Fluorocarbon ions in oxide contact etching with CF_4/Ar plasma

摘要

Using Langmuir probe and mass spectrometer, the kinetics of fluorocarbon ions is investigated in CF_4/Ar plasma. Average kinetic energies for the fluoro-carbon ions decrease with increasing both pressure and source power. At high pressures, charge transfer reactions occur predominantly. The ion intensity ratios of CF/Ar are determined with varying pressure and source power. In a SiO_2 contact etching, ion composition in the bulk plasma is an important factor in determining the microtrench depth as well as sidewall slope. The microtrenches are suppressed by increasing pressure while decreasing both source and bias power.