Method and device for measuring impedance and power of plasma

Abstract

The invention relates to a method and a device for measuring impedance and power of plasma. The method comprises the following steps: acquiring a voltage waveform and a current waveform; acquiring a voltage amplitude and a voltage phase according to the voltage waveform; acquiring a current amplitude and a current phase according to the current waveform; performing phase difference calibration according to the voltage phase and the current phase to obtain a V-I phase difference; and calculating the impedance and power of the plasma according to the voltage waveform, the current waveform, the voltage amplitude, the current amplitude and the V-I phase difference. Aiming at the problems in the prior art, pulse modulation is carried out on a pulse radio frequency power supply, and the evolution process of radio frequency power and plasma impedance along with time is further obtained by prolonging the pulse turn-off time and calibrating the V-I phase difference; when the plasma is stable, stable-state (continuous wave-driven) plasma can absorb power.

Description

technical field [0001] The invention relates to the technical field of plasma measurement, in particular to a method and device for measuring plasma impedance and power. Background technique [0002] Plasma is a state of matter mainly composed of electrons, ions, and neutral particles, and is called the fourth state besides solid, liquid, and gaseous states. It exists widely in nature and is generally electrically neutral macroscopically. During the plasma discharge process, many chemically active ions and neutral free radicals are generated. In the processing of integrated circuit chips, nearly one-third of the processes are based on low-temperature plasma processing technology. [0003] In the process of surface treatment and modification of low-temperature plasma materials, etching is one of the most important processes. Using plasma etching, only one material is removed from the surface without affecting other materials, and only the material at the bottom of the tren...

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Problems solved by technology

To date, little scientific literature has been published on

[0006] Moreover, the commercial V-I sensor is designed for continuous wave (power on continuously) driven plasma, the equivalent impedance of continuous wave driven plasma discharge is constant, the sensor is only suitable for this type of plasma

However, in the plasma driven by the pulse waveform, the plasma is in an alternate state of igniting-extinguishing-igniting, and its impedance is in a changing state. Therefore, none of the commercial V-I sensors can be directly used for this dynamic plasma absorbed power monitoring.

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