Voltage distribution over capacitively coupled plasma electrode for atmospheric-pressure plasma generation

Area of Science:

• Plasma Physics
• Electrical Engineering
• Materials Science

Background:

• Large-area plasma generation using capacitively coupled plasma (CCP) reactors is vital for industrial processes like etching and chemical vapor deposition.
• The standing wave effect significantly impacts uniformity in large-area CCPs, posing challenges for consistent process outcomes.
• Understanding voltage distribution is key to mitigating non-uniformity caused by standing waves.

Purpose of the Study:

• To investigate the influence of the standing wave effect on voltage distribution in large-area CCPs.
• To analyze how excitation frequency and plasma impedance affect voltage uniformity.
• To identify optimal conditions for uniform plasma generation in large-area CCP systems.

Main Methods:

• Utilized the transmission line modeling method to calculate voltage distribution across large atmospheric-pressure CCP electrodes (1 m × 0.2 m).
• Incorporated previously measured plasma impedance data into the voltage distribution calculations.
• Analyzed the impact of different excitation frequencies (150 MHz and 13.56 MHz) on voltage distribution.

Main Results:

• The standing wave effect was shown to significantly alter voltage distribution, particularly after plasma ignition.
• A notable difference in voltage distribution was observed between 150 MHz and 13.56 MHz excitation frequencies.
• The position of power application was identified as a critical factor for achieving uniform voltage distribution.

Conclusions:

• Excitation frequency and plasma impedance critically influence voltage distribution and standing wave effects in large-area CCPs.
• The 150 MHz frequency exhibited a more pronounced standing wave effect compared to 13.56 MHz.
• Strategic placement of power application is essential for optimizing voltage uniformity in large-area CCP systems, improving process consistency.