Synchronous undersampling for high-frequency voltage and current measurements

Abstract

A power source may generate signals (RF or microwave), when driven by a drive signal from a controller. A sensor may measure the voltage and current of the signals generated by the power source, and may generate sensor signals representative of the measured voltage and current. A sampler may be configured to undersample the sensor signals, synchronously with the drive signal that drives the power source. The sampling frequency may be a scalar multiple of the fundamental frequency of the sensor signals. At RF frequencies, either synchronous undersampling or synchronous oversampling may be performed. At microwave frequencies, synchronous undersampling may be performed.

Description

Background technique [0001] In many applications, reliable and accurate measurement of high frequency voltages and currents is required. These applications may include, for example, RF plasma generation and RF plasma etching. A typical RF plasma generator may include a high power RF source that generates an RF signal at a given frequency (eg, 13.56 MHz). An RF signal can be provided to the plasma chamber. Since there may be a considerable impedance mismatch between the RF power source and the plasma chamber, an impedance matching network may be used between the RF power source and the plasma chamber. A VI (voltage-current) sensor or detector may be provided for detecting the voltage and current of the RF signal entering the plasma chamber and generating a sensor signal representative of the detected voltage and current. [0002] The magnitude and phase of these high frequency voltage and current measurements need to be obtained accurately and repeatably. Digital processing...

AI Technical Summary

Problems solved by technology

If measurements affected by jitter or resonance are used in high-speed closed-loop control, the performance of this system can be significantly degraded

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