Effect of Discharge Frequency in Plasma Etching and Ultrahigh Frequency Plasma Source for High-Performance Etching for ULSI

A low-temperature, uniform, high-density plasma is produced by applying ultra-high-frequency (UHF) power through a spokewise antenna. The plasma is uniform within +-5% over a diameter of 30 cm. No magnetic field is needed to maintain the high-density plasma. Consequently, the plasma source is fairly simple and lightweight. This plasma creates a high electron density and a low degree of dissociation of the feed gas at the same time because the electron energy distribution function is not Maxwellian (bi-Maxwellian distributions). The plasma characteristics are very suitable for precise etching of Al and gate electrodes. Additionally, by the combination of bi-Mazwellian electron distribution in the UHF plasma and new fluorocarbon gas chemistries (C sub 2 F sub 4, CP sub 3 I), selective radical generations of CF sub 2 and CF sub 3 could be realized for high-aspect contact hole patterning of SiO sub 2.