Production of large-area surface-wave plasmas with an internally mounted planar cylindrical launcher

Abstract

We studied the characteristics of two different types of planar cylindrical microwave launchers installed inside the vacuum chamber for the production of a large-area processing plasma. The microwave launcher consisted of a coaxial waveguide and a cylindrical planar cavity, inside which a large-area thin quartz plate was inserted. We tested two configurations of microwave launchers; one was a closed cylindrical cavity structure and the other was a leaky open cavity structure. With a 1.5 kW microwave source, we demonstrated the production of large-area, surface-wave plasma (SWP) using Ar gas. Using the microwave launcher with a leaky open cavity structure, a spatial uniformity of SWP within ±3.5% over 160 mm in radius was achieved at a pressure of 20 ∼ 30 Pa. Numerical analyses using the electromagnetic wave simulator, MAFIA, were also carried out to study the electric field distribution radiated from the microwave launcher and to explain the experimental results.