A power radio frequency power supply circuit and control method

Abstract

The present application relates to the technical field of plasma matching control, in particular to a power radio frequency power supply circuit and a control method, adopting a current type inverter topology framework, constructing a current type inverter structure through a direct current voltage division branch, a half bridge switch bridge arm and the like, so that the circuit has a current stabilizing characteristic, can produce an inhibiting effect on abnormal arc of a plasma load, is helpful to reduce the probability of damage of radio frequency power supply itself devices, improve the operation reliability of equipment under a dynamic load, and the matching control method can realize closed loop control of forward power by adjusting the amplitude of a power supply voltage, optimize the state of reflected power and impedance matching by adjusting the switching frequency, and the cooperative control of power regulation and impedance matching is helpful to improve the adaptation ability of the power supply to different loads; meanwhile, a high voltage pulse can be generated by controlling the working time sequence of a switch tube, directly completing the ignition and arc striking operation of plasma, without the need of additionally configuring a special ignition device, which is helpful to simplify the system structure and reduce the overall cost of equipment.

Description

Technical Field

[0001] This invention relates to the field of plasma control technology, specifically a power radio frequency power supply circuit and control method. Background Technology

[0002] Radio frequency (RF) power supplies are key equipment that provide high-frequency energy to various industrial and scientific research equipment to generate plasma or directly perform radio frequency heating. As a plasma power supply, it has been widely used in many key fields such as etching and deposition processes in semiconductor manufacturing, neutral beam injection devices in nuclear fusion, high-performance material preparation, cutting and coagulation in medical surgery, as well as communication and energy.

[0003] The output power and frequency stability of the radio frequency power supply directly affect the parameters of the plasma, and are further related to core process results such as chip manufacturing yield, neutral beam injection effect in nuclear fusion, and material preparation quality.

[0004] Current RF power supplies still face multiple challenges due to the combined effects of technical characteristics and application environments. In terms of conversion efficiency and thermal management, the overall energy conversion efficiency of existing RF power supplies is relatively low. For example, in RF sputtering processes, the efficiency of some RF power supplies is often below 70%, and the performance is even worse in low-pressure process scenarios. A large amount of unconverted energy is converted into heat, which not only requires a supporting complex heat dissipation system such as water cooling, significantly increasing the energy consumption and operating costs of the equipment, but also easily leads to an increase in the temperature of the processed substrate, limiting its application in the processing of temperature-sensitive materials.

[0005] In terms of load adaptation, plasma loads exhibit dynamic characteristics, making real-time and rapid impedance matching challenging and typically requiring specialized matching devices, thus increasing system complexity. Furthermore, sudden load changes can easily trigger abnormal arcing, posing a risk of damaging RF power supply components, limiting the dynamic range of loads the power supply can adapt to. In terms of ignition implementation, conventional RF power supplies usually require additional equipment for plasma ignition and arc initiation, further increasing system cost and operational complexity. Summary of the Invention

[0006] The purpose of this invention is to provide a power radio frequency power supply circuit and control method to address the aforementioned problems.

[0007] The technical solution adopted in this invention is as follows: a power radio frequency power supply circuit, wherein the power radio frequency power supply circuit is based on Vdc power supply and the negative terminal of Vdc is grounded, including a DC voltage divider branch, a half-bridge switch arm and an inter-bridge inductor-capacitor network.

[0008] The DC voltage divider branch is used to divide Vdc to form a stable voltage divider midpoint, providing a half-amplitude DC voltage reference for the inverter output. At the same time, it smooths the bus voltage fluctuations through capacitor energy storage and maintains the stability of the inverter input potential.

[0009] The half-bridge switch arm is used to alternately switch on and off at a megahertz frequency under the control of complementary drive signals, and to invert DC input power into a high-frequency rectangular AC voltage with a duty cycle of 50% to provide radio frequency excitation to the load.

[0010] The inter-bridge inductor-capacitor network, together with the voltage divider capacitor and the switching transistor, constitutes a current-mode inverter architecture.

[0011] As a preferred embodiment, the DC voltage divider branch includes capacitors C1 and C2 connected in series; the upper end of capacitor C1 is connected to the positive terminal of Vdc, the lower end of capacitor C1 is connected to the upper end of capacitor C2 to form the midpoint of the voltage divider, and the lower end of capacitor C2 is connected to the negative terminal of Vdc.

[0012] The half-bridge switch arm is used for the inverter operation of the power RF power supply circuit. The half-bridge switch arm includes a switch S1 and a switch S2 arranged in series. The drain of the switch S1 is the upper node of the bridge arm, the source of the switch S1 is connected to the drain of the switch S2 to form an inverter output node, and the source of the switch S2 is the lower node of the bridge arm.

[0013] The inter-bridge inductor-capacitor network is used to connect the DC voltage divider branch and the half-bridge switch arm, and forms an energy storage and buffer network for the current-type inverter. It includes inductor L1, inductor L2, capacitor C3, and capacitor C4. One end of inductor L1 is connected to the positive terminal of Vdc, and the other end is connected to the drain of switch S1.

[0014] One end of the inductor L2 is connected to the negative terminal of Vdc, and the other end is connected to the source of the switching transistor S2;

[0015] One end of the capacitor C3 is connected to the drain of the switching transistor S1, and the other end is connected to the negative terminal of Vdc.

[0016] One end of the capacitor C4 is connected to the positive terminal of Vdc, and the other end is connected to the source of the switching transistor S2;

[0017] The midpoint of the voltage divider is connected to one end of the load.

[0018] The inverter output node is connected to the other end of the load.

[0019] As a preferred embodiment, this circuit also adds an LC series-parallel resonant network; the LC series-parallel resonant network is arranged between the midpoint of the voltage divider and the inverter output node, and can form a resonant circuit with the junction capacitance of the power switching transistor itself, so as to enable the switching transistor to achieve zero-voltage soft switching, thereby reducing switching losses and improving the overall energy conversion efficiency.

[0020] As a first embodiment of the resonant network, the LC series-parallel resonant network includes inductor L3, inductor L4, capacitor C5, capacitor C6, and load equivalent resistance R;

[0021] One end of the inductor L3 is connected to the midpoint of the DC voltage divider branch, and the other end is connected to one end of the inductor L4.

[0022] The other end of the inductor L4 is connected to one end of the capacitor C5;

[0023] The other end of the capacitor C5 is connected to the inverter output node of the switch bridge arm, and the capacitor C5 and the inductor L3 form a series resonant branch.

[0024] The capacitor C6 is connected in parallel with the load equivalent resistance R and then spans across the two ends of the inductor L4, forming a parallel resonant branch together with the inductor L4.

[0025] As a second implementation of the resonant network, the LC series-parallel resonant network includes an inductor L3, an isolation high-frequency transformer T1, a capacitor C5, and a capacitor C6.

[0026] One end of the inductor L3 is connected to the midpoint of the DC voltage divider branch, and the other end is connected to one end of the primary side of the isolation high-frequency transformer T1.

[0027] The other end of the primary side of the high-frequency transformer T1 is connected to one end of the capacitor C5.

[0028] The other end of the capacitor C5 is connected to the inverter output node of the switch bridge arm, and the inductor L3 and the primary leakage inductance of the high-frequency transformer T1 participate in series resonance together, forming a series resonant branch with the capacitor C5.

[0029] The capacitor C6 is connected across the two ends of the primary side of the high-frequency transformer T1, and together with the magnetizing inductance Lm of the primary side of the transformer, it forms a parallel resonant branch.

[0030] As a preferred embodiment, the parameters of inductor L1 and inductor L2 are the same.

[0031] As a preferred embodiment, capacitors C3 and C4 have the same capacitance value and are both non-polar thin-film capacitors.

[0032] This application also provides a power radio frequency power supply control method based on the above-mentioned power radio frequency power supply circuit, including the following steps:

[0033] S1. Parameter preset: Preset the initial value of the power supply voltage Vdc, the initial value of the switching frequency, the target forward power value, and the maximum allowable value of the reflected power of the power RF power supply circuit to complete the initialization of system operating parameters;

[0034] S2. Ignition start-up: The control switch tubes execute the instantaneous simultaneous conduction ignition sequence, outputting a high-voltage pulse to complete plasma ignition and arc initiation;

[0035] S3. Normal inverter operation: After successful ignition, the switching transistor switches to complementary drive timing to set the switching frequency for normal operation and outputs RF excitation voltage and current to the load.

[0036] S4. Forward power closed-loop regulation: The control system collects and calculates the forward power output of the circuit in real time, and completes the closed-loop regulation of the power supply voltage amplitude based on the deviation between the forward power and the target value.

[0037] S5. Reflection power impedance matching adjustment: After the forward power reaches the preset target value, the control system calculates the circuit reflection power and reflection coefficient in real time, and adjusts the operating frequency of the switching transistor according to the calculation results to reduce the reflection power and maintain the system impedance matching state.

[0038] Furthermore, in step S4, if there is a deviation between the forward power and the set value, the amplitude of the supply voltage Vdc is adjusted until the forward power meets the set requirements.

[0039] Furthermore, in step S5, if the reflected power and reflection coefficient exceed the allowable range, the operating frequency of the switching transistor is adjusted to reduce the reflected power by changing the phase characteristics of the output voltage, thereby maintaining the impedance matching state.

[0040] The beneficial effects of the present invention include at least one of the following;

[0041] 1. The current-mode inverter topology is adopted. The current-mode inverter structure is constructed by the cooperation of DC voltage divider branches, half-bridge switching arms and inter-bridge inductor-capacitor network. This gives the circuit certain current-stabilizing characteristics, which can suppress abnormal arcing of plasma load, help reduce the probability of damage to the RF power supply itself, and improve the reliability of the equipment under dynamic load.

[0042] 2. By adding an LC series-parallel resonant network, a resonant circuit can be formed together with the junction capacitance of the power switching transistor, realizing zero-voltage soft switching of the switching transistor. This helps reduce switching losses, improve the overall energy conversion efficiency of the device, and alleviate the thermal management pressure of the equipment. At the same time, the LC series-parallel network has relatively stable voltage transmission characteristics near the resonant frequency, which can support a wider operating range of switching frequencies. Compared with traditional single series or parallel resonant networks, it is more conducive to maintaining the stability of the output voltage, ensuring the consistency of plasma generation, and expanding the dynamic range of loads that the power supply can adapt to.

[0043] 3. The scheme of replacing the parallel inductor in the resonant network with an isolation-type high-frequency transformer can achieve electrical isolation between the primary inverter circuit and the load side while retaining the resonant soft-switching and wide-band voltage regulation characteristics. At the same time, it can complete the load impedance matching, which can better adapt to the application scenarios of inductively coupled radio frequency plasma devices.

[0044] 4. The supporting control method can achieve closed-loop control of forward power by adjusting the amplitude of the supply voltage, and optimize the reflected power and impedance matching state by adjusting the switching frequency. The coordinated control of power regulation and impedance matching helps to improve the adaptability of the power supply to different loads. At the same time, high-voltage pulses can be generated by controlling the working sequence of the switching tubes to directly complete the plasma ignition and arc initiation operation without the need for additional dedicated ignition devices, which helps to simplify the system structure and reduce the overall cost of the equipment. Attached Figure Description

[0045] Figure 1 The diagram shows the topology of the core inverter circuit for the RF power supply. In the diagram, A is the midpoint of the voltage divider, B is the inverter output node, and C, D, E, and F correspond to the positive terminal of Vdc, the drain terminal of switch S1, the negative terminal of Vdc ground, and the source terminal of switch S2, respectively.

[0046] Figure 2 This is a topology diagram of an RF power supply resonant circuit. In the diagram, G and H are the intermediate connection nodes of the LC series-parallel resonant branches.

[0047] Figure 3 The Bode plot of the amplitude-frequency characteristics of an LC series-parallel circuit;

[0048] Figure 4 The Bode plot of the phase frequency characteristics of an LC series-parallel circuit;

[0049] Figure 5 The Bode plot of the amplitude-frequency response of the LCR series circuit;

[0050] Figure 6 The diagram shows the topology of a current-source RF power inverter with a full-bridge structure. In the diagram, A and B are equivalent to the voltage divider midpoint and inverter output node of this invention.

[0051] Figure 7 This is a topology diagram of a full-bridge RF power supply equipped with an isolated high-frequency transformer. In the diagram, A and B are equivalent to the voltage divider midpoint and inverter output node of this invention.

[0052] Figure 8 The diagram shows the topology of a half-bridge RF power supply equipped with an isolated high-frequency transformer. In the diagram, A and B are equivalent to the voltage divider midpoint and inverter output node of this invention.

[0053] Figure 9 This is a flowchart of a power radio frequency power supply control method. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described in the accompanying drawings can generally be arranged and designed in various different configurations.

[0055] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0057] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0058] A power radio frequency power supply circuit, which is based on Vdc power supply and the negative terminal of Vdc is grounded, includes a DC voltage divider branch, a half-bridge switch arm and an inter-bridge inductor-capacitor network.

[0059] The DC voltage divider branch is used to divide Vdc to form a stable voltage divider midpoint, providing a half-amplitude DC voltage reference for the inverter output. At the same time, it smooths the bus voltage fluctuations through capacitor energy storage and maintains the stability of the inverter input potential.

[0060] The half-bridge switch arm is used to alternately switch on and off at a megahertz frequency under the control of complementary drive signals, and to invert DC input power into a high-frequency rectangular AC voltage with a duty cycle of 50% to provide radio frequency excitation to the load.

[0061] The inter-bridge inductor-capacitor network, together with the voltage divider capacitor and the switching transistor, constitutes a current-mode inverter architecture.

[0062] Meanwhile, the DC voltage divider branch includes capacitors C1 and C2 connected in series. The upper end of capacitor C1 is connected to the positive terminal of Vdc, and the lower end of capacitor C1 is connected to the upper end of capacitor C2, forming the midpoint of the voltage divider. The lower end of capacitor C2 is connected to the negative terminal of Vdc.

[0063] The half-bridge switch arm is used for the inverter operation of the power RF power supply circuit. The half-bridge switch arm includes a switch S1 and a switch S2 arranged in series. The drain of the switch S1 is the upper node of the bridge arm, the source of the switch S1 is connected to the drain of the switch S2 to form an inverter output node, and the source of the switch S2 is the lower node of the bridge arm.

[0064] The inter-bridge inductor-capacitor network is used to connect the DC voltage divider branch and the half-bridge switch arm, and forms an energy storage and buffer network for the current-type inverter. It includes inductor L1, inductor L2, capacitor C3, and capacitor C4. One end of inductor L1 is connected to the positive terminal of Vdc, and the other end is connected to the drain of switch S1.

[0065] One end of the inductor L2 is connected to the negative terminal of Vdc, and the other end is connected to the source of the switching transistor S2;

[0066] One end of the capacitor C3 is connected to the drain of the switching transistor S1, and the other end is connected to the negative terminal of Vdc.

[0067] One end of the capacitor C4 is connected to the positive terminal of Vdc, and the other end is connected to the source of the switching transistor S2;

[0068] The midpoint of the voltage divider is connected to one end of the load.

[0069] The inverter output node is connected to the other end of the load.

[0070] The purpose of this design is to adopt a current-mode inverter topology, and to construct a current-mode inverter structure through the cooperation of DC voltage divider branches, half-bridge switching arms and inter-bridge inductor-capacitor networks. This enables the circuit to have certain current-stabilizing characteristics, which can suppress abnormal arcing of plasma loads, help reduce the probability of damage to the RF power supply components, and improve the reliability of the equipment under dynamic loads.

[0071] To facilitate a clear explanation of the circuit topology of this invention in conjunction with the accompanying drawings, this embodiment uses the labels A, B, C, D, E, F, G, and H from the drawings to label each node in the circuit. The letter labels in the drawings correspond one-to-one with the standard functional nodes described in the claims: point A, formed by connecting capacitors C1 and C2, corresponds to the midpoint of the voltage divider described in the claims; point B, formed by connecting the source of switch S1 and the drain of switch S2, corresponds to the inverter output node described in the claims; C, D, E, and F are the DC bus and bridge arm auxiliary potential nodes; and G and H are the intermediate nodes of the LC resonant branch. In describing the component connections below, the letter labels in the drawings can be used to simplify the description. The above-mentioned drawing labels and the functional nodes in the claims refer to the same circuit locations.

[0072] like Figure 1As shown in the diagram, this embodiment provides a specific connection structure. Vdc is the DC bus voltage source for the external power supply input to the system, with its negative terminal grounded (zero potential), indicated by point E in the diagram. Capacitors C1 and C2 are connected in series, with the upper end of C1 connected to the positive terminal of Vdc (point C in the diagram), and the lower end of C2 connected to point E. The midpoint of the connection between C1 and C2 is A.

[0073] Switches S1 and S2 are connected in series, with point B as the midpoint. The drain of switch S1 is connected to point D, and the source of switch S2 is connected to point F. The midpoint B between the two switches is the inverter output node. Inductor L1 is connected between points C and D, inductor L2 is connected between points E and F, capacitor C4 is connected between points C and F, and capacitor C3 is connected between points D and E. The load is connected between points A and B.

[0074] Power MOSFETs can be used as switching transistors S1 and S2. When complementary control signals are used for S1 and S2, the switching frequency of the control signals is in the MHz range. This allows for a rectangular voltage waveform with a 50% duty cycle and a voltage amplitude half that of the supply voltage Vdc to be obtained across the load. This rectangular RF voltage can excite the generation of the plasma load. Meanwhile, inductors L1 and L2 are identical, and capacitors C3 and C4 have the same capacitance value; non-polarized thin-film capacitors are used.

[0075] Its working principle is that the power switching transistors S1 and S2 are turned on and off alternately in a complementary driving sequence. The entire half-bridge inverter circuit operates in a cycle according to a fixed switching frequency. The circuit operating frequency can be flexibly set in the range of several megahertz.

[0076] The entire circuit operates in a resonant state. During the first half-cycle, S1 is on and S2 is off, the DC input source Vdc outputs electrical energy, and the current returns to the midpoint A of the voltage divider after passing through inductor L1 and the load. During this stage, capacitor C1 discharges and C2 charges. In the other half-cycle, S1 is off and S2 is on, and the current flows out from the upper end of C2 (point A), passes through inductor L2, the load, and switch S2, and returns to the negative terminal of the power supply. Throughout the entire cycle, inductors L1 and L2 and capacitors C3 and C4 participate in charging and discharging, ensuring the stability of the voltage and current stress on the switch.

[0077] If the entire circuit operates in a weakly inductive state, the current will also complete the freewheeling through the parasitic diode built into the switching transistor for a short period of time, and the resonant network will form a reverse resonant path. During the dead time of power switches S1 and S2, the junction capacitance on the switching transistors will also participate in the soft switching operation.

[0078] However, in practice, it has been found that the power consumption of switching transistors S1 and S2 is high because they are operating in a hard-switching state.

[0079] To solve this problem, Figure 1A resonant network circuit is added between A and B, that is, an LC series-parallel resonant network is added between the voltage divider midpoint and the inverter output node. The LC series-parallel resonant network is used to form a resonant circuit with the junction capacitance of the power switch tube. It includes inductor L3, inductor L4, capacitor C5, capacitor C6 and load equivalent resistance R.

[0080] One end of the inductor L3 is connected to the midpoint of the DC voltage divider branch, and the other end is connected to one end of the inductor L4.

[0081] The other end of the inductor L4 is connected to one end of the capacitor C5;

[0082] The other end of the capacitor C5 is connected to the inverter output node of the switch bridge arm, and the capacitor C5 and the inductor L3 form a series resonant branch.

[0083] The capacitor C6 is connected in parallel with the load equivalent resistance R and then spans across the two ends of the inductor L4, forming a parallel resonant branch together with the inductor L4.

[0084] By adding an LC series-parallel resonant network, a resonant circuit can be formed together with the junction capacitance of the power switch, achieving zero-voltage soft switching of the switch. This helps reduce switching losses, improve the overall energy conversion efficiency, and alleviate the thermal management pressure of the equipment. At the same time, this LC series-parallel network has relatively stable voltage transmission characteristics near the resonant frequency, which can support a wider operating range of switching frequencies. Compared with traditional single series or parallel resonant networks, it is more conducive to maintaining the stability of the output voltage, ensuring the consistency of plasma generation, and expanding the dynamic range of loads that the power supply can adapt to.

[0085] Meanwhile, this embodiment provides a specific structural diagram, such as... Figure 2 As shown, one end of inductor L3 is connected between points A and G, inductor L4 is connected between points G and H, and capacitor C5 is connected between points H and B. Another capacitor C6 and the equivalent resistance R are connected in parallel with inductor L4. The positions of inductor L3 and capacitor C5 can be interchanged or changed, as long as it does not affect their series connection.

[0086] based on Figure 2 The structure and parameter design method of the LC series-parallel resonant circuit are as follows: Inductor L3 and capacitor C5 form a series resonant circuit, and inductor L4 and capacitor C6 form a parallel resonant circuit. The frequencies of the two resonant circuits should be the same, meaning the inductance of inductor L3 is k times that of inductor L4. Therefore, the capacitance of capacitor C5 should be 1 / kth of the capacitance of capacitor C6. Simultaneously, the characteristic impedances of inductor L4 and capacitor C6 should be as close as possible to the equivalent resistance R of the load. Assuming the resonant frequency of inductor L3 and capacitor C5 is fr, and the switching frequencies fs of switches S1 and S2 are greater than or equal to fr, zero-voltage switching of switches S1 and S2 can be achieved, improving the overall efficiency of the RF power supply.

[0087] In this way, inductors L1 and L2, capacitors C3 and C4, switching transistors S1 and S2, and capacitors C1 and C2 form a current-source inverter. This inverter has the performance of stabilizing current, resisting the occurrence of abnormal arcing (sparking) of radio frequency plasma, and reducing the probability of damage to the radio frequency power supply itself. At the same time, the junction capacitance of power switching transistors S1 and S2 and the series and parallel circuit of inductors and capacitors form a resonant network to realize soft switching technology, so that the whole machine has high conversion efficiency.

[0088] The inductor-capacitor series-parallel circuit network exhibits stable voltage transfer characteristics near the resonant frequency and allows for a wider operating frequency range for the switching transistor. This is significantly superior to traditional LC series resonant networks or parallel networks. Comparing the two, this embodiment... Figure 2 The Bode plots of the amplitude-frequency and phase-frequency characteristics of the circuit structure are as follows: Figure 3 and Figure 4 The Bode plot of the amplitude-frequency response of a conventional LCR series circuit is as follows: Figure 5 As shown, a comparison reveals that while the existing conventional LCR series circuit can also achieve soft switching, the output voltage changes significantly during frequency conversion, which is detrimental to the consistency of plasma generation.

[0089] Meanwhile, in the specific implementation, by controlling the working sequence of the switching transistors S1 and S2, S1 and S2 are turned on simultaneously momentarily, and then the output is switched on in complementary mode. A pulse voltage higher than the input DC voltage can be obtained between points A and B. This voltage can directly start the plasma ignition operation, which is more cost-effective than conventional RF power supplies and makes the ignition operation easier.

[0090] because Figure 2 This is a half-bridge current-source inverter. The maximum output voltage between points A and B is half of the DC power supply voltage Vdc. To increase the output power, in Figure 2 Based on this, capacitors C1 and C2 are replaced with power switches S3 and S4. The maximum output voltage between A and B is equal to the supply voltage Vdc, thus further increasing the output power. The circuit topology is as follows: Figure 6 As shown. Figure 2 and Figure 6 It can be directly applied to capacitively coupled radio frequency plasma excitation devices, or the inductor L4 can be made into a hollow ring shape, and the plasma generator device (such as a quartz glass tube) can be placed inside the hollow of the inductor L4.

[0091] In practical implementation, for inductively coupled radio frequency plasma devices, the following can be adopted: Figure 8 The RF power supply main circuit shown uses a high-frequency transformer instead of... Figure 2 Inductor L4 in the middle, where Figure 8T1 is an isolation-type high-frequency transformer, Lm is the magnetizing inductance of T1, and part of the inductance of inductor L3 also comes from the leakage inductance of the high-frequency transformer T1. This scheme can achieve further electrical isolation and impedance matching between the power supply and the load. Similarly... Figure 7 yes Figure 6 Based on this, a high-frequency transformer is used to replace the inductor L4.

[0092] Specifically, the LC series-parallel resonant network includes inductor L3, isolation high-frequency transformer T1, capacitor C5, and capacitor C6.

[0093] One end of the inductor L3 is connected to the midpoint of the DC voltage divider branch, and the other end is connected to one end of the primary side of the isolation high-frequency transformer T1.

[0094] The other end of the primary side of the high-frequency transformer T1 is connected to one end of the capacitor C5.

[0095] The other end of the capacitor C5 is connected to the inverter output node of the switch bridge arm, and the inductor L3 and the primary leakage inductance of the high-frequency transformer T1 participate in series resonance together, forming a series resonant branch with the capacitor C5.

[0096] The capacitor C6 is connected across the two ends of the primary side of the high-frequency transformer T1, and together with the magnetizing inductance Lm of the primary side of the transformer, it forms a parallel resonant branch.

[0097] The purpose of this design is to replace the parallel inductor in the resonant network with an isolated high-frequency transformer. This approach can achieve electrical isolation between the primary inverter circuit and the load side while retaining the resonant soft-switching and wide-band voltage regulation characteristics. It also achieves load impedance matching, making it better suited for the application scenarios of inductively coupled RF plasma devices.

[0098] like Figure 9 As shown, in this embodiment, a power radio frequency power supply control method is also provided based on the power radio frequency power supply circuit, including the following steps:

[0099] S1. Parameter preset: Preset the initial value of the power supply voltage Vdc, the initial value of the switching frequency, the target forward power value, and the maximum allowable value of the reflected power of the power RF power supply circuit to complete the initialization of system operating parameters;

[0100] S2. Ignition start-up: The control switch tubes execute the instantaneous simultaneous conduction ignition sequence, outputting a high-voltage pulse to complete plasma ignition and arc initiation;

[0101] S3. Normal inverter operation: After successful ignition, the switching transistor switches to complementary drive timing to set the switching frequency for normal operation and outputs RF excitation voltage and current to the load.

[0102] S4. Forward power closed-loop regulation: The control system collects and calculates the forward power output of the circuit in real time, and completes the closed-loop regulation of the power supply voltage amplitude based on the deviation between the forward power and the target value.

[0103] S5. Reflection power impedance matching adjustment: After the forward power reaches the preset target value, the control system calculates the circuit reflection power and reflection coefficient in real time, and adjusts the operating frequency of the switching transistor according to the calculation results to reduce the reflection power and maintain the system impedance matching state.

[0104] The purpose of this design is that the supporting control method can achieve closed-loop control of forward power by adjusting the amplitude of the supply voltage, optimize the reflected power and impedance matching state by adjusting the switching frequency, and the coordinated control of power regulation and impedance matching helps to improve the adaptability of the power supply to different loads; at the same time, high-voltage pulses can be generated by controlling the working sequence of the switching tubes to directly complete the plasma ignition and arc initiation operation without the need for additional dedicated ignition devices, which helps to simplify the system structure and reduce the overall cost of the equipment.

[0105] Meanwhile, in S4, if there is a deviation between the forward power and the set value, the amplitude of the supply voltage Vdc is adjusted until the forward power meets the set requirements.

[0106] Furthermore, in S5, if the reflected power and reflection coefficient exceed the allowable range, the operating frequency of the switching transistor is adjusted to reduce the reflected power by changing the phase characteristics of the output voltage, thus maintaining the impedance matching state.

[0107] And by using Figure 2 The structure is pre-set with the power supply voltage Vdc, switching frequency, forward power, and maximum allowable value of reflected power. Then, the ignition process is started. After successful ignition, the excitation voltage and current are generated according to the normal timing sequence. The control system then calculates the forward power. If the forward power meets the set value, the reflected power is then calculated to see if it meets the requirements. Otherwise, the power supply voltage is adjusted. If the reflected power and reflection coefficient are too high, the phase of the output voltage is changed by changing the switching frequency to reduce the reflected power.

[0108] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A power radio frequency power supply circuit, wherein the power radio frequency power supply circuit is powered by Vdc, and the negative terminal of Vdc is grounded, characterized in that, This includes DC voltage divider branches, half-bridge switch arms, and inter-bridge inductor-capacitor networks; The DC voltage divider branch is used to divide Vdc to form a stable voltage divider midpoint, providing a half-amplitude DC voltage reference for the inverter output. At the same time, it smooths the bus voltage fluctuations through capacitor energy storage and maintains the stability of the inverter input potential. The half-bridge switch arm is used to alternately switch on and off at a megahertz frequency under the control of complementary drive signals, and to invert DC input power into a high-frequency rectangular AC voltage with a duty cycle of nearly 50% to provide radio frequency excitation to the load. The inter-bridge inductor-capacitor network, together with the voltage divider capacitor and the switching transistor, constitutes a current-mode inverter architecture.

2. The power radio frequency power supply circuit according to claim 1, characterized in that, The DC voltage divider branch includes capacitors C1 and C2 connected in series. The upper end of capacitor C1 is connected to the positive terminal of Vdc, and the lower end of capacitor C1 is connected to the upper end of capacitor C2, forming the midpoint of the voltage divider. The lower end of capacitor C2 is connected to the negative terminal of Vdc. The half-bridge switch arm is used for the inverter operation of the power RF power supply circuit. The half-bridge switch arm includes a switch S1 and a switch S2 arranged in series. The drain of the switch S1 is the upper node of the bridge arm, the source of the switch S1 is connected to the drain of the switch S2 to form an inverter output node, and the source of the switch S2 is the lower node of the bridge arm. The inter-bridge inductor-capacitor network is used to connect the DC voltage divider branch and the half-bridge switch arm, and forms an energy storage and buffer network for the current-type inverter. It includes inductor L1, inductor L2, capacitor C3, and capacitor C4. One end of inductor L1 is connected to the positive terminal of Vdc, and the other end is connected to the drain of switch S1. One end of the inductor L2 is connected to the negative terminal of Vdc, and the other end is connected to the source of the switching transistor S2; One end of the capacitor C3 is connected to the drain of the switching transistor S1, and the other end is connected to the negative terminal of Vdc. One end of the capacitor C4 is connected to the positive terminal of Vdc, and the other end is connected to the source of the switching transistor S2; The midpoint of the voltage divider is connected to one end of the load. The inverter output node is connected to the other end of the load.

3. The power radio frequency power supply circuit according to claim 2, characterized in that, It also includes an LC series-parallel resonant network, which is located between the midpoint of the voltage divider and the inverter output node. The LC series-parallel resonant network is used to form a resonant circuit with the junction capacitance of the power switch tube.

4. The power radio frequency power supply circuit according to claim 3, characterized in that, The LC series-parallel resonant network includes inductor L3, inductor L4, capacitor C5, capacitor C6 and load equivalent resistance R; One end of the inductor L3 is connected to the midpoint of the DC voltage divider branch, and the other end is connected to one end of the inductor L4. The other end of the inductor L4 is connected to one end of the capacitor C5; The other end of the capacitor C5 is connected to the inverter output node of the switch bridge arm, and the capacitor C5 and the inductor L3 form a series resonant branch. The capacitor C6 is connected in parallel with the load equivalent resistance R and then spans across the two ends of the inductor L4, forming a parallel resonant branch together with the inductor L4.

5. A power radio frequency power supply circuit according to claim 3, characterized in that, The LC series-parallel resonant network includes an inductor L3, an isolation high-frequency transformer T1, a capacitor C5, and a capacitor C6. One end of the inductor L3 is connected to the midpoint of the DC voltage divider branch, and the other end is connected to one end of the primary side of the isolation high-frequency transformer T1. The other end of the primary side of the high-frequency transformer T1 is connected to one end of the capacitor C5. The other end of the capacitor C5 is connected to the inverter output node of the switch bridge arm, and the inductor L3 and the primary leakage inductance of the high-frequency transformer T1 participate in series resonance together, forming a series resonant branch with the capacitor C5. The capacitor C6 is connected across the two ends of the primary side of the high-frequency transformer T1, and together with the magnetizing inductance Lm of the primary side of the transformer, it forms a parallel resonant branch.

6. A power radio frequency power supply circuit according to claim 2, characterized in that, The parameters of inductor L1 and inductor L2 are the same.

7. A power radio frequency power supply circuit according to claim 2, characterized in that, The capacitors C3 and C4 have the same capacitance value and are both non-polarized thin-film capacitors.

8. A power radio frequency power supply control method, implemented based on a power radio frequency power supply circuit according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Parameter preset: Preset the initial value of the power supply voltage Vdc, the initial value of the switching frequency, the target forward power value, and the maximum allowable value of the reflected power of the power RF power supply circuit to complete the initialization of system operating parameters; S2. Ignition start-up: The control switch tubes execute the instantaneous simultaneous conduction ignition sequence, outputting a high-voltage pulse to complete plasma ignition and arc initiation; S3. Normal inverter operation: After successful ignition, the switching transistor switches to complementary drive timing to set the switching frequency for normal operation and outputs RF excitation voltage and current to the load. S4. Forward power closed-loop regulation: The control system collects and calculates the forward power output of the circuit in real time, and completes the closed-loop regulation of the power supply voltage amplitude based on the deviation between the forward power and the target value. S5. Reflection power impedance matching adjustment: After the forward power reaches the preset target value, the control system calculates the circuit reflection power and reflection coefficient in real time, and adjusts the operating frequency of the switching transistor according to the calculation results to reduce the reflection power and maintain the system impedance matching state.

9. A power radio frequency power supply control method according to claim 8, characterized in that, In step S4, if there is a deviation between the forward power and the set value, the amplitude of the supply voltage Vdc is adjusted until the forward power meets the set requirements.

10. A power radio frequency power supply control method according to claim 8, characterized in that, In step S5, if the reflected power and reflection coefficient exceed the allowable range, the operating frequency of the switching transistor is adjusted to reduce the reflected power by changing the phase characteristics of the output voltage, thereby maintaining the impedance matching state.

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