High-frequency magnetoplasmas in electronegative gases

Discharges in electronegative gases are routinely used for the sub-micron etching of thin films in the microelectronics industry. Because of the strong electronegative character of these gases, negative ions constitute a significant fraction of the charged particles content of the discharge. The presence of these negative charge carriers affects the whole behavior of the discharge and, in particular, its electron power balance. This article compares a few characteristics of a high-density plasma produced either in SF₆ or in Cl₂ with those of an argon plasma under similar experimental conditions. We show that the plasma presents characteristics when the gas is electronegative that significantly differ from those observed in argon.