Molybdenum etching with chlorine atoms and molecular chlorine plasmas

Thin films of molybdenum were etched both within and downstream from a Cl₂ plasma at 200‐mTorr pressure and temperatures below 180 °C. When samples were positioned downstream from the discharge, etching proceeded solely by chemical reaction of the film with chlorine atoms. Without a discharge, molecular chlorine did not etch molybdenum. Downstream and in‐discharge etch rates were <20 nm/min and etching by atoms was not observed below 100 °C. The chemical reaction between chlorine atoms and molybdenum was proportional to the gas phase Cl atom mole fraction.