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JP-2026514248-A - A control device for controlling a plasma process supply system, a plasma process supply system having such a control device, and a method for operating the control device.

JP2026514248AJP 2026514248 AJP2026514248 AJP 2026514248AJP-2026514248-A

Abstract

The present invention relates to a control device (1) used to control a plasma process supply system (100). The plasma process supply system comprises an RF generator (101) and an impedance matching circuit (102) used for connection to a load (103). The control device (1) is designed to determine the supply power of the RF generator (101) and the output power of the impedance matching circuit (102). The control device (1) is designed to adjust the RF generator (101) and/or the impedance matching circuit (102), specifically by changing the frequency of the RF generator (101), thereby increasing the overall efficiency of the plasma process supply system (100) obtained from the determined supply power of the RF generator (101) and the output power of the impedance matching circuit (102).

Inventors

  • アレクサンダー アルト

Assignees

  • トゥルンプフ ヒュッティンガー ゲゼルシャフト ミット ベシュレンクテル ハフツング ウント コンパニー コマンディートゲゼルシャフト

Dates

Publication Date
20260507
Application Date
20240502
Priority Date
20230503

Claims (20)

  1. A control device (1) for controlling a plasma process supply system (100) having an RF generator (101) and an impedance matching circuit (101) for connection to a load (103), wherein the control device (1) has the following characteristics: - The control device (1) is designed to determine the power supplied by the RF generator (101) and the output power of the impedance matching circuit (102), - The control device (1) is designed to adjust the RF generator (101) and/or the impedance matching circuit (102), specifically by changing the frequency of the RF generator (101), thereby increasing the overall efficiency of the plasma process supply system (100) obtained from the determined supply power of the RF generator (101) and the output power of the impedance matching circuit (102), the control device (1).
  2. The following characteristics: - The control device (1) according to claim 1, characterized in that the control device (1) is designed to calculate the overall efficiency of the plasma process supply system (100) based on the determined supply power and output power.
  3. The following characteristics: - The control device (1) according to claim 1 or 2, characterized in that the control device (1) is designed to specifically continuously change the frequency of the RF generator (101) during operation, and the control device (1) is further designed to specifically continuously check whether the overall efficiency improves after the frequency change.
  4. The following characteristics: - The control device (1) is designed to further change the frequency in the same direction when the overall efficiency is improved, and/or - The control device (1) is designed to change the frequency in the opposite direction when the overall efficiency is reduced, as described in claim 3.
  5. The following characteristics: - The control device (1) according to claim 3 or 4, characterized in that the control device (1) is designed to select a step size for changing the frequency depending on the change in the overall efficiency.
  6. The following characteristics: - The control device (1) according to any one of claims 3 to 5, characterized in that the control device (1) is designed to set the frequency only within a specific frequency range.
  7. The following characteristics: - The control device (1) according to any one of claims 3 to 6, further comprising an AI module (4) which is factory-trained to adjust the RF generator (101) and/or the impedance matching circuit (102) based on at least the supply power and the output power, specifically to change the frequency of the RF generator (101).
  8. The following characteristics: - The control device (1) according to any one of claims 3 to 7, characterized in that the control device (1) is designed to change the frequency of the RF generator (101) only when the overall efficiency exceeds a threshold.
  9. The following characteristics: - The control device (1) according to any one of claims 1 to 8, characterized in that the control device (1) is designed to control the impedance matching circuit (102) such that the conversion ratio between the input impedance of the impedance matching circuit (102) and the output impedance of the impedance matching circuit (102) can be changed during operation, and the control device (1) is further designed to check whether the overall efficiency is improved after the change in the conversion ratio.
  10. The following characteristics: The control device (1) according to claim 9, characterized in that the control device (1) is designed to control the impedance matching circuit (102) such that the input impedance and/or output impedance remain unchanged when the conversion ratio changes.
  11. The following characteristics: - A control device (1) according to any one of claims 1 to 10, characterized in that the supplied power is active power and/or the output power is active power.
  12. The following characteristics: - The control device (1) includes a first measuring unit (2), - The control device (1) according to any one of claims 1 to 11, characterized in that the first measurement unit (2) is designed to determine the supplied power from AC voltage and AC current that can be obtained from the power grid and are present at the input of the power supply unit (109) of the RF generator (101), or the first measurement unit (2) is designed to determine the supplied power from DC voltage and DC current that are present at the output of the power supply unit (109) of the RF generator (101) and function to supply to at least one RF amplifier (111) of the RF generator (101).
  13. The following characteristics: - The control device (1) includes a second measuring unit (3), - The second measuring unit (3) comprises at least one directional coupler or current sensor (5) and voltage sensor (6), - The control device (1) according to any one of claims 1 to 12, characterized in that the control device (1) is designed to determine the output power based on the measurement results of at least one directional coupler or the current sensor (5) and the voltage sensor (6).
  14. The following characteristics: - The control device (1) according to claim 13, characterized in that the second measurement unit (3) can be placed at the output of the impedance matching circuit (102), or - The second measurement unit (3) can be placed at the input of the impedance matching circuit (102), and the control device (1) is designed to determine the output power based on the conversion ratio of the impedance matching circuit (102).
  15. The following characteristics: - The voltage sensor (6) of the second measuring unit (2) is a capacitive voltage divider, and the first capacitance (9) is formed by a conductive ring or cylinder through which a cable (104b) for transporting RF power can be routed. - The control device (1) according to claim 13 or 14, characterized in that the current sensor (5) of the second measuring unit (3) is a coil arranged around the conductive ring (6) or cylinder.
  16. The following characteristics: - Specifically, the control device (1) is designed to determine the reflectance at the output section of the RF generator (101). - The control device (1) according to any one of claims 1 to 15, characterized in that the control device (1) is designed to adjust the RF generator (101) and/or the impedance matching circuit (102) so that the reflectance is reduced, specifically by changing the frequency of the RF generator (101), and further designed to adjust the RF generator (101) and/or the impedance matching circuit (102) so that the reflectance is increased when the overall efficiency is simultaneously improved.
  17. A plasma process supply system (100) having a control device (1) according to any one of claims 1 to 16, wherein the following characteristics: - The plasma process supply system (100) includes an RF generator (101) and an impedance matching circuit (102), - Preferably, the RF generator (101) is connected to the impedance matching circuit (102) via the first cable connection (104a). - A plasma process supply system (100) characterized in that the impedance matching circuit (102) can be connected to a load (103) via a second cable connection (104b), specifically in the form of a plasma chamber.
  18. The following characteristics: - The RF generator (101) comprises at least one power supply (109) and at least one RF amplifier (111). - The at least one power supply (109) comprises an input section for connecting to the power supply and an output section for connecting to the at least one RF amplifier (111), - The at least one power supply (109) is designed to convert the AC voltage at the input section into a DC voltage, to output the DC voltage at the output section, and to supply the DC voltage to the at least one RF amplifier (111). - The plasma process supply system (100) according to claim 17, characterized in that the control device (1) is designed to determine the supplied power in the input unit, or in the output unit, or between the input unit and the output unit.
  19. The following characteristics: - The impedance matching circuit (102) includes at least one adjustable reactance to change the impedance conversion ratio between the input section to which the RF generator (101) is connected and the output section to which the load (103) can be connected. - The plasma process supply system (100) according to claim 17 or 18, characterized in that the reactance is mechanically adjustable and/or electrically adjustable and, specifically, is formed by at least one varactor and/or at least one switchable inductance and/or capacitance (115, 116), and/or at least one PIN diode.
  20. A method for operating a control device (1) according to any one of claims 1 to 16, specifically for controlling a plasma process supply system (100) according to any one of claims 17 to 19, which has an RF generator (101) and an impedance matching circuit (102) for connection to a load (103), the method comprising the following steps: - Determining the power supplied by the RF generator (101) ( S1 ), and determining the output power of the impedance matching circuit (102), A method comprising setting the RF generator (101) by changing the frequency of the RF generator (101) and/or the impedance matching circuit (102) so as to increase the overall efficiency of the plasma process supply system (100) obtained from the determined supply power of the RF generator (101) and the output power of the impedance matching circuit (102) ( S2 ).

Description

The present invention relates to a control device for controlling a plasma process supply system, a plasma process supply system having such a control device, and a method for operating the control device. Surface treatment of workpieces using plasma lasers and gas lasers is an industrial process in which plasma is generated in a plasma chamber using a direct current or high-frequency alternating current signal with an operating frequency ranging from several tens of kHz to GHz, specifically up to 100 GHz. The plasma chamber is connected to a radio frequency generator (RF generator) via additional electronic components such as coils, capacitors, cables, or transformers. These additional components can be oscillator circuits, filters, or impedance matching circuits. Plasma processes have a problem in that the electrical load impedance of the plasma chamber (the plasma consumption part) generated during the process can vary significantly depending on the conditions inside the plasma chamber. Specifically, the characteristics of the workpiece, electrodes, and gas conditions must be considered. A high-frequency generator has a limited operating range with respect to the impedance of the connected electrical load (i.e., the consumption unit). If the load impedance falls outside the acceptable range, the RF generator may be damaged or even destroyed. Therefore, an impedance matching circuit (matchbox) is usually required to convert the load impedance to the nominal impedance of the generator output. Various impedance matching circuits are known. An impedance matching circuit can be fixed and have a predetermined conversion effect; that is, it consists of electrical components that do not change during operation, specifically coils and capacitors. This is particularly useful for always consistent operation, such as that of a gas laser. Furthermore, impedance matching circuits are known in which at least some of the components are mechanically variable. For example, a motor-driven rotary capacitor is known, whose capacitance can be changed by changing the arrangement of the capacitor plates relative to each other. Plasma can generally be assigned to three impedance ranges. Before ignition, a very high impedance exists. During normal operation, i.e., during the intended operation using the plasma, a lower impedance exists. In the case of undesirable local discharges (arcs) or plasma fluctuations, very low impedance may occur. In addition to these three specified impedance ranges, other special conditions with other associated impedance values may arise. If the load impedance changes suddenly and the load impedance or converted load impedance falls outside the acceptable impedance range, the RF generator or the transmission equipment between the RF generator and the plasma chamber may be damaged. Undesirable plasma stabilization states also exist. Impedance matching circuits are described, for example, in the document DE 10 2009 001 355 A1. Plasma processes are known to require a significant amount of energy, which plays an increasingly important role today. Specifically, losses arise from high idle currents flowing through impedance matching circuits, reducing their efficiency. To transfer the desired power to the plasma, the high-frequency generator must therefore provide higher output power, which further increases power losses. Objective of the Invention: Therefore, the objective of the present invention is to establish a plasma process that is as energy-efficient as possible. Summary of the Invention The object is achieved by a control device for controlling the plasma process supply system described in claim 1, by the plasma process supply system described in claim 17, and by a method for operating the control device described in claim 20. Claims 2 to 16 describe advantageous embodiments of the control device, and claims 18 and 19 describe advantageous embodiments of the plasma process supply system. The control device according to the present invention comprises an RF generator and an impedance matching circuit, and functions to control a plasma supply system used to connect to a load, specifically a plasma chamber. The control device is designed to determine the supply power of the RF generator and the output power of the impedance matching circuit. The term "supply power" specifically refers to the power required to operate the RF generator. This refers in particular to the power that at least one of the RF generator's power sources receives from or delivers to the (public) power grid. If the RF generator has several power sources, "supply power" is the sum of the power that the RF generator's power sources receive from or deliver to the (public) power grid. The term "output power" refers to the power derived from the power delivered by the RF generator and output by the impedance matching circuit. If multiple signals from different RF generators or DC generators are fed to the impedance matching circuit, th