As a radio-frequency (RF) power and plasma process monitoring sensor, the voltage-current (VI) probe has been utilized and developed to monitor and optimize the plasma processes in the semiconductor fabrication. However, there are many components to deliver the RF power from power supply to the plasma electrodes such as RF connector and RF cable which affect to the RF power transmission efficiency, it is necessary to analyze the characteristics of RF power transmission lines using the VI probe with respect to external parameter configuration. In this study, we investigated the characteristics of the RF signals using the VI probe under various RF power transmission lines, including the VI probe installation position, RF connector type, and RF cable length. The RF signals were measured as a function of input power in a low-pressure argon discharge. As a result, RF power loss was significant when long-length RF cables were used for the transmission line. Analyzed characteristic of the RF transmission lines using the VI probe is able to contribute to increasing the measurement reliability of RF measurement properties for the plasma processing applications.

Keywords: Voltage current probe, RF power transmission line