Improvement of slot antennas for microwave plasma source through electromagnetic analysis

Abstract

Microwave plasma has been widely used for plasma processing. However, most of the antennas used for the process have been designed without considering the influence of plasma. For that reason, microwaves could not radiate effectively actually. So, we simulated it by using an electromagnetic analysis software and tried to understand the problem. Based on the results, in order to irradiate microwave toward the chamber efficiently, we changed the shape of the waveguide slot antennas from a rectangle to an ellipse for the microwave plasma processing apparatus. As a result, we were able to improve S-parameters (S₁₁) from approximately 0 dB to -44 dB.