Low-temperature, uniform, and high-density plasma produced by a new ultra-high-frequency discharge with a spokewise antenna

A low-temperature, uniform, high-density plasma is produced by an ultra-high-frequency (UHF) discharge with a new spokewise antenna. The plasma is uniform within ±5% over a diameter of 20 cm. The plasma density, 5×1010 cm−3 for low-electron temperatures of 1.5–2.0 eV, is almost proportional to the UHF power even at a low-UHF power of 100 W. No magnetic field is needed to maintain a high-density plasma. Consequently, the plasma source is fairly simple and lightweight. The plasma source should ease serious problems in etching processes that use conventional high-density plasmas.