A technique for uniform generation of very-high-frequency plasma suited to large-area thin-film deposition

Abstract

Two very-high-frequency powers between which the phase difference is varying in split of time are supplied to a ladder-shaped electrode through multiple feeding points located at symmetrical positions of the electrode to generate a large-area uniform plasma. Theoretical calculations of the voltage distribution at several phase difference show good agreement with experiments. Plasma emission uniformity within ±15% is demonstrated at 60MHz for the substrate size of 1.4×1.1m, with nitrogen gas of 10Pa.

Large area VHF plasma production using a ladder-shaped electrode

“…We attempted to improve the plasma uniformity by employing the phase modulation method [23,24], that is, the pattern of the standing wave on the electrode can be controlled by changing the phase of the RF power supplied to the electrode. The RF frequency of 60 MHz was used in this experiment.…”

“…In the experiments, a heated Langmuir probe was adopted in order to avoid the deposition of contaminations on the probe. Furthermore, we attempted to improve the plasma uniformity by employing the phase modulation method [23,24], that is, the pattern of the standing wave on the electrode can be controlled by changing the phase of the RF power supplied to the electrode.…”

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

“…Nevertheless, for VHF plasmas, the standing wave pattern depends on the wavelength ( λ ) of electromagnetic wave in the plasma region, which could be influenced by a variety of experimental parameters, such as frequency, discharge gap, power, pressure, and gas compositions. According to the available literatures, the actual wavelength in plasma ranges from 12 to 60% of that in vacuum …”

“…According to the available literatures, the actual wavelength in plasma ranges from 12 to 60% of that in vacuum. [4,5,[13][14][15][16] Theoretically, an effective method to solve the problem is to create a traveling wave in the discharge region. Even if the wavelength is different as the operation parameters vary, the only thing that changes is the number of A.C. cycles appearing on the electrodes at a given moment.…”

Characteristics of monopole antenna plasmas for TEOS PECVD

“…In particular, manufacturing processes using a large-sized glass substrate for LCD panels need a plasma source with a scale length in meters. To satisfy the requirement, the development of the scalable plasma sources, such as a surface-wave plasma (SWP) [1,2], a laddershaped antenna [3,4] and an internal low impedance antenna (LIA) [5,6], has been carried out.…”