are pulser inefficiencies and undesired voltage oscillations. Therefore, voltage pulses with an (almost) ideal rectangular shape are desired. Summary of the invention

[0004] The object of the present invention is to provide an energy re-feeding module, a switching circuit, a switching implementation structure, a plasma processing system and a method for generating high-voltage rectangular pulses.

[0005] This object is achieved by an energy refeeding module according to claim 1 and / or a switching circuit according to claim 8 and / or a switching embodiment according to claim 11 and / or a plasma system according to claim 12 and / or a method according to claim 13. Further aspects of the invention are given in the dependent claims and / or in the description.

[0006] According to one aspect of the present invention, an energy re-feeding module for a switching circuit is provided, wherein the switching circuit has a switching unit, which is configured to be connectable to a DC voltage source and to provide one or a combination of the following features at its output:

[0007] i) High voltage value,

[0008] ii) High voltage rise value,

[0009] iii) high current values ​​for capacitive loads, especially for plasma processing loads,

[0010] The energy re-feed module includes:

[0011] a. a rectifier circuit configured to connect the positive end of its DC side to the positive connection of a DC voltage source and the negative end of its DC side to the negative connection of the DC voltage source, in particular to ground potential, and

[0012] b. Transformer, including:

[0013] i. A primary winding configured to be connected in series between the switching unit and the output and configured to have a stray inductance and parasitic resistance low enough to cause one or a combination of the following characteristics:

[0014] - High voltage value,

[0015] -High voltage rise value,

[0016] -High current value

[0017] and

[0018] ii. The secondary winding, which is connected to the AC side of the rectifier circuit.

[0019] According to another aspect of the present invention, a switching circuit connected to a plasma processing load is provided, comprising:

[0020] A series connection of a high-side switching element and a low-side switching element, the series connection being connected to a voltage source and configured to produce a high voltage (HV) at an output connectable to a plasma load

[0021] Pulse signal,

[0022] A rectifier circuit connected to a voltage source, and

[0023] Transformer, including:

[0024] o a primary winding connected in series between a connection point between the high-side switching element and the low-side switching element and the output, and

[0025] oConnected to the secondary winding of the rectifier circuit.

[0026] According to another aspect of the present invention, a switching circuit is provided, which is configured to deliver a high voltage (HV) fast rising pulse to a plasma processing load, comprising:

[0027] a) a switching unit comprising a high-side switching element and a low-side switching element connected in series, a connection point of the two switching elements, a low-side connection and a high-side connection, the low-side connection and the high-side connection being connected to a voltage source,

[0028] b) An energy re-feeding module as described herein, wherein

[0029] i. The DC side of the rectifier circuit is connected to a voltage source, and

[0030] ii. the primary winding of the transformer is connected in series between the connection point between the high-side switching element and the low-side switching element and the output, and

[0031] iii. The secondary winding is connected to the AC side of the rectifier circuit.

[0032] Such a switching circuit allows the generation of voltage pulses with an almost ideal rectangular shape. In particular, undesired voltage oscillations can be prevented. In addition, the efficiency of such a switching circuit is very high. If such a switching circuit is used in a high-voltage pulse generator, the efficiency of the pulse generator can be increased.

[0033] The stray inductance may be 100 μH or less, in particular 10 μH or less.

[0034] The parasitic resistance may be 1Ω or less, in particular 0.1Ω or less.

[0035] The high voltage value may be 800 V or more, in particular 1.5 kV or more, especially at least 5 kV.

[0036] A high voltage rise value may be a voltage rise of at least 1 kV / μs, in particular 10 kV / μs or more, preferably 100 kV / μs or more. A voltage rise may also mean a voltage drop.

[0037] The high current value may be at least 30 A, in particular 100 A or more.

[0038] The high-voltage pulse signal may be a pulse signal with a high voltage as defined above, in particular, a pulse signal with a high voltage rise value as defined above.

[0039] The modules, units, circuits and / or implemented structures may be configured to deliver power to a plasma load, particularly during pulses, at an output of at least 10 kW, advantageously 20 kW or more.

[0040] The rectifier circuit can be connected with its positive DC side to the positive connection of the DC voltage source and with its negative DC side to the negative connection of the DC voltage source, in particular to ground potential.

[0041] The energy re-feeding module, the switching circuit and / or the switching unit may be part of a high power generator as described in EP22461510.4 filed on February 28, 2022, entitled “High power generator and method for supplying high power pulses”.

[0042] The transformer may be a step-up transformer. During the generation of the pulse, the high-side switching element switch may be turned on, so that energy from the voltage source flows to an output that may be connected to a load, in particular a plasma load having capacitive characteristics. At the beginning of this process, almost the entire voltage difference between the voltage source and the voltage on the load occurs on the primary winding of the transformer. A voltage is induced on the secondary winding of the transformer. The value of this voltage is equal to the voltage of the primary winding multiplied by the transformation ratio. If this induced voltage is higher than the supply voltage on the bus, the rectifying part of the rectifier begins to conduct. In this way, the induced voltage of the secondary winding is limited to the value of the voltage on the bus, i.e. the supply voltage. Due to the transformation ratio, the voltage of the primary winding is also reduced (to a voltage corresponding to the voltage on the bus divided by the transformation ratio). Therefore, at the beginning of the load charging, the impedance of the transformer is relatively low and the load can be charged quickly. In this state, the core of the transformer does not accumulate any energy, which may cause an overvoltage on the load.

[0043] When the charging current decreases so that the voltage induced in the secondary winding is no higher than the voltage on the bus, the current in the secondary winding stops flowing, so the transformer acts only as an inductor. The inductance of the transformer primary winding increases, so the current charging the load capacitance decreases. Therefore, the charging process slows down, reducing unwanted oscillations.

[0044] When the high-side switching element is open and the low-side switching element is closed, that is, during the falling edge of the output voltage pulse, basically the same situation occurs. In this state, the energy from the load capacitance is released through the low-side switching element. At the beginning of this process, the voltage of the primary winding of the transformer is high enough that some energy is returned to the bus through the rectifier circuit.

[0045] This process is relatively fast because the current is limited mainly by the transformer leakage inductance. At the end of the capacitive load discharge, the voltage on the transformer's primary winding is low (the voltage on the transformer's secondary winding is lower than the bus voltage), so the transformer starts to behave as a normal inductor that limits the current and slows down the load discharge process. Again, since there is little energy stored in the transformer's inductance, the unwanted oscillations are relatively small.

[0046] Because some of the energy is returned to the bus and thus to the power source for a period of time during the charging and discharging of the load capacitance, the overall efficiency of the circuit is improved.

[0047] The rectifier circuit may include one component, in particular a rectifier diode, configured to conduct current in one way only.

[0048] The rectifier circuit may include two components, in particular two rectifier diodes, configured to conduct current in one direction only.

[0049] The rectifier circuit may comprise four components, in particular four rectifier diodes, configured to conduct current in only one direction, in particular in a bridge circuit. In this way, the rectifier circuit may be implemented with inexpensive standard components.

[0050] An overvoltage protection unit, in particular an overvoltage protection diode, may be configured to be connected between the output and the rectification circuit to protect the load from overvoltage.

[0051] At least one overvoltage protection unit, in particular an overvoltage protection diode, may be configured to be connected between the output and at least one connection of the voltage source.

[0052] As mentioned before, the transformer charges itself. Therefore, it stores some energy. This will generate some overvoltage (the load capacitance will be charged to a voltage higher than the bus voltage). In order to avoid this, an overvoltage protection unit, in particular an overvoltage protection diode, can be provided to protect the load from overvoltage. In this way, undesired oscillations can be prevented. The first damping resistor can be connected in series with the overvoltage protection unit. This can better stabilize the energy re-feeding module. The resistance value of the first damping resistor can be 1Ω to 100Ω, preferably 20Ω to 70Ω.

[0053] A negative voltage protection unit (particularly a negative voltage protection diode) may be configured to be connected between the output and the ground potential to protect the load from negative voltage. In addition, undesirable oscillations may be limited by adding such a negative voltage protection unit (particularly a negative voltage protection diode connected in parallel with the load) to prevent the load from charging to a negative voltage. A second damping resistor may be connected in series with the negative voltage protection unit to further stabilize the energy re-feeding module, and the resistance of the second damping resistor may be 1Ω to 100Ω, preferably 20Ω to 70Ω.

[0054] The diode can be connected in parallel to one switching element, in particular to each switching element in parallel. In this way, the switching element can be protected from high voltages. This is especially true if the switching element comprises a MOSFET as a switching part. Each switching element can comprise one or more switching parts, such as a MOSFET or a bipolar transistor.

[0055] One aspect of the present invention relates to a switch implementation structure having

[0056] a. Several switching units as described above, which in particular include a series connection of a high-side switching element and a low-side switching element, a connection of two switching elements, a low-side connection and a high-side connection, the low-side connection and the high-side connection are connected to a voltage source, and

[0057] b. at least one switching circuit as described above,

[0058] Therein, the switching unit is connected in series with a voltage source connection point of a switching circuit, and the voltage source connection point is connected to the output of the next switching circuit in the series connection line.

[0059] Another aspect of the present invention relates to a plasma system, comprising a plasma load and a switch circuit as described above, and / or a switch implementation structure as described above. Such a plasma system can be advantageously used in semiconductor production processes, in particular in the production of 3D memory devices, such as 3D NAND memory devices, and is preferred when etching deep holes for connecting 3D structures.

[0060] Another aspect of the present invention relates to a method for generating a rectangular voltage output pulse, comprising the following steps:

[0061] · generating an HV pulse signal at the output of the switching circuit using a series connection of a high-side switching element and a low-side switching element, the series connection being connected to a voltage source,

[0062] Provides HV pulse signal at output through primary winding of transformer,

[0063] ·Rectify the current induced in the secondary winding of the transformer.

[0064] This method can generate voltage pulses that are close to an ideal rectangular shape. It can prevent voltage overshoot and oscillation, thereby improving efficiency.

[0065] During the charging and discharging process of the load capacitor connected to the output, energy is fed back to the bus. This improves the efficiency of the switching circuit. Power loss can be greatly prevented.

[0066] The oscillation can be reduced by providing a diode connected to the output.

[0067] More precisely, the oscillation can be reduced by providing:

[0068] a. an overvoltage protection unit, in particular an overvoltage protection diode, and / or

[0069] b. Negative voltage protection unit, especially the negative voltage protection diode connected to the output (OUT),

[0070] And in particular, the oscillation is further reduced by a first and / or second damping resistor respectively connected in series with the protection unit, in particular a diode.

[0071] Further features and advantages of the invention are derived from the following detailed description of embodiments of the invention based on the drawings, which show the essential details of the invention, and from the claims. The features shown here are not necessarily drawn to scale, but are shown in such a way that the special features according to the invention can be clearly seen. The various features can be implemented individually or in any combination in a variant of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In the schematic diagram, examples of the invention in various stages of use are shown and are explained in more detail in the following description.

[0073] Figure 1 A first example of a plasma processing system having a switching circuit and an energy re-feed module is shown,

[0074] Figure 2 shows the output voltage obtained by using the switching circuit of the present invention,

[0075] Figure 3a , 3b 4a, 4b show additional examples of plasma processing systems, each having a series combination of switching circuits including one or more energy re-feed modules,

[0076] Figure 5a Shown together in simplified form Figure 1 and Figure 2 The picture,

[0077] Figure 5b-5d Shows Figure 5a related possibilities. DETAILED DESCRIPTION

[0078] Figure 1 A first example of a plasma processing system 100 is shown, which has a plasma processing load 12, a switching circuit 101, which includes an energy re-feeding module 15 and a switching unit 24, both of which are connected to a DC voltage source V1. The switching circuit 101 is configured to provide a high voltage value, a high voltage rise value and / or a high current value to a capacitive load, in particular the plasma processing load 12, at its output OUT. The plasma processing load 12 includes a resistive element R L and the capacitance element C L . Resistor element R L Typical values ​​are between 0.5kΩ and 50kΩ. LA typical value of is a value between 0.1 μF and 1 μF. This may be a plasma load similar to or identical to that described in European patent application number EP22461510.4 filed on February 28, 2022, entitled “High Power Generator and Method for Providing High Power Pulses”, the entire contents of which are incorporated herein by reference. The plasma processing system 100 described herein may be similar to or identical to the system described in FIG. 10 of EP22461510.4. The switching unit 24 comprises a series connection of a high-side switching element S1 and a low-side switching element S2, and may be similar to or identical to the switching units 24, 26, and 28 in EP22461510.4. The switching unit 24 may be connected to the positive connection of the DC voltage source V1 with its positive terminal 26, and to the negative connection of the DC voltage source V1 with its negative terminal 25, in particular to the ground potential PE.

[0079] The switch circuit 101 further includes an energy re-feeding module 15, a positive end of the energy re-feeding module 15 is connected to the positive connection of the DC voltage source V1, and a negative end of the energy re-feeding module 15 is connected to the negative connection of the DC voltage source V1. The energy re-feeding module 15 is also connected to a connection point 16 between the high-side switch element S1 and the low-side switch element S2, and the energy re-feeding module 15 is also connected to the output OUT of the switch circuit 101.

[0080] The energy re-feeding module 15 includes a rectifier circuit 14 and a transformer TF1. The DC side positive end of the rectifier circuit 14 is connected to the positive connection of the DC voltage source V1, and the DC side negative end is connected to the negative connection of the DC voltage source V1, which is specifically the ground potential PE. The transformer TF1 includes a primary winding 18 and a secondary winding 19. The primary winding 18 is connected in series between the output OUT of the switching circuit 101 and the switching unit 24, in particular, between the connection point 16 between the high-side switching element S1 and the low-side switching element S2. The transformer TF1 is configured to have sufficiently low stray inductance and parasitic resistance, thereby causing the above-mentioned high voltage value, high voltage rise value and / or high current value. Both ends of the secondary winding 19 of the transformer TF1 are connected to the AC side of the rectifier circuit 14. The rectifier circuit 14 includes four diodes DR1-DR4, which are connected in a bridge circuit here. The DC side of the rectifier circuit 14 is connected to the voltage source V1, and the AC side is connected to the secondary winding of the transformer TF1. The transformer TF1 may include a magnetic core.

[0081] Diodes D1, D2 are arranged in parallel with the respective switching elements S1, S2. They can be used as freewheeling diodes and / or protect the switching elements S1, S2 from negative voltages.

[0082] The overvoltage protection unit (specifically another diode D01) is connected between the output OUT and the positive connection of the voltage source V1 to protect the load from overvoltage. The negative voltage protection unit (specifically another diode D02) is connected between the negative connection of the voltage source V1 (specifically the ground potential PE here) and the output OUT, that is, in parallel with the load 12 to protect the load from negative voltage. These diodes D01 and D02 can also reduce oscillation. In addition, the first damping resistor R1 is connected in series with the overvoltage protection unit (specifically the diode D01). In addition, the second damping resistor R2 is connected in series with the negative voltage protection unit (specifically the diode D02). Using these resistors can better reduce oscillation.

[0083] The operation of the switching circuit 101 is as follows. During the generation of the pulse, the high-side switching element S1 can be turned on so that the energy from the voltage source V1 flows to the output OUT. At the beginning of this process, almost the entire voltage difference between the voltage source V1 and the voltage on the load 12 is generated on the primary winding of the transformer TF1. Therefore, a voltage will be generated on the secondary winding 19 of the transformer TF1. The voltage value is equal to the voltage on the primary winding multiplied by the transformation ratio. If this induced voltage is higher than the voltage on the voltage source V1, the forward-biased diodes DR1-DR4 of the rectifier 14 begin to conduct, so that the induced voltage on the secondary winding is limited to the voltage value of the voltage source V1. Due to the transformation ratio, the voltage of the primary winding is also reduced to a voltage corresponding to the voltage on the voltage source V1 divided by the transformation ratio. Therefore, when the load 12 starts to charge, the transformer TF1 has a relatively low impedance and allows the load 12 to be charged quickly. In this state, the core of the transformer does not accumulate any energy, which may cause overvoltage of the load 12.

[0084] When the charging current decreases so that the voltage induced in the secondary winding is not higher than the voltage on the bus V1, the current in the secondary winding stops flowing, so the transformer TF1 acts only as an inductor. The inductance of the primary winding of the transformer TF1 increases, so the current charging the load 12 decreases. Therefore, the charging process slows down, thereby reducing undesirable oscillations.

[0085] The same happens when the high-side switching element S1 is open and the low-side switching element 2 is closed, i.e. during the falling edge of the output voltage pulse. In this state, the energy of the load is released through the low-side switching element S2. At the beginning of this process, the voltage of the primary winding of the transformer TF1 is high enough that some energy is returned to the voltage source V1 through the rectifier circuit 14.

[0086] This process is relatively fast, since the current is mainly limited by the leakage inductance of the transformer TF1. At the end of the load discharge, the voltage across the primary winding of the transformer TF1 is low (the voltage across the secondary winding of the transformer TF1 is lower than the voltage of the voltage source V1). Therefore, the transformer TF1 starts to behave like a normal inductor, limiting the current and slowing down the discharge process of the load 12. Again, the undesired oscillations are relatively small, since little energy is stored in the inductance of the transformer TF1.

[0087] Figure 2 The voltage waveform VOUT generated by the switching circuit 101 at its output OUT is shown. It can be seen that a rectangular voltage pulse is obtained, which has steep edges and no oscillations at the corners of the pulse shape.

[0088] Figure 3a A second example of a plasma processing system 300 is shown having a series combination of switch circuits 301, 301i, ..., 301n, each switch circuit comprising an energy refeed module 315, 315i, ..., 315n and a switch unit 324, ..., 324i, 324n.

[0089] Each switch unit 324, 324i, ..., 324n is connected to a corresponding voltage source V1, Vi, ..., Vn, respectively.

[0090] The series combination of the switch circuits 301 , 301 i , . . . , 301 n may constitute a switch implementation structure 311 .

[0091] The switch units 324, ..., 324i, ..., 324n are connected in series with a voltage source connection point of one switch circuit 301, 301i, which is connected to the output OUT of the next switch circuit 301i, 301n in the series connection line.

[0092] The re-feeding modules 315i, ... 315n are optional here. To achieve this effect, only one re-feeding module 315 is sufficient at the output of the switch implementation structure 311.

[0093] Figure 3b A third example of a plasma processing system 300' having a series combination of switch circuits 301, 301i, ... 301n is shown. Figure 3a In contrast, the plasma processing system 300' comprises only one energy refeed module 315z, which is connected to the output of one of the switching circuits 301, the voltage source V1 of the switching circuit 301 (in particular the switching circuit 301) and the different voltage source Vn of the switching circuit 301n (in particular the ground potential PE).

[0094] Figure 4aA fourth example of a plasma processing system 400 is shown having a series combination of switch circuits 401, 401i, ..., 401n, each switch circuit comprising an energy refeed module 415, 415i, ..., 415n and a switch unit 424, ..., 424i, 424n.

[0095] Each switch unit 424, 424i, ..., 424n is connected to a corresponding voltage source V1, Vi, ..., Vn, respectively.

[0096] The series combination of the switch circuits 401 , 401 i , . . . , 401 n can construct a switch implementation structure 411 .

[0097] The switch units 424, ... 424i, ... 424n are connected in series with a voltage source connection point of one switch circuit 401n, 401i, and the voltage source connection point is connected to the output OUT of the next switch circuit 401i, 401 in the series connection line.

[0098] The re-feeding modules 415i, ... 415n are optional here. To achieve this effect, only one re-feeding module 415 is sufficient at the output of the switch implementation 411 . Figure 4b A switch implementation 411 having such an implementation is shown, wherein the plasma processing system 400' has only one energy re-feed module 415z.

[0099] exist Figure 5a-5d In the present invention, the advantages of the energy re-feeding module 15, 315, 415, the switching circuit 24, 324, 424 comprising such an energy re-feeding module, the switching implementation structure 311, 411 comprising at least one such switching circuit 324, 424, the plasma system 100, 300, 400 comprising such a switching circuit and / or such a switching implementation structure, and the method for generating rectangular voltage output pulses will become more obvious.

[0100] Figure 5a In simplified form, it also shows Figure 1 and Figure 2 .

[0101] Figure 5b-5d Shows Figure 5a The corresponding output voltages are Voutb, Voutc, and Voutd. The voltage swing can be about 8 kV or more. At the same time, the current, not shown, can be about 30 A or more. The duration of such a pulse can be 0.5 μs to 2 μs. Therefore, the rise time of the voltage can be about 300 ns or less. It is easy to see that Vouta rises much faster than Figure 5c and Figure 5dThe voltages Voutc and Voutd in the corresponding circuit and system. Therefore, Figure 5a Modules, circuits, implementation structures and systems of Figure 5c and Figure 5d In addition, it is easy to see that Vouta does not rise any faster than Figure 5b The voltage Voutb in the corresponding circuit and system is fast. However, Figure 5b The voltage Voutb in the Figure 5a The voltage Vouta in does not show an overvoltage swing. Figure 5b Compared with the circuit in Figure 5a The modules, circuits, implementation structures and systems in the present invention have the advantages of fast switching, reduced overshoot and reduced oscillation.

Claims

1. An energy re-feeding module (15) for A switching circuit (101) having a switching unit (24), the switching unit being configured to be connectable to a DC voltage source (V1) and configured to provide one or a combination of the following features at an output (OUT) of the switching circuit: i) High voltage value, ii) High voltage rise value, iii) high current values ​​for capacitive loads, in particular for plasma processing loads (12), The energy re-feeding module (15) comprises: a. a rectifier circuit (14) configured to be connected with its positive DC side terminal to a positive connection of a DC voltage source (V1) and with its negative DC side terminal to a negative connection of a DC voltage source (V1), in particular to a ground potential (PE), and b. Transformer (TF1), including: i. A primary winding (18) configured to be connected in series between the switch unit (24) and the output (OUT), and configured to have a stray inductance and a parasitic resistance low enough to cause one or a combination of the following characteristics: - High voltage value, -High voltage rise value, - High current value, and ii. The secondary winding (19) is connected to the AC side of the rectifier circuit (14).

2. The energy refeed module (15) according to claim 1, wherein the transformer (TF1) is a step-up transformer.

3. The energy refeeding module (15) according to any one of the preceding claims, wherein: The rectifier circuit (14) comprises two components, in particular two rectifier diodes (DR1, DR3), configured to conduct current only in one direction, in particular four components, in particular four rectifier diodes (DR1-DR4), configured to conduct current only in one direction, in particular a bridge circuit.

4. The energy refeeding module (15) according to any one of the preceding claims, wherein The overvoltage protection unit, in particular the overvoltage protection diode (D01), is configured to be connected between the output (OUT) and the positive end of the DC side of the rectifier circuit (14) to protect the load (12) from overvoltage. 5 . The energy refeed module ( 15 ) according to claim 4 , comprising a first damping resistor ( R1 ) connected in series with the overvoltage protection unit.

6. The energy refeeding module (15) according to any one of the preceding claims, wherein The negative voltage protection unit, in particular the negative voltage protection diode (D02), is configured to be connected between the output (OUT) and the negative connection of the voltage source (V1), in particular to the ground potential (PE), to protect the load (12) from negative voltage.

7. The energy re-feeding module (15) according to claim 6, comprising a second damping resistor (R2) connected in series with the undervoltage protection unit.

8. A switching circuit (101, 301, 401) configured to deliver a high voltage (HV) fast rise pulse to a plasma processing load (12), comprising: a. a switching unit (24), comprising a high-side switching element (S1) and a low-side switching element (S2) connected in series, a connection point (16) of the two switching elements (S1, S2), a low-side connection (25) and a high-side connection (26), the low-side and high-side connections (25, 26) being connected to a voltage source (V1), b. The energy refeed module (15) according to one of the preceding claims, comprising: i. a rectifier circuit (14), the DC side of which is connected to a voltage source (V1), and ii. a primary winding (18) of a transformer (TF1) connected in series between a connection point (16) between the high-side switching element (S1) and the low-side switching element (S2) and the output (OUT), and iii. A secondary winding (19) connected to the AC side of the rectifier circuit (14).

9. The switch circuit (101, 301, 401) according to claim 8, wherein: The diode (D1, D2) is connected in parallel with one of the switching elements (S1, S2), in particular, is connected in parallel with each of the switching elements (S1, S2).

10. The switching circuit (101, 301, 401) according to claim 8 or 9, wherein: At least one overvoltage protection unit, in particular a diode (D01, D02), is connected between the output (OUT) and at least one connection of a voltage source (V1).

11. A switch implementation structure (311, 411), comprising: a. A plurality of switch units (324, ... 324i, ... 324n, 425, ... according to the features of claim 8. 324i, ...324n), and b. at least one switching circuit (301) according to one of the preceding claims 8-10, c. In which, the switch unit (324, ...324i, ...324n, 424...424i, ...424n) is connected in series with a voltage source connection point of a switch circuit (301, 301i, 401i, 401n), and the voltage source connection point is connected to the output (OUT) of the next switch circuit (301i, 301n, 401, 401i) in the series connection line.

12. A plasma system (100, 300, 400), comprising a plasma load (12, 312, 412) and: a. A switching circuit (101, 301, 401) according to any one of the preceding claims 8-10, and / or b. The switch implementation structure (311, 411) according to claim 11.

13. A method of generating a rectangular voltage output pulse (Vout) for a plasma processing load (12), comprising the steps of: a. generating a high voltage (HV) pulse signal at the output (OUT) of the switching circuit (10) using a high-side switching element (S1) and a low-side switching element (S2) connected in series, the series connection being connected to a voltage source (V1), b. Provide a high voltage pulse signal at the output (OUT) through the primary winding of the transformer (TF1), c. Rectify the current induced in the secondary winding of the transformer (TF1).

14. The method according to claim 13, wherein: During the charging and discharging of the load capacitance connected to the output (OUT), energy is fed back to the bus (V1).

15. The method according to claim 13 or 14, wherein: Reduce oscillation by providing: a. an overvoltage protection unit, in particular an overvoltage protection diode (D01), and / or b. A negative voltage protection unit, in particular a negative voltage protection diode (D02) connected to the output (OUT), and In particular, the oscillations are further reduced by a first and / or second damping resistor (R1, R2) respectively connected in series with the protection unit, in particular the diode (D01, D02).

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