Generation of Uniform Large-Area VHF Plasmas by Launching a Traveling Wave

An innovative technique, i.e., creating a traveling wave by launching two specific standing waves at the same time, is proposed to generate uniform large‐area very high frequency (VHF) plasmas. The viability of this approach has been verified by numerical simulation in this study. The electric field distribution for each standing wave is controlled by the phase difference between the corresponding two feeding points (φ) placed on opposite sides of electrode and designated to produce a specific standing wave pattern. The simulated electric filed distributions obtained at various φ are consistent with numerous experimental works. By applying these two standing waves at the same time, a traveling wave can be lanuched as the conditions that these two standing waves must have the same amplitude and be spatially and temporally out of phase by 90° are met. This paper proposes an innovative technique to generate uniform large‐area very high frequency (VHF) plasmas by launching two specific standing waves simultaneously. The feasibility of this technique has been successfully demonstrated using HFSS (high frequency structure simulator). The simulation results obtained with HFSS are surprisingly comparable with a 2D self‐consistent plasma model for the typical operation regime of VHF PECVD.