Kibatsu Shinohara

New Ultra-High-Frequency Plasma Source for Large-Scale Etching Processes.

A low temperature, uniform, high-density plasma is produced by an ultra-high-frequency (UHF) discharge using a new spokewise antenna. The plasma is uniform within ±5% over a diameter of 30 cm. The plasma density, 1×1011 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. No magnetic field is needed to maintain a high-density plasma. Consequently, the plasma source is fairly simple and lightweight. The plasma source can accomplish a notch-free poly-Si etching profile with a high etching rate at a narrow space pattern of less than 0.3 µ m.

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.