A radio frequency power supply with phase synchronous frequency modulation function

Abstract

The present invention discloses a radio frequency power supply with phase synchronous frequency modulation function, belonging to the technical field of radio frequency power supply. It mainly includes a power supply module, a radio frequency module and a digital control module. A digital phase-locked loop is arranged in the digital control module, and the digital phase-locked loop includes a phase detector, a loop filter and a voltage-controlled oscillator; the radio frequency input synchronization signal of the radio frequency module is multiplied by the output signal of the voltage-controlled oscillator, and the phase difference information between the two can be obtained after calculation. At this time, the phase difference information is a signal quantity with large fluctuations. The phase difference information is filtered through a loop filter, and then added to the local oscillator signal output by the voltage-controlled oscillator to obtain a local oscillator signal with a new frequency and a new phase. After a period of closed-loop operation, the filter control signal output by the previous loop filter is used. The radio frequency power supply with phase synchronous frequency modulation function of the present application can achieve the effect of compensating for the phase drift caused by the temperature drift of electronic devices.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency power supply, and more particularly to a radio frequency power supply with phase synchronous frequency modulation function. Background Art

[0002] In the process of plasma processing, in order to improve the process efficiency, cascade or synchronous excitation is usually adopted to make two or more RF power supplies work at the same time to improve the efficiency of equipment use. However, due to the differences in its own devices, the RF power signal waveform will inevitably have a certain phase difference, which will cause crosstalk and cause the plasma in the cavity to be unstable, which in turn affects the process and reduces the efficiency of wafer production.

[0003] Therefore, it is necessary to provide a radio frequency power supply with phase synchronous frequency modulation function to solve the above problems. Summary of the invention

[0004] Based on the above problems existing in the prior art, the purpose of the embodiments of the present application is to provide a radio frequency power supply with a phase synchronous frequency modulation function to achieve the effect of compensating for the phase drift caused by the temperature drift of electronic devices.

[0005] The technical solution adopted by the present application to solve its technical problem is: a radio frequency power supply with phase synchronous frequency modulation function, including a power module, a radio frequency module and a digital control module, wherein a digital phase-locked loop is arranged in the digital control module, and the digital phase-locked loop includes a phase detector, a loop filter and a voltage-controlled oscillator;

[0006] The RF input synchronization signal of the RF module is multiplied by the output signal of the voltage-controlled oscillator, and the phase difference information Upd between the two can be obtained after calculation. At this time, the phase difference information Upd is a signal quantity with large fluctuations. The phase difference information Upd is filtered through a loop filter, and then added to the local oscillator signal output by the voltage-controlled oscillator to obtain a local oscillator signal Uf with a new frequency and new phase. After a period of closed-loop operation, the signal synchronization is finally achieved according to the filtering control signal output by the previous loop filter.

[0007] Furthermore, the power supply module includes an electromagnetic interference filter, a soft start module, a phase-shifted full bridge, a high-power voltage module and an auxiliary power supply module;

[0008] The radio frequency module includes a voltage and current detection module, a power amplification module and an output filtering module.

[0009] Furthermore, the power supply module supplies power to the digital control module through the auxiliary power supply module.

[0010] Furthermore, the digital control module is used to control the power supply module to output a high voltage signal.

[0011] Furthermore, a voltage monitoring module is provided inside the digital control module to monitor whether the power supply module operates normally.

[0012] Furthermore, the digital control module controls the radio frequency module to output radio frequency waves, and the high voltage signal and the radio frequency module are finally combined to output radio frequency power.

[0013] The beneficial effects of the present invention are:

[0014] According to currently known conditions, any electronic device will have temperature drift if it is not specially processed or optimized. This solution uses two methods to solve this problem.

[0015] The first solution is to rely on the algorithm itself. By selecting appropriate filter coefficients, it can adaptively track and capture changes in frequency or phase when electronic devices experience temperature drift.

[0016] The second solution is an optional solution that is a superposition solution on the first solution. When the two solutions are executed at the same time, the effect is optimal. If the second solution is not executed, the basic requirements of the device can also be met. The premise for the execution of the second solution is that there is a temperature sensor in the device equipped with this algorithm. The algorithm mentioned in this solution can obtain the temperature value of the device in real time through the temperature sensor. Specifically, when the device leaves the factory, the device equipped with this algorithm is calibrated at the factory, and all the temperature drift parameters within the frequency range that the device can output are stored in the power-off non-volatile memory of the device. Then, in actual application, the temperature compensation parameters are called according to the real-time temperature value, so as to achieve adaptive compensation for the phase drift caused by the temperature drift of electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 This is an overall schematic diagram of a radio frequency power supply with phase synchronous frequency modulation function in this application;

[0019] Figure 2 for Figure 1 Schematic diagram of the structure of the digital phase-locked loop;

[0020] Figure 3 A physical connection diagram of a hardware solution used in the prior art;

[0021] Figure 4 It is a schematic diagram of a hardware phase-locked loop synchronization circuit in the prior art;

[0022] Figure 5Lock for calibration points Figure 1 ;

[0023] Figure 6 Lock for calibration points Figure 2 ;

[0024] Figure 7 Lock for calibration points Figure 3 ;

[0025] Figure 8 This is a frequency tracking diagram displayed in variable frequency mode;

[0026] Fig. 9 Pulse wave Figure 1 ;

[0027] Fig.10 Pulse wave Figure 2 ;

[0028] Fig.11 This is a schematic diagram of hardware connection after the carrier carried by this application is implemented;

[0029] Fig.12 This is a schematic diagram of the specific effect of the phase difference changed through the software interface in this application Figure 1 ;

[0030] Fig.13 This is a schematic diagram of the specific effect of the phase difference changed through the software interface in this application Figure 2 ;

[0031] Fig.14 This is a schematic diagram of the specific effect of the phase difference changed through the software interface in this application Figure 3 ;

[0032] In the figure:

[0033] 1. Power module; 11. Electromagnetic interference filter; 12. Soft start module; 13. Phase-shifted full bridge; 14. High power voltage module; 15. Auxiliary power module;

[0034] 2. RF module; 21. Voltage and current detection module; 22. Power amplifier module; 23. Output filter module;

[0035] 3. Digital control module;

[0036] 4. Digital phase-locked loop; 41. Phase detector; 42. Loop filter; 43. Voltage-controlled oscillator. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0039] In the present invention, unless otherwise specified, the directions used, such as "up" and "down", usually refer to the directions shown in the drawings, or to the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "left" and "right" usually refer to the left and right shown in the drawings; "inside" and "outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directions are not used to limit the present invention.

[0040] The existing technology mainly adopts hardware solutions. A signal RF signal generator has multiple RF signal output terminals. It provides the same RF excitation to itself and the other two RF power supplies through the multiple output terminals. At the same time, the same RF output cable length is used. In this way, the phase of the power signals output by the three RF power supplies can be kept consistent, or the phase difference between devices can be fine-tuned by cable length. However, it is difficult to keep the temperature drift performance of electronic devices consistent in various environments. This will result in the need to adjust the phase of the power signal of each RF power supply by extending or shortening the RF coaxial cable in practical scenarios. This operation method is complicated and inconsistent, and it is difficult to coordinate in actual application scenarios. Physical connection such as Figure X shown.

[0041] Another implementation method is a hardware phase-locked loop synchronization circuit, including an external clock shaping circuit, a phase-locked loop feedback circuit, a phase adjustment circuit, a threshold comparison circuit, a clock selection circuit, a second frequency division circuit and an internal clock generation circuit. Figure X shown.

[0042] The defects in this solution are mainly reflected in the following: first, the hardware circuit cannot solve the problem of temperature drift of electronic devices under long-term operation, and cannot be adaptively compensated; second, at different RF power supply frequencies, it is necessary to design corresponding filters, local oscillator signals, etc. according to the existing RF power supply frequency. The same set of phase synchronization circuits cannot be used in RF power supply equipment at another frequency. It has poor adaptability and is not reproducible. Finally, under modern technical conditions, especially under the premise that the processing speed of MCU is getting faster and faster, the synchronization time of the hardware circuit solution is far from reaching the speed of software synchronization.

[0043] In addition, the above two solutions are based on fixed-frequency RF power. Once the RF power works in variable frequency mode, it will not work properly. RF cables cannot be adaptively changed in variable frequency mode. In addition to its own defects, the hardware phase-locked loop solution cannot adaptively follow the frequency changes.

[0044] like Figure 1-14 As shown, the present application provides a radio frequency power supply with phase synchronous frequency modulation function, including a power supply module 1, a radio frequency module 2 and a digital control module 3.

[0045] The power supply module includes an electromagnetic interference filter 11 , a soft start module 12 , a phase-shifted full bridge 13 , a high power voltage module 14 and an auxiliary power supply module 15 .

[0046] The radio frequency module 2 includes a voltage and current detection module 21 , a power amplification module 22 and an output filtering module 23 .

[0047] The digital control module 3 is composed of a digital microprocessor module equipped with the present solution and its peripheral circuits.

[0048] The power module 1 supplies power to the digital control module 3 via the auxiliary power module 15 .

[0049] The digital control module 3 is used to control the power module 1 to output a high voltage signal (i.e. Figure 1 Psu voltageoutput in ).

[0050] The digital control module 3 is internally provided with a voltage monitoring module (i.e. Figure 1 DC module control in the power module is used to monitor whether the power module 1 is working properly (i.e. Figure 1 Module Monitor in the .

[0051] The digital control module 3 also controls the RF module 2 to output RF waves, and the high voltage signal and the RF module 2 are finally combined to output RF power.

[0052] A digital phase-locked loop 4 is provided in the digital control module 3 . The digital phase-locked loop 4 includes a phase detector 41 , a loop filter 42 and a voltage-controlled oscillator 43 .

[0053] The RF input synchronization signal is multiplied by the output signal of the voltage-controlled oscillator 43, and the phase difference information Upd between the two can be obtained after calculation. At this time, the phase difference information Upd is a signal quantity with large fluctuations, so in actual processing, the phase difference information Upd is filtered through a loop filter, and then added to the local oscillator signal output by the voltage-controlled oscillator 43 to obtain a local oscillator signal Uf with a new frequency and new phase. The voltage-controlled oscillator is usually also called NCO or DDS in digital solutions. After a period of closed-loop operation, the signal synchronization is finally achieved according to the filter control signal output by the previous loop filter.

[0054] According to currently known conditions, any electronic device will have temperature drift if it is not specially processed or optimized. This solution uses two methods to solve this problem.

[0055] The first solution is to rely on the algorithm itself. By selecting appropriate filter coefficients, it can adaptively track and capture changes in frequency or phase when electronic devices experience temperature drift.

[0056] The second solution is an optional solution that is a superposition solution on the first solution. When the two solutions are executed at the same time, the effect is optimal. If the second solution is not executed, the basic requirements of the device can also be met. The premise for the execution of the second solution is that there is a temperature sensor in the device equipped with this algorithm. The algorithm mentioned in this solution can obtain the temperature value of the device in real time through the temperature sensor. Specifically, when the device leaves the factory, the device equipped with this algorithm is calibrated at the factory, and all the temperature drift parameters within the frequency range that the device can output are stored in the power-off non-volatile memory of the device. Then, in actual application, the temperature compensation parameters are called according to the real-time temperature value, so as to achieve adaptive compensation for the phase drift caused by the temperature drift of electronic devices.

[0057] Embodiment 1

[0058] According to the description in the prior art, the synchronization technology implemented by hardware solutions is selective for the frequency of the synchronizable signal. Once the frequency is changed, it is necessary to adapt by changing the voltage range of the filter and local oscillator signal in the circuit device, which has certain limitations. Because this solution is a software design solution, it can realize the adaptive synchronization of different frequency bands of different devices by changing the frequency range parameters and filter coefficients. It is convenient, fast and highly reproducible. It only needs to write the minimum frequency value and the maximum frequency value in the frequency parameters in the software interface. The algorithm will automatically adjust the new local oscillator signal according to the input frequency parameters, and then combine the written filter parameters to perform synchronization calculations. The parameters can be observed based on the exported data graph to see if they meet the synchronization point number or synchronization time requirements. Correction point lock under different parameters Figure 5-7 shown.

[0059] in, Figure 5 The number of calibration points is 80. Figure 6 The number of calibration points is 60. Figure 5 The number of calibration points is 30.

[0060] Embodiment 2

[0061] According to the actual application scenario, this solution also has the function of switching the coarse or fine phase adjustment through software settings. The coarse adjustment function is the default in this solution. The specific implementation method is that the dual threshold anti-jitter function is adopted in the algorithm. When the algorithm detects that the frequency difference between the input signal and the output signal within 1ms does not exceed 5K (the frequency difference parameter is related to the loop filter parameters, etc., and is not fixed here. 5K is an example value here, the same below) and the phase difference between the input signal and the output signal does not exceed 1° (the phase difference parameter is related to the loop filter parameters, etc., and is not fixed here. 1° is an example value here, the same below), it is considered that the synchronization has been successfully completed. When one of the conditions, such as the difference within 1ms, exceeds 5K or 1°, it is considered that the synchronization has failed, and the synchronization function needs to be reopened at this time. The dual threshold parameters can be modified through the software interface. When switching to the fine adjustment function, the threshold parameters in this solution will also be modified adaptively, but it is also obvious that at this time, the synchronization stabilization time will also increase accordingly.

[0062] Embodiment 3

[0063] After stable synchronization, the frequency of the input signal and the output signal are consistent, and the phase of the input signal and the output signal are also consistent. However, according to the actual application scenario, the phase difference between the input signal and the output signal may have different requirements. For example, in actual applications, when the phases of the two devices need to be different, this solution can also modify the synchronization phase angle through the software interface. The specific implementation method is to modify the default synchronization phase reference parameter in this solution from 0° to a specified angle, such as 30°. The algorithm itself will adaptively change to 30° based on the input synchronization phase basic parameters without changing other frequency and filter parameters.

[0064] Embodiment 4

[0065] Embodiment 3 modifies or adjusts the phase difference between the input signal and the output signal by means of software. This embodiment is also compatible with the prior art method of adjusting the phase difference between the input signal and the output signal by means of cables. According to the actual application scenario, the site engineer can meet his needs of manually adjusting the phase by adjusting the cable length. This solution can solve the situation when there is no computer at the site or the software interface cannot be operated.

[0066] Embodiment 5

[0067] In the first embodiment, it has been described that this solution can be applied to the frequency point or bandwidth range specified by the user within the frequency band, but in certain process conditions, when the reflection stabilization speed is required to be relatively high, the RF power supply often needs to work in the frequency modulation mode to quickly adjust the reflected power under this process condition to the minimum. In the frequency modulation mode, this solution can still track during the host mode frequency modulation and after the frequency modulation is stable, and finally lock with the signal after the host frequency modulation is stable.

[0068] like Figure 8 As shown, the frequency tracking displayed in the variable frequency mode is stable at 12.882Mhz.

[0069] Embodiment 6

[0070] Under normal conditions, the signals output by the host phase synchronization are all continuous waves. According to all the above descriptions, this solution can track the waveform of the continuous input and calculate the corresponding frequency and phase. When the slave is set to single-stage pulse mode, this solution only needs to calculate the output frequency and phase to allow the slave to output a pulse wave phase-locked with the host in single-stage pulse mode.

[0071] like Fig. 9 As shown, pulse frequency 1KHz Duty=15%, RF frequency 400KHz CH3 is Master, CH4 is slave.

[0072] like Fig.10 As shown, pulse frequency 1KHz Duty=15% RF frequency 340KHz CH3 is Master, CH4 is slave.

[0073] The hardware connection after the carrier of this application is implemented is as follows Fig.11 shown.

[0074] The specific effect of the phase difference changed through the software interface in this application is as follows Figure 12-14 shown.

[0075] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0076] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0077] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

Claims

1. A radio frequency power supply with phase synchronous frequency modulation function, characterized in that: It comprises a power supply module (1), a radio frequency module (2) and a digital control module (3), wherein a digital phase-locked loop (4) is arranged in the digital control module (3), and the digital phase-locked loop (4) comprises a phase detector (41), a loop filter (42) and a voltage-controlled oscillator (43); The RF input synchronization signal of the RF module (2) is multiplied by the output signal of the voltage-controlled oscillator (43), and the phase difference information Upd between the two can be obtained after calculation. At this time, the phase difference information Upd is a signal quantity with large fluctuations. The phase difference information Upd is filtered through a loop filter and then added to the local oscillator signal output by the voltage-controlled oscillator (43) to obtain a local oscillator signal Uf with a new frequency and a new phase. After a period of closed-loop operation, signal synchronization is finally achieved according to the filter control signal output by the previous loop filter.

2. The radio frequency power supply with phase synchronous frequency modulation function according to claim 1, characterized in that: The power supply module (1) comprises an electromagnetic interference filter (11), a soft start module (12), a phase-shifted full bridge (13), a high-power voltage module (14) and an auxiliary power supply module (15); The radio frequency module (2) comprises a voltage and current detection module (21), a power amplification module (22) and an output filtering module (23).

3. The radio frequency power supply with phase synchronous frequency modulation function according to claim 2, characterized in that: The power module (1) supplies power to the digital control module (3) via the auxiliary power module (15).

4. The radio frequency power supply with phase synchronous frequency modulation function according to claim 2, characterized in that: The digital control module (3) is used to control the power supply module (1) to output a high-voltage signal.

5. The radio frequency power supply with phase synchronous frequency modulation function according to claim 2, characterized in that: A voltage monitoring module is provided inside the digital control module (3) for monitoring whether the power supply module (1) is operating normally.

6. The radio frequency power supply with phase synchronous frequency modulation function according to claim 2, characterized in that: The digital control module (3) controls the radio frequency module (2) to output radio frequency waves, and the high voltage signal and the radio frequency module (2) are finally combined to output radio frequency power.

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