Necessary constraints on process temperature, geometric latitude, and impurity control have led to continual increases in the use of plasma processing (i.e., "dry" processes) in IC manufacturing. Gaseous discharges, which form the basis of plasma processing, exhibit unique physical and chemical characteristics that enable or facilitate such processes as anisotropic etching, dielectric deposition, and ion implantation.
Plasma technologies have become so dominant that, without them, most current and forthcoming generations of IC devices could not be fabricated. However, as device dimensions are scaled down, any damage caused by plasma processing becomes an increasing concern. Among the observed deleterious effects are gate-oxide damage and distortion of the etching profile caused by an electrical charge buildup [1, 2]; contamination of oxide and silicon, especially by heavy metals [3]; and damage from plasma radiation to the oxide, the Si-Si[O.sub.2] interface, and the underlying silicon [4].
