An amplifier circuit includes a first port, a second port, a reference potential port, and an RF amplifier device having a first terminal electrically coupled to the first port, a second terminal electrically coupled to the second port, and a reference potential terminal electrically coupled to the reference potential port. The RF amplifier device amplifies an RF signal across an RF frequency range that includes a fundamental RF frequency. An impedance matching network is electrically coupled to the first terminal and the first port. The impedance matching network includes a baseband termination circuit that presents low impedance in a baseband frequency region, a fundamental frequency matching circuit that presents a complex conjugate of an intrinsic impedance of the RF amplifier device in the RF frequency range, and a second order harmonic termination circuit that presents low impedance at second order harmonics of frequencies in the fundamental RF frequency range.

An amplifier circuit includes a first port, a second port, a reference potential port, and an RF amplifier device having a first terminal electrically coupled to the first port, a second terminal electrically coupled to the second port, and a reference potential terminal electrically coupled to the reference potential port. The RF amplifier device amplifies an RF signal across an RF frequency range that includes a fundamental RF frequency. An impedance matching network is electrically coupled to the first terminal and the first port. The impedance matching network includes a baseband termination circuit that presents low impedance in a baseband frequency region, a fundamental frequency matching circuit that presents a complex conjugate of an intrinsic impedance of the RF amplifier device in the RF frequency range, and a second order harmonic termination circuit that presents low impedance at second order harmonics of frequencies in the fundamental RF frequency range.

In one embodiment, an impedance matching network includes a mechanically variable capacitor (MVC), a second variable capacitor, and a control circuit. The control circuit carries out a first process of determining a second variable capacitor configuration for reducing a reflected power at the RF source output, and altering the second variable capacitor to the second variable capacitor configuration. The control circuit also carries out a second process of determining an RF source frequency, and, upon determining that the RF source frequency is outside, at a minimum, or at a maximum of a predetermined frequency range, determining a new MVC configuration to cause the RF source frequency, according to an RF source frequency tuning process, to be altered to be within or closer to the predetermined frequency range. The determination of the new MVC configuration is based on the RF source frequency and the predetermined frequency range.

In one embodiment, an impedance matching network includes a mechanically variable capacitor (MVC), a second variable capacitor, and a control circuit. The control circuit carries out a first process of determining a second variable capacitor configuration for reducing a reflected power at the RF source output, and altering the second variable capacitor to the second variable capacitor configuration. The control circuit also carries out a second process of determining an RF source frequency, and, upon determining that the RF source frequency is outside, at a minimum, or at a maximum of a predetermined frequency range, determining a new MVC configuration to cause the RF source frequency, according to an RF source frequency tuning process, to be altered to be within or closer to the predetermined frequency range. The determination of the new MVC configuration is based on the RF source frequency and the predetermined frequency range.

An adjustment method for filter units in a plasma processing apparatus includes a first measurement process of measuring a frequency characteristic of a reference filter unit selected among the filter units, and an adjustment process of adjusting a frequency characteristic of each of remaining filter units selected among the filter units excluding the reference filter unit. Further, the adjustment process includes an attachment process of attaching a capacitive member for adjusting a capacitance between wirings in each of the remaining filter units, a second measurement process of measuring a frequency characteristic of each of the remaining filter units to which the capacitive member is attached, and an individual adjustment process of adjusting a capacitance of the capacitive member such that the frequency characteristic of each of the remaining filter unit to which the capacitive member is attached becomes close to the frequency characteristic of the reference filter unit.

An adjustment method for filter units in a plasma processing apparatus includes a first measurement process of measuring a frequency characteristic of a reference filter unit selected among the filter units, and an adjustment process of adjusting a frequency characteristic of each of remaining filter units selected among the filter units excluding the reference filter unit. Further, the adjustment process includes an attachment process of attaching a capacitive member for adjusting a capacitance between wirings in each of the remaining filter units, a second measurement process of measuring a frequency characteristic of each of the remaining filter units to which the capacitive member is attached, and an individual adjustment process of adjusting a capacitance of the capacitive member such that the frequency characteristic of each of the remaining filter unit to which the capacitive member is attached becomes close to the frequency characteristic of the reference filter unit.

An impedance matching device includes: a variable capacitor; a calculation unit that calculates a reflection coefficient on the load side; a storage unit that stores the reflection coefficient calculated within a predetermined period so as to be associated with ON/OFF states of the semiconductor switches; a determination unit that determines ON/OFF states to be taken by the semiconductor switches using a calculation result within the predetermined period; a control unit that turns on or off the semiconductor switches based on the determined ON/OFF states; and a counting unit that counts the number of times the determined ON/OFF states have changed. In a case where the counted number of times is larger than a predetermined number of times, the control unit turns on or off the semiconductor switches so as to match ON/OFF states associated with a reflection coefficient closer to 0, among the stored reflection coefficients, and then prohibits ON/OFF switching.

An impedance matching device includes: a variable capacitor; a calculation unit that calculates a reflection coefficient on the load side; a storage unit that stores the reflection coefficient calculated within a predetermined period so as to be associated with ON/OFF states of the semiconductor switches; a determination unit that determines ON/OFF states to be taken by the semiconductor switches using a calculation result within the predetermined period; a control unit that turns on or off the semiconductor switches based on the determined ON/OFF states; and a counting unit that counts the number of times the determined ON/OFF states have changed. In a case where the counted number of times is larger than a predetermined number of times, the control unit turns on or off the semiconductor switches so as to match ON/OFF states associated with a reflection coefficient closer to 0, among the stored reflection coefficients, and then prohibits ON/OFF switching.

A high frequency power supply alternately outputs a first AC voltage and a second AC voltage to a plasma generator. The amplitudes of the first AC voltage and the second AC voltage are different from each other. An impedance adjustment device is disposed in midway of the transmission line of the first AC voltage and the second AC voltage. When the AC voltage output from the high frequency power supply is switched to a first AC voltage, a microcomputer changes the capacitance of a variable capacitor circuit to a first target value. When the AC voltage output from the high frequency power supply is switched to a second AC voltage, the microcomputer changes the capacitance of the variable capacitor circuit to a second target value.

A high frequency power supply alternately outputs a first AC voltage and a second AC voltage to a plasma generator. The amplitudes of the first AC voltage and the second AC voltage are different from each other. An impedance adjustment device is disposed in midway of the transmission line of the first AC voltage and the second AC voltage. When the AC voltage output from the high frequency power supply is switched to a first AC voltage, a microcomputer changes the capacitance of a variable capacitor circuit to a first target value. When the AC voltage output from the high frequency power supply is switched to a second AC voltage, the microcomputer changes the capacitance of the variable capacitor circuit to a second target value.