CN-115136493-B - Control method for high-frequency power supply device and high-frequency power supply device

Abstract

The output command value is suppressed not to exceed the upper limit of the output command allowed by the high frequency amplifier in the frequency range. The control method of the high-frequency power supply device and the high-frequency power supply device of the present invention perform frequency control in a frequency range of a variable frequency, and limit an upper limit of an output command value for controlling an output of a high-frequency amplifier by an output limit value in the frequency range of the variable frequency, thereby preventing damage of the high-frequency amplifier caused by an excessive command.

Inventors

• Gao Liudun
• Jyutoku Takeuchi
• TAKADA KOICHI
• YOICHI YOKOYAMA
• NAKAYAMA HIROSHI

Assignees

• 株式会社京三制作所

Dates

Publication Date

20260508

Application Date

20210212

Priority Date

20200218

Claims (7)

1. 1. A control method of a high-frequency power supply device for supplying high-frequency power to a load, characterized in that, The control method includes an output control for controlling an output of a high-frequency amplifier that outputs high-frequency power by DC-AC conversion based on an output instruction, The output control controls the high-frequency amplifier so that a power feedback value of LOAD power which is effective LOAD power supplied to a LOAD or traveling wave power supplied from a high-frequency power supply device to the LOAD becomes a power command value, (Alpha) in the case where the output command value is increased by the output control and exceeds the output limit value, shifting to an output limit state in which the output command value is suppressed to the output limit value, restricting the increase of the output command value, The output limit state is a reflected power limit state in which the reflected power exceeds a limit value, or a lost power limit state in which the lost power exceeds a limit value, (Beta) switching to variable frequency control when the output reaches the output limit state before the output reaches the set output, and performing control to get rid of the output limit state by reducing the traveling wave feedback value, The control method includes impedance matching control for matching the impedance between the high-frequency amplifier and the load, The impedance matching control device is provided with: (A) Frequency control for impedance matching by varying a control frequency based on a feedback signal of the high frequency amplifier, and (B) A frequency limit value control for determining whether or not the output limit state is an upper limit of the output command value and setting a frequency limit value, determining a frequency limit value for defining a frequency range of the frequency control, (C) The frequency control controls the frequency of the high-frequency amplifier within a frequency range of a frequency limit value determined by the frequency limit value control, The output control includes: (D) An output limit value control for determining an output limit value for limiting an output in the frequency range, (E) Controlling the output of the high frequency amplifier by setting the output limit value determined by the output limit value control as an output instruction value of an upper limit, (F) The output control and the impedance matching control are independent controls, respectively.
2. 2. The control method of a high-frequency power supply device according to claim 1, wherein, In a continuous control process, the output control freely switches the instruction value of the output instruction in a plurality of stages.
3. 3. The control method of a high-frequency power supply device according to claim 1, wherein, In the output limit value control, when the output command value of the high-frequency amplifier exceeds an output limit value, the output command value is replaced with the output limit value to limit the output command value.
4. 4. The control method of a high-frequency power supply device according to claim 1, wherein, The feedback signal is at least any one signal of traveling wave power, reflected wave power, output voltage, direct current voltage and direct current of the high-frequency amplifier, The output limit value is a traveling wave power limit value, a reflected wave power limit value, an output voltage limit value, a direct current limit value and/or a loss power limit value which are respectively set corresponding to the feedback signals, In each control frequency, when the output command value exceeds an output command limit value, the output command value is limited to the output limit value, and the output of the high-frequency amplifier is controlled based on the limited output command value.
5. 5. The control method of a high-frequency power supply device according to claim 1, wherein, The frequency characteristic of the output limit value is symmetrical with respect to a reference frequency in the frequency range.
6. 6. The control method of a high-frequency power supply device according to claim 1, wherein, The frequency characteristic of the output limit value is asymmetric with respect to a reference frequency in the frequency range, The asymmetry is a frequency characteristic corresponding to the frequency characteristic of amplification of the high-frequency amplifier and the frequency characteristic of the load impedance.
7. 7. A high-frequency power supply device that supplies high-frequency power to a load, the high-frequency power supply device comprising: a high-frequency amplifier that outputs the high-frequency power; an output control section that controls an output from the high-frequency amplifier that outputs high-frequency power by direct-alternating-current conversion based on an output instruction, The output control unit controls the output from the high-frequency amplifier based on an output command value so that a power feedback value of LOAD power, which is effective LOAD power supplied to a LOAD, or traveling wave power supplied from a high-frequency power supply device to the LOAD, becomes a power command value, (Alpha) in the case where the output command value is increased by the output control and exceeds an output limit value, shifting to an output limit state in which the output command value is suppressed to the output limit value, restricting an increase in the output command value, The output limit state is a reflected power limit state in which the reflected power exceeds a limit value, or a lost power limit state in which the lost power exceeds a limit value, And (beta) switching to variable frequency control to be released from the output limit state by decreasing the traveling wave feedback value when the output reaches the output limit state before the output reaches the set output, and An impedance matching control unit for matching the impedance of the high-frequency amplifier and the impedance of the load, The impedance matching control unit includes: (a) A frequency control unit for impedance matching by varying a control frequency based on frequency control of a feedback signal of the high-frequency amplifier, and (B) A frequency limit value control unit that determines whether or not the output limit state is an output limit state limiting the upper limit of the output command value and sets a frequency limit value in the output control, determines a frequency limit value for defining a frequency range of the frequency control, The frequency control unit performs control as follows: (c) The frequency of the high-frequency amplifier is controlled in a frequency range of the frequency limit value determined by the frequency limit value control part, The output control unit includes: (d) An output limit value control for determining an output limit value for limiting an output control value of the output control section in the frequency range, (E) Controlling the output of the high frequency amplifier by setting the output limit value determined by the output limit value control as an output instruction value of an upper limit, (F) The output control unit and the impedance matching control unit are independent controls.

Description

Control method for high-frequency power supply device and high-frequency power supply device Technical Field The present invention relates to a control method of a high-frequency power supply device for supplying high-frequency power to a load, and a high-frequency power supply device. Background In order to efficiently supply high-frequency power from a high-frequency power supply device to a load, a technique is known in which impedance matching (IMPEDANCE MATCHING) is performed according to impedance variation of the load in order to reduce reflected wave power. For example, when the load is a plasma load, the impedance of the load varies due to a change in the chamber environment such as a gas state and a pressure state in the chamber, in addition to a process of converting the plasma from an unignited state to an ignited state. When impedance mismatch occurs due to fluctuation of load impedance, reflected wave power returned from the load to the high-frequency power supply device increases, and load power effectively supplied to the load decreases. The load power is obtained by subtracting the amount of reflected wave power returned from the load from the traveling wave power supplied to the load by the high-frequency power supply device, and is power effectively supplied to the load. As an impedance matching technique, a technique is known in which reflected wave power returned from a load side to a high-frequency power supply side is detected, and traveling wave power supplied from the high-frequency power supply to the load side is increased based on the detected reflected wave power, thereby compensating for a decrease in load power caused by the reflected wave power. Patent document 1 shows impedance matching based on frequency control. When the load power is reduced by adding a power corresponding to the reflected wave power to the traveling wave power, if the reflected wave power is large, the traveling wave power may be excessive and the output may be excessive. Patent document 1 discloses a technique of controlling the output so that the power corresponding to the reflected wave power is added to the traveling wave power after the reflected wave is reduced in order to reduce the excessive output (patent document 1). Patent document 2 discloses a technique for limiting a frequency range of a variable frequency in impedance matching by frequency control, in which an oscillation frequency is changed so that an absolute value of a reflection coefficient becomes minimum in a predetermined frequency range including a reference frequency. When the oscillation frequency is changed, the impedance of the load varies greatly even when the variation width of the oscillation frequency is narrow. If the load impedance varies greatly, the voltage applied to the load may be reduced, and it may be difficult to maintain the discharge state. Therefore, in patent document 2, the frequency range of the frequency control is limited, and the reduction of the supply power is suppressed (patent document 2). Prior art literature Patent literature Patent document 1 Japanese patent laid-open publication No. 2013-197080 Patent document 2 Japanese patent laid-open No. 2006-310245 (paragraph 0073) Disclosure of Invention Problems to be solved by the invention As described above, the frequency control is a control system for changing the oscillation frequency. In this control method, in order to suppress a large impedance change caused by a change in the oscillation frequency, the frequency range of the variable frequency of the frequency control is limited. As a problem of frequency control, patent document 2 exemplifies a decrease in supply power caused by a fluctuation in load impedance. In patent document 2, a reduction in supply power is suppressed by limiting the frequency range of the variable frequency. In this case, the variable frequency of the frequency control is limited to a frequency range, and frequencies outside the frequency range are outside the frequency control target. Therefore, under a load condition in which the fluctuation range of the impedance is large, there is a problem that the control cannot be sufficiently performed by the frequency control in the limited narrow frequency range, and it is desired to perform the frequency control in a wider frequency range. In frequency control, the output of a high-frequency amplifier included in a high-frequency power supply device is increased in order to compensate for a decrease in output due to a constraint of the output characteristics of the high-frequency amplifier. In this case, when the frequency range of the variable frequency is widened, the output of the high-frequency amplifier increases more, and therefore, there is a possibility that the voltage and the applied current applied to the capacitor and the coil, which are components of the circuit such as the high-frequency filter, increase and exceed the rated values. The output rise of the high fre