Amorphous silicon and tungsten etching employing environmentally benign plasma process

A novel dry etching process for amorphous silicon (a-Si) and tungsten (W) f or chemical vapor deposition (CVD) chamber cleaning has been performed by e lectron cyclotron resonance (ECR) O-2 plasma employing a solid-material eva poration system where fluorocarbon species are produced from fluorinated et hylene propylene (FEP) by CO2 laser evaporation for preventing global warmi ng. This process enables us to realize etching of materials without using a ny perfluorocompound (PFC) feed gases which have a high global warming pote ntial (GWP). Etching characteristics together with diagnostics of the F ato m density, CFx (x = 1-3) radical densities, electron density and temperatur e have been investigated as functions of pressure. As a result, it was foun d that etching rates of a-Si and W films were determined based on the F ato m density, ion flux and ion bombardment energy. Furthermore, etching rates of a-Si and W films increased by heating the fluorocarbon species before in troducing them into the plasma reactor. Thus, high rates of etching of a-Si and W films were successfully achieved by this novel etching process compa red with conventional etching using ECR plasma with CF4/O-2 feed gases.