Antenna configuration for uniform large-area inductively coupled plasma production

An antenna configuration for uniform plasma generation in a large-area inductively coupled plasma (ICP) source is presented and investigated using numerical analysis. The numerical results show that a properly tuned, segmented coil system with an external variable capacitor can allow antenna voltage, currents, and plasma uniformity to be controlled in the large-area ICP source. The key element of this concept is to induce LC-resonance in the coil system by the external capacitance variation. Through the LC-resonance, not only a small antenna voltage can be obtained, but also a selected coil current near a low plasma density regime can be significantly enhanced. Self-consistent fluid simulations for Ar and Cl2 plasmas indicate that the radial plasma spread can be optimized near the LC-resonance condition.