In the anisotropic dry etching of conductive films deposited on topographic steps, it is difficult to remove the residue even with extended overetch. The resistances of the residues from aluminum and silicide etching are found not to depend on film thickness or step coverage but to depend on bias voltage and pressure. The etch profiles observed by SEM are discussed in terms of native oxide film and polymer film formation. A simple model is proposed to reveal the residue formation process and to explain the problem encountered during the removal of the etched residue. A simple method is presented to determine the minimum requirement of a reliable etch process associated with surface topology.