REMOVAL OF FLUOROCARBON RESIDUE ON SI WITH AN ELECTRON-CYCLOTRON RESONANCE EXCITED AR PLASMA

An electron cyclotron resonance-excited Ar plasma completely removes CF(x) residue on Si resulting in a clean surface that is free of native Si oxide. In situ x-ray photoelectron spectroscopy verifies the absence of C and F on the surface, and the presence of what is thought to be a small amount of adsorbed or interstitially implanted O. Mechanistically, the Ar ion bombardment affects a nearly instantaneous ablation of F from the CF(x) surface followed in succession by a low average energy (100 eV) sputtering of the C-rich remnant, the native Si oxide, and the Si substrate. The etching rate of thick CF(x) residue is approximately 15 nm/min without any heat applied to the substrate.