Additive oxygen effects in Cl₂ plasma etching of chrome films

Cr films were etched by Cl₂/O₂ plasmas, and the surface reaction of Cr etching was investigated by X ray photoelectron spectroscopy. The role of the additive O₂ gas, the relationship between the etch rate and the gas-mixing ratio, and the relationship between the etched profile and the ratio were examined. The vertical etch rate was measured through sheet resistance using a four-point probe and a Hitachi scanning electron microscope, while the lateral etch rate was measured by scanning electron microscopy alone.